CATARACT AND ARM EFFECTS ON VISUAL PERFORMANCE

年龄相关性黄斑病变（ARM）是严重视力障碍的主要原因

Age-related maculopathy (ARM) is the leading cause of severe visual impairment among older persons. From population-based studies it is estimated that over half of eyes with ARM also have cataract. Over the past two decades advances in cataract surgery have resulted in a procedure that is highly effective and involves very low risk. But frequently the surgery is postponed for ARM patients because it is felt that the benefits of removing the cataract would be minimal and outweighed by even a modest risk of vision loss due to surgical complications. The determination of the benefit of cataract surgery is usually based primarily on visual acuity. But is widely recognized that one also needs to consider the impact of the cataract on the patient's ability to perform essential activities related to self care and vocational needs. Considerable work has been done to establish the benefits of cataract surgery for patients without retinal pathology. But we still know very little about the benefits of cataract surgery in patients with retinal pathology. The overall goal of this project is to develop a set of techniques that will allow us to determine the potential benefits of cataract surgery in patients with ARM. A series of psychophysical studies is planned that will better characterize the visual effects of nuclear and cortical lens opacities. Cataracts will be modelled as a spatial-frequency dependent reduction in retinal image contrast and as a reduction in retinal illumination. The validity of this model will be established in patients undergoing routine cataract surgery. The combined effects of cataracts and ARM on reading, face recognition, other everyday visual activities, and health-related quality of life will be assessed by a combination of objective performance-based tests and questionnaires. A comprehensive battery of vision tests will be developed to differentiate ARM patients in whom cataract has a significant disabling impact from ARM patients whose visual function is not limited by the presence of cataract. The results of these studies will provide a rational basis for the development of surgical guidelines for cataract extraction in patients with ARM.