Patients with advanced retinitis pigmentosa (RP) have reduced macular vessel density compared with individuals who do not have the disease, according to a study published in Sociedad Española de Oftalmologia.
Researchers included individuals with RP (n=12; mean age, 47.08 years; 7 men) and control group participants (n=22; mean age, 51.57 years; 12 men) in an observational, case-control study designed to to examine macular vessel density changes associated with RP. Study participants underwent optical coherence tomography-angiography (OCT-A) imaging of the superficial vascular plexus (SVP) and deep vascular plexus (DVP) in addition to visual acuity, biomicroscopy, and visual field assessments. The investigators compared vessel density values between participants with RP and control group individuals and determined correlations between vessel density and macular thickness.
Mean visual field index among individuals with RP was 26.11%. In all sectors of the DVP, vessel density was significantly lower in the RP group compared with the control group (superior, P <.0001; nasal, P =.0002; inferior, P <.0001; temporal, P =.0001) and in all but the nasal sector in the SVP (superior, P <.0001; nasal, P =.0067; inferior, P =.0002; temporal, P = .0024). Correlation between VD and macular thickness was positive and significant (RP group: r, 0.59; P = .043; control group: r, 0.51; P =.018).
“Accurate measurements of these parameters and the monitoring of small changes could be useful in the investigation of new treatments in clinical trials, using a non-invasive and easily reproducible method such as OCTA,” the study authors explain.
Study limitations include a small sample size, cross-sectional nature, difficulty in obtaining valid images in patients with advanced disease, and failure to consider refractive errors that may have altered quantitative measurements due to defocusing.
Duch Hurtado M, Vidal Oliver L, Marín Lambies C, Salom Alonso D. Microvascular quantitative metrics in retinitis pigmentosa using optical coherence tomography angiography. Arch Soc Esp Oftalmol. Published online April 7, 2023. doi:10.1016/j.oftale.2023.04.004