Racial Differences in Diagnostic Accuracy of Retinal Nerve Fiber Layer Thickness in Primary Open-Angle Glaucoma.

Purpose: To evaluate the diagnostic accuracy of retinal nerve fiber layer thickness (RNFLT) by spectral-domain optical coherence tomography (OCT) in primary open-angle glaucoma (POAG) in eyes of African (AD) and European descent (ED). Design: Comparative diagnostic accuracy analysis by race. Participants: 379 healthy eyes (125 AD and 254 ED) and 442 glaucomatous eyes (226 AD and 216 ED) from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study. Methods: Spectralis (Heidelberg Engineering GmbH) and Cirrus (Carl Zeiss Meditec) OCT scans were taken within one year from each other. Main Outcome Measures: Diagnostic accuracy of RNFLT measurements. Results: Diagnostic accuracy for Spectralis-RNFLT was significantly lower in eyes of AD compared to those of ED (area under the receiver operating curve [AUROC]: 0.85 and 0.91, respectively, P=0.04). Results for Cirrus-RNFLT were similar but did not reach statistical significance (AUROC: 0.86 and 0.90 in AD and ED, respectively, P =0.33). Adjustments for age, central corneal thickness, axial length, disc area, visual field mean deviation, and intraocular pressure yielded similar results. Conclusions: OCT-RNFLT has lower diagnostic accuracy in eyes of AD compared to those of ED. This finding was generally robust across two OCT instruments and remained after adjustment for many potential confounders. Further studies are needed to explore the potential sources of this difference.

Longitudinal stability of inter-eye differences in optical coherence tomography measures for identifying unilateral optic nerve lesions in multiple sclerosis.

INTRODUCTION: Optical coherence tomography (OCT)-derived peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell+inner plexiform layer (GCIPL) thickness inter-eye differences (IEDs) are robust measurements for identifying clinical history acute ON in people with MS (PwMS). This study investigated the utility and durability of these measures as longitudinal markers to identify optic nerve lesions. METHODS: Prospective, multi-center international study of PwMS (with/without clinical history of ON) and healthy controls. Data from two sites in the International MS Visual System Consortium (IMSVISUAL) were analyzed. Mixed-effects models were used to compare inter-eye differences based on MS and acute ON history. RESULTS: Average age of those with MS (n = 210) was 39.1 ± 10.8 and 190 (91%) were relapsing-remitting. Fifty-nine (28.1%) had a history of acute unilateral ON, while 9/210 (4.3%) had >1 IB episode. Median follow-up between OCT scans was 9 months. By mixed-effects modeling, IEDs were stable between first and last visits within groups for GCIPL for controls (p = 0.18), all PwMS (p = 0.74), PwMs without ON (p = 0.22), and PwMS with ON (p = 0.48). For pRNFL, IEDs were within controls (p = 0.10), all PwMS (p = 0.53), PwMS without ON history (p = 0.98), and PwMS with history of ON (p = 0.81). CONCLUSION: We demonstrated longitudinal stability of pRNFL and GCIPL IEDs as markers for optic nerve lesions in PwMS, thus reinforcing the role for OCT in demonstrating optic nerve lesions.

Exposure to Secondhand Smoke in Children is Associated with a Thinner Retinal Nerve Fiber Layer: The Hong Kong Children Eye Study.

PURPOSE: We sought to assess the effects of exposure to secondhand smoke (SHS) on peripapillary retinal nerve fiber layer (p-RNFL) thickness in children. DESIGN: Cross-sectional study. METHODS: Children 6-8 years of age were consecutively recruited from the population-based Hong Kong Children Eye Study. All participants received comprehensive ophthalmic examinations and p-RNFL thickness was measured by spectral-domain optical coherence tomography. SHS data were derived from a validated questionnaire. Associations between p-RNFL thickness and SHS exposure status, number of smokers in the family, and quantity of smoking in the family were determined by multivariate linear regression after adjusting for potential confounders. RESULTS: Among the Hong Kong Children Eye Study cohort (n = 3,103), approximately one-third of children were exposed to SHS (35.4%, n = 1,097). Compared to those without exposure to SHS, children exposed to SHS had similar age (P = .83), gender (P = .17), body mass index (P = .44), birth weight (P = .23), and axial length (P = .34), but had lower family income (P < .001) and lower parental education level (P < .001). After adjusting for all the above factors, exposure to SHS was associated with a thinner global p-RNFL by 4.4 µm (P < .001). Reduced p-RNFL was also associated with increased numbers of smokers in the family (ß = -3.40, P < .001) and increased quantity of SHS (ß = -0.22, P < .001). CONCLUSIONS: Exposure to SHS in children was associated with a thinner p-RNFL. A thinner p-RNFL may increase the risk of irreversible visual impairment in the future. Our results provide evidence to recommend that children avoid exposure to SHS.

