Paul Courtright

Correlation of cytogenetic abnormalities with the outcome of patients with uveal melanoma

Cytogenetic investigations of choroid and ciliary body melanomas have revealed that the majority of cases are characterized by recurrent clonal abnormalities involving chromosomes 3, 6, and 8. The authors sought to determine whether these abnormalities were associated with outcome.

Correlation Between the Visual Field Indices and Heidelberg Retina Tomograph Parameters

Purpose:We wished to determine whether a relationship exists between Heidelberg retina tomograph (HRT) parameters and the visual field indices. Methods:One eye was randomly chosen from 59 normal patients [normal visual field and normal optic nerve head (ONH) and intraocular pressure (IOP) <21 mm Hg], 64 ocular hypertensive patients (normal visual field and normal OHN and IOP >22 mm Hg), 124 high-tension glaucoma patients (abnormal visual field and/or abnormal optic nerve and IOP >22 mm Hg) and 47 lowtension glaucoma patients (abnormal visual field and or optic disc and IOP <21 mm Hg). All the patients were examined with Humphrey Perimeter, program 30–2, and HRT. Findings were assessed by analysis of variance, Pearsons correlation coefficient, and multiple linear regression. Results:Among all subjects, we noted a statistically significant correlation (Pearsons r, p < 0.001) between cup area, cup/disc area ratio, rim area, rim volume, cup shape measure, and retinal nerve fiber layer cross-section area with mean deviation and corrected pattern SD. Multiple linear regression analysis demonstrated that rim area was the most important predictor of mean deviation and corrected pattern SD. Conclusions:The presence of significant correlations between some HRT parameters, such as rim area and cup shape measure and visual field indices, suggests that these HRT parameters could be good indicators of the degree of glaucomatous ONH damage.

Gender and use of cataract surgical services in developing countries

OBJECTIVEnTo determine, from the existing literature, cataract surgical coverage rates by sex and the proportion of cataract blindness that could be eliminated if women and men had equal access to cataract surgical services.nnnMETHODnMethodologically sound population-based cataract surveys from developing countries were identified through a literature search. Cataract surgical coverage rates were extracted from the surveys and rates for women were compared to those for men. Peto odds ratios were calculated for each survey and a meta-analysis of the surveys was performed.nnnFINDINGSnFrom a literature review and meta-analysis of cataract surveys in developing countries, we found that the cataract surgical coverage rate was 1.2-1.7 times higher for males than for females. For females, the odds ratio of having surgery, compared to males, was 0.67 (95% confidence interval (CI): 0.60- 0.74). Despite their lower coverage rate, females accounted for approximately 63% of all cataract cases in the study populations, and if they received surgery at the same rates as males, the prevalence of cataract blindness would be reduced by a median of 12.5% (range 4-21%).nnnCONCLUSIONnClosing the gender gap could thus significantly decrease the prevalence of cataract blindness, and gender-sensitive intervention programmes are needed to improve cataract surgical coverage among females.

Indirect costs associated with accessing eye care services as a barrier to service use in Ethiopia

Backgroundu2002 The prevalence of blindness and visual impairment are high in Ethiopia and use of services is limited. Determining the barriers to use of eye care services is critical for planning strategies to prevent blindness.

Interobserver variability of optic disk variables measured by confocal scanning laser tomography

PURPOSEnTo assess the interobserver variation of confocal laser scanning tomographic measurements of the optic nerve head and to address the question of whether the addition of clinical optic disk photographs is helpful in outlining the optic disk margin and in reducing the observer-related variation of the measurements.nnnPATIENTS AND METHODSnOptic disk variables for 16 eyes of 16 patients with glaucoma, generated by confocal laser scanning laser tomography (Heidelberg Retina Tomograph), were independently evaluated by four experienced glaucoma specialists, and the interobserver variability was calculated. A second separate review by the same observers included the use of clinical stereoscopic color optic nerve head photographs to aid definition of the optic disk margin.nnnRESULTSnOptic disk parameters with the smallest interobserver variation were cup shape measure, maximum cup depth, height variation contour, and mean height contour. The intraobserver variation of these parameters did not increase when clinical optic disk slides were additionally available. Parameters with the highest interobserver variation were volume below surface, volume below reference, volume above surface, and volume above reference. The observer variation of these optic disk parameters increased significantly for two of the four examiners when clinical optic disk slides were additionally available for outlining the optic disk margin.nnnCONCLUSIONnConfocal laser scanning tomography of the optic nerve head can be improved significantly if clinical optic disk photographs are additionally available to help in outlining the optic disk margin. Because interobserver variation in the tomographic optic disk measurements can be significant, even if experienced observer are involved, tomographic optic disk measurements may be centralized in reading centers in the case of multicenter studies.

