Location and stability of a newly established eccentric retinal locus suitable for reading, achieved through training of patients with a dense central scotoma
Location and stability of a newly established eccentric retinal locus suitable for reading, achieved through training of patients with a dense central scotoma
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DOI：
10.1097/00006324-199812000-00009
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发表时间：
1998-12-01
影响因子：
1.4
通讯作者：
Nilsson, EG
中科院分区：
文献类型：
--
作者：
Nilsson, UL;Frennesson, C;Nilsson, EG
6例患者，中位年龄71岁，一只眼睛有密集的中心暗点，同一只眼睛的中位视力为0.06（20/330），全部（100%）通过眼底照相显示，包括固定目标，以优选使用不利的视网膜位点进行固定，即，暗点（sotoma）。没有患者能够用受影响的眼睛阅读新的文本。使用计算机和视频显示系统来确定视野暗点上方或下方（视网膜病变下方或上方）最适合阅读的区域以及在该偏心率下所需的放大率。同样的设置也用于阅读单个单词以及滚动文本的入门训练，目的是在有利的偏心位置建立优选的视网膜轨迹（PRL），即训练的视网膜轨迹（TRL）。此后，为患者提供强正透镜（中位屈光度，40 D），用于在非常短的阅读距离（中位值，2.5 cm）下阅读印刷文本，首先是单个单词，在其上方和下方印刷帮助线以促进偏心固定，最后是新文本。总训练时间为4 ~ 5 h。此后，眼底照相显示，5名患者（83%）使用TRL作为PRL。阅读速度为每分钟71个单词（中位数）。我们的研究结果似乎表明，一个偏心的PRL有利于有效的阅读，可以通过培训，并需要一个相当低的培训课程。
Six patients, median age 71 years, with a dense central scotoma in one eye and a median visual acuity of 0.06 (20/330) in the same eye, were all (100%) shown by means of fundus photography including a fixation target to preferably use an unfavorable retinal locus for fixation, i.e., within the lesion (scotoma). None of the patients was able to read novel text with the affected eye. A computer and video display system were used to determine the most suitable area above or below the visual field scotoma (below or above the retinal lesion) for reading and the magnification needed at this eccentricity. The same setup was also used for an introductory training in reading single words as well as scrolled text with the aim of establishing a preferred retinal locus (PRL) at a favorable, eccentric position, the trained retinal locus (TRL). Thereafter, the patients were provided with strong positive lenses (median power, 40 D) for reading printed text at a very short reading distance (median, 2.5 cm), first single words, above and below which help lines were printed to facilitate eccentric fixation, and finally, novel text. The total training time was 4 to 5 h. Thereafter, fundus photography showed that five of the patients (83%) used their TRL as their PRL. Reading speed was 71 words per minute (median). Our results seem to indicate that an eccentric PRL favorable for effective reading can be established through training and that a fairly low number of training sessions is required.