Effect of eccentricity of overnight orthokeratology lenses on axial growth and visual quality / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To explore the effect of eccentricity of overnight orthokeratology(OK)lenses on 2-year eye axial growth and visual quality.<p>METHODS:Based on the degree of eccentricity of OK lenses, patients were divided into three groups: a low degree of eccentricity group(degree of eccentricity ≤0.5 mm), a group of moderate eccentricity(eccentric degree >0.5-≤1.0 mm)and a group with a high degree of eccentricity(eccentric degree >1-≤1.5 mm). The degree of eccentricity of the OK lens, spherical equivalent(SE), the uncorrected visual acuity after wearing OK lenses(UCVA), axial length before and after wearing OK lenses(AL), total higher-order aberrations(HOA), comas, and spherical aberrations(SA)for 3 mm pupils were analyzed. The difference among the three groups for all parameters was compared using the Kruskal-Wallis H Rank-Sum test.<p>RESULTS:The study retrospectively analyzed 75 cases(139 eyes). In the low eccentricity group(53 eyes), the mean age was 11.4±2.4 years, SE was -3.24±1.48 D, and AL was 24.85±1.01 mm. In the moderate eccentricity group(53 eyes), the mean age was 11.4±2.2 years, SE was -3.22±1.29 D, and AL was 25.15±0.92 mm. In the high eccentricity group(31 eyes), the mean age was 11.5±1.9 years, SE was -3.54±1.43 D, and AL was 24.95±0.84mm. After two years, there was no significant difference in the changes of the axis among the three groups(<i>P</i>=0.089). The HOA, SA, and coma in the high eccentric group were significantly higher than in the middle eccentric group(<i>P</i><0.05). The HOA, SA, and coma in the high eccentric group were also significantly higher than those in the low eccentric group(<i>P</i><0.05).<p>CONCLUSION:For OK lenses, it is unnecessary to strictly require the absolute centralization of the lens position. An unnecessary change of the lenses may delay the eye-axis control. However, the balance between axial control and visual quality should be assessed.

Oxidative Stress Levels in Aqueous Humor from High Myopic Patients

PURPOSE: To compare oxidative stress status in the aqueous humor of highly myopic eyes and control eyes. METHODS: Aqueous humor samples were collected from 15 highly myopic eyes (high myopia group) and 23 cataractous eyes (control group) during cataract surgery. Central corneal thickness, corneal endothelial cell density, hexagonality of corneal endothelial cells, and cell area of corneal endothelial cells were measured using specular microscopy. Axial length was measured using ultrasound biometry. 8-Hydroxydeoxyguanosine (8-OHdG) and malondialdehyde levels were measured using enzyme-linked immunosorbent assay. RESULTS: 8-OHdG level was lower in the aqueous humor of myopic patients than in that of control group (p = 0.014) and was positively correlated with central corneal thickness and negatively correlated with axial length (r = 0.511, p = 0.02; r = -0.382, p < 0.001). There was no correlation between 8-OHdG level and corneal endothelial cell density, hexagonality, or cell area. Malondialdehyde level did not show any correlation with any parameters evaluated. CONCLUSIONS: 8-OHdG might be a sensitive biomarker for evaluating oxidative stress status in the eye. Oxidative stress level was lower in the aqueous humor of highly myopic eyes compared to that in control eyes, which indicates lower metabolic activity in these eyes.

The Effect of Axial Length on the Variability of Stratus Optical Coherence Tomography

PURPOSE: To evaluate the effect of axial length on the variability of retinal nerve fiber layer (RNFL) thickness measurements using the Stratus optical coherence tomography (OCT) in normal and glaucomatous eyes. METHODS: We measured the RNFL thickness in 474 subjects using the Stratus OCT twice during the same day. Axial length was measured with the IOLMaster, and refractive error was the absolute value of the spherical equivalent measured with an auto ref-keratometer. Standard deviation in overall mean RNFL thickness was used as the dependent variable to identify significant correlations. RESULTS: Long axial length affected the variability in the RNFL thickness value by stratus OCT at the temporal quadrant (p = 0.006) and clock-hour sector 9 (p = 0.001). Refractive error also affected the variability of the RNFL thickness value by stratus OCT at the temporal quadrant (p = 0.025) and clock-hour sector 9 (p = 0.024). CONCLUSIONS: It is clinically significant that longer axial length demonstrates greater variability in temporal area as detected by OCT, a measurement which correlates with the preferably damaged position in the myopic glaucoma eye.

Experimental Study on Effect of Ginkgo Biloba Extract on Form-Deprivation Myopia in the Chick / 中成药

Objective: To observe the effect of Ginkgo Biloba extract (EGb) on Form deprivation Myopia (FDM) in the chick. Methods: 30 two day chicks were divided into three groups (Control Group, Drug Group Ⅰ, Drug Group Ⅱ). All of them were monocularly deprived by suturation of eyelids. Axial length was measured by A Scan ultrasonograph, the posterior cartilaginous sclera, the sclera fibrous and retina were observed under the light microscope. Results: Both refraction and axial eye length were changed by form deprivation in control group. refraction change ( P