Visual acuity and visual field impairment in Usher syndrome

Area of Science:

• Ophthalmology
• Genetics
• Retinal Degeneration

Background:

• Usher syndrome is a leading genetic cause of combined vision and hearing loss.
• Types 1 and 2 Usher syndrome are distinct genetic subtypes with varying clinical manifestations.

Purpose of the Study:

• To compare the extent of visual acuity and visual field impairment between patients with Usher syndrome type 1 and type 2.
• To provide data for improved patient counseling regarding visual prognosis.

Main Methods:

• Retrospective review of medical records for 53 patients with type 1 and 120 patients with type 2 Usher syndrome.
• Visual acuity and visual field areas (II4e and V4e isopters) were measured using Goldmann perimetry and planimetry.
• Statistical analysis included ordinary and logistic regression models to assess differences between the two groups.

Main Results:

• Type 1 Usher syndrome patients demonstrated significantly greater visual acuity and visual field impairment compared to type 2 patients.
• Age-adjusted odds ratios indicated higher impairment in type 1 patients for visual acuity (3.9), V4e visual field (2.9), and II4e visual field (4.9).
• While 51% of type 1 patients had visual acuity of 20/40 or better, 72% of type 2 patients achieved this level.

Conclusions:

• Usher syndrome type 1 is associated with more severe visual impairment than type 2.
• These findings underscore the importance of differentiating Usher syndrome types for accurate patient counseling and management.
• The data provide valuable insights into the visual prognosis for individuals diagnosed with Usher syndrome.