Choroideremia Carriers: Dark-Adapted Perimetry and Retinal Structures

Area of Science:

• Ophthalmology
• Genetics
• Retinal Imaging

Background:

• Choroideremia (CHM) is an X-linked genetic disorder affecting the retina.
• Understanding visual function and structural changes in CHM carriers is crucial for monitoring disease progression.

Purpose of the Study:

• To assess scotopic sensitivity using dark-adapted chromatic perimetry (DACP) in CHM carriers.
• To evaluate outer retinal structure in CHM carriers using multimodal imaging techniques.

Main Methods:

• Nine CHM carriers and 13 controls underwent DACP with cyan and red stimuli in peripapillary, macular, and peripheral regions.
• Multimodal imaging included spectral domain optical coherence tomography (SD-OCT) and various fundus autofluorescence (AF) methods (SW-AF, NIR-AF, qAF).

Main Results:

• Rod-mediated vision was comparable to controls in macular and peripheral areas.
• Scotopic sensitivity was significantly decreased in the peripapillary area of CHM carriers (P < 0.05).
• Structural abnormalities, including outer retinal changes and peripapillary atrophy, were observed, correlating with peripapillary vision deficits.

Conclusions:

• Scotopic sensitivity is preserved in the macula and periphery of CHM carriers.
• The peripapillary region shows reduced rod-mediated sensitivity and is the site of the most severe structural retinal changes in CHM carriers.