Glaucoma patients who have a family history of glaucoma are 10 times more likely to present with visual field defects at the time of diagnosis, according to a study by researchers in New Zealand.

"An increased focus on family history may help identify these patients earlier and prevent significant visual loss at the time of presentation," the authors said in the April issue of Clinical & Experimental Ophthalmology.

In the case-control study, Narme C. Deva, MBChB, and colleagues at the University of Auckland evaluated 107 consecutive newly diagnosed glaucoma patients to identify risk factors associated with visual field loss. The researchers based all visual field grading on Advanced Glaucoma Intervention Study (AGIS) scoring. The presence of a nasal step, paracentral scotoma or arcuate scotoma was also assessed.

The patients had an average IOP of 21.4 mm Hg, an average cup-to-disc ratio of 0.69 and an average age of 59 years.

The investigators identified a positive family history of glaucoma in 37% of the patients.

"Older age was associated with a [visual field] defect at presentation," the authors said.

Specifically, patients with no visual field defects averaged 54 years at presentation, while patients with mild, moderate or severe visual field defects averaged 63 years at presentation (P = .0014).

Through multivariate logistic regression analysis, the investigators identified positive family history (odds ratio 10.43) and age (odds ratio 1.15) as independent risk factors for visual field loss at presentation, according to the study.

Of 107 total patients, 56% had a paracentral visual field defect at initial diagnosis and 29% had AGIS scores of 6 or higher, representing a substantial visual field loss at initial presentation.