Primary open-angle glaucoma (POAG) patients with a single-hemifield defect have slightly less than fifty-fifty odds of developing a similar defect in the opposite hemifield after eight years, but older patients and those with an absence of optic disc vertical tilt may be at greater risk, a team of Korean researchers suggest.

Their study, published in the Journal of Glaucoma, included 108 POAG eyes with an initial single-hemifield defect found with visual field (VF) testing. During an eight-year follow up, the investigators found 41.7% of eyes had involvement in the opposite hemifield.

The study divided patients into two groups: group A consisted of 63 patients with a single hemifield defect and group B included 45 subjects who had involved opposite hemifields based on patterns of VF progression.

The average follow-up period was slightly less than eight years.

The study found significant differences in age (approximately 56 years vs. 61 years, respectively) and the presence of optic disc vertical tilt (54% vs. 28.9%, respectively) between the two groups.

Older age is a potential risk factor for glaucoma and is positively correlated with faster progression, the researchers noted. Also, the absence of optic disc vertical tilt represents a lesser effect of specific-directionality morphologic deformations on the optic nerve head, they added.

“Therefore, it is probable that older patients without optic disc vertical tilt and exhibiting an initial single-hemifield defect will eventually show progression to the opposite hemifield. On the other hand, in POAG patients of young age with an optic disc vertical tilt, involvement of the opposite hemifield is less likely to occur,” the researchers wrote in their paper.

Accordingly, young POAG patients with an optic disc vertical tilt who present with an initial single hemifield defect can be considered to be clinically more stable in terms of the area of the affected hemifield, they added.