Association between corneal biomechanical properties and optic nerve head morphology in newly diagnosed glaucoma patients.

BACKGROUND: To investigate the association between corneal biomechanics and optic nerve head morphology in newly diagnosed primary open-angle glaucoma patients. DESIGN: Hospital based prospective study. PARTICIPANTS: Forty-two untreated newly diagnosed primary open-angle glaucoma patients. METHODS: Patients underwent corneal hysteresis measurement using the Ocular Response Analyzer and confocal scanning laser ophthalmoscopy for optic nerve head topography evaluation. One eye was selected randomly for analysis. Data collected included age, race, gender, intraocular pressure and central corneal thickness. MAIN OUTCOME MEASURES: Multiple regression analysis (controlling for baseline intraocular pressure and disc area) was used to investigate factors associated with the following optic nerve head topographic parameters: linear cup-to-disc ratio and mean cup depth. RESULTS: Mean age of participants was 66.7 ± 11.8 years. Corneal hysteresis was the only factor significantly associated with both mean cup depth (correlation coefficient [r] = -0.34, P = 0.03) and cup-to-disc ratio (r = -0.41, P = 0.01). Central corneal thickness was significantly associated with mean cup depth (r = -0.35, P = 0.02), but not with cup-to-disc ratio (r = -0.25, P = 0.13). Although a trend towards a positive association between age and cup-to-disc ratio was identified (r = 0.26, P = 0.08), age was not significantly associated with mean cup depth (r = 0.06, P = 0.72). When comparing fellow eyes of patients with bilateral glaucoma, the eye with higher corneal hysteresis had smaller cup-to-disc ratio in 75% of the cases. CONCLUSIONS: In untreated newly diagnosed primary open-angle glaucoma patients, those with thinner corneas and mainly lower corneal hysteresis values had a larger cup-to-disc ratio and deeper cup, independently of intraocular pressure values and disc size.

Short duration transient visual evoked potentials in glaucomatous eyes.

PURPOSE: To investigate the correlation between structural and functional damage in patients with asymmetric glaucoma using a newly developed short duration transient visual evoked potential (SD-tVEP) device. METHODS: Twenty-five patients with visual acuity ≥20/30 and asymmetric visual field (VF) loss [inter-eye difference in mean deviation index (MD) of at least 3 dB] were enrolled. Patients underwent optical coherence tomography (OCT) for macular thickness measurement, scanning laser polarimetry with variable corneal compensation for retinal nerve fiber layer measurement, and SD-tVEP (10% and 85% Michelson contrast, acquisition time of 20 s) in both eyes within 2 months. We correlated VF MD and structural test results with SD-tVEP P100 latency and Delta Amplitude (N75-P100). RESULTS: Using 10% contrast, there was a significant difference in SD-tVEP latency and amplitude between eyes with better and worse VF MD (P<0.001). MD correlated significantly with both SD-tVEP parameters (r>0.33, P≤0.01). When using 85% contrast, SD-tVEP amplitude differed between eyes (P=0.01) and MD values correlated significantly with amplitude results (r=0.32, P=0.01), but not with latency (P=0.46). In eyes with more advanced VF loss, there was a positive and significant correlation between SD-tVEP amplitude (85% contrast) and macular thickness on OCT (r=0.47, P=0.01), but not with retinal nerve fiber layer measured with polarimetry (P=0.26). CONCLUSIONS: In cases of asymmetric glaucoma, SD-tVEP results correlate significantly with the level of VF damage as measured by MD. In the eyes with more advanced VF loss, reduced SD-tVEP amplitude was associated with decreased macular thickness on OCT. These findings suggest that SD-tVEP may be a fast and objective method to assess or screen for functional damage in glaucomatous eyes.

Macular changes detected by Fourier-domain optical coherence tomography in patients with hypotony without clinical maculopathy.

PURPOSE: To investigate macular changes in eyes with postoperative hypotony without clinical maculopathy using high-resolution Fourier-domain optical coherence tomography (FD-OCT). METHODS: Fourteen eyes of 12 patients with postoperative intraocular pressure (IOP) ï¿¡ 6 mmHg for at least 4 weeks but with no detectable clinical features associated with hypotony maculopathy were imaged by FD-OCT prospectively. Images were analysed by two retina specialists masked to clinical findings. RESULTS: Most patients were female (83%) and myopic (75%) with a mean age of 65 ± 17 [standard deviation (SD)] years (range 2­86 years). Mean central corneal thickness was 519 ± 34 lm [95% confidence interval (CI) 502­537] and mean IOP before surgery was 20 ± 8 mmHg (95% CI 15­24). During the period of hypotony (mean 15 ± 6 weeks), the average mean IOP was 4 ± 1 mmHg (95% CI 3­5). Abnormal FD-OCT findings (retinal folds and / or intraretinal fluid) were present in eight eyes. These patients had a higher rate of visual symptoms (75% versus 17%), visual acuity loss (‡ 2 lines; 63% versus 17%) and increased mean foveal thickness (250 ± 26 versus 210 ± 12 lm; p < 0.01, Mann­Whitney U-test) compared with those with normal FD-OCT. CONCLUSION: FD-OCT identified subclinical macular abnormalities in over half of the eyes with postoperative hypotony. These findings were accompanied by visual disturbances and central macular thickening. FD-OCT can be an important diagnostic tool for this disorder when clinical features are absent.

