Abstract
Purpose :
Full-field stimulus thresholds (FST) are essential in assessing visual function, especially in patients with severe visual impairment. We describe the distribution of luminance thresholds in subjects with retinitis pigmentosa (RP), aiming to establish a deep phenotyping system.
Methods :
Cases with RP who have severe visual acuity decline (counting finger or worse) were enrolled. Comprehensive clinical examinations were performed, including full-field electroretinograms (ffERGs) recorded according to the ISCEV standard. Full-field color stimuli were generated by the Diagnosys Profile ganzfeld ColorDome (Diagnosys, LLC, MA, USA) which utilizes narrow-band LEDs of 448 nm (blue), 530nm (green), and 627 nm (red). FST was performed according to the previously published method (Klein, Birch 2009). The dark-adapted color FST was performed after 40 minutes dark adaptation in the following order: (i) blue; (ii) red; and (iii) white stimulus. The FST data obtained in RP patients were compared with those of seven healthy participants (median age 29, range 23 to 45 years) with no ocular diseases.
Results :
The median age of disease onset/age at examination of 28 eyes from 14 cases with RP was 9.0 (range, 0 to 40)/64.0 (36 to 75). The median visual acuity of 28 eyes was 2.7(range, 1.98 to 3.00) LogMAR unit. The full-field ERGs were undetectable both in dark-adapted and light adapted conditions in all 14 RP cases. The median value of thresholds for blue/red/white FST was 7.06(range, -33.1 to 21.8)/10.00(-6.5 to 18.9)/9.37(-25.5 to 24.7) dB. The median value of thresholds for blue/red/white FST was -59.9/-35.8/-54.0 dB in the seven healthy subjects. FST revealed a significant different range of thresholds for each colour stimulus between severe RP patients and healthy subjects.
Conclusions :
Distribution of luminance thresholds was demonstrated in 14 cases with severe RP, which was significantly higher than that of healthy participants. Quantitative assessment for patients with severe visual impairment was available with FST, in keeping with previous reports (Roman AJ et al. Prog Retin Eye Res. 2021; Klein et al. Doc Ophthalmol. 2019). Further data from additional affected participants are required to validate the clinical investigation in patients with severe visual impairment.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.