Sandep Grover - Academia.edu (original) (raw)

Papers by Sandep Grover

Research paper thumbnail of Inhibition of proliferation of retinal vascular endothelial cells more effectively than choroidal vascular endothelial cell proliferation by bevacizumab

International journal of ophthalmology, 2017

To evaluate the differential inhibitory effects of bevacizumab on cell proliferation of vascular ... more To evaluate the differential inhibitory effects of bevacizumab on cell proliferation of vascular endothelial growth factor (VEGF)-stimulated choroidal vascular endothelial cells (CVECs) and retinal vascular endothelial cells (RVECs) in vitro. VEGF (400 ng/mL) enriched CVECs and RVECs were treated with escalating doses of bevacizumab (0.1, 0.5, 1, 1.5 and 2 mg/mL). Cell proliferation changes were analyzed with WST-1 assay and trypan blue exclusion assay at 48, 72h and 1wk. Morphological changes were recorded with bright field microscopy. VEGF enriched RVECs showed significantly more decline of cell viability than CVECs after bevacizumab treatment. One week after treatment, RVEC cell proliferation decreased by 29.7%, 37.5%, 52.8%, 35.9% and 45.6% at 0.1, 0.5, 1.0, 1.5 and 2 mg/mL bevacizumab respectively compared to CVEC proliferation decrease of 4.1%, 7.7%, 2.4%, 4.1% and 17.7% (P<0.05) by WST-1 assay. Trypan blue exclusion assay also revealed similar decrease in RVEC proliferatio...

Research paper thumbnail of Clinical applications of spectral domain optical coherence tomography in retinal diseases

Biomedical Journal, 2016

Peer review under responsibility of Chang Gung University.

Research paper thumbnail of Comparison of central corneal thickness: ultrasound pachymetry versus slit-lamp optical coherence tomography, specular microscopy, and Orbscan

Clinical Ophthalmology, 2015

Background: Central corneal thickness (CCT) can be measured by using contact and non-contact meth... more Background: Central corneal thickness (CCT) can be measured by using contact and non-contact methods. Ultrasound pachymetry (US pachymetry) is a contact method for measuring CCT and is perhaps the most commonly used method. However, non-contact methods like scanning slit topography (Orbscan II), slit-lamp optical coherence tomography (SL-OCT), and specular microscopy are also used. Not many studies have correlated the measurement of CCT with all four modalities. The purpose of this study was to compare and correlate the CCT measurements obtained by US pachymetry with SL-OCT, specular microscopy, and Orbscan. Method: This is a prospective, comparative study done in an institutional setting. Thirty-two eyes of 32 subjects with no known ocular disease and best-corrected visual acuity of 20/20 were enrolled. CCT measurements were obtained using SL-OCT, specular microscopy, scanning slit topography (Orbscan), and US pachymetry. Three measurements were made with each instrument by the same operator. Mean, standard deviation, and coefficient of variation were calculated for CCT measurements acquired by the four measurement devices. Bland-Altman plot was constructed to determine the agreements between the CCT measurements obtained by different equipment. Results: The mean CCT was 548.16±48.68 µm by US pachymetry. In comparison, CCT averaged 546.36±44.17 µm by SL-OCT, 557.61±49.92 µm by specular microscopy, and 551.03±48.96 µm by Orbscan for all subjects. Measurements by the various modalities were strongly correlated. Correlations (r 2) of CCT, as measured by US pachymetry compared with other modalities, were: SL-OCT (r 2 =0.98, P,0.0001), specular microscopy (r 2 =0.98, P,0.0001), and Orbscan (r 2 =0.96, P,0.0001). All modalities had a linear correlation with US pachymetry measurements. Conclusion: In subjects with healthy corneas, SL-OCT, specular microscopy, and Orbscan (with correction factor) can be used interchangeably with US pachymetry in certain clinical settings. The four modalities showed significant linear correlations with one another.

Research paper thumbnail of Effect of distance and duration of illumination on retinal ganglion cells exposed to varying concentrations of brilliant blue green

Journal of clinical medicine research, 2015

The objective of the study was to determine the safety parameters of using brilliant blue green (... more The objective of the study was to determine the safety parameters of using brilliant blue green (BBG) for chromovitrectomy by assessing the cytotoxicity of BBG on cultured retinal ganglion cells (RGCs) exposed to illumination. RGCs were exposed to two concentrations of BBG (0.25 and 0.5 mg/mL) under metal halide illumination at varying distances (1 and 2.5 cm), intensities (990 and 2,000 Fc), and durations (1, 5 and 15 minutes). Cell viability was assessed using the WST-1 and CellTiter 96(®) AQueous One solution cell proliferation assays. Using the WST-1 assay, with high-intensity illumination, viability of RGCs ranged from 97.5±16.4% of controls with minimum BBG and light exposure (0.25 mg/mL BBG and illuminated for 1 minute at 2.5 cm distance) to 53.1±11.3% of controls with maximum BBG and light exposure (0.50 mg/mL and illuminated for 15 minutes at 1 cm distance; P < 0.01). With medium-intensity illumination, RGCs showed better viability, ranging from 95.1±7.2% of controls wit...

Research paper thumbnail of Retinal thickness measurement obtained with spectral domain optical coherence tomography assisted optical biopsy accurately correlates with ex vivo histology

PloS one, 2014

This study determines 'correlation constants' between the gold standard histological meas... more This study determines 'correlation constants' between the gold standard histological measurement of retinal thickness and the newer spectral-domain optical coherence tomography (SD-OCT) technology in adult C57BL/6 mice. Forty-eight eyes from adult mice underwent SD-OCT imaging and then were histologically prepared for frozen sectioning with H&E staining. Retinal thickness was measured via 10x light microscopy. SD-OCT images and histological sections were standardized to three anatomical sites relative to the optic nerve head (ONH) location. The ratios between SD-OCT to histological thickness for total retinal thickness (TRT) and six sublayers were defined as 'correlation constants'. Mean (± SE) TRT for SD-OCT and histological sections was 210.95 µm (± 1.09) and 219.58 µm (± 2.67), respectively. The mean 'correlation constant' for TRT between the SD-OCT and histological sections was 0.96. The retinal thickness for all sublayers measured by SD-OCT vs. histology...