Baseline 24-2 Central Visual Field Damage Is Predictive of Global Progressive Field Loss.

PURPOSE: Central visual field (VF) damage in glaucoma patients can significantly hinder daily activities. The present study investigates whether the presence of localized baseline damage to the central 10 degrees of the VF is predictive of faster global mean deviation (MD) progression. DESIGN: Prospective cohort study. METHODS: Eyes from the multicenter African Descent and Glaucoma Evaluation Study (ADAGES) with established glaucoma and VF loss and a minimum of 5 24-2 VFs were eligible. Baseline central 24-2 damage was defined as any of the 12 central-most points with total deviation (TD) values at P < 0.5% on 2 consecutive examinations. Progression was determined using trend-based and event-based criteria: (1) rates of MD change significantly faster than zero and (2) >-5 dB MD loss over the entire follow-up. RESULTS: A total of 827 eyes of 584 patients were studied. Mean rate of MD change of the entire sample was -0.15 dB/year (95% CI: -0.19 to -0.12, P < .001). Eyes with baseline central damage progressed faster than those without (difference: ßcentral = -0.07 dB/year, 95% CI: -0.11 to -0.01, P = .011) and were more likely to experience MD loss greater than 5 dB (hazard ratio = 3.0 [95% CI: 2.1-4.1, P < .001]). These differences remained significant after adjusting for confounders. CONCLUSION: The presence of central VF damage at baseline is significantly associated with more rapid global progression. Detection of central VF damage aids in stratification of high-risk patients who may need intensive surveillance and aggressive treatment.

Diagnostic utility of combined retinal ganglion cell count estimates in Japanese glaucoma patients.

PURPOSE: To assess the combined estimate of retinal ganglion cell (RGC) count developed by Medeiros et al. as a tool for diagnosis of glaucoma in Japanese patients. STUDY DESIGN: Cross-sectional study. METHODS: Thirty-one eyes of 19 healthy controls and 106 eyes of 70 glaucoma patients underwent standard automated perimetry (SAP) and three types of spectral domain optical coherence tomography (SD-OCT) imaging using the Cirrus, RTVue, and 3D-OCT instruments. RGC counts derived from SAP and SD-OCT data were estimated using the Harwerth model (SAPrgc and OCTrgc, respectively), from which the combined RGC count estimates (CRGC) were calculated using the formula developed by Medeiros et al. Receiver operating characteristic curve (ROC) analyses were conducted for mean deviation (MD), retinal nerve fiber layer thickness (RNFLT), and CRGC. RESULTS: The mean OCTrgc derived from the Cirrus, RTVue, and 3D-OCT instruments were 1150, 1245, and 1316 (× 1000 cells), respectively, for the control group and 463, 519, and 516 (× 1000 cells), respectively, for the patient group. SAPrgc of the controls' group was 1526 and the patients' group, 731 (× 1000 cells), and were consistently greater than OCTrgc in both groups (a generalized estimating equation model, p < 0.001). Partial area under the curve (pAUC) of MD was 0.178, and that of RNFLT and CRGC for the three OCT instruments were 0.185, 0.18, 0.189 and 0.196, 0.196, 0.197, respectively. CRGC had larger pAUC than MD, whereas there was no or marginal difference in pAUC between CRGC and cpRNFLT, irrespective of OCT device used or glaucoma severity. CONCLUSION: CRGC proved well suited to discriminate glaucoma patients from controls. However, its clinical utility did not seem to overwhelm isolated structural measures in the tested Japanese patients.

