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Papers by Richard Parrish

American Journal of Ophthalmology, 2017

Background: In microbial keratitis, infection of the cornea can threaten vision through permanent... more Background: In microbial keratitis, infection of the cornea can threaten vision through permanent corneal scarring and even perforation resulting in the loss of the eye. A literature review was conducted by Karsten, Watson and Foster (2012) to determine the spectrum of microbial keratitis. Since this publication, there have been over 2600 articles published investigating the causative pathogens of microbial keratitis.

Ophthalmic surgery, lasers & imaging retina, May 1, 2016

To compare elevated intraocular pressure (IOP) management and outcomes among patients with diabet... more To compare elevated intraocular pressure (IOP) management and outcomes among patients with diabetic macular edema who received fluocinolone acetonide (FAc) implants versus sham-control treatment and explore the prior ocular steroid exposure impact on IOP outcomes. Best-corrected visual acuity (BCVA) was measured using Early Treatment Diabetic Retinopathy Study charts or electronic VA testers. Goldmann applanation tonometry was used to measure IOP. Elevated IOP was more common in FAc-versus sham control-treated patients. Medication, and less often trabeculoplasty or surgery, was used to lower IOP without affecting VA outcomes. No patient treated with 0.2 µg/day FAc who received prior ocular steroid required IOP-lowering surgery. Elevated IOP may occur following FAc implant receipt; however, in the present study, it was manageable and did not impact vision outcomes. Patients previously treated with ocular steroid did not require IOP-lowering surgery following 0.2 µg/day FAc implant ad...

Regenerative biomaterials, 2016

The InnFocus MicroShunt® is a minimally invasive glaucoma drainage microtube used to shunt aqueou... more The InnFocus MicroShunt® is a minimally invasive glaucoma drainage microtube used to shunt aqueous humor from the anterior chamber of the eye to a flap formed under the conjunctiva and Tenon's capsule. The safety and clinical performance of this device approaches that of trabeculectomy with mitomycin C, the current 'gold standard' treatment for advanced glaucoma. The invention of a new biomaterial called poly(styrene-block-isobutylene-block-styrene) or 'SIBS' is the enabling factor which led to the success of this product. SIBS is ultrastable with virtually no foreign body reaction in the body, which manifests as clinically insignificant inflammation and capsule formation in the eye. The lack of capsule formation enables unobstructed flow through the 70 µm lumen tube and the achievement of controlled low intraocular pressure, which is important for the management of glaucoma. This article summarizes the integration of SIBS into a glaucoma drainage device and conf...

Journal of biomedical materials research. Part B, Applied biomaterials, Jan 18, 2015

Glaucoma is the second leading cause of blindness with ∼70 million people worldwide who are blind... more Glaucoma is the second leading cause of blindness with ∼70 million people worldwide who are blind from this disease. The currently practiced trabeculectomy surgery, the gold standard treatment used to stop the progression of vision loss, is rather draconian, traumatic to the patient and requires much surgical skill to perform. This article summarizes the more than 10-year development path of a novel device called the InnFocus MicroShunt®, which is a minimally invasive glaucoma drainage micro-tube used to shunt aqueous humor from the anterior chamber of the eye to a flap formed under the conjunctiva and Tenon's Capsule. The safety and clinical performance of this device approaches that of trabeculectomy. The impetus to develop this device stemmed from the invention of a new biomaterial called poly(styrene-block-isobutylene-block-styrene), or…

The Macula, 2004

A common diseased condition includes eye infections like conductivities and corneal disorder such... more A common diseased condition includes eye infections like conductivities and corneal disorder such as glaucoma etc. Some of the typical classes of drugs used for the ocular delivery are miotics, mydriatics/cycloplegics, anti-inflammatory, anti-infective, surgical adjuvant and diagnostics. This review presents an outline of the prospective of chitosan-based nanomedicine for the treatment of ocular infection for improving the corneal residence time and in vitro bioavailability. In addition, its minimum toxicity and good ocular tolerance, chitosan exhibits constructive biological behavior, like bioadhesion and good permeability with optimum physiochemical characteristics, which make it a unique biocompatible material for the ophthalmic application. The review summarizes the application of chitosan based nanomedicine such as nanoparticles, solid lipid nanoparticles, nanosuspention, nanosponge and nanogels for the treatment of ocular diseases. The results reported provide evidence of the potential of chitosan being natural polymers for enhancing therapeutics effect of drugs.