Research paper thumbnail of Dark Adaptation of Rod Photoreceptors in Normal Subjects, and in Patients with Stargardt Disease and anABCA4Mutation

Investigative Opthalmology & Visual Science, 2004

Research paper thumbnail of Sequential spectral domain OCT documentation of retinal changes after branch retinal artery occlusion

Clinical Ophthalmology, 2010

Branch retinal artery occlusions (BRAO) are characterized histopathologically by inner retinal ed... more Branch retinal artery occlusions (BRAO) are characterized histopathologically by inner retinal edema initially and atrophy in the presence of persistent ischemia. The duration of ischemia leading to irreversible atrophic retinal changes is not clear. Spectral-domain optical coherence tomography (SD-OCT) provides non-invasive detailed in-vivo histological changes in the retina. In this case report, we show sequential in vivo pathological changes seen in the inner retinal layers, in spite of clinical improvement, following the migration of an intraretinal embolus on the optic nerve head, which had previously resulted in symptomatic BRAO.

Research paper thumbnail of A New 2–Base Pair Deletion in the RPGR Gene in a Black Family With X-Linked Retinitis Pigmentosa

Archives of Ophthalmology, 1998

To report the genetic and ophthalmic findings in a black family with X-linked retinitis pigmentos... more To report the genetic and ophthalmic findings in a black family with X-linked retinitis pigmentosa resulting from a newly identified mutation in the RPGR (retinitis pigmentosa GTPase regulator) gene. Patients: Four affected hemizygotes with retinitis pigmentosa and 2 obligate carriers were examined. Two unaffected family members, 1 woman and her unaffected son, were also examined. Methods: Patients underwent a routine ocular examination including slitlamp examination and a dilated fundus examination. Certain patients also underwent testing with Goldmann visual field kinetic perimetry and electroretinography. DNA screening from affected male patients, 2 obligatecarriers,and2unaffectedfamilymemberswasperformed to determine the presence of any mutation in the RPGR gene. Results: A 2-base pair deletion in exon 13 of the RPGR gene that creates a frameshift was found to segregate with the retinal disease in affected males and the carrier state in female heterozygotes in this family. The ophthalmic findings in hemizygotes and carriers were within the spectrum of findings characteristically noted in families with X-linked retinitis pigmentosa. In 2 obligate carriers, a tapetal-like reflex was not clinically apparent. Conclusions: The described mutation is the first RPGR gene mutation reported in a black family. A 2-base pair deletion in exon 13 segregates with a clinical phenotype of X-linked retinitis pigmentosa.

Research paper thumbnail of Visual Acuity and Visual Field Impairment in Usher Syndrome

Archives of Ophthalmology, 1998

To determine the extent of visual acuity and visual field impairment in patients with types 1 and... more To determine the extent of visual acuity and visual field impairment in patients with types 1 and 2 Usher syndrome. Methods: The records of 53 patients with type 1 and 120 patients with type 2 Usher syndrome were reviewed for visual acuity and visual field area at their most recent visit. Visual field areas were determined by planimetry of the II4e and V4e isopters obtained with a Goldmann perimeter. Both ordinary and logistic regression models were used to evaluate differences in visual acuity and visual field impairment between patients with type 1 and type 2 Usher syndrome. Results: The difference in visual acuity of the better eye between patients with type 1 and type 2 varied by patient age (P=.01, based on a multiple regression model). The maximum difference in visual acuity between the 2 groups occurred during the third and fourth decades of life (with the type 1 patients being more impaired), while more similar acuities were seen in both younger and older patients. Fifty-one percent (n=27) of the type 1 patients had a visual acuity of 20/40 or better in at least 1 eye compared with 72% (n=87) of the type 2 patients (age-adjusted odds ra

Research paper thumbnail of Legal Blindness and Employment in Patients with Juvenile-Onset Macular Dystrophies or Achromatopsia

Research paper thumbnail of Intracameral Avastin Dramatically Resolves Iris Neovascularization and Reverses Neovascular Glaucoma

European Journal of Ophthalmology, 2008

PurposeTo report the biologic effect of intracameral bevacizumab in patients with iris neovascula... more PurposeTo report the biologic effect of intracameral bevacizumab in patients with iris neovascularization secondary to proliferative retinal vasculopathies.MethodsSixteen eyes of 15 patients with iris neovascularization associated with or without neovascular glaucoma secondary to proliferative retinal vasculopathies received intracameral bevacizumab (1.25 mg). Ophthalmic evaluations included Snellen visual acuity (VA), complete ophthalmic examination, fluorescein iris angiography, and slit lamp photography Main outcome measure was change in degree of iris neovascularization. Secondary outcomes included fluorescein iris angiographic leakage, control of intraocular pressure, and changes in VA.ResultsAll patients with neovascularization demonstrated by slit lamp photography and fluorescein angiography (16/16 eyes) had complete (or at least partial) reduction in leakage of the neovascularization within 3 weeks after the injection. Leakage from iris neovascularization resolved in 12 of 1...

