Risk factors for primary open-angle glaucoma in a Burmese population: the Meiktila Eye Study

PURPOSE: To report the risk factors associated with primary open-angle glaucoma (POAG) in the Burmese population. METHODS: The Meiktila Eye study, a population-based cross-sectional study, included inhabitants 40 years of age and over from villages in the Meiktila District. Of 2481 eligible participants identified, 2076 participated in the study and sufficient examination data to diagnose glaucoma in at least one eye was obtained in 1997 participants. The ophthalmic examination included slit-lamp examination, tonometry, gonioscopy and dilated stereoscopic fundus examination. Definitions adhered to the International Society for Geographic and Epidemiological Ophthalmology's recommendations. Univariate and multivariate analyses of potential risk factors were performed. RESULTS: The overall prevalence of POAG was 2.0% (95% CI 0.9-3.1). In the univariate analysis, increasing age (P = 0.024), spherical equivalent (P = 0.01), axial length (P = 0.023) and intraocular pressure (IOP; P < 0.001) were significantly associated with POAG. And in the multivariate analysis, myopia <0.5 D (P = 0.049), increasing age and IOP (P < 0.001) were significant risk factors for POAG. CONCLUSION: POAG in this Burmese population was associated with increasing age, axial myopia and IOP.     

Ocular biometry in occludable angles and angle closure glaucoma: a population based survey

Aim: To compare ocular biometric values in a population based sample of eyes with occludable angles, angle closure glaucoma, and normal subjects. METHOD: 2850 subjects from a population based glaucoma prevalence study underwent complete ocular examination including indentation gonioscopy. Ocular biometry was performed in all subjects classified to have occludable angles (n = 143); angle closure glaucoma (n = 22), and a random subgroup of 419 normal subjects. Ocular biometry readings between the groups were compared and statistically analysed using "t," "z," and Mann-Whitney U tests. RESULTS: The mean age among subjects with occludable angles (54.43 (SD 9.53) years) and angle closure glaucoma (57.45 (8.5) years) was significantly higher (p<0.001) than normal subjects (49.95 (9.95) years). Axial length was shorter (p<0.001) in the occludable angle group (22.07 (0.69) mm) compared to the normal group (22.76 (0.78) mm). Anterior chamber depth (ACD) was shallower (p<0.001) among subjects with occludable angles (2.53 (0.26) mm) than normal subjects (3.00 (0.30) mm). Lens thickness (LT) was greater (p<0.001) in people with occludable angles (4.40 (0.53) mm) compared to normal subjects (4.31 (0.31) mm). No significant difference was noted in axial length, ACD (p = 0.451), and LT (p = 0.302) between angle closure glaucoma and occludable eyes. CONCLUSION: South Indian eyes with angle closure glaucoma and occludable angles seem to have significantly shorter axial lengths, shallower anterior chambers and greater lens thickness compared to the normal group.     

Prevalence of glaucoma in rural Myanmar: the Meiktila Eye Study

AIM: To determine the prevalence of glaucoma in the Meiktila district of central, rural Myanmar. METHODS: A cross-sectional, population-based survey of inhabitants > or =40 years of age from villages in Meiktila district, Myanmar, was performed; 2481 eligible participants were identified and 2076 participated in the study. The ophthalmic examination included Snellen visual acuity, slit-lamp examination, tonometry, gonioscopy, dilated stereoscopic fundus examination and full-threshold perimetry. Glaucoma was classified into clinical subtypes and categorised into three levels according to diagnostic evidence. RESULTS: Glaucoma was diagnosed in 1997 (80.5%) participants. The prevalence of glaucoma of any category in at least one eye was 4.9% (95% CI 4.1 to 5.7; n = 101). The overall prevalence of primary angle-closure glaucoma (PACG) was 2.5% (95% CI 1.5 to 3.5) and of primary open-angle glaucoma (POAG) was 2.0% (95% CI 0.9 to 3.1). PACG accounted for 84% of all blindness due to glaucoma, with the majority due to acute angle-closure glaucoma (AACG). CONCLUSION: The prevalence of glaucoma in the population aged > or =40 years in rural, central Myanmar was 4.9%. The ratio of PACG to POAG was approximately 1.25:1. PACG has a high visual morbidity and AACG is visually devastating in this community. Screening programmes should be directed at PACG, and further study of the underlying mechanisms of PACG is needed in this population.     

