yaniv barkana | Tel Aviv University (original) (raw)

Papers by yaniv barkana

Hong Kong Journal of Ophthalmology, Dec 1, 2007

Angle-closure is often erroneously considered synonymous with pupillary block, the most common me... more Angle-closure is often erroneously considered synonymous with pupillary block, the most common mechanism leading to acute or chronic iridocorneal apposition. However, abnormalities exist in structures and/or forces other than those related to pupillary block and may cause apposition despite a patent iridotomy. A 4-point classification of these mechanisms has been described, and includes mechanisms originating in the ciliary body, lens, or posterior segment. This review outlines the characteristics of angle-closure specific to each of these 3 levels.

Humana Press eBooks, Jun 4, 2008

Investigative Ophthalmology & Visual Science, May 1, 2006

Investigative Ophthalmology & Visual Science, May 1, 2005

Scientific Reports, Feb 26, 2021

To investigate sensitive outcome measures based exclusively on abnormal points in microperimetry ... more To investigate sensitive outcome measures based exclusively on abnormal points in microperimetry testing of eyes with intermediate age-related macular degeneration (iAMD). 25 eyes of 25 subjects with iAMD had undergone 2 successive tests of mesopic microperimetry with the Macular Integrity Assessment Microperimeter (MAIA), using a custom grid of 33 points spanning the central 14 degrees of the macula. Each point was defined as abnormal if its threshold sensitivity was lower than 1.65 standard deviations (SD) (5%) or 2 SD (2.5%) than the expected threshold in healthy eyes according to the MAIA internal database. Among the 25 eyes there were 11.8 ± 9 and 8.4 ± 8.2 abnormal points at < 5% and < 2.5%, with mean deviation of thresholds from normal − 4.9 ± 1.2 dB and − 5.8 ± 1.5 dB, respectively. These deviations were greater, and their SD smaller, compared with the complete microperimetry grid, − 2.3 ± 2.0 dB. The 95% limits of agreement for average threshold between the 2 successive tests were smaller when only abnormal points were included. Analyzing only abnormal grid points yields an outcome parameter with a greater deviation from normal, a more homogenous dataset, and better test-retest variability, compared with analysis of all grid points. This parameter may thus be more sensitive to change, while moderately limiting the number of potential recruits. The proposed outcome measures should be further investigated as potential endpoints in clinical trials in iAMD. Age-related macular degeneration (AMD) is the leading cause of blindness in the industrialized world, and remains an important unmet medical need 1. Currently there is no approved treatment that can halt the progression of AMD from the early or intermediate (iAMD) forms to the advanced, visually-devastating forms. Clinical trials of novel interventions to stop or delay the progression of AMD are dependent on the use of sensitive outcomes to demonstrate efficacy. Accepted and validated functional endpoints are currently not available. The commonly used parameter of best corrected visual acuity is inadequate for trials of early or iAMD since it is affected only late in the disease spectrum, often only after progression to advanced AMD has occurred 2. Microperimetry using the Macular Integrity Assessment microperimeter (MAIA; CenterVue, Padova, Italy, now distributed by Icare, Finland) can be used to measure the threshold of differential light sensitivity in different locations in the macula, with the machine projecting the light stimulus directly on the retina while tracking the fundus using a scanning laser ophthalmoscope 3. Such testing provides a wealth of data compared with the single-point assessment of foveal visual acuity or contrast sensitivity. Several reports have documented reduced microperimetry retinal sensitivity in eyes with iAMD despite preserved visual acuity 4-9. Some clinical trials in iAMD have a main goal of demonstrating improved vision, theorizing that removing the source of disease or providing "neuroenhancing" treatment may not only slow long-term neural degeneration, but also enhance function of sick retinal cells in the short-term, as has been suggested in a few early-phase clinical trials 10-12. Of note, this concept of neuronal functional improvement is established in neurology, with several approved drugs in use that improve reduced function, e.g. cognitive improvement in Alzheimer or motor improvement in Parkinson's disease 13 .

