Abstract
Purpose :
The health of outer retinal layers (ORL) have been reported to be predictive of visual function in a number of retinal disorders including Retinitis Pigmentosa (RP). The purpose of this study is to correlate the integrity of the ORL with visual acuity and response to treatment in patients with RP and Macular Edema (ME).
Methods :
All patients with RP and ME who had been imaged as part of the All Ireland Retinal Degenerations Partnership Study were reviewed.
All patients had full visual function assessment and OCT imaging was performed on the Heidelberg Spectralis using the pre-defined posterior pole scan. Scans were reviewed for presence of Macular Edema (ME) and history of treatment for ME was recorded. The integrity of the Outer Limiting Membrane (OLM) and the Ellipsoid Zone (EZ) in the central macular area were categorized as follows: Grade 1 – Normal, 2 – Irregular, 3- Focal Loss, 4 - Absent and 5 - Ungradable. A correlation was made between the integrity of the ELM and EZ, visual function and response to treatment.
Results :
23 patients (46 eyes) were identified as having ME in this cohort of patients. Best corrected distance visual acuity (BCDVA) measured in LogMar units, ranged between (0.0 – HM). The pattern of loss of the ELM was almost exactly mirrored by the pattern of loss in the EZ, therefore the results were combined into one grade for the ORL. The RPE was well preserved in all eyes.
The ORL was Grade 1 in 54.3 % of eyes, 2 in 15.2%, 3 in 1.7%, 4 in 21.7% and 5 in 0.2% of eyes. Correlation of BCDVA with ORL integrity showed that the mean BCDVA (LogMar) in eyes with Grade 1 was +0.3; 2 -,+0.5; 3 - +0.9; 4 +0.8 and 5 - HM. Twenty-five eyes received treatment for ME; 16% showed improvement in BCDVA; 44% were stable and 40% showed deterioration in BCDVA. Table 1 shows the percentage of eyes showing improvement, stabilization or deterioration of BCDVA correlated with ORL grade in eyes that received treatment for ME by ORL grade.
Conclusions :
In ME secondary to RP, loss of integrity of the ORL was associated with a mean reduction in BCDVA. In addition, only 16% of eyes treated gained an improvement. All of these eyes had normal ORL. However 33.3% eyes with normal ORL did not improve but maintained stable vision and 40% experienced deterioration. Therefore the presence of a normal ORL does not guarantee improvement or stabilization of BCDVA with treatment of ME in RP.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.