Comparison of Octopus perimetry isopter area and Ellipsoid Zone (EZ) width in Retinitis Pigmentosa (RP) patients with and without Cystoid Macular Edema (CME).

Abstract

Purpose : CME is a common occurrence in patients with RP. In this study, we have compared isopter area measured by Octopus perimetry and EZ width measured by Spectral domain Optical Coherence Tomography (SD-OCT) in RP patients with or without CME.

Methods : Retrospective chart review of RP patients with Octopus and SD-OCT done on the same day was performed. Patients with visual acuity ≥ 50 letters, and no ocular co-morbidities such as history of retinal detachment and vitreomacular interface abnormality were included. Ellipsoid zone (EZ) width (^o) and foveal thickness (mm) were measured using Heidelberg HEYEX software. A MATLAB program was written to measure the I4e, III4e, and V4e isopter areas (o²) from Octopus maps. Mann-Whitney U and two-proportion Z test were performed to compare the CME with the non-CME group.

Results : Forty eyes of 24 patients (9 males, age 22-63 years) qualified based on criteria listed above. Twelve eyes of 7 patients had CME. Peripheral island of III4e was found in 8 non-CME eyes vs. 2 CME yes (p=0.49), and I4e found in 6 non-CME eyes vs. 1 CME eye (p=0.32). Table 1 shows the results.

Conclusions : Patients with CME had a statistically significant reduction in all isopter areas, both central and peripheral, as well as a decline in EZ-width when compared to non-CME eyes. This along with the lack of peripheral islands of vision on Octopus perimetry in CME eyes may suggest that CME is more likely to be present in more advanced disease. Further studies are recommended to study the relationship between presence of CME and stage of RP.

This is a 2021 ARVO Annual Meeting abstract.