Photoreceptor Outer Segment Reflectivity With Ultrahigh-Resolution Visible-Light Optical Coherence Tomography in...

Area of Science:

• Ophthalmology
• Retinal Imaging
• Toxicology

Background:

• Hydroxychloroquine (HCQ) is widely used for autoimmune conditions.
• HCQ can cause retinal toxicity, potentially leading to vision loss.
• Early detection of HCQ retinopathy is crucial for preserving vision.

Purpose of the Study:

• To evaluate outer retinal organization in normal subjects and those using HCQ.
• To assess the utility of ultrahigh-resolution visible-light optical coherence tomography (VIS-OCT) in detecting HCQ-induced retinal changes.

Main Methods:

• Forty eyes from 22 adult subjects (controls and HCQ users) were imaged.
• A custom-built VIS-OCT device with 1.3 µm axial resolution was used.
• Comparison was made with U.S. Food and Drug Administration-approved OCT devices.

Main Results:

• VIS-OCT identified distinct hyperreflective bands in the outer retina of controls.
• Subjects using HCQ showed reduced intensity of these bands, particularly bands two to four.
• Attenuation of band 3i was the most consistent and earliest sign of HCQ toxicity.

Conclusions:

• VIS-OCT reveals a unique outer retinal banding pattern related to photoreceptor distribution.
• Early HCQ toxicity is associated with reduced photoreceptor outer segment reflectivity.
• Attenuation of band 3i may be an early, potentially reversible sign of HCQ retinopathy, primarily affecting cones.