Research paper thumbnail of Difficulty in performing everyday activities in patients with juvenile macular dystrophies: comparison with patients with retinitis pigmentosa

British Journal of Ophthalmology, 1998

Aims-To ascertain the level of perceived diYculty experienced by patients with central vision los... more Aims-To ascertain the level of perceived diYculty experienced by patients with central vision loss due to juvenile macular dystrophies in the performance of everyday activities. A second objective was to compare their perceived diYculty with that of patients with retinitis pigmentosa (RP) with primarily peripheral vision loss. Methods-72 patients with Stargardt disease, cone dystrophy, or cone-rod dystrophy who had visual acuities worse than 20/40 and normal peripheral visual fields rated themselves on their diYculty in the performance of 33 activities encompassing a wide variety of everyday tasks. These findings were compared with the responses of 120 patients with typical RP or Usher syndrome type 2 who had visual acuities of 20/40 or better and peripheral visual field loss. Results-The juvenile macular dystrophy group reported the greatest level of overall self perceived diYculty with activities involving central vision, and lesser and variable degrees of diYculty with items within the mobility, negotiating steps, driving, and miscellaneous categories. Consistent with these findings, there were highly significant correlations between subjects' rated performances of activities involving central vision and the clinical measures of vision, including visual acuity and size of central scotoma. There were fewer significant correlations between perceived performance of activities in the other categories and the clinical measures. In general, those activities that showed significant correlations with the clinical measures of vision for the patients with juvenile macular dystrophies also showed significant diVerences in the patterns of responses between the juvenile macular dystrophy group and the RP group. Those items which were not correlated with the clinical measures in the juvenile macular dystrophy group tended not to show significant diVerences in the response patterns between the two groups. Conclusion-These results provide insight into the types of perceived diYculties in performing tasks of everyday life in patients with these disorders which aVect counselling of these patients.

Research paper thumbnail of Macular edema after cataract surgery in eyes without preoperative central-involved diabetic macular edema

JAMA Ophthalmology, 2013

IMPORTANCE The incidence of development or worsening of macular edema (ME) is variable in eyes wi... more IMPORTANCE The incidence of development or worsening of macular edema (ME) is variable in eyes without diabetic ME (DME) undergoing cataract surgery. OBJECTIVE To estimate the incidence of central-involved ME 16 weeks following cataract surgery in eyes with diabetic retinopathy without definite central-involved DME preoperatively. DESIGN, SETTING, AND PARTICIPANTS In a multicenter, prospective, observational study, 293 participants with diabetic retinopathy without definite central subfield thickening on optical coherence tomography (OCT) underwent cataract surgery. EXPOSURE Cataract extraction surgery performed within 28 days of enrollment of eyes without DME in individuals with diabetes mellitus. MAIN OUTCOMES AND MEASURES Development of central-involved ME defined as the following: (1) OCT central subfield thickness of 250 μm or greater (time-domain OCT) or 310 μm or greater (spectral-domain OCT) with at least a 1-step increase in logOCT central subfield thickness preoperatively to the 16-week visit; (2) at least a 2-step increase in logOCT central subfield thickness preoperatively to the 16-week visit; or (3) nontopical treatment for ME received before the 16-week visit with either of the OCT criteria met at the time of treatment. RESULTS The median participant age was 65 years. The median visual acuity letter score was 69 letters (Snellen equivalent 20/40). Forty-four percent of eyes had a history of treatment for DME. Sixteen weeks postoperatively, central-involved ME was noted in 0% (95% CI, 0%-20%) of 17 eyes with no preoperative DME. Of eyes with non-central-involved DME, 10% (95% CI, 5%-18%) of 97 eyes without central-involved DME and 12% (95% CI, 7%-19%) of 147 eyes with possible central-involved DME at baseline progressed to central-involved ME. History of DME treatment was significantly associated with central-involved ME development (P < .001). CONCLUSIONS AND RELEVANCE In eyes with diabetic retinopathy without concurrent central-involved DME, presence of non-central-involved DME immediately prior to cataract surgery or history of DME treatment may increase the risk of developing central-involved ME 16 weeks after cataract extraction.

Research paper thumbnail of Exploratory analysis of the effect of intravitreal ranibizumab or triamcinolone onworsening of diabetic retinopathy in a randomized clinical trial

JAMA Ophthalmology, 2013

IMPORTANCE The standard care for proliferative diabetic retinopathy (PDR) usually is panretinal p... more IMPORTANCE The standard care for proliferative diabetic retinopathy (PDR) usually is panretinal photocoagulation, an inherently destructive treatment that can cause iatrogenic vision loss. Therefore, evaluating the effects of therapies for diabetic macular edema on development or worsening of PDR might lead to new therapies for PDR. OBJECTIVE To evaluate the effects of intravitreal ranibizumab or triamcinolone acetonide, administered to treat diabetic macular edema, on worsening of diabetic retinopathy. DESIGN Exploratory analysis was performed on worsening of retinopathy, defined as 1 or more of the following: (1) worsening from no PDR to PDR, (2) worsening of 2 or more severity levels on reading center assessment of fundus photographs in eyes without PDR at baseline, (3) having panretinal photocoagulation, (4) experiencing vitreous hemorrhage, or (5) undergoing vitrectomy for the treatment of PDR. SETTING Community-and university-based ophthalmology practices. PARTICIPANTS Individuals with central-involved diabetic macular edema causing visual acuity impairment. INTERVENTIONS Eyes were assigned randomly to sham with prompt focal/grid laser, 0.5 mg of intravitreal ranibizumab with prompt or deferred (Ն24 weeks) laser, or 4 mg of intravitreal triamcinolone acetonide with prompt laser. MAIN OUTCOMES AND MEASURES Three-year cumulative probabilities for retinopathy worsening. RESULTS For eyes without PDR at baseline, the 3-year cumulative probabilities for retinopathy worsening (P value comparison with sham with prompt laser) were 23% using sham with prompt laser, 18% with ranibizumab with prompt laser (P = .25), 7% with ranibizumab with deferred laser (P = .001), and 37% with triamcinolone with prompt laser (P = .10). For eyes with PDR at baseline, the 3-year cumulative probabilities for retinopathy worsening were 40%, 21% (P = .05), 18% (P = .02), and 12% (P < .001), respectively. CONCLUSIONS AND RELEVANCE Intravitreal ranibizumab appears to be associated with a reduced risk of diabetic retinopathy worsening in eyes with or without PDR. Intravitreal triamcinolone also appears to be associated with a reduced risk of PDR worsening. These findings suggest that use of these drugs to prevent worsening of diabetic retinopathy may be feasible. Given the exploratory nature of these analyses, the risk of endophthalmitis following intravitreal injections, and the fact that intravitreal triamcinolone can cause cataract or glaucoma, use of these treatments to reduce the rates of worsening of retinopathy, with or without PDR, does not seem warranted at this time.

