[Review on the etiology of focal photoreceptor defects].

Focal photoreceptor defects refer to a group of diseases characterized by changes in the foveal structure caused by rarefaction or absence of the outer retina. Due to their diverse clinical manifestations and the limitations of previous imaging techniques, these diseases have not received sufficient attention and accurate diagnosis. Their causes can be mainly classified into diseases with primary lesions occurring in the outer retina and outer retinal lesions secondary to other sites of disease. Understanding the potential causes of foveal photoreceptor damage can provide better guidance for the clinical diagnosis and treatment of these diseases. This article reviews the etiology of focal photoreceptor defects.