Racioethnic Differences in Human Posterior Scleral and Optic Nerve Stump Deformation.

Purpose: The purpose of this study was to quantify the biomechanical response of human posterior ocular tissues from donors of various racioethnic groups to better understand how differences in these properties may play a role in the racioethnic health disparities known to exist in glaucoma. Methods: Sequential digital image correlation (S-DIC) was used to measure the pressure-induced surface deformations of 23 normal human posterior poles from three racioethnic groups: African descent (AD), European descent (ED), and Hispanic ethnicity (HIS). Regional in-plane principal strains were compared across three zones: the optic nerve stump (ONS), the peripapillary (PP) sclera, and non-PP sclera. Results: The PP scleral tensile strains were found to be lower for ED eyes compared with AD and HIS eyes at 15 mm Hg (P = 0.024 and 0.039, respectively). The mean compressive strains were significantly higher for AD eyes compared with ED eyes at 15 mm Hg (P = 0.018). We also found that the relationship between tensile strain and pressure was significant for those of ED and HIS eyes (P < 0.001 and P = 0.004, respectively), whereas it was not significant for those of AD (P = 0.392). Conclusions: Our results suggest that, assuming glaucomatous nerve loss is caused by mechanical strains in the vicinity of the optic nerve head, the mechanism of increased glaucoma prevalence may be different in those of AD versus HIS. Our ONS strain analysis also suggested that it may be important to account for ONS geometry and material properties in future scleral biomechanical analysis.

24-2 Visual Fields Miss Central Defects Shown on 10-2 Tests in Glaucoma Suspects, Ocular Hypertensives, and Early Glaucoma.

PURPOSE: To investigate the prevalence of visual field defects in glaucomatous eyes, glaucoma suspects, and ocular hypertensives with 24-2 and 10-2 visual fields. DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Patients with or suspected glaucoma tested with 24-2 and 10-2. Patients were classified into 3 groups on the basis of the presence of glaucomatous optic neuropathy (GON) and 24-2 visual field abnormalities: early glaucoma (GON and abnormal visual field, mean deviation >-6 decibels [dB]), glaucoma suspects (GON and normal visual field), and ocular hypertensives (normal disc, normal visual field, and intraocular pressure >22 mmHg). For the classification of visual field abnormalities, 24-2 and 10-2 tests performed on the same visit were analyzed. MAIN OUTCOME MEASURES: Comparison of the prevalence of abnormal 24-2 versus 10-2 visual field results based on cluster criteria in each diagnostic group. RESULTS: A total of 775 eyes (497 patients) were evaluated. A total of 364 eyes had early glaucoma, 303 eyes were glaucoma suspects, and 108 eyes were ocular hypertensives. In the glaucoma group, 16 of the 26 eyes (61.5%) classified as normal based on cluster criteria on 24-2 tests were classified as abnormal on 10-2 visual fields. In eyes with suspected glaucoma, 79 of the 200 eyes (39.5%) classified as normal on the 24-2 test were classified as abnormal on 10-2 visual fields. In ocular hypertensive eyes, 28 of the 79 eyes (35.4%) classified as normal on the 24-2 were classified as abnormal on the 10-2. Patients of African descent were more likely to have an abnormal 10-2 result (67.3 vs. 56.8%, P = 0.009). CONCLUSIONS: Central visual field damage seen on the 10-2 test is often missed with the 24-2 strategy in all groups. This finding has implications for the diagnosis of glaucoma and classification of severity.

Myopic Maculopathy and Optic Disc Changes in Highly Myopic Young Asian Eyes and Impact on Visual Acuity.