AJNR. American journal of neuroradiology

A glaucoma drainage implant was detected on plain skull radiographs before MR imaging examination... more A glaucoma drainage implant was detected on plain skull radiographs before MR imaging examination of the brain. The patient was denied the MR imaging for fear of dislodging the "metallic foreign body." The Baerveldt glaucoma drainage implant was mistakenly identified as an orbital metallic object based on its radiographic characteristics. Because none of the current glaucoma drainage implants contain ferromagnetic material, patients with these devices can undergo MR imaging without special precaution.

Ophthalmology, 2005

Purpose-To determine the existence of retinal ganglion cell dysfunction and associated risk facto... more Purpose-To determine the existence of retinal ganglion cell dysfunction and associated risk factors in glaucoma suspects with increased optic disc cupping and normal visual field. Design-Cross-sectional, observational study. Participants-Two hundred glaucoma suspect (GS) patients were identified based on optic disc abnormalities (vertical cup-to-disc ratios [C/D]>0.5; vertical C/D asymmetry ≥ 0.2; disc hemorrhages; notching) in association with known glaucoma risk factors (positive family history, African American descent, increased intraocular pressure [IOP]), but normal visual fields. Forty-two patients had early manifest glaucoma (EMG). Sixteen normal black subjects were added to update previous pattern electroretinogram (PERG) normative data and to establish a normal control (NC) group with a racial breakdown comparable with that of the study groups. Methods-Pattern electroretinograms were recorded simultaneously from both eyes using skin electrodes and automated analysis; visual fields were monitored with standard white-on-white automated perimetry (SAP) central 24-2 program; vertical C/D was evaluated by an independent reader from stereo disc photographs; and univariate and multivariate statistical analysis between PERG and other outcome measures was evaluated. Main Outcome Measures-Pattern electroretinogram amplitude (μV), phase (π rad), and interocular asymmetry in amplitude and phase (%); and SAP mean deviation (MD; decibels), vertical C/D, age (years), IOP (mmHg), and race (black vs. nonblack). Results-The PERG results were abnormal in at least 1 of the outcome measures in 52% of GS patients and 69% of EMG patients. The PERG amplitude was correlated weakly with both MD (P<0.01) and vertical C/D (P = 0.05). The correlation between PERG amplitude and MD and C/D was stronger (P<0.001) for interocular differences rather than absolute measures. Interocular PERG amplitude asymmetry increased with severity of disease (EMG>GS>NC; P<0.01). The PERG amplitude decline with age was steeper in patients with a more negative MD (P<0.01) and in patients with a more negative MD and a larger vertical C/D (P = 0.06). Black race (but not family history) was associated with lower PERG amplitude (P > 0.005) in GS and EMG patients, but not in normal controls (P = 0.44). Conclusions-The correlation between PERG abnormality and known risk factors for glaucoma indicates that PERG has a predictive potential for the development or progression of the disease, or both.

