Clinicians caring for patients with unilateral normal-tension glaucoma (NTG) should keep a close watch on the fellow eye, as new data suggests many will see glaucomatous changes within five years. A recent study in the British Journal of Ophthalmology looked at 76 patients diagnosed with unilateral NTG and followed them for more than five years. 

The researchers found that, after a follow-up period of approximately 7.3±2.4 years, 26.6% of the patients developed glaucoma in the contralateral eye, and the five-year rate of conversion was 19.7%. They noted that eyes that converted had a few key baseline characteristics compared with the controls: a significantly greater rate of disc hemorrhage and a greater maximum width of the β-zone parapapillary atrophy (MWβPPA)­–disc diameter ratio.

Further analysis showed that IOP over 17mm Hg, a central corneal thickness under 491μm and a MWβPPA-DD ratio over 0.32 in the contralateral eye at baseline were all independent risk factors for glaucoma conversion.