PURPOSE: To determine the prevalence and risk factors of myopic maculopathy and specific optic disc and macular changes in highly myopic eyes of young Asian adults and their impact on visual acuity. DESIGN: Prospective cross-sectional study. METHODS: In total, 593 highly myopic (spherical equivalent refraction [SER] less than -6.00 diopters [D]) and 156 emmetropic (SER between -1.00 and +1.00 D) male participants from a population-based survey were included. All participants underwent standardized medical interviews, ophthalmic examination, and color fundus photographs. These photographs were graded systematically to determine the presence of optic disc and macular lesions. Myopic maculopathy was classified based on the International Classification of Myopic Maculopathy. RESULTS: The mean age was 21.1 ± 1.2 years. The mean SER for the highly myopic and emmetropic group was -8.87 ± 2.11 D and 0.40 ± 0.39 D, respectively (P < .001). Compared to emmetropic eyes, highly myopic eyes were significantly more likely to have optic disc tilt, peripapillary atrophy (PPA), posterior staphyloma, chorioretinal atrophy, and myopic maculopathy (all P < .001). The main findings included PPA (98.3%), disc tilt (22.0%), posterior staphyloma (32.0%), and chorioretinal atrophy (8.3%). Myopic maculopathy was present in 8.3% of highly myopic eyes and was associated with older age (odds ratio [OR] 1.66; 95% CI: 1.22, 2.26), reduced choroidal thickness (OR 0.99; 95% CI: 0.98, 0.99), and increased axial length (AL) (OR 1.52; 95% CI: 1.06, 2.19). The presence of disc tilt, posterior staphyloma, and chorioretinal atrophy were associated with reduced visual acuity. CONCLUSIONS: Our study showed that myopia-related changes of the optic disc and macula were common in highly myopic eyes even at a young age. The risk factors for myopic maculopathy include increased age, longer AL, and reduced choroidal thickness. Some of these changes were associated with reduced central visual function.

Glaucoma Structural and Functional Progression in American and Korean Cohorts.

PURPOSE: To compare the rate of glaucoma structural and functional progression in American and Korean cohorts. DESIGN: Retrospective longitudinal study. PARTICIPANTS: Three hundred thirteen eyes from 189 glaucoma and glaucoma suspects, followed up for an average of 38 months. METHODS: All subjects were examined semiannually with visual field (VF) testing and spectral-domain optical coherence tomography. All subjects had 5 or more reliable visits. MAIN OUTCOME MEASUREMENTS: The rates of change of retinal nerve fiber layer (RNFL) thickness, cup-to-disc (C/D) ratios, and VF mean deviation (MD) were compared between the cohorts. Variables affecting the rate of change for each parameter were determined, including ethnicity, refraction, baseline age and disease severity, disease subtype (high- vs. normal-tension glaucoma), clinical diagnosis (glaucoma vs. glaucoma suspect), and the interactions between variables. RESULTS: The Korean cohort predominantly demonstrated normal-tension glaucoma, whereas the American cohort predominantly demonstrated high-tension glaucoma. Cohorts had similar VF parameters at baseline, but the Korean eyes had significantly thicker mean RNFL and larger cups. Korean glaucoma eyes showed a faster thinning of mean RNFL (mean, -0.71 µm/year vs. -0.24 µm/year; P < 0.01). There were no detectable differences in the rate of change between the glaucoma cohorts for C/D ratios and VF MD and for all parameters in glaucoma suspect eyes. Different combinations of the tested variables significantly impacted the rate of change. CONCLUSIONS: Ethnicity, baseline disease severity, disease subtype, and clinical diagnosis should be considered when comparing glaucoma progression studies.

Rate and Pattern of Rim Area Loss in Healthy and Progressing Glaucoma Eyes.

