Probability of myopic macular degeneration in dependence on axial length and age: The two‐continent eye study

PURPOSE: To assess the probability of myopic macular degeneration (MMD). METHODS: The project included four population-based investigations: Beijing Eye Study (BES) (n = 3325; age: 50+ years), Ural Eye and Medical Study (UEMS) (n = 5586 participants; age: 40+ years), Ural Very Old Study (UVOS) (n = 541;age: 85+ years) and Central India Eye and Medical Study (CIEMS) (n = 4467; age: 30+ years). MMD was defined according to the Meta-analysis for Pathologic Myopia Study Group. Based on binary regression analyses, probability equations were formulated. RESULTS: The total study population (27 607 eyes; 14 108 individuals) was randomly divided in a ratio of 1:1 into a development subgroup for the probability score development and into a validation subgroup. In the validation subgroup, the probability assessment for MMD stage 2+ and 3+ had an area under the receiver operating characteristic curve of 0.996 and 0.998, respectively. Applying the probability equations, MMD stage 2+ probability for myope with an axial length of 28 and 30 mm increased from age 30 to 75 years from 55.0% to 88.1% and from 99.3% to 99.8%, respectively. MMD stage 3+ probability at an axial length of 28 and 30 mm increased from age 30 to 75 years from 8.3% to 57.5% and from 81.8% to 98.5%, respectively. CONCLUSIONS: The MMD probability assessment offers a rough estimate of the MMD probability at present and at older age, based on axial length and age. For an axial length of 28 and 30 mm, the probability of MMD stage 3+ at 75 years was 57.5% and 98.5%, respectively.