Ophthalmology, 1998

To examine the effect of cataract extraction (CE) after trabeculectomy on intraocular pressure (I... more To examine the effect of cataract extraction (CE) after trabeculectomy on intraocular pressure (IOP) control. Design: Retrospective noncomparative case series. Participants: A total of 115 consecutive patients who underwent extracapsular CE (N 5 58) or phacoemulsification (N 5 57) with intraocular lens (IOL) placement after trabeculectomy were studied. Intervention: Cataract extraction with IOL after trabeculectomy was performed. Main Outcome Measures: Preoperative, intraoperative, and postoperative factors were evaluated for association with loss of IOP control requiring additional medications, bleb needling, or further glaucoma surgery, using Kaplan-Meier survival analysis and Cox multivariate proportional hazards survival regression. Results: After mean postoperative follow-up of 21.1 6 14.3 months, additional glaucoma medication or needling of the filtering bleb to maintain IOP control was required in 35 eyes (30.4%) and was significantly associated with intraoperative iris manipulation and early postoperative peak IOP greater than 25 mmHg. Additional glaucoma surgery was eventually required in 11 eyes (9.6%) and was significantly associated with age of 50 years or younger, preoperative IOP greater than 10 mmHg, and early postoperative peak IOP greater than 25 mmHg. The cumulative proportion of patients who did not require reoperation for glaucoma was 93% and 90% at 1 and 2 years, respectively. The mean IOP at last visit had increased 1.6 mmHg above the pre-CE level and did not vary significantly after the first postoperative month. The median interval from CE to the addition of glaucoma medication or bleb needling was 1.6 months (within 3 months in 20 of 33 eyes) and that from nonsurgical intervention to further glaucoma surgery was 3.6 months (before the 7th postoperative month in 6 of 11 eyes). Of 19 eyes with hypotony (IOP ∂ 6 mmHg) before CE, 11 eyes remained hypotonous after CE despite an increase in the mean IOP from 4.6 to 7.5 mmHg. Conclusions: When CE is performed after trabeculectomy, age of 50 years or younger, preoperative IOP greater than 10 mmHg, intraoperative iris manipulation, and early postoperative IOP greater than 25 mmHg are associated with worsened postoperative IOP control. Most bleb failures occur soon after CE. Resolution of pre-existing hypotony after CE is unpredictable.

Ophthalmic Surgery, Lasers and Imaging Retina, 2012

The authors describe a 92-year-old man who developed delayed-onset endophthalmitis secondary to B... more The authors describe a 92-year-old man who developed delayed-onset endophthalmitis secondary to Bacillus sp. in his left eye 3 years after placement of an Ex-PRESS mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel). Seidel testing was positive over the Ex-PRESS mini glaucoma shunt. The patient underwent vitreous tap followed by intravitreal injections of vancomycin (1 mg/0.1 mL), ceftazadime (2.25 mg/0.1 mL), and dexamethasone (0.4 mg/0.1 mL), along with subconjunctival injection of vancomycin and tobramycin. The last recorded visual acuity was 3/200 in the left eye. With a 1-month follow-up, this case illustrates successful treatment with a vitreous tap and injection of intravitreal antibiotics. Vitrectomy and removal of the Ex-PRESS mini glaucoma shunt were not performed.

Ophthalmic Surgery, Lasers and Imaging Retina, 2011

BACKGROUND AND OBJECTIVE: To assess the biocompatibility and intraocular pressure (IOP) lowering ... more BACKGROUND AND OBJECTIVE: To assess the biocompatibility and intraocular pressure (IOP) lowering effect of a novel glaucoma drainage implant in rabbits. MATERIALS AND METHODS: Sixteen New Zealand white rabbits received one of three glaucoma drainage implants fabricated from poly-(styrene-b-isobutylene-b-styrene [SIBS]) with an internal diameter of the lumen of either 70 (6 eyes), 100 (6 eyes), or 150 (4 eyes) μm. Clinical follow-up examinations were performed during 6 months and postmortem eyes were studied with light microscopy. RESULTS: Smaller internal diameter implants were associated with fewer complications. IOP levels were not statistically different among the groups. No eyes developed serious complications. Mild chronic inflammation was observed around the tube using light microscopy. CONCLUSION: SIBS glaucoma drainage implants did not produce clinically detectable intraocular inflammation in a rabbit model. The 70- and 100-μm SIBS drainage devices demonstrated fewer postope...