PURPOSE: To characterize the rate and pattern of age-related and glaucomatous neuroretinal rim area changes in subjects of African and European descent. DESIGN: Prospective longitudinal study. PARTICIPANTS: Two hundred ninety-six eyes of 157 healthy subjects (88 patients of African descent and 69 of European descent) and 73 progressing glaucoma eyes of 67 subjects (24 patients of African descent and 43 of European descent) from the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study were included. METHODS: Global and sectoral rim areas were measured using confocal laser scanning ophthalmoscopy. Masked stereophotograph review determined progression of glaucomatous optic disc damage. The rates of absolute rim area loss and percentage rim area loss in healthy and progressing glaucomatous eyes were compared using multivariate, nested, mixed-effects models. MAIN OUTCOME MEASURES: Rate of rim area loss over time. RESULTS: The median follow-up time was 5.0 years (interquartile range, 2.0-7.4 years) for healthy eyes and 8.3 years (interquartile range, 7.5-9.9 years) for progressing glaucoma eyes. The mean rate of global rim area loss was significantly faster in progressing glaucomatous eyes compared with healthy eyes for both rim area loss (-10.2×10(-3) vs. -2.8×10(-3) mm(2)/year, respectively; P < 0.001) and percentage rim area loss (-1.1% vs. -0.2%/year, respectively; P < 0.001), but considerable overlap existed between the 2 groups. Sixty-three percent of progressing glaucoma eyes had a rate of change faster than the fifth quantile of healthy eyes. For both healthy and progressing eyes, the pattern of rim area loss and percentage rim area loss were similar, tending to be fastest in the superior temporal and inferior temporal sectors. The rate of change was similar in progressing eyes of patients of African or European descent. CONCLUSIONS: Compared with healthy eyes, the mean rate of global rim area loss was 3.7 times faster and the mean rate of global percentage rim area loss was 5.4 times faster in progressing glaucoma eyes. A reference database of healthy eyes can be used to help clinicians distinguish age-related rim area loss from rim area loss resulting from glaucoma.

The African Descent and Glaucoma Evaluation Study (ADAGES): predictors of visual field damage in glaucoma suspects.

PURPOSE: To evaluate racial differences in the development of visual field (VF) damage in glaucoma suspects. DESIGN: Prospective, observational cohort study. METHODS: Six hundred thirty-six eyes from 357 glaucoma suspects with normal VF at baseline were included from the multicenter African Descent and Glaucoma Evaluation Study (ADAGES). Racial differences in the development of VF damage were examined using multivariable Cox proportional hazard models. RESULTS: Thirty one of 122 African-descent participants (25.4%) and 47 of 235 European-descent participants (20.0%) developed VF damage (P = .078). In multivariable analysis, worse baseline VF mean deviation, higher mean arterial pressure during follow-up, and a race ∗ mean intraocular pressure (IOP) interaction term were significantly associated with the development of VF damage, suggesting that racial differences in the risk of VF damage varied by IOP. At higher mean IOP levels, race was predictive of the development of VF damage even after adjusting for potentially confounding factors. At mean IOPs during follow-up of 22, 24, and 26 mm Hg, multivariable hazard ratios (95% confidence intervals) for the development of VF damage in African-descent compared to European-descent subjects were 2.03 (1.15-3.57), 2.71 (1.39-5.29), and 3.61 (1.61-8.08), respectively. However, at lower mean IOP levels (below 22 mm Hg) during follow-up, African descent was not predictive of the development of VF damage. CONCLUSION: In this cohort of glaucoma suspects with similar access to treatment, multivariate analysis revealed that at higher mean IOP during follow-up, individuals of African descent were more likely to develop VF damage than individuals of European descent.

Meta-analysis of Genome-Wide Association Studies Identifies Novel Loci Associated With Optic Disc Morphology.

Primary open-angle glaucoma is the most common optic neuropathy and an important cause of irreversible blindness worldwide. The optic nerve head or optic disc is divided in two parts: a central cup (without nerve fibers) surrounded by the neuroretinal rim (containing axons of the retinal ganglion cells). The International Glaucoma Genetics Consortium conducted a meta-analysis of genome-wide association studies consisting of 17,248 individuals of European ancestry and 6,841 individuals of Asian ancestry. The outcomes of the genome-wide association studies were disc area and cup area. These specific measurements describe optic nerve morphology in another way than the vertical cup-disc ratio, which is a clinically used measurement, and may shed light on new glaucoma mechanisms. We identified 10 new loci associated with disc area (CDC42BPA, F5, DIRC3, RARB, ABI3BP, DCAF4L2, ELP4, TMTC2, NR2F2, and HORMAD2) and another 10 new loci associated with cup area (DHRS3, TRIB2, EFEMP1, FLNB, FAM101, DDHD1, ASB7, KPNB1, BCAS3, and TRIOBP). The new genes participate in a number of pathways and future work is likely to identify more functions related to the pathogenesis of glaucoma.

Normative Databases for Imaging Instrumentation.

