Imaging endpoints for clinical trials in MacTel type 2.

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Macular Telangiectasia type 2 (MacTel) is a bilateral neurodegenerative condition affecting Muller cells and photoreceptors.
• Disease progression involves vascular abnormalities, retinal transparency loss, pigment redistribution, and central retinal thinning.
• Photoreceptor loss extent, visualized via Optical Coherence Tomography (OCT), correlates with functional deficits, making its limitation a key therapeutic goal.

Purpose of the Study:

• To review imaging techniques for MacTel assessment.
• To discuss objective quantification of MacTel severity and its correlation with visual function.
• To evaluate imaging endpoints for clinical treatment trials.

Main Methods:

• Review of imaging modalities including fluorescein and OCT angiography, blue light reflectance, and multi-wavelength autofluorescence.
• Analysis of Optical Coherence Tomography (OCT) for quantifying photoreceptor loss.
• Correlation of imaging findings with functional measures like best-corrected visual acuity (BCVA) and microperimetry.

Main Results:

• En face OCT provides precise and reproducible quantification of photoreceptor loss area.
• Photoreceptor loss area measured by en face OCT shows a highly significant correlation with functional loss assessed by microperimetry.
• This imaging endpoint is crucial for evaluating treatment efficacy in MacTel.

Conclusions:

• En face OCT analysis of photoreceptor loss area is the most reliable imaging endpoint for MacTel treatment trials.
• This quantitative imaging method is currently utilized in ongoing randomized clinical trials for MacTel.
• Precise and reproducible outcome measures are essential for assessing therapeutic interventions in MacTel.