The normal optic nerve variations in an optometric population:Possible ocular and systemic influences (original) (raw)
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Racial Differences in the Association between Optic Disc Topography and Early Glaucoma
Investigative Ophthalmology & Visual Science, 2003
PURPOSE. To determine the structural characteristics of the optic disc that are associated with early glaucoma in African Americans and whites and whether these characteristics differ between the races. METHODS. Parameters of optic disc topography from 260 African American eyes and 193 white eyes were included in the analysis. One hundred forty-four eyes of African Americans and 109 eyes of normal white subjects were used as a control group. Logistic regression was used to calculate the association between early glaucoma, defined by the visual field, and cup, rim, and disc margin confocal scanning laser ophthalmoscopic (CSLO) parameters, using odds ratios at binary cut points. The cup, rim, and disc margin parameters identified as being independently associated with glaucoma in these reduced models were then included in a single multivariate model. Optic disc area was included in the analysis at each level of the model. This approach was used for the total study group and then separately for the African American and white groups. RESULTS. When accounting for difference in optic disc area, rim area had the highest independent association with early glaucoma in both groups, but this association was lower in African Americans (odds ratio [95% confidence interval]: 1.63 [1.12-2.36]) than in whites (odds ratio: 4.74 [2.18-10.28]). Additional independently associated parameters included cup shape, maximum elevation along the contour line, and the temporal-to-inferior contour line modulation ratio in whites and cup shape and the temporal-to-superior contour line modulation ratio in African Americans. CONCLUSIONS. Structural characteristics of the optic disc that are best associated with early glaucoma included cup shape and rim area in both groups, but with a less pronounced association in African Americans. In addition, several other racespecific parameters that were independently associated with early glaucoma differed significantly between African Americans and whites. These race-specific differences were independent from the effect of optic disc area.
Bioscientia Medicina : Journal of Biomedicine and Translational Research
Background: Glaucoma poses a public health problem because it is the second leading cause of blindness after cataracts. A thinner central corneal thickness (CCT) is also a contributor to the development of primary open-angle glaucoma (POAG). Lamina cribrosa (LC) is a structure of the optic nerve head (ONH). LC structural changes such as thinning, posterior displacement, and connective tissue deficiency are associated with the mechanism of retinal nerve fiber layer (RNFL) thickness damage, leading to glaucomatous optic neuropathy. Methods: Cross-sectional analytic observational study. A total of 36 eyes from 36 research subjects participated in this study. Data analysis was carried out using SPSS version 25. Then, univariate and bivariate analyzes were carried out to see the difference in CCT and LC thicknesses. Results: The average CCT in ethnic Indians is 514.33 ± 14,142 μm and in ethnic Malays, 542.06 ± 17,234 μm. In this study, there were differences in the average CCT in Indian ...
British Journal of Ophthalmology, 2009
Aim To examine ethnic differences in optic nerve head and retinal nerve fibre layer (RNFL) parameters between European Caucasian and East Asian children aged 6e12 years. Methods Of 4118 children examined in the Sydney Childhood Eye Study (incorporating the Sydney Myopia Study) from 34 randomly selected primary and 21 secondary schools during 2003e5, 3382 (82.1%) had optical coherence tomography (OCT; Zeiss Stratus) data suitable for analysis. 'Fast' optic disc and RNFL scans were used. Ethnicity was defined only when both parents were of the same ethnicity. Results East Asian children tended to have a lower birth weight, were shorter with a smaller body mass index and were less hyperopic than European Caucasian children of the same age. After adjusting for age, gender, axial length, birth weight and optic-disc area, East Asian children had similar mean vertical disc diameters to European Caucasians (p¼0.38, p¼0.64 for 6e12 years, respectively) but 30e43% larger mean vertical cup diameters (p<0.0001 for both), resulting in larger mean cup/disc ratios (p<0.0001 for both). Compared with European Caucasians (101.95 mm and 104.57 mm, respectively), East Asian children had thicker mean average RNFL (105.45 mm and 107.92 mm, respectively; p¼0.0006 and 0.0001) and thicker non-nasal RNFL quadrants in both ages. Conclusions Compared with European Caucasian children, East Asian children generally had thicker RNFL and larger mean cup/disc ratios. Given the relatively lower prevalence of open angle glaucoma in Asians, these anatomical variations could contribute to better understanding of apparent racial differences in glaucoma susceptibility.