PURPOSE: To describe the process by which imaging devices undergo reference database development and regulatory clearance. The limitations and potential improvements of reference (normative) data sets for ophthalmic imaging devices will be discussed. METHOD: A symposium was held in July 2013 in which a series of speakers discussed issues related to the development of reference databases for imaging devices. RESULTS: Automated imaging has become widely accepted and used in glaucoma management. The ability of such instruments to discriminate healthy from glaucomatous optic nerves, and to detect glaucomatous progression over time is limited by the quality of reference databases associated with the available commercial devices. In the absence of standardized rules governing the development of reference databases, each manufacturer's database differs in size, eligibility criteria, and ethnic make-up, among other key features. CONCLUSIONS: The process for development of imaging reference databases may be improved by standardizing eligibility requirements and data collection protocols. Such standardization may also improve the degree to which results may be compared between commercial instruments.

Optic nerve gray crescent can confound neuroretinal rim interpretation: review of the literature.

The optic nerve gray crescent can be of clinical significance if unrecognized during assessment for glaucoma. It has a characteristic appearance of a slate gray area of pigmentation within the disc margins and commonly appears along the inferotemporal or temporal neuroretinal rim areas. This type of disc rim pigmentation can create the impression of neuroretinal rim thinning, and thus lead to the misdiagnosis of glaucoma or "glaucoma suspect" with attendant implications for overtreatment or unnecessary close monitoring of such patients. The gray crescent is more common in African Americans than whites (prevalence rate 27% vs 7%) and is bilateral in at least 58% of cases. It has been reported in association with Kjer optic atrophy type 1. Suggested causes of the gray crescent include an accumulation of melanocytes, or retinal pigment epithelium cells partially located in the optic nerve head region if Bruch's membrane extends internal to the peripapillary scleral ring. Other causes of pigmentation that may resemble gray crescent are conus pigmentosus and variations of peripapillary atrophy. When a gray crescent is present, clinicians should endeavour to identify the true anatomical disc margins via the scleral lip and, if necessary, evaluate the patient further with imaging and visual field studies.

Can an inexperienced observer accurately plot disc contours using Heidelberg retinal Tomograph?

OBJECTIVE: To examine the reliability of inexperienced observers in plotting optic disc contours on Heidelberg retinal tomography images before and after training. DESIGN: Observational study. PARTICIPANTS: One hundred eyes that were randomly selected from the Singapore Indian Eye Study. METHODS: Both eyes of subjects were imaged with Heidelberg Retina Tomograph 3 (HRT-3; Heidelberg Engineering, Heidelberg, Germany). Optic disc contours were plotted on the same images by 2 new observers on 2 separate occasions, before and after 2-hour standardized training on the skills and tools available to accurately identify and delineate optic disc contours. These plottings were compared with an experienced, trained glaucoma expert (gold standard). Agreement and variability were analyzed by interclass correlation tests and Bland-Altman plots. RESULTS: A total of 182 images (18 excluded because of poor quality) from 89 Indian subjects were included. The mean age was 53.27 ± 7.25 years and 54.8% were male. There was moderate-to-high agreement between pretraining (both new observers) and experienced observer's results (interclass correlation values range, 0.76-0.99). The interclass correlation improved for all the HRT-3 parameters after the 2 new observers were adequately trained. Comparing the interclass correlation values before and after training, the differences for mean retinal nerve fibre layer thickness for Observer 1 and all the HRT-3 parameters for Observer 2 were statistically significant. CONCLUSIONS: This study shows that it is easy to train a new inexperienced observer to plot optic disc contours on HRT images, which translates into improved and acceptable interobserver variability and agreement.

Validity of a new optic disc grading software for use in clinical and epidemiological research.

