Parafoveal cone function in choroideremia assessed with adaptive optics optoretinography

Area of Science:

• Ophthalmology
• Retinal Imaging
• Vision Science

Background:

• Choroideremia (CHM) is an X-linked retinal degeneration impacting photoreceptors, retinal pigment epithelium (RPE), and choroid.
• Adaptive optics optoretinography (AOO) is an emerging noninvasive technique for objective photoreceptor function assessment.

Purpose of the Study:

• To investigate parafoveal cone function in CHM patients using AOO.
• To compare AOO findings with cone structure and clinical vision assessments.
• To evaluate the potential of AOO-derived population optoretinograms (ORGs) as a biomarker for photoreceptor function.

Main Methods:

• Parafoveal cone mosaics in 10 CHM and 4 normal-sighted participants were imaged using adaptive optics scanning light ophthalmoscopy.
• A visual stimulus was presented during video acquisition, and cone intensity was extracted, normalized, and aggregated to generate population optoretinograms (ORGs).
• ORG amplitude was analyzed and correlated with cone density, ellipsoid zone to RPE/Bruch's membrane distance, and foveal sensitivity.

Main Results:

• ORG amplitude was significantly reduced in CHM patients compared to normal controls (0.22 ± 0.15 vs. 1.34 ± 0.31).
• CHM ORG amplitude showed positive correlations with cone density, ellipsoid zone to RPE/Bruch's membrane distance, and foveal sensitivity.
• These findings highlight the utility of ORG in quantifying functional deficits in CHM.

Conclusions:

• Population optoretinograms show promise as a sensitive biomarker for assessing photoreceptor function in choroideremia.
• AOO-derived ORG can objectively measure functional deficits in retinal degeneration.
• This technique may aid in monitoring disease progression and evaluating therapeutic interventions for CHM.