Abstract
Purpose :
To correlate the optical coherence tomography angiography (OCTA) findings with macular structure - central macular thickness (CMT) and ellipsoid zone (EZ) width on OCT, and macular function - best-corrected visual acuity (BCVA) in patients with retinitis pigmentosa (RP).
Methods :
Retrospective study evaluated 30 eyes of 16 subjects (age range, 12 to 59 years) with RP. The BCVA was measured in all subjects and they underwent SD-OCT scans (Heidelberg, Germany) and OCTA scans (RTVue XR 100Avanti, Optovue, CA, USA). The CMT and EZ width were calculated from the SD-OCT scans and the ‘vessel density (VD)’ was calculated for various retinal en-face zones and choriocapillaris layer from the OCTA scans.
Results :
The mean visual acuity was 0.40±0.3 (range, 0-1.2; median, 0.3) and the CMT was 268.23±61.15µ (range, 133-387µ; median, 282µ). The mean EZ width was 1204.23±907.24µ (n=26). OCTA of the foveal area showed a VD of 30.07±6.01 in the superficial zone, 28.84±5.77 in the deep zone, 47.67±5.69 in the photoreceptor zone and 62.37±5.41 in the choriocapillaris zone.
GraphPad InStat v.3; (San Diego, California, USA) was used for statistical analysis. Spearman’s correlation coefficient was tested to evaluate the linear correlation among variables in RP patients. P value of <0.05 for multiple correlation coefficients was considered significant.
The EZ width correlated significantly only with the superficial zone VD. The CMT correlated significantly wit the VD of all 3 retinal zones – more so with superficial and photoreceptor zones. The visual acuity correlated significantly with the VD of the superficial and photoreceptor zones. None of the macular structural tests or functional tests correlated significantly with choriocapillaris VD.
Conclusions :
Macular structure (CMT and EZ width) and function (visual acuity) correlate most with the superficial foveal VD and photoreceptor VD. The significance of photoreceptor VD is unknown as there are no vessels in that area. These findings may provide a clue to the pathophysiology of RP and the vascular attenuation. Future studies in RP patients may shed further light on the role of the developing novel technology of OCTA in this condition. OCTA may become a new useful additional tool to monitor disease activity and efficacy of new therapeutic approaches.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.