BACKGROUND: To determine the reliability and agreement of a new optic disc grading software program for use in clinical, epidemiological research. DESIGN: Reliability and agreement study. SAMPLES: 328 monoscopic and 85 stereoscopic optic disc images. METHODS: Optic disc parameters were measured using a new optic disc grading software (Singapore Optic Disc Assessment) that is based on polynomial curve-fitting algorithm. Two graders independently graded 328 monoscopic images to determine intergrader reliability. One grader regraded the images after 1 month to determine intragrader reliability. In addition, 85 stereo optic disc images were separately selected, and vertical cup-to-disc ratios were measured using both the new software and standardized Wisconsin manual stereo-grading method by the same grader 1 month apart. Intraclass correlation coefficient (ICC) and Bland-Altman plot analyses were performed. MAIN OUTCOME MEASURES: Optic disc parameters. RESULTS: The intragrader and intergrader reliability for optic disc measurements using Singapore Optic Disc Assessment was high (ICC ranging from 0.82 to 0.94). The mean differences (95% limits of agreement) for intergrader vertical cup-to-disc ratio measurements were 0.00 (-0.12 to 0.13) and 0.03 (-0.15 to 0.09), respectively. The vertical cup-to-disc ratio agreement between the software and Wisconsin grading method was extremely close (ICC = 0.94). The mean difference (95% limits of agreement) of vertical cup-to-disc ratio measurement between the two methods was 0.03 (-0.09 to 0.16). CONCLUSIONS: Intragrader and intergrader reliability using Singapore Optic Disc Assessment was excellent. This software was highly comparable with standardized stereo-grading method. Singapore Optic Disc Assessment is useful for grading digital optic disc images in clinical, population-based studies.

Branch retinal vein occlusion and optic nerve head topographic parameters: the Singapore Indian eye study.

AIM: To examine the association between branch retinal vein occlusion (BRVO) and quantitative optic disc topographic parameters. METHODS: The Singapore Indian Eye Study (SINDI) is a population-based study of 3400 Singapore Indians aged 40+ years. BRVO was defined and graded from retinal photographs. Optic disc parameters were quantified using the Heidelberg Retinal Tomograph III (HRT III). Associations were evaluated for individual eyes; the generalised estimating equation was used to account for correlation between fellow eyes. RESULTS: 6173 eyes (comprising 19 BRVO) had gradable retinal photographs and HRT images. After controlling for age, gender, and systemic (hypertension, diabetes, myocardial infarction) and ocular factors (intraocular pressure, glaucoma, central corneal thickness, axial length, previous laser photocoagulation), BRVO was associated with larger optic disc area (OR highest vs lowest tertile, 4.70; 95% CI 1.00 to 22.01; p=0.036), larger cup area (OR highest vs lowest tertile, 4.80; 95% CI 1.03 to 22.35; p=0.029) and larger cup-disc area ratio (OR highest vs lowest tertile, 4.44; 95% CI 0.95 to 20.66; p=0.037). After excluding glaucoma eyes, BRVO remained significantly associated with these parameters (p=0.027, p=0.018, p=0.024, respectively). CONCLUSIONS: Quantitative optic disc parameters (optic cup and disc area) are associated with BRVO, even in non-glaucomatous eyes. Optic nerve head morphology may play a role in BRVO pathogenesis.

Quantification of retinal nerve fiber layer thickness after unilateral acute primary angle closure in Asian Indian eyes.

PURPOSE: To determine retinal nerve fiber layer thickness (RNFLT) using Spectral optical coherence tomography/scanning laser ophthalmoscope (Spectral OCT/SLO) in Asian Indian eyes after single, unilateral attack of acute primary angle closure (APAC). METHODS: Thirty-two patients with unilateral attack of APAC with normal optic disc and normal visual field, unaffected fellow eyes, and 35 age-matched normal control eyes were enrolled for the study. Six weeks after the remission of acute attack, peripapillary average, quadrant, and clock-hour RNFLT were compared between 3 groups using Spectral OCT/SLO. RESULTS: APAC patients had mean IOP of 51.3±13.3 mm Hg (range, 40-74) at the time of presentation with acute attack in the affected eye and 14.9±2.9 mm Hg at 6 weeks after resolution of APAC. Duration of symptoms of acute attack was 35.9±23.8 hours. Significant differences were found between RNFLT in APAC and fellow eyes for most the parameters except for 1, 4, 6, and 7-o'clock-hour sector. Most of the RNFLT parameters showed statistically significant difference between APAC and normal control eyes except for temporal quadrant, 6, 7-o'clock-hour sectors. Statistically significant differences were found between RNFLT in unaffected fellow and normal control eyes for most of the parameters except for 6, 7, 11 o'clock-hour sectors. CONCLUSIONS: RNFLT was found to be significantly thinner in APAC and unaffected fellow eyes when compared with normal age-matched controls. Hence, patients with APAC should be monitored carefully to determine its long-term effects on optic disc, RNFLT, and visual fields. Longitudinal studies can determine whether the RNFLT measurements remained stable or showed progression in these patients.

