Acuities through annular and central pupils after radial keratotomy.
Acuities through annular and central pupils after radial keratotomy.
复制标题
放射状角膜切开术后通过环形和中央瞳孔的视力。
DOI：
10.1097/00006324-199108000-00003
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Applegate,RA
中科院分区：
文献类型：
--
作者：
Applegate,RA
放射状角膜切开术(RK)后，角膜曲率半径在非手术区中心增加，而在手术区中心旁和周边相对保持不变。这些角膜地形图的变化表明，角膜的成像特性应该随允许参与成像的角膜面积而变化。为了验证这一假设，我们测量了正常人和RK患者术后通过中央和环形瞳孔的视力随时间的变化。环状视力在RK后显著降低，并随着时间的推移而持续降低。术后最佳矫正中心视力随时间增加，明显好于术前视力，但不如具有类似低屈光度的正常人。临床启示包括：(1)视表现(如视力、对比敏感度、眩光)和光学质量指标(如屈光、高阶像差)随瞳孔大小的变化；(2)使用尽可能大的非手术区域；(3)仔细地将非手术区域居中放置在自然瞳孔上；(4)设计新的隐形眼镜以矫正RK患者的残余屈光不正；及(5)就视功能可能随瞳孔大小而发生的变化向一般患者，尤其是自然大瞳孔患者提供咨询。综上所述，这项研究表明，与低屈光度的正常眼或手术前同一只眼相比，RK旁中心/周边角膜光学手术后的光学质量有所下降。
The corneal radius of curvature after radial keratotomy (RK) increases centrally in the surgery-free area while remaining relatively unchanged paracentrally and peripherally in the surgical areas. These corneal topography changes suggest that the imaging properties of the cornea should vary with the area of the cornea allowed to participate in image formation. To test this hypothesis visual acuities were measured both through a central and an annular pupil for normals and RK patients as a function of time after surgery. Annular acuities were decreased significantly after RK and remained decreased over time. Best corrected central acuity increased as a function of time after surgery, becoming significantly better than presurgery acuities but not as good as normals with similar low refractive corrections. Clinical implications include:(1) variations in visual performance (eg, acuity, contrast sensitivity, glare) and optical quality measures (eg, refraction, higher-order aberrations) as a function of pupil size;(2) use of as large a surgery-free area as possible;(3) careful centering of the surgery-free area on the natural pupil;(4) new contact lens designs for correcting RK patients' residual refractive error; and (5) counseling patients in general, and patients with naturally large pupils in particular, concerning possible variation in visual function with pupil size. In summary, this study indicates that postsurgery RK paracentral/peripheral corneal optics experience a loss in optical quality as compared to either normal eyes with a low refractive correction or the same eye before surgery.