Cone dysfunction in ARR3-mutation-associated early-onset high myopia: an electrophysiological study

Area of Science:

• Ophthalmology
• Genetics
• Retinal Physiology

Background:

• Myopia-26 is a rare Mendelian form of early-onset high-myopia (eoHM) linked to mutations in the X-chromosomal ARR3 gene.
• This condition predominantly affects females and offers a unique model to study retinal mechanisms in pathological eye growth.

Purpose of the Study:

• To investigate the electrophysiological characteristics of Myopia-26 patients.
• To differentiate the effects of ARR3 mutations from general high myopia on retinal function.

Main Methods:

• A case-control study involving 26 participants: healthy controls, high myopes without ARR3 mutations, and Myopia-26 patients.
• Full-field electroretinograms (ERGs) were recorded under light and dark-adapted conditions.
• Genetic analysis confirmed ARR3 gene status.

Main Results:

• Myopia-26 patients exhibited significantly reduced best-corrected visual acuity (BCVA) compared to controls.
• Light-adapted ERG amplitudes (a- and b-waves) were reduced by ~35% in Myopia-26 patients and ~55% in ARR3 mutation carriers.
• Dark-adapted a-wave amplitudes showed a ~20% reduction in all myopic patients, regardless of ARR3 genotype.

Conclusions:

• Cone dysfunction in Myopia-26 patients is directly attributable to ARR3 mutations, not solely to eye elongation.
• The ARR3 mutation may contribute to myopic refractive error development via an as-yet-unconfirmed pathway.