African Descent and Glaucoma Evaluation Study (ADAGES)
Archives of Ophthalmology, 2010
To define differences in optic disc, retinal nerve fiber layer, and macular structure between healthy participants of African (AD) and European descent (ED) using quantitative imaging techniques in the African Descent and Glaucoma Evaluation Study (ADAGES). Methods: Reliable images were obtained using stereoscopic photography, confocal scanning laser ophthalmoscopy (Heidelberg retina tomography [HRT]), and optical coherence tomography (OCT) for 648 healthy subjects in ADAGES. Findings were compared and adjusted for age, optic disc area, and reference plane height where appropriate. Results: The AD participants had significantly greater optic disc area on HRT (2.06 mm 2 ; P Ͻ.001) and OCT (2.47 mm 2 ; PϽ.001) and a deeper HRT cup depth than the ED group (PϽ .001). Retinal nerve fiber layer thickness was greater in the AD group except within the temporal region, where it was significantly thinner. Central macular thickness and volume were less in the AD group. Conclusions: Most of the variations in optic nerve morphologic characteristics between the AD and ED groups are due to differences in disc area. However, differences remain in HRT cup depth, OCT macular thickness and volume, and OCT retinal nerve fiber layer thickness independent of these variables. These differences should be considered in the determination of disease status.
Methods and design of the Chennai Glaucoma Study
PURPOSE: To describe the methodology of a population-based study to estimate the prevalence of glaucoma in a rural and urban South Indian population and to study the genetics of glaucoma in this population.METHODS: A sample size of 4758 each for rural and urban populations in the Indian state of Tamil Nadu was calculated. Eligible subjects aged 40 years and above from the rural study area covering 32 contiguous villages and the urban area comprising five random clusters in Chennai city are enumerated. Demographic data are collected in the field. A detailed clinical examination, including glaucoma diagnostic procedures, is conducted at the examination centre. Pedigree ascertainment and genetic studies are performed for subjects with occludable angles or glaucoma. Data are recorded in a computerised database.CONCLUSIONS: This study is expected to result in an estimation of the prevalence and a better understanding of the genetics of glaucoma in this region.
Ophthalmology, 2008
To estimate the prevalence and risk factors of primary open-angle glaucoma (POAG) in an urban population and compare the same with that of our published rural population data in southern India. Design: Population-based cross-sectional study. Participants: Four thousand eight hundred subjects 40 years or older were selected using a multistage random cluster sampling procedure in Chennai city. Intervention: Three thousand eight hundred fifty (80.2%) subjects underwent a complete ophthalmic examination, including applanation tonometry, gonioscopy, pachymetry, optic disc photography, and automated perimetry. Main Outcome Measures: Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology Classification. Results: The distribution of intraocular pressure (IOP) and vertical cup-to-disc ratio (VCDR) was obtained from the right eye of the 2532 subjects with normal suprathreshold visual fields. Mean IOP was 16.17 Ϯ3.74 mmHg (97.5th and 99.5th percentiles, 24 mmHg and 30 mmHg). The mean VCDR was 0.43Ϯ0.17 (97.5th and 99.5th percentiles, 0.7 and 0.8). One hundred thirty-five (64 men, 71 women) subjects had POAG (3.51%; 95% confidence interval [CI], 3.04-4.0). Primary open-angle glaucoma subjects (58.4Ϯ11.3 years) were older (PϽ0.0001) than the study population (54.8Ϯ10.6 years). One hundred twenty-seven (94%) subjects were diagnosed to have POAG for the first time. Two subjects (1.5%) were bilaterally blind, and 3 (3.3%) were unilaterally blind due to POAG. The urban population prevalence was more than that of the rural population (1.62%; 95% CI, 1.4%-1.8%; PϽ0.0001). In both populations, increasing IOP (per millimeter of mercury) and older age were associated with the disease. There was no association with gender, myopia, systemic hypertension, diabetes, or central corneal thickness. Conclusions: The prevalence of POAG in a Ն40-year-old south Indian urban population was 3.51%, higher than that of the rural population. The prevalence increased with age, and Ͼ90% were not aware of the disease.
