Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Invest Ophthalmol Vis Sci. 2012 Aug 15;53(9):5545-51. doi: 10.1167/iovs.12-10011.
To evaluate the effects on visual acuity of forward scatter and aberrations typical of those after Descemet stripping endothelial keratoplasty (DSEK).
Twenty normal eyes of 20 subjects (ages 22-57 years) were examined with best spectacle correction. Under photopic conditions, high-contrast visual acuities (HCVAs) were measured by using ETDRS charts. Visual acuity was also measured by using aberrated charts that simulated the typical high-order aberrations at 12 months after DSEK. Forward scatter was induced by viewing the eye charts through a 1-mm-thick layer of scattering solution (Amco Clear, at a concentration of 4000 nephelometric turbidity units) and was measured with a straylight meter.
Forward scatter increased from 1.19 ± 0.11 log straylight parameter (log[s]; mean ± SD) without induced scatter to 1.57 ± 0.06 log(s) with induced scatter (P < 0.001). Induced scatter reduced HCVA on the nonaberrated chart by 2.7 Snellen letters, from 20/19 (Snellen equivalent) to 20/21 (P < 0.001) and by 2.1 letters on the aberrated chart, from 20/25 to 20/28 (P = 0.005). Addition of aberrations reduced HCVA by more than twice the number of Snellen letters than did induced scatter, by 6.4 letters with low scatter (P < 0.001), and by 5.8 letters with high scatter (P < 0.001).
Under typical clinical testing conditions, increased forward scatter has minimal effect on visual acuity. High-order aberrations are a more likely cause of degraded visual acuity than is forward scatter in eyes with clear corneas after DSEK.
评估类似于去表皮角膜内皮移植术（DSEK）后所产生的前向散射和像差对视力的影响。
20 名受试者（年龄 22-57 岁）的 20 只正常眼均经最佳矫正眼镜进行检查。在明视条件下，使用 ETDRS 图表测量高对比度视力（HCVA）。还使用像差图表来测量视力，这些图表模拟了 DSEK 后 12 个月的典型高阶像差。通过在 1 毫米厚的散射溶液（Amco Clear，浓度为 4000 浊度单位）中观察眼图来诱导前向散射，并使用杂散光仪进行测量。
前向散射从无诱导散射时的 1.19 ± 0.11 log 杂散光参数（log[s]；平均值 ± SD）增加到有诱导散射时的 1.57 ± 0.06 log（s）（P < 0.001）。诱导散射使非像差图表上的 HCVA 降低了 2.7 个 Snellen 字母，从 20/19（Snellen 等效值）降低到 20/21（P < 0.001），在像差图表上降低了 2.1 个字母，从 20/25 降低到 20/28（P = 0.005）。与诱导散射相比，加入像差使 HCVA 降低的 Snellen 字母数多出两倍以上，低散射时降低了 6.4 个字母（P < 0.001），高散射时降低了 5.8 个字母（P < 0.001）。
在典型的临床测试条件下，前向散射对视力的影响很小。在 DSEK 后角膜透明的眼中，高阶像差比前向散射更有可能导致视力下降。