Comparison of glaucoma diagnoses using Stratus and Cirrus optical coherence tomography in different glaucoma types in a Chinese population.

PURPOSE: To compare the glaucoma diagnostic power of Stratus and Cirrus optical coherence tomographies (OCTs) in a Taiwan Chinese population with different glaucoma types. PATIENTS AND METHODS: One eye each was chosen from 21 ocular hypertension (OH) patients, 27 glaucoma-suspect (GS) patients, 35 primary open-angle glaucoma (POAG) patients, 26 primary angle-closure glaucoma (PACG) patients, and 52 normal subjects. Early glaucoma (EG) was identified among glaucomatous eyes on the basis of the visual field severity (better than -9 dB). All participants were imaged using 2 OCT units at the same visit. The area under the receiver operator characteristic (AROC) curve was used to differentiate normal eyes from OH, GS, POAG, PACG, and EG eyes, and the sensitivity and specificity of each parameter from internal normative classifications were analyzed. RESULTS: For normal versus OH eyes, the best AROC value was the average thickness (Stratus, 0.693; Cirrus, 0.697). For normal versus GS eyes, the best AROC value was the average thickness (Stratus, 0.807; Cirrus, 0.776). For normal versus POAG eyes, the best AROC value was the average thickness (Stratus, 0.943; Cirrus, 0.930). For normal versus PACG eyes, the best AROC value was the 5-o'clock hour (Stratus, 0.830; Cirrus, 0.817). For normal versus EG eyes, the best AROC value was the average thickness with Stratus (0.868) and the 5-o'clock hour with Cirrus (0.876). All sensitivities in the 5 groups were fair on the basis of the internal normal classification database of both OCTs. CONCLUSIONS: Cirrus and Stratus OCTs showed equal diagnostic power in EG, OH, GS, POAG, and PACG eyes in a Taiwan Chinese population. The utility of the current internal databases of both OCT units for the Chinese population is an interesting issue that needs to be addressed in the future.

Frequency and associated factors of structural progression of open-angle glaucoma in the Beijing Eye Study.

BACKGROUND: To examine factors associated with progression of open-angle glaucoma in a population-based setting. METHODS: The population-based Beijing Eye Study, which included 4439 subjects with an age of 40+ years in the year 2001, was repeated in 2006. Optic disc photographs of the baseline examination versus follow-up examination were compared. RESULTS: Out of 111 open-angle glaucoma patients examined in 2001, 77 (69%) subjects participated in the follow-up examination and 16 (21%) eyes showed glaucoma progression. Glaucoma progression was associated with smaller rim area (p=0.001), larger ß zone (p=0.037), higher frequency of ß zone increase during follow-up (p=0.01), higher prevalence of disc haemorrhages (p=0.01) and higher single intraocular pressure (p=0.04). In multiple regression analysis, only smaller rim area remained significantly associated with glaucoma progression. Glaucoma progression was not associated with optic disc size (p=0.70), mean blood pressure (p=0.43), ocular perfusion pressure (p=0.96), retinal vessel diameter and retinal microvascular abnormalities (all p>0.10), prevalence of diabetes mellitus (p=0.75) and arterial hypertension (p=0.26), prevalence of dyslipidaemia (p=0.28), refractive error (p=0.69), and central corneal thickness (p=0.97). CONCLUSIONS: In a population-based setting in adult Chinese, factors showing an association with open-angle glaucoma progression were an advanced stage of the disease (ie, small rim), presence of disc haemorrhages, larger area of ß zone and higher frequency of ß zone increase, and higher intraocular pressure. Glaucoma progression was not significantly associated with optic disc size, central corneal thickness, retinal vessel diameter and retinal microvascular abnormalities, and systemic diseases such as diabetes mellitus and arterial hypertension.