Investigative Ophthalmology & Visual Science, Jun 16, 2013

Investigative Ophthalmology & Visual Science, Jun 23, 2017

Journal of Glaucoma, Aug 1, 2013

Purpose: To describe a new familial syndrome consisting of anterior segment dysgenesis, glaucomat... more Purpose: To describe a new familial syndrome consisting of anterior segment dysgenesis, glaucomatous optic neuropathy, and intraocular pressure (IOP) in the normal range. Design: Observational case series. Methods: Subjects were available for examination from a 2-generation pedigree. Ophthalmic examination and photography, visual field examination, and optical coherence tomography of the peripapillary retinal nerve fiber layer were performed. In some subjects, medical work-up was performed. Results: Eight affected subjects were identified. All had signs of Axenfeld-like anterior segment dysgenesis, ranging from a single fine iris process to diffuse broad iris synechiae extending to a prominent posterior embryotoxon. Four of the 8 subjects had glaucoma-appearing optic nerve heads with corresponding visual field defects; in a fifth subject, glaucoma was suspected on the basis of optic nerve appearance, but the visual field was full. IOP was consistently in the low-teens to mid-teens except in 1 eye in which it was 22 mm Hg, the highest recorded pressure in all examined subjects. Conclusions: A new phenotype is presented, characterized by IOP in the normal range, glaucomatous-appearing optic nerve cupping, and anterior segment dysgenesis. The suggested mode of inheritance is autosomal dominant with marked intrafamilial variability.

Journal of Cataract and Refractive Surgery, Sep 1, 2005

To assess the intraoperator repeatability and interoperator reproducibility of central corneal th... more To assess the intraoperator repeatability and interoperator reproducibility of central corneal thickness measurements by the Pentacam Scheimpflug imaging system (Oculus) and the optical low-coherence reflectometer (OLCR) pachymeter (Haag-Streit) and to compare them with those of ultrasound (US) pachymetry.

Journal of Cataract and Refractive Surgery, Feb 1, 2010

Journal of Glaucoma, Oct 1, 2009

Purpose: To correlate the amount of glaucomatous field loss with amount of retinal nerve fiber la... more Purpose: To correlate the amount of glaucomatous field loss with amount of retinal nerve fiber layer (RNFL) loss using a novel model consisting of eyes of subjects with pseudoexfoliation syndrome (PXS) in 1 eye only with elevated intraocular pressure, using the fellow eye as a marker of baseline healthy anatomy, allowing precise correlation by elimination of intersubject anatomic variation. Methods: In each eye with PXS we recorded standard automated perimetry mean deviation and the percentage loss of Stratus optical coherence tomography-RNFL thickness relative to the fellow non-PXS eye, and correlated these 2 measurements. Results: Twenty-six subjects with unilateral hypertensive PXS were enrolled. Twelve of 26 eyes had glaucomatous visual field loss. In eyes without field defect there was a broad range of RNFL thickness loss from almost none to nearly 50%. In some of these eyes whereas RNFL thickness was within normal limits it was clearly reduced compared with the fellow eye. All eyes with field defect except one had lost greater than 50% RNFL thickness. Conclusions: This model of unilateral hypertensive PXS allows correlation of functional and structural loss in glaucoma while eliminating interindividual anatomic variability. It suggests that optical coherence tomography can have an important role in the diagnosis and management of early glaucoma before visual field loss is detected.

