At-Home Pressure Measurements Aid Risk Stratification in Primary Open Angle Glaucoma

Intraocular pressure (IOP) polygenic risk scores may be useful in risk stratification among people with glaucoma, and at-home measurements can provide insight into patients’ IOP profiles outside of office hours, according to research results published in Ophthalmology Glaucoma. 

Previous research has demonstrated the poor correlation of IOP measurements made during traditional office hours with peak diurnal IOP. Researchers hypothesized that IOP polygenic risk score could provide useful information about IOP measurements when made outside of office hours. In a cross-sectional study, a team investigated the association between genetic markers of high IOP and circadian IOP measurements. 

Participants (n=177; 334 eyes) of European ancestry diagnosed with primary open angle glaucoma (POAG) or optic nerve head changes with suspected early glaucoma were recruited. Each received a home tonometry device and underwent training to measure IOP in both eyes 4 times daily (early morning, midday, late afternoon, and late evening). 

Age was negatively correlated with maximum IOP and IOP fluctuation (P =.031 and .006). The associations were modest but persisted even after adjustment for gender, central corneal thickness, and the number of topical glaucoma medications. 

Increased IOP polygenic risk score strongly correlated with higher mean and maximum IOP measurements across all time periods, with the highest magnitude of effect for highest-recorded IOP in the early morning. Those who were stratified in the highest IOP polygenic risk score quintile had the highest-recorded early morning IOP increase of 4.3 mm Hg (95% CI, 1.4-7.3 mm Hg; P =.005), compared with the lowest quintile. 

Investigators also performed an analysis to assess the added utility of IOP polygenic risk score in predicting parameters of home tonometry by including clinician measured Goldmann applanation tonometry (GAT) IOP; data from 277 eyes were included. After accounting for numerous variables (in-clinic GAT, IOP, CCT, and age) IOP polygenic risk score remained significantly associated with highest-recorded IOP in the early morning (3.6 mm Hg increase in the highest IOP quintile; 95% CI, 0.72-6.5; P =.017). 

Finally, the researchers compared the performance of the IOP polygenic risk score to a multitrait glaucoma polygenic risk score, which includes additional variants associated with VCDR and glaucoma diagnosis. IOP-only polygenic risk score was “more strongly associated with circadian IOP parameters” than the multitrait glaucoma polygenic risk score. 

Study limitations include the limiting of results only to patients with established or suspected open angle glaucoma, a lack of continuous at-home IOP monitoring, and the choice to not study nocturnal IOP. 

“These findings support a role for genetic risk prediction of susceptibility to elevated IOP that may not be apparent in-clinic hours, requiring more detailed clinical phenotyping using home tonometry, the results of which may guide additional interventions to improve IOP control,” the research shows. 

Reference

Qassim A, Mullany S, Awadalla MS, et al. A polygenic risk score predicts intraocular pressure readings outside office hours and early morning spikes as measured by home tonometry. Ophthalmol Glaucoma. Published online December 11, 2020. doi:10.1016/j.ogla.2020.12.002