Simulated and natural changes in intraocular transparency selectively affect photoreceptor-specific pupil responses

Area of Science:

• Ophthalmology
• Neuroscience
• Vision Science

Background:

• The pupillary light reflex (PLR) is crucial for vision and regulated by retinal photoreceptors.
• Intraocular media (IOM) transparency, affected by scattering, transmittance, and yellowing, can alter light reaching photoreceptors.
• The specific impact of IOM transparency variations on photoreceptor-specific PLR is not well understood.

Purpose of the Study:

• To investigate how variations in IOM transparency influence PLR responses mediated by different photoreceptors (Melanopsin, S-cones, L+M cones).
• To correlate individual IOM properties with specific PLR dynamics.
• To understand the implications for ophthalmic and neurological assessments.

Main Methods:

• Measured PLR using silent substitution and chromatic pupillometry in young adults.
• Assessed individual IOM properties (scattering, transmittance, yellowing).
• Correlated PLR measurements with IOM properties and simulated IOM changes with external filters.

Main Results:

• Cone-driven PLR responses were significantly impacted by IOM scattering and transmittance.
• Increased scattering consistently slowed S-cone-driven PLR.
• Melanopsin-driven PLR and effects of IOM yellowing were not statistically significant.

Conclusions:

• Normal variations in IOM transparency modulate the dynamics of cone-mediated PLR.
• Melanopsin-driven PLR remains robust against typical IOM transparency changes.
• Findings contribute to understanding individual differences in pupil responses and their influence on visual and clinical assessments.