Research paper thumbnail of Aqueous interleukin-6 levels are superior to vascular endothelial growth factor in predicting therapeutic response to bevacizumab in age-related macular degeneration

Journal of ophthalmology, 2014

Objective. To prospectively evaluate the effect of intravitreal bevacizumab on aqueous levels of ... more Objective. To prospectively evaluate the effect of intravitreal bevacizumab on aqueous levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in patients with exudative age-related macular degeneration (AMD) and correlate clinical outcomes with cytokine levels. Methods. 30 eyes of 30 patients with exudative AMD underwent intravitreal injection of bevacizumab three times at monthly intervals. The aqueous samples prior to the 1st injection (baseline) and 3rd injection were analyzed for VEGF and IL-6 levels. Subjects were subgrouped based upon change in the central subfield (CSF) macular thickness on SD-OCT at 8 weeks. Group 1 included patients (n = 14) with a decrease in CSF thickness greater than 10% from the baseline (improved group). Group 2 included patients (n = 16) who had a decrease in CSF thickness 10% or less (treatment-resistant). Results. In subgroup analysis, in both groups 1 and 2 patients, compared to aqueous VEGF, aqueous IL-6 levels showed a bette...

Research paper thumbnail of Evaluation of the iPad as a low vision aid for improving reading ability

Clinical Ophthalmology, 2014

Purpose: To evaluate the effect of the iPad as a low vision aid in improving the reading ability ... more Purpose: To evaluate the effect of the iPad as a low vision aid in improving the reading ability of low vision patients (LVPs). Methods: In this study, 228 consecutive patients that came for their routine eye care examination at the University of Florida, Jacksonville eye clinic, were enrolled. Patients met inclusion criteria if they had best-corrected visual acuity (BCVA) of 20/100 or worse in the best corrected eye and were willing to participate in the study. The patient's reading ability was assessed both with the patient's own spectacles and an iPad. Patients were encouraged to enlarge the reading material as well as change the contrast until they could read comfortably. The number of patients able to read the text comfortably was recorded. Results: Out of the total 228 participants who qualified, 103 (45%) were male and 125 (55%) were female. Only 22% could read standard newsprint-sized text (N8) without the help of an iPad. With the help of an iPad, 94% participants with impaired vision were able to read standard newsprint-sized text (N8) or smaller text (P0.01). Conclusion: The iPad, a new portable electronic media device, can be adapted by LVPs to improve their reading ability.

Research paper thumbnail of Retinal Thickness Normative Data in Wild-Type Mice Using Customized Miniature SD-OCT

Research paper thumbnail of Comparison of Retinal Thickness in Normal Eyes Using Stratus and Spectralis Optical Coherence Tomography

Investigative Opthalmology & Visual Science, 2010

Spectral-domain optical coherence tomography (SD-OCT) is an advancement over time-domain OCT (TD-... more Spectral-domain optical coherence tomography (SD-OCT) is an advancement over time-domain OCT (TD-OCT) in the imaging of retinal disorders. Retinal thickness measured by SD-OCT differs from that measured by TD-OCT because the delineation of the outer boundary of the retina differs in the two instruments. The present study aims to evaluate this difference by comparing macular thickness, as obtained by Stratus and Spectralis OCT, in subjects without any known retinal disease. METHODS. Thirty-six subjects with no history of retinal disease and with normal vision and normal intraocular pressure were enrolled in the study. Both Stratus and Spectralis OCT scanning were performed by the same operator on all subjects in one eye. Central point thickness (CPT) and retinal thickness in nine ETDRS subfields, including central subfield (CSF), were measured. Student's t-test was used to determine statistical significance. RESULTS. Mean CPT, as measured by the Stratus and Spectralis OCT, was 166.9 Ϯ 20.9 m and 225.1 Ϯ 17.1 m (P Ͻ 0.0001), and mean CSF was 202.3 Ϯ 19.6 m and 271.4 Ϯ 19.6 m (P Ͻ 0.0001), respectively. Although the mean difference in CSF thickness was 69.1 m, it ranged from 61.9 to 74 m in the other eight ETDRS subfields. CONCLUSIONS. An increased measurement in retinal thickness of approximately 65 to 70 m, as measured by Spectralis OCT compared with Stratus OCT, is consistent with the extent of axial retinal thickness measured by the two instruments. This increased measurement corresponds to the inclusion of the outer segment-RPE-Bruch's membrane complex by Spectralis OCT, which is relevant to studies using the newer SD-OCT for assessment of retinal thickness.

