The correlation between Glaucoma polygenic risk score and IOP measured by Icare® HOME tonometry within and outside of office hours.

Abstract

Purpose : We have recently described a glaucoma polygenic risk score (PRS) which is associated with intraocular pressure (IOP) and could help in glaucoma prediction. In this study we aim to investigate the correlation between IOP as measured by Icare® HOME tonometry, worsening glaucoma, and the PRS.

Methods : 137 participants with glaucoma were invited from within a 5-year prospective study of glaucoma progression (PROGRESSA) to perform home tonometry. Patients were instructed on the use of the Icare® HOME tonometry device. Patients were asked to measure their eye pressure four times per day for 2 to 4 consecutive days including early morning, midday, afternoon and late evening time points. A glaucoma PRS was developed by characterizing glaucoma endophenotypes on 67,040 UK Biobank (UKBB), and previously published data, and combining data on IOP, vertical cup to disc ratio (VCDR) and glaucoma, using multi trait analysis of GWAS (MTAG). Glaucoma progression was assessed using optical coherence tomography (Zeiss Cirrus^TM HD OCT) of the peripapillary retinal nerve fibre layer (pRNFL).

Results : There was a correlation between structural loss of retinal nerve fibre layer structure and maximum recorded IOP during the Icare® HOME measurement period (p = 0.045). In addition, maximum recorded IOP and mean IOP values were correlated with worsening VCDR with p-value of 0.028 and 0.021, respectively. There was a trend towards association between the GPRS and the maximum recorded IOP difference between inside office hours (8AM to 6PM) and outside office hours (6PM to 8AM) (p= 0.070).

Conclusions : A significant association was found between the maximum recorded IOP and glaucoma progression as determined by RNFL loss and increased VCDR. The possible association of the glaucoma polygenic risk score with IOP fluctuation between in and out of office hours raises the possibility that a genetic test could provide useful information about IOP fluctuation beyond what is currently achievable with twice yearly snapshot measurement of IOP.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.