Frequency of retinal pathology in high myopia. The MYST study

Abstract

Purpose: High myopia is a common cause of irreversible blindness, mostly due to myopic macular lesions. Recently, an international classification and grading system for myopic retinopathy was developed by the META-PM Study Group. Here, we investigated the frequency of retinal lesions in a Dutch cohort of high myopes using this protocol.

Methods: Persons with high myopia (SE ≤ -6 D, age ≥25 years) were recruited for the MYST study by eye care providers from university and community hospitals from the Netherlands, and by public media. Participants were examined at a single research center where they underwent an extensive ophthalmologic examination. We performed 35° fundus photography (Topcon TRC 50EX with a Sony DXC-950P digital camera;0.44 megapixel) after pharmacological mydriasis and measured axial length (Lenstar, Haag-Streit International). We graded fundus photographs according to the international classification and grading system for myopic retinopathy from the META-PM study group. We investigated frequencies of retinal lesions, and evaluated differences between sex and axial length). Inter-observer reliability for the graded lesions was calculated using Cohen’s kappa statistics.

Results: We included 517 cases with high myopia, of which 508 had gradable fundus photographs. Myopic peripapillary atrophy was the most common abnormality (83%), followed by tessellated fundus (62%), posterior staphyloma (41%), and peripapillary intrachoroideal cavitation (26%). Myopic macular lesions (MML) were observed in 17% of the cases. The cases with MML had eyes with a greater axial length (mean 29.6 mm vs 26.7 mm, P<0.001), but did not differ in age (mean 41.7 years vs 41.8 years, P=0.98) than those without MML. Diffuse and patchy chorioretinal atrophy were the most common MML (69% and 23% respectively). Intra-observer κ values ranged from 0.56 for tessellated fundus to 0.84 for MML.

Conclusions: Retinal lesions are highly frequent in high myopes. Macular pathology was less frequent than optic disc lesions, and was related to axial length. The international grading and classification system can be used with good reproducibility to grade retinal pathology in high myopes of European descent.

Keywords: 605 myopia • 465 clinical (human) or epidemiologic studies: systems/equipment/techniques • 551 imaging/image analysis: non-clinical