高度近视偏心注视优势位置的研究

Preferred retinal locus of eccentric fixation in eyes with high myopia

目的 探讨高度近视眼因黄斑病理损害形成中心暗点以及丧失中心视力后偏心固视的形成规律，确定偏心注视点的优势位置。方法应用微视野计（MP-1）对因黄斑病变形成偏心固视的40例高度近视患者的54只眼作固视检查。利用正常成人中心固视的90％置信椭圆，确定偏心固视相对于中心凹的位置。根据观察到的偏心固视的位置，将所有患眼分为preferred retinal locucs（PRL）优势组和PRL非优势组；并将两组视力作统计学比较。结果54只高度近视眼中，中心视力丧失后偏心固视点形成在暗点下方视野者24只眼，占本组患眼的44．44％；左侧19只眼，占35．19％；上方6只眼，占11．11％；右侧5只眼，占9．26％。双眼均形成偏心固视者14例，其中13例双眼偏心固视模式一致，均为下方者7例，占双眼偏心固视者的50．00％；均为左侧者5例，占35．71％；均为上方者1例，占7．14％。偏心固视位于下方、左侧视野组与偏心位置位于右侧和上方的非优势组之间比较，其视力差异无统计学意义（F=0．144，P〉0．05）。结论高度近视患者偏心固视会形成在尽量靠近中心凹有功能的视网膜。下方视野是形成偏心固视的优势位置。

Objective To investigate the distribution of the preferred retinal locus （PRL） of eccentric fixation in eyes with high myopia. Methods A total of 40 highly myopic patients （54 eyes ） with eccentric fixation were examined by MP-1 microperimeter to identify the PRL. The position of PRL relative to the fovea was estimated using the 90% confidence ellipse of normal adult foveal fixation. The differences of visual acuity between ＂desirable＂ and ＂undesirable＂ PRL were tested by analysis of variance. Results In 54 eyes with high myopia, 24 eyes （44.44%） had PRL of eccentric fixation below the scotoma after loss of central vision; 19 eyes （ 35.19%） had a left-field PRL; 6 eyes （ 11.11% ） had an upper-field PRL; and 5 eyes （ 9.26% ） had right-field PRL. In 14 patients who had binocular eccentric fixation, 13 had the same fixation pattern in both eyes, including lower-field PRL in 7 （50.00%）, left-field PRL in 5 （35.71%）, and upper-field PRL in 1 patient （7. 14%）. The difference of visual acuity between lower- and left-field PRL group and right- and upper-field undesirable PRL group was not statistically significant （F = 0. 144, P〉 0.05）. Conclusions The eccentric fixation in eyes with high myopia is usually situated as near as possible to the fovea. The optimal PRL is inferior visual field.