Abstract
Purpose :
To compare the biometric parameters and gonioscopic findings in retinitis pigmentosa patients with age and gender matched normal subjects.
Methods :
Patients with clinically diagnosed retinitis pigmentosa above 18 years of age were recruited. Patients with prior peripheral iridotomy /any ocular procedure and who cannot undergo biometry were excluded from the study. Participants underwent visual acuity testing, refraction, slitlamp examination, applanation tonometry, gonioscopy, fundus examination and ocular biometry evaluation which included the measured values - axial length (AL), anterior chamber depth (ACD), lens thickness (LT), central corneal thickness (CCT), keratometry (K) and computed values - lens position (LP), relative lens position(RLP), lens thickness axial length factor (LAF). Outcome measures included the prevalence of angle closure disease in retinitis pigmentosa by comparing the biometric and gonioscopic findings between cases (RP) and controls (N). Results were compared using students t- test for mean values, p value of <0.05 was considered statistically significant.
Results :
Two hundred and seventy-seven eyes of 140 RP patients [RP] and 280 eyes of 140 controls [N] (n-81 males, n-59 females) were studied, the average age of cases and controls was 45.79 and 45.14 years respectively. Compared to normal subjects the patients with RP presented with similar AL (RP=23.08mm, N=23.16mm, p=0.30), a shallower chamber depth ACD (RP=3.01mm, N=3.16mm, p=<0.001*), a similar lens thickness LT (RP=3.95mm, N=3.99mm, p=0.46), a anteriorly located lens LP (RP=4.99, N=5.16, p=<0.001*), RLP values (RP=0.21, N=0.22, p<0.01*), the LAF value in RP=0.17, N=0.17 respectively. The anterior chamber angle was occludable in 36 (12.8%) individuals (RP=18.57 % (n=26), N= 7.14 % (n=10), (chi square test P<0.01*)). Log MAR vision of 0 to 0.3 was present in 95% of cases. The most common refractive error in cases was myopic astigmatism. There was no significant difference in central corneal thickness, intra ocular pressure, keratometry variables (p>0.05).
Conclusions :
RP patients had a crowded anterior segment compared to controls because of significant shallower anterior chamber and anteriorly located lens. Hence angle closure glaucoma may be successfully prevented by timely identification and prompt treatment.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.