Long-term Follow-up of Myopic Glaucoma: Progression Rates and Associated Factors

Purpose: To investigate the progression rate of myopic glaucoma and associated factors by long-term analysis of its clinical course. Design: Longitudinal observational study. Methods: Patients who had had at least 5 years of follow-up and a spherical equivalent of – 0.5 diopters or less were included in this study. They were divided into three myopia groups according to myopic grade, namely mild myopia (-0.5 to -3.0 diopters), moderate myopia (-3.0 to -6.0 diopters), and high myopia (-6.0 diopters or more), and the clinical course, progression rate, and associated factors were compared among the groups and analyzed. Results: A total of 121 eyes of 121 glaucoma patients with myopia were included in the study. The average follow-up period was 10.4 ± 2.9 years. In the analysis of progression rate, the change rate of average retinal nerve fiber layer (RNFL) thickness [-0.75 μm/yr in mild myopia, -0.82 μm/yr in moderate myopia, -0.84 μm/yr in high myopia] and the mean deviation change [-0.30 dB/yr in mild myopia, -0.37 dB/yr in moderate myopia, -0.39 dB/yr in high myopia] both tended to be faster as the myopic grade increased. In a Kaplan-Meier survival analysis, the high myopia groups demonstrated a significantly faster visual acuity loss (of more than 3 lines) and a higher incidence of newly developed central visual field defect (CVFD) than did the mild and moderate myopia groups. Longer axial length (OR: 1.72, CI : 1.03 – 3.07, P = 0.047) and retinal nerve fiber layer defect (RNFLD) extending to the macula (OR: 4.14, CI : 1.54 – 12.30, P = 0.007) were significantly associated with newly developed CVFD. Conclusions: In myopic glaucoma patients, the higher the degree of myopia, the faster the rate of visual acuity loss and CVFD occurrence. Occurrence of CVFD was associated with longer axial length and widening of RNFLD to the macula.