Frequency-dependent retinal responsiveness to sinusoidal electrical stimulation in achromatopsia

Area of Science:

• Ophthalmology
• Neuroscience
• Physiology

Background:

• Assessing cell-specific retinal function is crucial for understanding visual disorders.
• Electrophysiological methods can probe retinal cell activity.
• Achromatopsia, a severe inherited retinal disease, affects color vision and visual acuity.

Purpose of the Study:

• To evaluate alterations in retinal responsiveness in achromatopsia patients using transcorneal electrostimulation.
• To explore the frequency-selectivity of photoreceptor function in achromatopsia.
• To investigate the potential of electrostimulation for assessing retinal function independent of light response.

Main Methods:

• Sinusoidal transcorneal electrostimulation with variable carrier frequencies (4-30 Hz) applied to achromatopsia patients.
• Measurement of retinal responsiveness via velocity and synchronicity of electrically evoked pupillary oscillations.
• Comparison of achromat responses to healthy retinal tuning curves.

Main Results:

• Achromatopsia patients exhibited a distinct peak in retinal responsiveness within the 6-10 Hz frequency range.
• Stimulus frequencies above 16 Hz elicited weak pupil responses and phosphenes in achromats.
• Low-frequency stimulation appeared to activate rods, while higher frequencies suggested cone activation, differing from healthy retinas.

Conclusions:

• Electrostimulation reveals frequency-selective retinal dysfunction in achromatopsia.
• Rod and cone pathway contributions to electrical responses differ in achromats.
• This technique offers a novel approach to assess cell-specific retinal function, potentially aiding gene therapy evaluation.