Even normal tension glaucoma (NTG) patients who have low intraocular pressures (IOP) are at significant risk for progression in visual field loss, according to a study recently published in the British Journal of Ophthalmology. The new data shows that over the course of 8.7 years, 35.3% of patients with NTG who maintained pressures in the low teens showed signs of disease progression. The investigators say a combination of various factors other than IOP were more significantly associated with progression.

The researchers evaluated 102 eyes of 102 NTG patients with pretreatment IOPs equal to or lower than 12mm Hg. Patients were divided into progressors (35.3%) and non-progressors (64.7%) according to their visual field progression that correlated with any change of optic disc or retinal nerve fiber layer defect. Baseline demographic and clinical characteristics, including diurnal IOP and 24-hour blood pressure monitoring, were compared between the two groups.

Between the two groups, no significant differences were found in the follow-up periods, baseline visual field mean deviation or pretreatment IOP. However, the researchers found that greater diurnal IOP at baseline, fluctuations of diastolic blood pressure and optic disc hemorrhaging during follow-up were all risk factors for progression.