Objective To observe the effects of local macular foveal photoreceptor defects on visual acuity.Methods Thirty-one patients (31 eyes) with photoreceptor defect in macular fovea (case group) diagnosed by spectral domain optical coherence tomography (SD-OCT) and 30 patients (30 eyes) age- and diopter- matched normal subjects (control group) were enrolled in this study. There were 22 eyes with full photoreceptor defects and 9 eyes with outer segment defects in case group. All subjects were examined for best corrected visual acuity (BCVA), slit-lamp microscopy, direct ophthalmoscope and SD-OCT. Independent sample t-test was used to compare central foveal thickness (CFT) between case group and control group. Difference of logMAR BCVA, CFT, maximum width and height of photoreceptor defects, defected area and residual retinal thickness in macular between patients with full photoreceptor defects and outer segment defects were also compared.Results The CFT of case group and control group were (225.32plusmn;19.70),(240.02plusmn;10.70) mu;m, the difference was not statistically significant (t=-1.96, P＞0.05). In full photoreceptor defects and outer segment defects patients, the mean logMAR BCVA were 0.22plusmn;0.31, 0.32plusmn;0.43; the mean CFT were (224.09plusmn;20.57), (228.33plusmn;18.17) mu;m; the maximum width of photoreceptor defects were (131.32plusmn;108.18), (143.22plusmn;66.93) mu;m; the mean defected area were (0.022plusmn;0.054), (0.019plusmn;0.019) mm2; the mean maximum height of photoreceptor defects were (77.41plusmn;6.62), (44.89plusmn;4.26) mu;m; the mean residual retinal thickness were (87.00plusmn;20.31), (128.33plusmn;23.54) mu;m respectively. There was no statistical significance between full photoreceptor defects and outer segment defects patients in the mean logMAR BCVA, CFT, maximum width of photoreceptor defects and defected area (t=-0.76, -0.538, -0.305, 0.166; P＞0.05), but there were significant difference in mean maximum width of photoreceptor defects and residual retinal thickness (t=12.72, -4.91;P＜0.05). Conclusions The local photoreceptor defects in macular fovea can lead to decrease of visual acuity. The wider the photoreceptor defects, the worse the visual acuity.
Objective To investigate the morbidity of ocular fundus diseases in Tibetan above 40 in Maqin county, Qinghai Province. Methods A total of 2511 Tibetan above 40 in Maqin county, Qinghai Province were seelected by cluster sampling method. The sampling survey of ocular fundus diseases was performed on the individuals with indirect ophthalmoscope, and the results were compared with the domestic existing epidemiological data. Results Two hundred and thirty five (9.35%) cases were found to have abnormal ocular fundus, and the blindness rate due to the abnormal ocular fundus was 20.5% (80/391 eyes) which was lower than the blindness rate due to cataract (52.5%). Low vision and blindness led by ocular fundus diseases were found in 155 eyes (65.96%)，including 74(47.74%) with age-related macular degeneration (AMD) and 23 (9.79%) with retinoangiopathy. Conclusions The morbidity of ocular fundus disorder is higher in high plateau than that in backland; AMD and retinoangiopathy are the main diseases leading to blindness. (Chin J Ocul Fundus Dis, 2006, 22: 321-323)