Research paper thumbnail of Retinal Thickness in People with Diabetes and Minimal or No Diabetic Retinopathy: Heidelberg Spectralis Optical Coherence Tomography

Investigative Opthalmology & Visual Science, 2012

Research paper thumbnail of Editorial: Abstracts of the 46th symposium of ISCEV, Morgantown, WV, USA

Documenta Ophthalmologica, 2008

Research paper thumbnail of Inhibition of proliferation of retinal vascular endothelial cells more effectively than choroidal vascular endothelial cell proliferation by bevacizumab

International journal of ophthalmology, 2017

To evaluate the differential inhibitory effects of bevacizumab on cell proliferation of vascular ... more To evaluate the differential inhibitory effects of bevacizumab on cell proliferation of vascular endothelial growth factor (VEGF)-stimulated choroidal vascular endothelial cells (CVECs) and retinal vascular endothelial cells (RVECs) in vitro. VEGF (400 ng/mL) enriched CVECs and RVECs were treated with escalating doses of bevacizumab (0.1, 0.5, 1, 1.5 and 2 mg/mL). Cell proliferation changes were analyzed with WST-1 assay and trypan blue exclusion assay at 48, 72h and 1wk. Morphological changes were recorded with bright field microscopy. VEGF enriched RVECs showed significantly more decline of cell viability than CVECs after bevacizumab treatment. One week after treatment, RVEC cell proliferation decreased by 29.7%, 37.5%, 52.8%, 35.9% and 45.6% at 0.1, 0.5, 1.0, 1.5 and 2 mg/mL bevacizumab respectively compared to CVEC proliferation decrease of 4.1%, 7.7%, 2.4%, 4.1% and 17.7% (P<0.05) by WST-1 assay. Trypan blue exclusion assay also revealed similar decrease in RVEC proliferatio...

Research paper thumbnail of Clinical applications of spectral domain optical coherence tomography in retinal diseases

Biomedical Journal, 2016

Peer review under responsibility of Chang Gung University.

Research paper thumbnail of Comparison of central corneal thickness: ultrasound pachymetry versus slit-lamp optical coherence tomography, specular microscopy, and Orbscan

Clinical Ophthalmology, 2015

Background: Central corneal thickness (CCT) can be measured by using contact and non-contact meth... more Background: Central corneal thickness (CCT) can be measured by using contact and non-contact methods. Ultrasound pachymetry (US pachymetry) is a contact method for measuring CCT and is perhaps the most commonly used method. However, non-contact methods like scanning slit topography (Orbscan II), slit-lamp optical coherence tomography (SL-OCT), and specular microscopy are also used. Not many studies have correlated the measurement of CCT with all four modalities. The purpose of this study was to compare and correlate the CCT measurements obtained by US pachymetry with SL-OCT, specular microscopy, and Orbscan. Method: This is a prospective, comparative study done in an institutional setting. Thirty-two eyes of 32 subjects with no known ocular disease and best-corrected visual acuity of 20/20 were enrolled. CCT measurements were obtained using SL-OCT, specular microscopy, scanning slit topography (Orbscan), and US pachymetry. Three measurements were made with each instrument by the same operator. Mean, standard deviation, and coefficient of variation were calculated for CCT measurements acquired by the four measurement devices. Bland-Altman plot was constructed to determine the agreements between the CCT measurements obtained by different equipment. Results: The mean CCT was 548.16±48.68 µm by US pachymetry. In comparison, CCT averaged 546.36±44.17 µm by SL-OCT, 557.61±49.92 µm by specular microscopy, and 551.03±48.96 µm by Orbscan for all subjects. Measurements by the various modalities were strongly correlated. Correlations (r 2) of CCT, as measured by US pachymetry compared with other modalities, were: SL-OCT (r 2 =0.98, P,0.0001), specular microscopy (r 2 =0.98, P,0.0001), and Orbscan (r 2 =0.96, P,0.0001). All modalities had a linear correlation with US pachymetry measurements. Conclusion: In subjects with healthy corneas, SL-OCT, specular microscopy, and Orbscan (with correction factor) can be used interchangeably with US pachymetry in certain clinical settings. The four modalities showed significant linear correlations with one another.

Research paper thumbnail of Effect of distance and duration of illumination on retinal ganglion cells exposed to varying concentrations of brilliant blue green

Journal of clinical medicine research, 2015

The objective of the study was to determine the safety parameters of using brilliant blue green (... more The objective of the study was to determine the safety parameters of using brilliant blue green (BBG) for chromovitrectomy by assessing the cytotoxicity of BBG on cultured retinal ganglion cells (RGCs) exposed to illumination. RGCs were exposed to two concentrations of BBG (0.25 and 0.5 mg/mL) under metal halide illumination at varying distances (1 and 2.5 cm), intensities (990 and 2,000 Fc), and durations (1, 5 and 15 minutes). Cell viability was assessed using the WST-1 and CellTiter 96(®) AQueous One solution cell proliferation assays. Using the WST-1 assay, with high-intensity illumination, viability of RGCs ranged from 97.5±16.4% of controls with minimum BBG and light exposure (0.25 mg/mL BBG and illuminated for 1 minute at 2.5 cm distance) to 53.1±11.3% of controls with maximum BBG and light exposure (0.50 mg/mL and illuminated for 15 minutes at 1 cm distance; P < 0.01). With medium-intensity illumination, RGCs showed better viability, ranging from 95.1±7.2% of controls wit...

Research paper thumbnail of Retinal thickness measurement obtained with spectral domain optical coherence tomography assisted optical biopsy accurately correlates with ex vivo histology

PloS one, 2014

This study determines 'correlation constants' between the gold standard histological meas... more This study determines 'correlation constants' between the gold standard histological measurement of retinal thickness and the newer spectral-domain optical coherence tomography (SD-OCT) technology in adult C57BL/6 mice. Forty-eight eyes from adult mice underwent SD-OCT imaging and then were histologically prepared for frozen sectioning with H&E staining. Retinal thickness was measured via 10x light microscopy. SD-OCT images and histological sections were standardized to three anatomical sites relative to the optic nerve head (ONH) location. The ratios between SD-OCT to histological thickness for total retinal thickness (TRT) and six sublayers were defined as 'correlation constants'. Mean (± SE) TRT for SD-OCT and histological sections was 210.95 µm (± 1.09) and 219.58 µm (± 2.67), respectively. The mean 'correlation constant' for TRT between the SD-OCT and histological sections was 0.96. The retinal thickness for all sublayers measured by SD-OCT vs. histology...