Journal of Glaucoma, 2014

Purpose: To compare directly the results of 4 tonometers in measuring postural change in the intr... more Purpose: To compare directly the results of 4 tonometers in measuring postural change in the intraocular pressure (IOP) between sitting and lying body positions. Methods: In 19 healthy subjects, the IOP was measured both eyes with a Goldmann applanation tonometer (GAT) while sitting, then using the same GAT with the subject in the left lateral decubitus position after lying for 15 minutes, using a novel system comprising a motorized bed and a modified slit-lamp table. On the next day, the sitting IOP was measured in 1 eye using GAT, and additionally in random order Tonopen XL and pneumatonometer. Then subjects were asked to lie down, and the IOP was measured with these tonometers and also with a hand-held applanation tonometer (HA-2) after lying for 15 minutes and for 45 minutes; measurements were made with subjects in the supine position except with GAT. Results: There were 10 male and 9 female subjects, with a mean age of 33.0 ± 12.4 years. On day 1, the sitting GAT IOP (mm Hg) was 13.7 ± 3.0 right eye and 13.6 ± 2.8 left eye (P = 0.7) and the lying GAT IOP was 17.8 ± 3.5 right eye and 18.1 ± 3.2 left eye (P = 0.3 for intereye postural IOP change). Postural change in the right and the left eyes was moderately correlated, with a coefficient of 0.453. On day 2, postural changes after lying for 15 minutes as measured with a GAT, a Tonopen, a pneumatonometer, and a HA-2 were 4.9 ± 2.6, 1.6 ± 1.8, 4.2 ± 2.0, and 3.1 ± 2.7, respectively. After lying for 45 minutes, it decreased to 3.3 ± 2.1, 1.1 ± 4.3, 3.1 ± 2.5, and 2.6 ± 3.3, respectively; this IOP decrease was statistically significant for the GAT and the pneumatonometer. The inter-subject variability was large, as in some subjects there was nearly no postural change in the IOP, whereas in some the IOP increased by 8 to 10 mm Hg. Ninety-five percent limits of agreement showed a poor agreement between GAT and the other 3 tonometers in the sitting and lying IOPs and postural IOP changes measured. Conclusions: The average postural IOP change was similar when measured with GAT and a pneumatonometer, smaller with a handheld GAT, and much smaller with a Tonopen XL. This change decreased significantly when lying between the 15-and 45-minute time points. The inter-subject variability in postural IOP was remarkable, consistent with previous reports, suggesting the importance of this parameter in clinical glaucoma practice. Interdevice agreement was poor and similar to previous reports.

Pharmaceuticals

Decreased blood flow to the optic nerve (ON) and neuroinflammation are suggested to play an impor... more Decreased blood flow to the optic nerve (ON) and neuroinflammation are suggested to play an important role in the pathophysiology of glaucoma. This study investigated the potential neuroprotective effect of azithromycin, an anti-inflammatory macrolide, and sildenafil, a selective phosphodiesterase-5 inhibitor, on retinal ganglion cell survival in a glaucoma model, which was induced by microbead injection into the right anterior chamber of 50 wild-type (WT) and 30 transgenic toll-like receptor 4 knockout (TLR4KO) mice. Treatment groups included intraperitoneal azithromycin 0.1 mL (1 mg/0.1 mL), intravitreal sildenafil 3 µL, or intraperitoneal sildenafil 0.1 mL (0.24 μg/3 µL). Left eyes served as controls. Microbead injection increased intraocular pressure (IOP), which peaked on day 7 in all groups and on day 14 in azithromycin-treated mice. Furthermore, the retinas and ON of microbead-injected eyes showed a trend of increased expression of inflammatory- and apoptosis-related genes, m...