Blindness in childhood in developing countries: time for a reassessment?

Paul Courtright and colleagues argue that the changing patterns of global childhood blindness suggest a need to reassess research, training, and programmatic requirements.

Contribution of sex-linked biology and gender roles to disparities with trachoma.

Gender roles, rather than biology, dictate why trachoma is more common in women.

Low vision and blindness in adults in Gurage Zone, central Ethiopia.

Aim: To determine the magnitude and causes of low vision and blindness in the Gurage zone, central Ethiopia. Methods: A cross sectional study using a multistage cluster sampling technique was used to identify the study subjects. Visual acuity was recorded for all adults 40 years and older. Subjects who had a visual acuity of <6/18 were examined by an ophthalmologist to determine the cause of low vision or blindness. Results: From the enumerated population, 2693 (90.8%) were examined. The prevalence of blindness (<3/60 better eye presenting vision) was 7.9% (95% CI 6.9 to 8.9) and of low vision (6/24–3/60 better eye presenting vision) was 12.1% (95% CI 10.9 to 13.3). Monocular blindness was recorded in 16.3% of the population. Blindness and low vision increased with age. The odds of low vision and blindness in women were 1.8 times that of the men. The leading causes of blindness were cataract (46.1%), trachoma (22.9%), and glaucoma (7.6%). While the prevalence of vision reducing cataract increased with age, the prevalence of trachoma related vision loss did not increase with age, suggesting that trichiasis related vision loss in this population might not be cumulative. Conclusion: The magnitude of low vision and blindness is high in this zone and requires urgent intervention, particularly for women. Further investigation of the pattern of vision loss, particularly as a result of trachomatous trichiasis, is warranted.

Awareness of eye diseases and risk factors: identifying needs for health education and promotion in Canada

BACKGROUNDnLittle is known about the level of general public knowledge in Canada regarding the risk factors, prevention, and treatment of major blinding eye diseases.nnnMETHODSnThe study was a cross-sectional survey using self-administered questionnaires of patients presenting to 33 family practitioners offices in British Columbia. We asked patients opinions on the value of preventing blindness; the possibility of preventing cataract, glaucoma, and macular degeneration; the possibility of treating these conditions; and their knowledge of risk factors.nnnRESULTSnA total of 882 adults completed the questionnaires. Preventing vision loss was reported as one of 2 top health priorities in 28% of the questionnaires, more commonly by those with higher education and non-European ancestry. Overall, 69.2% reported familiarity with cataract as a cause of vision loss, 41.2% with glaucoma, and 20.2% with macular degeneration. Of these, 97.5% recognized the possibility of treatment for cataract, 91.5% for glaucoma, and 77.0% for macular degeneration, yet few respondents knew risk factors (amenable to intervention) for specific eye diseases. Men and younger respondents were more likely to report not knowing risk factors. Chinese-Canadians were least familiar with the association between smoking and cataract. Family history, probably the most important factor to help diagnose glaucoma, was recognized by only 23% of respondents.nnnINTERPRETATIONnAlthough loss of vision was reported as a major medical concern, there is little understanding of the risk factors for different eye diseases. The association of non-European ancestry and low educational attainment with poor knowledge of eye diseases suggests that innovative education programmes in primary and secondary schools and in non-English languages are needed to improve knowledge, attitudes, and practices.

Causes of blindness among children identified through village key informants in Malawi.

BACKGROUNDnTo determine the causes of blindness among children in rural Malawi.nnnMETHODSnThis was a cross-sectional study of children in communities of Chikwawa district, Malawi. Children were identified through trained, community-based key informants. All identified children were examined by an ophthalmologist and the cause of blindness determined.nnnRESULTSnIn total, 151 children were identified, of whom 37 (25%) were blind. Among the blind, 21 (60%) were girls and 16 (40%) were boys. Cataract (congenital/developmental) was the leading cause of blindness (35%), followed by corneal conditions (22%).nnnINTERPRETATIONnIn an area once noted for vitamin A deficiency in children, cataract is now the leading cause of blindness in children, replacing cornea blindness. Priorities for early cataract detection and intervention need to be considered for restoration of sight in children.