Proceedings of the 104th Indian Science Congress, 2017
Glaucoma is a group of eye diseases causing optic nerve damage leading to progressive, irreversible vision loss.The exact causes of optic nerve damage from glaucoma are not fully understood, but it involves mechanical compression and/or decreased blood flow of the optic nerve. The most common type is open-angle glaucoma and angle- closure glaucoma, while the less common forms being the secondary glaucomas. It has been seen earlier that this disease may be linked with other physiological conditions like eye power (hypermetropia / myopia), blood sugar levels, blood pressure etc. and non-physiological factors like age, gender and family history. This review tries to further elucidate on these links and their biological significances with surveys (in both rural and urban areas), followed by statistical analysis (Chi-squared Tests).The results illustrate that high Ocular Perfusion Pressures and prolonged hyperglycemia are strong risk factors for glaucoma (chances of glaucoma are heightened with diabetic retinopathy), myopia or nearsightedness is closely related to glaucoma and glaucoma may or may not have a sex bias. Our studies have further opened up avenues towards new approaches for treating glaucoma, like, female sex hormones might be used as a therapeutic potential or treatment on a genetic level.
Racial Differences in Optic Disc Topography
Archives of Ophthalmology, 2004
To examine racial differences in optic disc topography among ocular hypertensive participants in the Ocular Hypertension Treatment Study. Methods: Four hundred thirty-nine participants from 7 Ocular Hypertension Treatment Study centers who had good-quality baseline images obtained using a quantitative 3-dimensional confocal scanning laser ophthalmoscope, the Heidelberg Retina Tomograph (Heidelberg Engineering, Dossenheim, Germany), were included in this study. The first 10°-or 15°-field of view mean topographic image acquired was included in all analyses. Differences in Heidelberg Retina Tomograph topographic optic disc parameter measurements by self-identified race were assessed using a mixed-effects linear model to control for confounders and for the use of both eyes in the model. Results: By self-attribution, 74 (17%) of the 439 participants were of African origin, 329 (75%) were white, 24 (5%) were Hispanic, and 12 (3%) were Native American, Native Alaskan, Asian, Pacific Islander, or unknown. The African American participants had statistically significantly (PϽ.001) larger mean (SD) optic disc areas than the other participants, 2.17 (0.41) mm 2 vs 1.87 (0.38) mm, 2 respectively. African American participants had a larger cup area, cup volume, cup depth, neuroretinal rim area, rim volume, and smaller rim-optic disc area ratios than the other participants. No difference between African American and the other participants was found for cup shape and retinal nerve fiber layer thickness. After controlling for optic disc area, none of the differences between African American and the other participants found in the univariate analysis remained statistically significant (PϾ.10). Conclusions: This study demonstrated in a large cohort of subjects with ocular hypertension, that African Americans have significantly larger optic discs, optic cups, neuroretinal rims, and cup-disc ratios than other racial groups. Furthermore, this study found that differences in topographic optic disc parameters between African Americans with ocular hypertension and other racial groups are largely explained by the larger optic disc area in the African Americans. These results highlight the need to consider race and optic disc size when evaluating the appearance of the optic disc in glaucoma.
Normative Data of Optic Nerve Head in Nepalese Population by Confocal Scanning Laser Ophthalmoscopy
Purpose: The present study had an aim to ascertain normative data of Optic Nerve Head parameters by using Confocal Scanning Laser Ophthalmoscopy. These normal data can be used as baseline reading for future references; can be used for comparison with special cases like with those having high myopia, glaucoma and other pathologies. Keywords: Optic Nerve Head; Confocal Scanning Laser Ophthalmoscopy; HRT; Glaucoma Methods: The present study design was a cross-sectional descriptive study. Normal subjects who attended the eye clinic of B.P. Koi- rala Lions Center for Ophthalmic Studies, Institute of Medicine, Tribhuvan University Teaching Hospital, Kathmandu were recruited in the present study. All subjects completed an ophthalmological examination that included refraction, best corrected visual acuity, slit-lamp biomicroscopy, fundoscopy, and standard white on white automated perimetry (Humphrey 24-2). Participants were then imaged with HRT II, with the scanner’s focus being adjusted according to the patient’s refraction and to obtain the best image. Results: Fifty normal participants (100 eyes) were included in the study. There were 28 female (56%) and 22 males (44%). The mean ± SD values of age, refractive error (SE) and IOP were 21.38 ± 3.849 years, -0.05 ± 0.174 D and 16.64 ± 2.285 mmHg respec- tively. Average CDR was 0.187 ± 0.010; mean disc area was 2.777 ± 0.641 mm2; mean cup area was 0.55 ± 0.356 mm2; mean cup depth was 0.205 ± 0.798 mm; mean RNFL thickness was 0.292 ± 0.061 mm. Conclusion: All pathologies are due to deviation of normal anatomy and physiology. Hence, establishing normative data of optic nerve head worth a lot in glaucoma diagnosis and other optic nerve head pathology screening. HRT can detect optic disc