Research paper thumbnail of Dark Adaptation of Rod Photoreceptors in Normal Subjects, and in Patients with Stargardt Disease and anABCA4Mutation

Investigative Opthalmology & Visual Science, 2004

Research paper thumbnail of Sequential spectral domain OCT documentation of retinal changes after branch retinal artery occlusion

Clinical Ophthalmology, 2010

Branch retinal artery occlusions (BRAO) are characterized histopathologically by inner retinal ed... more Branch retinal artery occlusions (BRAO) are characterized histopathologically by inner retinal edema initially and atrophy in the presence of persistent ischemia. The duration of ischemia leading to irreversible atrophic retinal changes is not clear. Spectral-domain optical coherence tomography (SD-OCT) provides non-invasive detailed in-vivo histological changes in the retina. In this case report, we show sequential in vivo pathological changes seen in the inner retinal layers, in spite of clinical improvement, following the migration of an intraretinal embolus on the optic nerve head, which had previously resulted in symptomatic BRAO.

Research paper thumbnail of A New 2–Base Pair Deletion in the RPGR Gene in a Black Family With X-Linked Retinitis Pigmentosa

Archives of Ophthalmology, 1998

To report the genetic and ophthalmic findings in a black family with X-linked retinitis pigmentos... more To report the genetic and ophthalmic findings in a black family with X-linked retinitis pigmentosa resulting from a newly identified mutation in the RPGR (retinitis pigmentosa GTPase regulator) gene. Patients: Four affected hemizygotes with retinitis pigmentosa and 2 obligate carriers were examined. Two unaffected family members, 1 woman and her unaffected son, were also examined. Methods: Patients underwent a routine ocular examination including slitlamp examination and a dilated fundus examination. Certain patients also underwent testing with Goldmann visual field kinetic perimetry and electroretinography. DNA screening from affected male patients, 2 obligatecarriers,and2unaffectedfamilymemberswasperformed to determine the presence of any mutation in the RPGR gene. Results: A 2-base pair deletion in exon 13 of the RPGR gene that creates a frameshift was found to segregate with the retinal disease in affected males and the carrier state in female heterozygotes in this family. The ophthalmic findings in hemizygotes and carriers were within the spectrum of findings characteristically noted in families with X-linked retinitis pigmentosa. In 2 obligate carriers, a tapetal-like reflex was not clinically apparent. Conclusions: The described mutation is the first RPGR gene mutation reported in a black family. A 2-base pair deletion in exon 13 segregates with a clinical phenotype of X-linked retinitis pigmentosa.

Research paper thumbnail of Visual Acuity and Visual Field Impairment in Usher Syndrome

Archives of Ophthalmology, 1998

To determine the extent of visual acuity and visual field impairment in patients with types 1 and... more To determine the extent of visual acuity and visual field impairment in patients with types 1 and 2 Usher syndrome. Methods: The records of 53 patients with type 1 and 120 patients with type 2 Usher syndrome were reviewed for visual acuity and visual field area at their most recent visit. Visual field areas were determined by planimetry of the II4e and V4e isopters obtained with a Goldmann perimeter. Both ordinary and logistic regression models were used to evaluate differences in visual acuity and visual field impairment between patients with type 1 and type 2 Usher syndrome. Results: The difference in visual acuity of the better eye between patients with type 1 and type 2 varied by patient age (P=.01, based on a multiple regression model). The maximum difference in visual acuity between the 2 groups occurred during the third and fourth decades of life (with the type 1 patients being more impaired), while more similar acuities were seen in both younger and older patients. Fifty-one percent (n=27) of the type 1 patients had a visual acuity of 20/40 or better in at least 1 eye compared with 72% (n=87) of the type 2 patients (age-adjusted odds ra

Research paper thumbnail of Legal Blindness and Employment in Patients with Juvenile-Onset Macular Dystrophies or Achromatopsia

Research paper thumbnail of Intracameral Avastin Dramatically Resolves Iris Neovascularization and Reverses Neovascular Glaucoma

European Journal of Ophthalmology, 2008

PurposeTo report the biologic effect of intracameral bevacizumab in patients with iris neovascula... more PurposeTo report the biologic effect of intracameral bevacizumab in patients with iris neovascularization secondary to proliferative retinal vasculopathies.MethodsSixteen eyes of 15 patients with iris neovascularization associated with or without neovascular glaucoma secondary to proliferative retinal vasculopathies received intracameral bevacizumab (1.25 mg). Ophthalmic evaluations included Snellen visual acuity (VA), complete ophthalmic examination, fluorescein iris angiography, and slit lamp photography Main outcome measure was change in degree of iris neovascularization. Secondary outcomes included fluorescein iris angiographic leakage, control of intraocular pressure, and changes in VA.ResultsAll patients with neovascularization demonstrated by slit lamp photography and fluorescein angiography (16/16 eyes) had complete (or at least partial) reduction in leakage of the neovascularization within 3 weeks after the injection. Leakage from iris neovascularization resolved in 12 of 1...

