Diabetic retinopathy is not associated with carbonic anhydrase gene polymorphisms.

PURPOSE: Carbonic anhydrase is elevated in the vitreous of patients with proliferative diabetic retinopathy (PDR). This study aimed to determine if common polymorphisms in the carbonic anhydrase (CA) gene influence susceptibility to diabetic retinopathy (DR). METHODS: In this multicentered study, a total of 235 control subjects with no DR, 158 subjects with nonproliferative DR (NPDR), 132 with proliferative DR (PDR), and 93 with clinically significant macular edema (CSME) were recruited. Blinding DR was defined as severe NPDR, PDR or CSME. DR subjects were drawn from both type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM) populations. Ten tag single nucleotide polymorphisms were selected to cover the majority of genetic diversity across the CA gene. RESULTS: After adjustments were made for sex, disease duration, and HbA(1)c, no associations were found between any CA polymorphisms or haplotypes with any type of retinopathy in T1DM or T2DM. CONCLUSIONS: Sequence variation in CA is not associated with the risk of developing retinopathy in T1DM or T2DM and increases the likelihood that elevated vitreous CA may be a consequence rather than cause of DR. Further genetic studies are required to have a better understanding of the pathogenesis of this debilitating diabetic complication.

The prevalence, severity and risk factors for pterygium in central Myanmar: the Meiktila Eye Study.

AIMS: To determine the prevalence, severity and risk factors associated with pterygium in adults in central Myanmar. METHODS: Population-based, cross-sectional survey of the people 40 years and over residing in rural Myanmar. Pterygium was graded for severity (T1 to T3) by visibility of episcleral vessels, and the apical extent was recorded. An autorefractor was used to measure refractive error. RESULTS: There were 2481 subjects identified, and 2076 (83.7%) participated. The prevalence of pterygium in either eye was 19.6% (95% confidence interval (CI) 16.9 to 22.2) and of bilateral pterygium 8.0% (95% CI 7.7 to 8.3). Outdoor occupation was an independent predictor of pterygium (p<0.01). The mean apical extent from the limbus was 2.2 mm (95% CI 2.05 to 2.35). Higher-grade pterygia did not have a significantly greater apical extent (p = 0.35). The presence of pterygium was associated with astigmatism, (p = 0.01), and the amount of astigmatism increased as both the severity (p<0.01) and apical extent increased (p<0.01). Two people of the 84 people blinded in both eyes were bilaterally blind from pterygium (1.7%; 95% CI 0.2 to 6.1), and pterygium accounted for 2.2% (95% CI 0.7 to 5.0) of blindness in at least one eye. No participant had low vision in both eyes due to pterygium, but pterygium led to 0.8% (95% CI 0.3 to 1.6) of low vision in at least one eye. Pterygium was therefore associated with 0.4% (95% CI 0.04 to 1.3) of binocular visual impairment and 1.0% (95% CI 0.6 to 1.8) of visual impairment in a least one eye. CONCLUSIONS: There is a high prevalence of pterygium in central Myanmar, and the risk of developing this condition increases with outdoor occupation. Pterygium in this population is associated with considerable visual morbidity, including blindness.