Glaucoma Progression in Treatment-Naïve Normal-Tension Glaucoma Patients with Myopia - Role of Intraocular Pressure

Precis: While myopia has been recognized as a positive prognostic factor for NTG progression in the adult population, some myopic NTG eyes exhibited significant progression within two years when left untreated, even under low IOP.

Purpose: To determine the natural history and risk factors associated with progressive retinal nerve fiber layer (RNFL) thinning in previously stable, treatment-naïve, normal-tension glaucoma (NTG) patients with myopia.

Methods: This study included 111 myopic NTG eyes without intraocular pressure (IOP)-lowering treatment for at least 1 year and without disease progression during the treatment-free period. The RNFL thickness was measured and a visual field (VF) test was performed every 6 to 12 months for >2 years. Patients with progressive changes were classified as the P(+) group, while those without progression were classified as the P(-) group. Cox proportional-hazards model assessed risk factors of progression, while linear regression determined factors associated with the rate of RNFL thinning.

Results: Progressive change was observed in 25 of the 111 participants [P(+) group, 22.5%]. A family history of glaucoma, higher mean IOP, and maximum IOP during the follow-up were significant factors both for being in the P(+) group and for a faster RNFL thinning. None with a mean IOP <11 mmHg were in the P(+) group. Davies' test identified that 14.2 mmHg was a significant breakpoint (P=0.042), above which the rate of RNFL thinning increased significantly with the mean IOP (R2=0.252, P=0.034).

Conclusions: Myopic NTG patients untreated for IOP, especially those with a family history of glaucoma or higher IOP, are at increased risk of progression. Early treatment initiation is advised for high-risk myopic NTG patients, even when their condition appears stable.