Research paper thumbnail of Difficulty in performing everyday activities in patients with juvenile macular dystrophies: comparison with patients with retinitis pigmentosa

British Journal of Ophthalmology, 1998

Aims-To ascertain the level of perceived diYculty experienced by patients with central vision los... more Aims-To ascertain the level of perceived diYculty experienced by patients with central vision loss due to juvenile macular dystrophies in the performance of everyday activities. A second objective was to compare their perceived diYculty with that of patients with retinitis pigmentosa (RP) with primarily peripheral vision loss. Methods-72 patients with Stargardt disease, cone dystrophy, or cone-rod dystrophy who had visual acuities worse than 20/40 and normal peripheral visual fields rated themselves on their diYculty in the performance of 33 activities encompassing a wide variety of everyday tasks. These findings were compared with the responses of 120 patients with typical RP or Usher syndrome type 2 who had visual acuities of 20/40 or better and peripheral visual field loss. Results-The juvenile macular dystrophy group reported the greatest level of overall self perceived diYculty with activities involving central vision, and lesser and variable degrees of diYculty with items within the mobility, negotiating steps, driving, and miscellaneous categories. Consistent with these findings, there were highly significant correlations between subjects' rated performances of activities involving central vision and the clinical measures of vision, including visual acuity and size of central scotoma. There were fewer significant correlations between perceived performance of activities in the other categories and the clinical measures. In general, those activities that showed significant correlations with the clinical measures of vision for the patients with juvenile macular dystrophies also showed significant diVerences in the patterns of responses between the juvenile macular dystrophy group and the RP group. Those items which were not correlated with the clinical measures in the juvenile macular dystrophy group tended not to show significant diVerences in the response patterns between the two groups. Conclusion-These results provide insight into the types of perceived diYculties in performing tasks of everyday life in patients with these disorders which aVect counselling of these patients.

Research paper thumbnail of Macular edema after cataract surgery in eyes without preoperative central-involved diabetic macular edema

JAMA Ophthalmology, 2013

IMPORTANCE The incidence of development or worsening of macular edema (ME) is variable in eyes wi... more IMPORTANCE The incidence of development or worsening of macular edema (ME) is variable in eyes without diabetic ME (DME) undergoing cataract surgery. OBJECTIVE To estimate the incidence of central-involved ME 16 weeks following cataract surgery in eyes with diabetic retinopathy without definite central-involved DME preoperatively. DESIGN, SETTING, AND PARTICIPANTS In a multicenter, prospective, observational study, 293 participants with diabetic retinopathy without definite central subfield thickening on optical coherence tomography (OCT) underwent cataract surgery. EXPOSURE Cataract extraction surgery performed within 28 days of enrollment of eyes without DME in individuals with diabetes mellitus. MAIN OUTCOMES AND MEASURES Development of central-involved ME defined as the following: (1) OCT central subfield thickness of 250 μm or greater (time-domain OCT) or 310 μm or greater (spectral-domain OCT) with at least a 1-step increase in logOCT central subfield thickness preoperatively to the 16-week visit; (2) at least a 2-step increase in logOCT central subfield thickness preoperatively to the 16-week visit; or (3) nontopical treatment for ME received before the 16-week visit with either of the OCT criteria met at the time of treatment. RESULTS The median participant age was 65 years. The median visual acuity letter score was 69 letters (Snellen equivalent 20/40). Forty-four percent of eyes had a history of treatment for DME. Sixteen weeks postoperatively, central-involved ME was noted in 0% (95% CI, 0%-20%) of 17 eyes with no preoperative DME. Of eyes with non-central-involved DME, 10% (95% CI, 5%-18%) of 97 eyes without central-involved DME and 12% (95% CI, 7%-19%) of 147 eyes with possible central-involved DME at baseline progressed to central-involved ME. History of DME treatment was significantly associated with central-involved ME development (P < .001). CONCLUSIONS AND RELEVANCE In eyes with diabetic retinopathy without concurrent central-involved DME, presence of non-central-involved DME immediately prior to cataract surgery or history of DME treatment may increase the risk of developing central-involved ME 16 weeks after cataract extraction.

Research paper thumbnail of Exploratory analysis of the effect of intravitreal ranibizumab or triamcinolone onworsening of diabetic retinopathy in a randomized clinical trial

JAMA Ophthalmology, 2013

IMPORTANCE The standard care for proliferative diabetic retinopathy (PDR) usually is panretinal p... more IMPORTANCE The standard care for proliferative diabetic retinopathy (PDR) usually is panretinal photocoagulation, an inherently destructive treatment that can cause iatrogenic vision loss. Therefore, evaluating the effects of therapies for diabetic macular edema on development or worsening of PDR might lead to new therapies for PDR. OBJECTIVE To evaluate the effects of intravitreal ranibizumab or triamcinolone acetonide, administered to treat diabetic macular edema, on worsening of diabetic retinopathy. DESIGN Exploratory analysis was performed on worsening of retinopathy, defined as 1 or more of the following: (1) worsening from no PDR to PDR, (2) worsening of 2 or more severity levels on reading center assessment of fundus photographs in eyes without PDR at baseline, (3) having panretinal photocoagulation, (4) experiencing vitreous hemorrhage, or (5) undergoing vitrectomy for the treatment of PDR. SETTING Community-and university-based ophthalmology practices. PARTICIPANTS Individuals with central-involved diabetic macular edema causing visual acuity impairment. INTERVENTIONS Eyes were assigned randomly to sham with prompt focal/grid laser, 0.5 mg of intravitreal ranibizumab with prompt or deferred (Ն24 weeks) laser, or 4 mg of intravitreal triamcinolone acetonide with prompt laser. MAIN OUTCOMES AND MEASURES Three-year cumulative probabilities for retinopathy worsening. RESULTS For eyes without PDR at baseline, the 3-year cumulative probabilities for retinopathy worsening (P value comparison with sham with prompt laser) were 23% using sham with prompt laser, 18% with ranibizumab with prompt laser (P = .25), 7% with ranibizumab with deferred laser (P = .001), and 37% with triamcinolone with prompt laser (P = .10). For eyes with PDR at baseline, the 3-year cumulative probabilities for retinopathy worsening were 40%, 21% (P = .05), 18% (P = .02), and 12% (P < .001), respectively. CONCLUSIONS AND RELEVANCE Intravitreal ranibizumab appears to be associated with a reduced risk of diabetic retinopathy worsening in eyes with or without PDR. Intravitreal triamcinolone also appears to be associated with a reduced risk of PDR worsening. These findings suggest that use of these drugs to prevent worsening of diabetic retinopathy may be feasible. Given the exploratory nature of these analyses, the risk of endophthalmitis following intravitreal injections, and the fact that intravitreal triamcinolone can cause cataract or glaucoma, use of these treatments to reduce the rates of worsening of retinopathy, with or without PDR, does not seem warranted at this time.

