Detailed evaluation of chromatic pupillometry and full-field stimulus testing to assess ultra-low vision function in retinitis pigmentosa
Purpose Novel therapeutic options, such as regenerative medicine and gene therapy are now emerging as viable treatment options for patients with severe visual impairments, such as retinitis pigmentosa (RP). Gradable assessment of patients′ visual function is essential to consider treatment options and to evaluate treatment outcomes, however, evaluation of visual function in advanced low vision patients is often challenging due to patients′ poor and sometimes unpredictable responses. In this
... y, we attempted to accurately assess the visual capabilities and disease stage in RP patients with visual acuity of 0.01 or lower, using chromatic pupillometry and full-field stimulus testing (FST), combined with retinal histological features, as determined by spectral-domain OCT. Design Retrospective analysis of visual function tests in 84 eyes of 43 patients with advanced RP with visual acuity of 0.01 and lower visited Kobe City Eye Hospital from 2019 to 2021. Methods: Eighty-four eyes of 43 patients with advanced RP with visual acuity of 0.01 and lower were evaluated by chromatic pupillometry, FST, BCVA (best-corrected visual acuity), and OCT (optical coherence tomography). Hierarchical (multilevel) Bayesian modeling was used to estimate individual eye′s pupil response and FST, taking into account the ambiguity and randomness often observed in ultra-low vision patients. Using the estimated ability obtained from each test, the correlation between each test and histological features was further analyzed to make a comprehensive assessment of the data and background pathology. Results FST and pupillometry measurements were moderately correlated with visual acuity, but exhibited a wide range of values within the same visual acuity groups. FST was not correlated with central retinal thickness at CF/HM VA range and seemed to reflect overall remaining photoreceptor function including peripheral retina. Pupillometry seemed to distinguish different levels of cone impairment. Conclusion The combination of pupillometry and FST allowed for graded evaluation of visual function within patients grouped in the same visual acuity groups in advanced RP patients with ultra-low vision.