Patients who develop primary open-angle glaucoma (POAG) may have a lot in common at the genetic level. Researchers from the UK and Australia developed an IOP polygenetic risk score that found strong correlations with disease severity, maximum IOP, need for surgery and number of family members who also had glaucoma.

The investigation looked at a set of similar glaucoma characteristics among 2,154 POAG patients enrolled in the Australian and New Zealand Registry of Advanced Glaucoma, including cases recruited from the UK. Researchers also examined an independent cohort of 624 early POAG patients.

Using IOP genome data, the researchers divided the POAG patients into three risk tiers: low, intermediate and high. They considered maximum recorded IOP, age of diagnosis, number of family members with glaucoma, cup-to-disc ratio, visual field deviation and number of medications taken.

The study found a dose-response link between the IOP polygenic risk score and the maximum-recorded IOP. Additionally, patients in the high-risk group had a greater maximum IOP by 1.7mm Hg compared with the low-risk group.

Age also appeared to be a factor. The high genetic risk group was diagnosed approximately 3.7 years earlier than the low genetic risk group. The high-risk group also had more family members with glaucoma (0.46 people), and additional higher rates of incisional surgery than the low risk group.

No significant differences were seen in mean deviation. Maximum IOP, number of family members with glaucoma and treatment intensity were also mirrored in the early POAG cohort.

“Genes acting via IOP mediated pathways, when considered in aggregate, have clinically important and reproducible implications for glaucoma patients and their close family members,” the researchers wrote in their paper.

Qassim A, Souzeau E, Siggs, O, et al. An intraocular pressure polygenic risk score stratifies multiple primary open angle glaucoma parameters including treatment intensity. Ophthalmology. January 6, 2020. [Epub ahead of print].