Risk factors in progression of normal tension glaucoma with intraocular pressure lowering medication

1. Martha Kim¹
2. Seok Hwan Kim²
3. Jin Wook Jeoung³
4. Tae-Woo Kim¹
5. Ki Ho Park³
6. Dong Myung Kim³

¹Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea
²Department of Ophthalmology, Seoul National University Boramae Hospital, Seoul, Korea
³Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea

Purpose: To investigate risk factors of progression in normal tension glaucoma (NTG) with intraocular pressure (IOP) lowering treatment during long-term follow-ups.

Methods: One hundred three eyes of 103 patients with NTG who were registered in glaucoma clinic of Seoul National University Hospital from May 1980 to December 1999 and followed-up regularly were included. Retrospective chart review was done with evaluation of disc photo, red-free fundus photography, Humphrey visual field and possible risk factors such as age, gender, intraocular pressure (IOP) of every visit, migraine and disc hemorrhage.

Results: Mean follow-up was 151.4 ± 38.6 months. Forty eyes (38.8%) showed the progression in either structural or functional tests. Multivariate logistic regression analysis showed that larger fluctuation of IOP [OR 3.528; 95% CI 1.160-10.731; P=0.026] and lower percentage of IOP reduction (100 x (baseline IOP – mean IOP)/baseline IOP) [OR 0.953; 95% CI 0.914-0.995; P=0.028] were associated with progression of normal tension glaucoma with treatment. However, the presence of disc hemorrhage [HR 2.799; 95% CI 1.173-6.681; P=0.020] and lower percentage of IOP reduction [HR 0.967; 95% CI 0.936-0.999; P=0.042] were significant risk factors for progression of NTG based on the Cox proportional hazard model.

Conclusions: In long term follow-up of NTG patients with IOP lowering treatment, lower percentage of IOP reduction was an important factor of progression. Disc hemorrhage was also related with the progression of NTG.