Research paper thumbnail of Aqueous interleukin-6 levels are superior to vascular endothelial growth factor in predicting therapeutic response to bevacizumab in age-related macular degeneration

Journal of ophthalmology, 2014

Objective. To prospectively evaluate the effect of intravitreal bevacizumab on aqueous levels of ... more Objective. To prospectively evaluate the effect of intravitreal bevacizumab on aqueous levels of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) in patients with exudative age-related macular degeneration (AMD) and correlate clinical outcomes with cytokine levels. Methods. 30 eyes of 30 patients with exudative AMD underwent intravitreal injection of bevacizumab three times at monthly intervals. The aqueous samples prior to the 1st injection (baseline) and 3rd injection were analyzed for VEGF and IL-6 levels. Subjects were subgrouped based upon change in the central subfield (CSF) macular thickness on SD-OCT at 8 weeks. Group 1 included patients (n = 14) with a decrease in CSF thickness greater than 10% from the baseline (improved group). Group 2 included patients (n = 16) who had a decrease in CSF thickness 10% or less (treatment-resistant). Results. In subgroup analysis, in both groups 1 and 2 patients, compared to aqueous VEGF, aqueous IL-6 levels showed a bette...

Research paper thumbnail of Evaluation of the iPad as a low vision aid for improving reading ability

Clinical Ophthalmology, 2014

Purpose: To evaluate the effect of the iPad as a low vision aid in improving the reading ability ... more Purpose: To evaluate the effect of the iPad as a low vision aid in improving the reading ability of low vision patients (LVPs). Methods: In this study, 228 consecutive patients that came for their routine eye care examination at the University of Florida, Jacksonville eye clinic, were enrolled. Patients met inclusion criteria if they had best-corrected visual acuity (BCVA) of 20/100 or worse in the best corrected eye and were willing to participate in the study. The patient's reading ability was assessed both with the patient's own spectacles and an iPad. Patients were encouraged to enlarge the reading material as well as change the contrast until they could read comfortably. The number of patients able to read the text comfortably was recorded. Results: Out of the total 228 participants who qualified, 103 (45%) were male and 125 (55%) were female. Only 22% could read standard newsprint-sized text (N8) without the help of an iPad. With the help of an iPad, 94% participants with impaired vision were able to read standard newsprint-sized text (N8) or smaller text (P0.01). Conclusion: The iPad, a new portable electronic media device, can be adapted by LVPs to improve their reading ability.

Research paper thumbnail of Retinal Thickness Normative Data in Wild-Type Mice Using Customized Miniature SD-OCT

Research paper thumbnail of Comparison of Retinal Thickness in Normal Eyes Using Stratus and Spectralis Optical Coherence Tomography

Investigative Opthalmology & Visual Science, 2010

Spectral-domain optical coherence tomography (SD-OCT) is an advancement over time-domain OCT (TD-... more Spectral-domain optical coherence tomography (SD-OCT) is an advancement over time-domain OCT (TD-OCT) in the imaging of retinal disorders. Retinal thickness measured by SD-OCT differs from that measured by TD-OCT because the delineation of the outer boundary of the retina differs in the two instruments. The present study aims to evaluate this difference by comparing macular thickness, as obtained by Stratus and Spectralis OCT, in subjects without any known retinal disease. METHODS. Thirty-six subjects with no history of retinal disease and with normal vision and normal intraocular pressure were enrolled in the study. Both Stratus and Spectralis OCT scanning were performed by the same operator on all subjects in one eye. Central point thickness (CPT) and retinal thickness in nine ETDRS subfields, including central subfield (CSF), were measured. Student's t-test was used to determine statistical significance. RESULTS. Mean CPT, as measured by the Stratus and Spectralis OCT, was 166.9 Ϯ 20.9 m and 225.1 Ϯ 17.1 m (P Ͻ 0.0001), and mean CSF was 202.3 Ϯ 19.6 m and 271.4 Ϯ 19.6 m (P Ͻ 0.0001), respectively. Although the mean difference in CSF thickness was 69.1 m, it ranged from 61.9 to 74 m in the other eight ETDRS subfields. CONCLUSIONS. An increased measurement in retinal thickness of approximately 65 to 70 m, as measured by Spectralis OCT compared with Stratus OCT, is consistent with the extent of axial retinal thickness measured by the two instruments. This increased measurement corresponds to the inclusion of the outer segment-RPE-Bruch's membrane complex by Spectralis OCT, which is relevant to studies using the newer SD-OCT for assessment of retinal thickness.

Research paper thumbnail of Retinal Thickness in People with Diabetes and Minimal or No Diabetic Retinopathy: Heidelberg Spectralis Optical Coherence Tomography

Investigative Opthalmology & Visual Science, 2012

Research paper thumbnail of Editorial: Abstracts of the 46th symposium of ISCEV, Morgantown, WV, USA

Documenta Ophthalmologica, 2008