ABSTRACT
To evaluate cortical and retinal activity by pattern visual evoked potentials [PVEP] in patients with type II diabetes mellitus. PVEP was recorded in 40 diabetic patients including 20 subjects with nonproliferative diabetic retinopathy [NPDR] and 20 others without any retinopathy on fundus photography, and compared to 40 age- and sex-matched normal non-diabetic controls. P100 wave latency was significantly longer in diabetic patients as compared to normal controls [P<0.001]; both diabetic subjects without retinopathy and those with NPDR had significantly longer P100 latency than controls [P<0.001 for both comparisons]. There was significant reduction in N75 [P=0.037] and P100 [P=0.001] amplitudes in diabetic subjects. No correlation was observed between VEP amplitude or wave latency, and the level of glycemia or duration of diabetes mellitus. Increased PVEP latency may be a sign of retinal ganglion cell damage which takes place before the appearance of the first ophthalmoscopically detectable signs of diabetic retinopathy. PVEP may be considered as a method for detecting prediabetic retinopathy and has the potential to reduce diabetic complications.
ABSTRACT
To determine the prevalence of refractive condition and its risk factors among students in Mashhad. A total of 2510 students representing a cross-sectional of the population of Mashhad were sampled using random cluster sampling strategy. Primary and middle school students underwent cycloplegic refraction. The refractive errors of high school students were measured using non-cycloplegic autorefraction. Myopia was defined as spherical equivalent [SE] of -0.5 diopter [D] or more, and hyperopia was defined as SE of +0.5 diopter [D] or more, and astigmatism of 0.75 cylinder diopter or greater. Examination was carried out in the school using standardized testing protocols. 2150 students [group 1: 1163 primary and middle school, group 2: 947 high school students and 13 missed data] participated. The prevalence of refractive errors in the 1st group was: myopia=2.4%, hyperopia=87.9%, astigmatism=9.8% and anisometropia=3.0% [SE difference at least 1.00 D], and in the 2nd group myopia=24.1%, hyperopia=8.4%, astigmatism=11.8% and anisometropia=5.6%. There was significant difference in refractive errors between girls and boys [P<0.001]. In primary and middle school prevalence of myopia increased with age [OR=1.3 95% CI: 1.03 to 1.7 and P=0.013]. The prevalence of refractive errors among students in Mashhad is high. Effective detection and treatment of these refractive errors is expected to reduce the incidence of amblyopia and strabismus and also can prevent substantive effects on academic performance