Klinische Monatsblätter für Augenheilkunde, 2006

I. Preamble S5 II. Fundamentals and Principles of Ophthalmology S6 III. Cornea and External Disea... more I. Preamble S5 II. Fundamentals and Principles of Ophthalmology S6 III. Cornea and External Diseases S7 IV. Lens and Cataract S7 V. Neuro−Ophthalmology S8 VI. Vitreoretinal Diseases S9 VII. Glaucoma S10 VIII. Pediatric Ophthalmology and Strabismus S11 IX. Diseases of Eyelid, Lacrimal System, and Orbit S12 X. Ocular Manifestations of Systemic Diseases S13 XI. Intraocular Tumors S14 XII. Refraction and Contact Lens S14 XIII. Refractive Surgery S15 XIV. References S16 XV. Ophthalmic Images by Anatomic Location and Diagnosis enclosed in Klin Monatsbl Augenheilkd 11/2006

Current Opinion in Ophthalmology, 2010

Purpose of review-The Tube Versus Trabeculectomy (TVT) Study is a multicenter randomized clinical... more Purpose of review-The Tube Versus Trabeculectomy (TVT) Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery to trabeculectomy with mitomycin (MMC) in eyes with previous cataract and/or unsuccessful glaucoma surgery. This article reviews published results from the TVT Study. Recent findings-Tube shunt surgery had a higher success rate than trabeculectomy with MMC during the first 3 years of follow-up. Trabeculectomy with MMC produced greater intraocular pressure (IOP) reduction in the early postoperative period compared with tube shunt placement, but similar IOPs were observed after 3 months. Tube shunt surgery was associated with greater use of adjunctive medical therapy than trabeculectomy with MMC during the first 2 years of the study, but no difference in medication use was seen at 3 years. The incidence of postoperative complications was higher after trabeculectomy with MMC compared to tube shunt surgery, but serious complications associated with vision loss and/or reoperation developed with similar frequency after both surgical procedures. No difference in the rate of vision loss was present following trabeculectomy with MMC and tube shunt surgery after 3 years of follow-up. Cataract progression was common, but occurred with similar frequency with both procedures. Summary-Intermediate-term results of the TVT Study support the expanded use of tube shunts beyond refractory glaucomas. Tube shunt surgery is an appropriate surgical option in patients who have undergone prior cataract and/or unsuccessful filtering surgery.

Archives of Ophthalmology, 2004

Archives of Ophthalmology, 1997

This study determines the relation between visual field impairment, visual functioning, and globa... more This study determines the relation between visual field impairment, visual functioning, and global quality of life in patients with glaucoma. Binocular visual field impairment was calculated from simultaneous Esterman visual field testing using the Humphrey automated perimeter. Visual acuity impairment, defined with the American Medical Association's Guides to the Evaluation of Permanent Impairment; visual functioning, measured with the VF-14 and the field test version of the National Eye Institute-Visual Functioning Questionnaire; and global quality of life, assessed with the Medical Outcomes Study 36-Item Short Form Health Survey, were determined in 147 consecutive patients with glaucoma. None of the Medical Outcomes Study 36-Item Short Form Health Survey domains demonstrated more than a weak correlation with visual field impairment. The VF-14 scores were moderately correlated (r=-0.58). Of the National Eye Institute-Visual Functioning Questionnaire scales, peripheral vision (r=\m=-\0.60), distance activities (r=\m=-\0.56), and vision-specific dependency (r=\m=-\0.56) were moderately correlated with visual field impairment; vision-specific social functioning, near activities, vision-specific role difficulties, general vision, vision-specific mental health, color vision, and driving were modestly correlated with visual field impairment (r value between \m=-\0.32and \m=-\0.55); visual pain was weakly correlated with visual field impairment; and general health and vision\x=req-\ specific expectations were not notably correlated with visual field impairment. Statistically adjusting for visual acuity weakened the correlations. The Medical Outcomes Study 36-Item Short Form Health Survey indicated that our patients with glaucoma were comparable with previously studied patients without severe systemic medical problems. However, the Medical Outcomes Study 36-Item Short Form Health Survey scores did not correlate with visual field impairment in our study. Based on the moderate correlation between binocular visual field impairment with the VF-14 and the National Eye Institute-Visual Functioning Questionnaire, these questionnaires may be useful among patients with glaucoma.