Journal of Glaucoma, 2021

Supplemental Digital Content is available in the text. Précis: During the past quarter century, t... more Supplemental Digital Content is available in the text. Précis: During the past quarter century, the rate of glaucoma-related publication in general ophthalmology journals increased due to higher representation in “experimentally oriented” journals. The rate of glaucoma randomized controlled clinical trial (RCT) articles decreased during the same time period. Purpose: To evaluate trends in rate of glaucoma publications in leading general ophthalmology journals over the past quarter century. Materials and Methods: Q1 ophthalmology journals Web sites were reviewed. Only journals not limited to certain subspecialty were considered “general” and included in the analysis. In addition we categorized journals orientation as either “clinical” or “experimental.” The PubMed search engine was used to collect publications from the selected journals between January 1, 1995 to December 31, 2019. Publications captured by “glaucoma” or “ocular hypertension” filters were considered glaucoma related. The fraction of glaucoma articles out of total number of articles within each year for each journal was calculated. A linear mixed effects model was applied to detect trends in glaucoma publication rates during the study period. Results: Eight journals were included: 4 “clinically oriented” and 4 “experimentally oriented.” The PubMed search yielded 72,750 publications, of which 9329 (12.8%) considered “glaucoma related.” Percentage of glaucoma publications remained stable within “clinically oriented” journals, and significantly increased within “experimentally oriented” journals (annual change of 0.3%, P<0.001). The number of glaucoma-related RCTs decreased significantly in each (annual change of −0.21% and −0.13%, respectively, P<0.05). Conclusions: There has been a significant rise in the rates of glaucoma publications in “experimentally oriented” journals, while their representation in “clinically oriented” journals remained stable over the past quarter century. This change might be due to the increasing efforts to develop more advanced methods for evaluation and treatment in glaucoma, although still unable to address clinical demands. The decrease in glaucoma-related RCT articles might indicate reduced funding for such research.

Investigative Ophthalmology & Visual Science, 2013

Acta Ophthalmologica, 2021

To investigate the effect of trabeculectomy and glaucoma drainage device implantation on posture ... more To investigate the effect of trabeculectomy and glaucoma drainage device implantation on posture related intraocular pressure (IOP) changes in glaucomatous eyes.

European Journal of Ophthalmology, 2021

Purpose: Accumulating evidence suggests that neuroinflammation and immune response are part of th... more Purpose: Accumulating evidence suggests that neuroinflammation and immune response are part of the sequence of pathological events leading to optic nerve damage in glaucoma. Changes in tissue temperature due to inflammation can be measured by thermographic imaging. We investigated the ocular surface temperature (OST) profile of glaucomatous eyes to better understand the pathophysiology of these conditions. Methods: Subjects diagnosed with glaucoma (primary open angle glaucoma [POAG] or pseudo exfoliation glaucoma [PXFG]) treated at the Sam Rothberg Glaucoma Center (11/2019–11/2020.) were recruited. Healthy subjects with no ocular disease served as controls. The Therm-App thermal imaging camera was used for OST acquisition. Room and body temperatures were recorded, and the mean temperatures of the medial cantus, lateral cantus, and cornea were calculated with image processing software. Results: Thermographic images were obtained from 52 subjects (52 eyes: 25 POAG and 27 PXFG) and 66 ...

Current Eye Research, 2020

Purpose: to compare the posture-related Intra-ocular pressure (IOP) changes in pseudo-exfoliation... more Purpose: to compare the posture-related Intra-ocular pressure (IOP) changes in pseudo-exfoliation glaucoma (PXFG) and in primary open-angle glaucoma (POAG) patients using the EyeOP, a novel Goldmann Applanation Tonometer (GAT) and to investigate the effect of ab externo trabeculectomy on these changes. Methods: Prospective, non-randomized, controlled, observational study. IOP was measured in sitting and in left lateral decubitus positions (LLDP), using GAT, GAT-EyeOP and Tonopen XL. Main Outcome Measure: Posture related IOP differences between groups. Results: Thirty-two eyes of 32 PXFG patients (21 non-operated, 11 posttrabeculectomy) and 47 eyes of 47 POAG patients (18 non-operated, 29 posttrabeculectomy) were included. Among non-operated patients, the average increase in GAT IOP between positions (∆IOP) was 2±1.86 mmHg for the PXFG group and 1.9±2.84 mmHg for the POAG group (P=0.87). The ∆IOP among operated patients (1.72±1.9) was slightly less than in non-operated (1.6±2.69; P=0.905). Generally, in the LLDP, the mean difference between GAT and Tonopen XL IOP measurements was 1.9±3.83 mmHg, (r=0.643; P<0.001). Similar correlation was demonstrated between tonometers when measured in the sitting position. Conclusions: Both PXFG and POAG patients have increased IOP in LLDP as compared to an upright position, with no statistical significant difference between groups. Trabeculectomy had no significant effect on the ∆IOP.