Abstract
Purpose:
To explore the prevalence of blindness in patients with bilateral normal tension glaucoma (NTG).
Methods:
We retrospectively investigated three-hundred twelve patients diagnosed as bilateral NTG between 1985 and 2006, and followed for at least 5 years. We reviewed the patients’ data of best corrected visual acuity and visual field from our records. The patients who developed other types of glaucoma or ocular diseases which can cause severe visual impairment including retinal vein occlusion and retinal detachment except cataract during the follow-up periods were excluded from the study. The blindness was defined by the criteria of World Health Organization (WHO).
Results:
The mean age at diagnosis was 57.4 ± 12.0 years with a range of 22 to 82 years. Men were 120, and women were 192. The mean follow-up period was 12.5 ± 5.0 years with a range of 5 to 28 years. 114 eyes of 74 patients had received glaucoma surgery during the follow-up period. 18 patients (5.8%) had already had unilateral blindness attributable to glaucoma at diagnosis. 37 cases (11.9%) had unilateral blindness, and 10 cases (3.2%) had bilateral blindness at the last visit. Blindness at least in one eye was estimated to be 3.4 ± 1.1 %, 7.0 ± 1.6 % and 10.8 ± 2.1 %, at 5,10 and 15 years, respectively, by a Kaplan-Meier estimate. Similarly, bilateral blindness was estimated to be 0.0 ± 0.0 %, 1.9 ± 1.1 % and 1.9 ± 1.1 %, at 5,10 and 15 years, respectively.
Conclusions:
Approximately 10% and 2% of NTG patients led to unilateral and bilateral blindness at a 15-year follow-up periods, respectively.
Keywords: 463 clinical (human) or epidemiologic studies: prevalence/incidence •
754 visual acuity •
758 visual fields