Intraocular pressure reduction and progression of highly myopic glaucoma: a 12-year follow-up cohort study

Aims To investigate any association between intraocular pressure (IOP) reduction amount and open-angle glaucoma (OAG) progression in highly myopic eyes and to determine the associated risk factors. Methods One hundred and thirty-one (131) eyes of 131 patients with highly myopic OAG, all of whom had received topical medications and been followed for 5 years or longer, were enrolled. Based on the IOP reduction percentage, patients were categorised into tertile groups, and subsequently, the upper-tertile and lower-tertile groups were compared for the cumulative probability of glaucoma progression. Kaplan-Meier survival analysis and log-rank testing were applied in the comparison, and multivariate analysis with Cox’s proportional hazard model, additionally, was performed to identify progression risk factors. Results Throughout the average 11.6±4.4 year follow-up on the 131 eyes (mean age, 41.2 years at initial visit; baseline IOP, 16.4 mm Hg), 72 eyes (55.0%) showed glaucoma progression. The upper-tertile group (IOP reduction percentage>23.7%) showed a high cumulative probability of non-progression relative to the lower-tertile group (IOP reduction percentage<11.0%; p=0.034), according to the Kaplan-Meier analysis. Presence of disc haemorrhage (DH; HR=2.189; p=0.032) was determined by the multivariate Cox’s proportional hazard model to be significantly associated with glaucoma progression. For progressors, the average rate of retinal nerve fibre layer thickness thinning was −0.88±0.74 µm/year, while the MD change was −0.42±0.36 dB/year. Conclusions Glaucoma progression is associated with amount of IOP reduction by topical medications in highly myopic eyes, and DH occurrence is a glaucoma progression risk factor.