Optic nerve crush modulates refractive development of the C57BL/6 mouse by changing multiple ocular dimensions

Area of Science:

• Ophthalmology
• Neuroscience
• Developmental Biology

Background:

• Local eye mechanisms and higher visual centers can modulate visually-guided ocular growth.
• Central modulation of ocular growth may be species-dependent.
• The role of visual centers in modulating refractive development in mice, a key myopia research model, is unclear.

Purpose of the Study:

• To investigate whether and how higher visual centers modulate refractive development in C57BL/6 mice.
• To examine the effects of optic nerve crush (ONC) on refractive development and ocular dimensions in mice.

Main Methods:

• Optic nerve crush (ONC) or sham surgery was performed at postnatal day 18 in C57BL/6 mice.
• Refractive error, corneal curvature, and ocular axial length were measured.
• Retinal dopamine and DOPAC levels, and dopaminergic amacrine cell density were analyzed.

Main Results:

• Sham surgery caused corneal steepening and a modest myopic shift without altering ocular axis length.
• ONC induced corneal flattening and bidirectional refractive shifts (myopic or hyperopic) in 72.7% of animals, primarily due to changes in ocular axial length.
• ONC increased retinal dopamine and DOPAC levels but did not alter dopaminergic amacrine cell density.

Conclusions:

• Higher visual centers play a role in fine-tuning ocular growth and refractive development in C57BL/6 mice.
• ONC-induced refractive errors are linked to alterations in corneal curvature and axial length.
• Central visual pathways modulate refractive development in mice, similar to other species.