American Journal of Ophthalmology, 2009

Purpose-To determine the effect of intraocular pressure (IOP) lowering on the optic disc in patie... more Purpose-To determine the effect of intraocular pressure (IOP) lowering on the optic disc in patients of the Collaborative Initial Glaucoma Treatment Study (CIGTS) after five years. Design-Randomized clinical trial Methods-The baseline and five-year stereoscopic optic disc photographs of 348 eyes (patients) randomized to medical or surgical treatment of open-angle glaucoma were assessed by two independent readers for change in a masked side-by-side comparison, and confirmed by an independent committee. Results-303 (87.1%) eyes showed no change, 22 (6.3%) showed enlargement of the cup along any meridian (progression), and 23 (6.6%) showed a reduction in the cup along any meridian (reversal of cupping). Incidence of optic disc progression was higher (p=0.007) in the medicine group, 18/185 (10%) than in the surgical group 4/163 (3%); and the incidence of reversal of cupping was higher (p<0.001) in the surgical group, 21/163 (13%), than the medicine group, 2/185 (1%), (P<0.001). Visual field worsening (mean deviation) was significantly associated with progression of optic disc cupping (P<0.001). Reversal of cupping was also associated with lower postoperative IOP (P<0.001).

American Journal of Ophthalmology, 2007

American Journal of Ophthalmology, 2005

showed segregation of the Q368STOP mutation with disease. 4 The Q368STOP mutation has mostly been... more showed segregation of the Q368STOP mutation with disease. 4 The Q368STOP mutation has mostly been detected in Caucasian, rather than Asian, populations. 3-7 In the present study, all individuals with the Q368STOP mutation were Caucasians and shared the same alleles at the four genotyped markers previously defined for the Q368STOP disease haplotype in 15 Tasmanian POAG families. 4 This finding further supports a global disease haplotype for the Q368STOP mutation in Caucasians rather than a series of de novo events. Additional genotyping of markers, including single nucleotide polymorphisms obtained from the HapMap project, should help define the approximate date of origin of the Q368STOP mutation in Caucasians.

American Journal of Ophthalmology, 2002

AND THE OCULAR HYPERTENSION TREATMENT STUDY GROUP • PURPOSE: To determine the reproducibility ove... more AND THE OCULAR HYPERTENSION TREATMENT STUDY GROUP • PURPOSE: To determine the reproducibility over time of visual estimates of the horizontal cup/disk ratio by trained technicians from optic disk stereophotographs. • METHODS: Baseline optic disk stereophotographs are graded at entry and regraded annually in a masked fashion. The 1,636 participants in the Ocular Hypertension Treatment Study (OHTS) undergo stereoscopic optic disk photography at study entry and annually thereafter. Stereophotographs are graded independently by two technicians at the Optic Disc Reading Center. If the readers' estimates of horizontal cup/disk ratio differ by more than 0.2 disk diameters (DD), they attempt to reach a consensus; if they cannot, the horizontal cup/disk ratio is adjudicated by a glaucoma specialist. • RESULTS: The percent of regradings differing by 0.2 DD or more from the estimate of horizontal cup/disk ratio made at entry was 4%, 6%, and 7%, respectively at years 1, 2, and 3. The percent differing by more than 0.2

Survey of Ophthalmology, 1987

Abetract. Successful glaucoma filtering surgery is characterized by the passage of aqueous humor ... more Abetract. Successful glaucoma filtering surgery is characterized by the passage of aqueous humor from the anterior chamber to the subconjunctival space, which results in the formation of a filtering bleb. Aqueous in the subconjunctival space may then exit by multiple pathways. Bleb failure most often results from fibroblast proliferation and subconjunctival fibrosis. Factors associated with an increased risk of bleb failure include youth, aphakia, active anterior segment neovascularization, inflammation, previously failed glaucoma filtering surgery, and, possibly, race. Several surgical and pharmacologic techniques have recently been introduced to enhance success in eyes with poor surgical prognoses. To elucidate the scientific rationale of these methods, we summarize the process of wound healing after glaucoma filtering surgery and describe postoperative clinical and histopathologic features, factors which may affect success, and specific methods to improve surgical success.