Visual photosensitivity threshold and objective photosensitivity luminance in healthy human eyes assessed using an automated ocular photosensitivity analyser: a step towards translation of a clinical tool for assessing photophobia

Correlations between the Michigan Retinal Degeneration Questionnaire and visual function parameters in patients with retinitis pigmentosa

PURPOSE

To validate the use of best-corrected visual acuity (BCVA), low-luminance visual acuity (LLVA), low-luminance deficit (LLD; the difference between BCVA and LLVA), mean macular sensitivity and fixation stability as parameters of vision-related quality of life based on the novel Michigan Retinal Degeneration Questionnaire (MRDQ) in retinitis pigmentosa (RP) patients.

METHODS

In this prospective cross sectional study, 30 patients with RP (47% female) were included with a median age of 41.0 years (interquartile range: 24.1-58.3 years). BCVA, LLVA and LLD were measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts. Mesopic microperimetry was performed to measure mean macular sensitivity and fixation stability. Patients completed a Dutch translation of the MRDQ which results in an experienced disability (Θ-)score of seven domains. Spearman's rank correlation was used.

RESULTS

BCVA correlated significantly to the MRDQ domain of central vision (r = 0.657; p < 0.001) and colour vision (r = 0.524; p = 0.003). Lower LLVA significantly correlated to higher experienced disability in the MRDQ domains for central vision (=0.550; p = 0.002) and contrast sensitivity (r = 0.502; p = 0.005). LLD was significantly correlated to the MRDQ domains of scotopic function (r = -0.484; p = 0.007) and mesopic peripheral function (r = -0.533; p = 0.002). Lower mean macular sensitivity was significantly associated with high experienced disability in all domains except for photosensitivity.

CONCLUSIONS

The majority of the MRDQ domains is strongly associated with visual function parameters. These findings show that visual function measurements, especially LLVA, LLD and mean macular sensitivity on microperimetry, reflect vision-related quality of life and can be used as relevant outcome measures in clinical trials for RP.

Correlation between higher-order aberration and photophobia after cataract surgery

Cataract surgery impinges on the spatial properties and wavelength distribution of retinal images, which changes the degree of light-induced visual discomfort/photophobia. However, no study has analyzed the alteration in photophobia before and after cataract surgery or the association between retinal spatial property and photophobia. Here, we measured the higher-order aberrations (HOAs) of the entire eye and the subjective photophobia score. This study investigated 71 eyes in 71 patients who received conventional cataract surgery. Scaling of photophobia was based on the following grading system: when the patient is outdoor on a sunny day, score of 0 and 10 points were assigned to the absence of photophobia and the presence of severe photophobia prevents eye-opening, respectively. We decomposed wavefront errors using Zernike polynomials for a 3-mm pupil diameter and analyzed the association between photophobia scores and HOAs with Spearman’s rank sum correlation (rs). We classified patients into two groups: photophobia (PP) unconcerned included patients who selected 0 both preoperatively or postoperatively and PP concerned included the remaining patients. After cataract surgery, photophobia scores increased, remained unchanged (stable), and decreased in 3, 41, and 27 cases, respectively. In the stable group, 35 of 41 cases belonged to PP unconcerned. In PP concerned, there were significant correlations between photophobia score and postoperative root-mean-square values of total HOAs (rs = 0.52, p = 0.002), total coma (rs = 0.52, p = 0.002), total trefoil (rs = 0.47, p = 0.006), and third-order group (rs = 0.53, p = 0.002). In contrast, there was no significant correlation between photophobia scores and preoperative HOAs. Our results suggest that the spatial properties of retinal image modified by HOAs may affect the degree of photophobia. Scattering light due to cataracts could contribute to photophobia more than HOAs, which may mask the effect of HOAs for photophobia preoperatively.