The use of vital dyes in ocular surgery.

Vital dyes have advanced diagnosis and surgical technique in various specialties, including oncology, gastroenterology, and ophthalmology. In ocular surgery vital dyes are widely used in cataract and vitreoretinal surgery. Worldwide, intra-operative use of trypan blue during cataract surgery has enhanced visualization of the anterior capsule during capsulorrhexis, and patent blue has been recently licensed in Europe for cataract surgery. For chromovitrectomy, the vital dyes indocyanine green, infracyanine green, and brilliant blue stain the internal limiting membrane, and trypan blue and triamcinolone acetonide help visualize epiretinal membranes and vitreous, respectively. Intra-operative vital dyes are finding uses in corneal, glaucoma, orbit, strabismus, and conjunctival surgery. We provide a summary of current knowledge of the use of vital dyes in ocular surgery. We review the properties of dyes, techniques of application, indications, and complications in ocular surgery. Vital dyes represent an expanding area of research, and novel dyes deserve further investigation.

Central retinal artery occlusion and non-arteritic anterior ischemic optic neuropathy associated with an overlap syndrome: a case report.

INTRODUCTION: An "overlap syndrome" is defined as the sequential appearance over time of two or more risk factors for glaucomatous damage. The appearance of a new risk factor can alter the course and prognosis of previously stable disease. Exfoliation syndrome is a leading cause of glaucoma and is associated with vascular disease. We report a case of central retinal artery occlusion and non-arteritic anterior ischemic optic neuropathy in a patient with overlap syndrome. CASE PRESENTATION: An 87-year-old woman with longstanding stable primary open-angle glaucoma developed bilateral exfoliation syndrome, after which her intraocular pressure became uncontrolled and her glaucomatous damage progressed rapidly. She also developed ischemic arterial events in both eyes. CONCLUSION: The case presented here shows that overlap syndromes can lead to rapid, irreversible vision impairment. To the best of our knowledge, this is the first reported case of central retinal artery occlusion and non-arteritic anterior ischemic optic neuropathy in a patient with overlap syndrome.

Correlation between water-drinking test outcomes and body mass index in primary open-angle glaucoma patients under clinical treatment.

AIMS: The aim of this study was to evaluate the correlation between water-drinking test (WDT) outcomes and body mass index (BMI) in primary open-angle glaucoma (POAG) patients. METHODS: This study enrolled 41 POAG patients (41 eyes) under glaucoma treatment. POAG was defined as any typical signs of glaucomatous optic neuropathy and/or visual-field finding, with open angle on gonioscopy. After inclusion, patients underwent weight and height measurements. The WDT was performed, consisting of a baseline intraocular pressure (IOP) measurement, followed by the ingestion of 1 L of tap water within 5 min. Then, IOP was measured four times, at 15-min intervals. IOP peak was considered the maximum value of the four measurements, and IOP fluctuation was defined as the difference between the peak and the baseline IOP. RESULTS: The analysis of the IOP profile during the WDT revealed significant differences between groups with different BMIs. Patients with a higher BMI presented lower IOP peaks and fluctuation (P < 0.043; P < 0.001). There was also a significant correlation between the IOP fluctuation (both absolute [P < 0.024] and percentage [P < 0.021] values) and the following baseline parameters: BMI, weight, height, and cup-to-disc ratio. CONCLUSIONS: These data suggest that patients' individual characteristics, including BMI and weight, may influence the results of the WDT. In addition, patients with a higher BMI presented lower IOP fluctuation in the WDT.

Diode laser transscleral cyclophotocoagulation-induced staphyloma following trabeculectomy with mitomycin C.

A 42-year-old man developed progressive scleral iatrogenic staphyloma in the region of a previous trabeculectomy with mitomycin C after three sessions of diode laser transscleral cyclophotocoagulation for a refractory glaucoma secondary to trauma. After clinical and laboratory evaluations, no signs of systemic or autoimmune disorders were found. The patient underwent a reinforcement of the eye wall with a scleral patch over the staphyloma area and a glaucoma drainage device was implanted. Repeated transscleral cyclophotocoagulation procedures should be performed cautiously in patients who have had previous trabeculectomy.