Functional Vision in Patients With Biallelic USH2A Variants

Area of Science:

• Ophthalmology
• Genetics
• Vision Science

Background:

• USH2A gene variants are linked to Usher syndrome type 2 (USH2) and autosomal recessive nonsyndromic retinitis pigmentosa (ARRP).
• Understanding functional vision (FV) is crucial for assessing the impact of these genetic conditions on patients' daily lives.

Purpose of the Study:

• To characterize functional vision (FV) in patients with biallelic USH2A variants.
• To explore the correlations between FV, visual acuity (VA), and the hill of vision (V OT) at the study's outset.

Main Methods:

• A multicenter, international, cross-sectional study involving 121 participants with biallelic USH2A variants.
• Clinical diagnosis of USH2 or ARRP was confirmed through audiology and patient history.
• The VALVVFQ-48 questionnaire was administered verbally, with VA and V OT measured to assess functional vision.

Main Results:

• Functional vision (FV) scores varied widely, from -2.0 to 7.6 logits, with no significant difference between ARRP and USH2 groups.
• Visual acuity (VA) and the hill of vision (V OT) each explained a substantial portion of the variance in FV scores (29% and 26%, respectively).
• Together, VA and V OT accounted for 36% of the observed variance in functional vision.

Conclusions:

• Biallelic USH2A variants are associated with a broad spectrum of functional vision impairments.
• Despite hearing loss in USH2 patients, FV outcomes were comparable between USH2 and ARRP groups.
• The modified VALVVFQ-48 may have limitations in fully assessing the daily living impacts of USH2A-related retinal degenerations.