Gonioscopy in adult Chinese: the Liwan Eye Study

PURPOSE: To assess gonioscopic characteristics of the drainage angle in adult Chinese in an urban area of southern China. METHODS: Clustered random sampling was used to select adults aged 50 years and older in Liwan District, Guangzhou. Gonioscopy was performed on all the subjects. The geometric angle width was graded in the superior and inferior quadrants, according to the Spaeth system. In addition, apparent and true iris insertion was classified in four quadrants with static and dynamic gonioscopy. The peripheral iris profile was described as steep, regular, concave, and plateau. Data are presented for all phakic right eyes. Secondary or iatrogenic cases were excluded in the analysis of peripheral anterior synechiae (PAS). RESULTS: Among 1405 participants in the study, data from 1330 (95%) right eyes were available for analysis. Iridotrabecular angles (ITA) < or =20 degrees were present in 36.9% (95% CI: 34.3%-40.0%) of eyes superiorly and in 27.9% (95% CI: 25.5%-30.4%) inferiorly. Narrower ITAs were more common in the older people (sex-adjusted odds ratio [OR] = 1.1 per year of life; P < 0.001) and the women (age-adjusted OR = 2.5, P < 0.001). Apparent iris insertion of grade A or B (with pigmented trabecular meshwork not visible) by quadrant was observed in 27.2% superiorly, 12.0% nasally, 7.7% inferiorly, and 14.2% temporally. Narrow angles (in which pigmented trabecular meshwork was not visible in three or more quadrants) were identified in 11.0% (95% CI: 9.3%-12.7%) of right eyes. Overall, 33.3% of eyes had a steep iris profile, 54.2% were normal, 2.7% were concave, and 10.1% were graded plateau. PAS were seen in 30 of 146 (20.5%) eyes with narrow angles and in 7 (0.6%) of 1184 eyes with angles that did not meet criteria for narrow angles. PAS were more likely with narrower angles, with 0%, 0.3%, and 1.9% of eyes with a mean ITA of 40 degrees, 30 degrees, and 20 degrees, respectively, having PAS as opposed to 12.6% and 27.5% for those with ITA 10 degrees and 0 degrees , respectively. CONCLUSIONS: Ten percent of this population of southern Chinese persons 50 years of age and older had narrow angles. PAS were present in one fifth of these people. From these cross-sectional data, it is unclear which of these individuals are at highest risk of the development of primary angle-closure (PAC) glaucoma. Longitudinal studies are necessary to determine appropriate strategies for preventing this potentially blinding outcome.     

Pentacam sensitivity and specificity in detecting occludable angles

Purpose. To assess the sensitivity and specificity of Pentacam measurements in detection of occludable angles and to provide cutoff values. Methods. Observational, single-center, cross-sectional study on 64 Caucasian eyes: 28 (43.7%) primary narrow angles or primary angle-closure glaucoma, and 36 (56.2%) controls: all subjects were evaluated and classified by gonioscopy (Shaffer classification). The following measurements have been considered: superior and inferior anterior chamber angle (ACA), temporal and nasal ACA, anterior chamber depth (ACD) using 5 value representation (central, superior, inferior, nasal, temporal), and anterior chamber volume (ACV). Validity of Pentacam parameters to detect patients in Shaffer 0 or I class was assessed by receiver operating characteristic (ROC) curves analysis; cutoffs were chosen as to maximize sensitivity and specificity. Results. All the considered Pentacam measures were statistically different between the 2 groups (p<0.0001). All Shaffer grade groups differed in all parameters (p<0.001), except for grade 0 and I, which did not differ in any. Area under the curve ROC analysis revealed high discriminant power of all Pentacam measures: ACA = 0.94; ACD = 0.91; ACD central = 0.89; and ACV = 0.89. Chosen cutoff values (ACA = 22.4°; ACD = 1.12 mm; ACD central = 1.93 mm; ACV = 84 mm3) allowed correct classification of narrow angles. Conclusions. The study pointed out a high power of Pentacam AVA, ACV, and ACD in detecting occludable angles. Pentacam is simple to use, reliable, and noncontact, provides parameters in a short period, and represents a possible screening tool.     

Color vision deficiency in a middle-aged population: the Shahroud Eye Study

International Ophthalmology - The aim of this study was to determine the prevalence of color vision defects in the middle-age population of Shahroud, Iran. We selected 6,311 people from the 40- to...     

Diabetic retinopathy in a black population: the Barbados Eye Study.

OBJECTIVE: The distribution of diabetic retinopathy in black populations is largely unknown. The authors present retinopathy data from the predominately black participants of the Barbados Eye Study (BES). DESIGN AND PARTICIPANTS: Prevalence study of 4631 participants based on a random sample of the Barbados population 40 to 84 years of age (84% participation). MAIN OUTCOME MEASURES: Diabetes was defined as self-reported history of physician-diagnosed diabetes or glycosylated hemoglobin greater than 10% (>2 standard deviations above the population mean of persons without a diabetes history). Retinopathy was assessed by independent gradings of 30 degrees color stereo fundus photographs of the disc and macula. RESULTS: Diabetes was present in 19.4% of black (n = 4314), 15.2% of mixed (black and white; n = 184), and 7.5% of white/other (n = 133) self-reported racial groups. In the black/mixed population, regardless of diabetes status, the prevalence of retinopathy was 5.9%. In the 636 black and mixed participants with diabetes, the prevalence of retinopathy was 28.5%: 19.8% had minimum changes, 7.7% had moderate changes, and 0.9% had severe retinopathy. Clinically significant macular edema (CSME) was found in 8.6% of those with diabetes. CONCLUSIONS: In the population of African origin, approximately 1 in 17 persons had retinopathy. Among those with diabetes, 28.5% had retinopathy and 8.6% had CSME. These results highlight the clinical and public health relevance of diabetic retinopathy in the black population.