Convergent strabismus in a white Bengal tiger

Area of Science:

• Veterinary Ophthalmology
• Genetics
• Comparative Medicine

Background:

• White Bengal tigers possess a genetic mutation causing reduced pigment.
• Strabismus, or crossed eyes, can affect vision and is observed in some white tigers.
• Comparative ocular examination aids in understanding vision abnormalities in rare coat colorations.

Observation:

• A white Bengal tiger cub presented with convergent strabismus and poor vision.
• A littermate with normal coloration had apparently normal eyes.
• Ocular examination under anesthesia revealed a fundus consistent with color-dilute animals in the white tiger.

Findings:

• The white tiger exhibited convergent strabismus but otherwise normal ocular structures.
• Electroretinography demonstrated similar retinal function between the white tiger and its normally pigmented littermate.
• The fundus appearance suggested a link between reduced pigmentation and visual pathway anomalies.

Implications:

• The strabismus may be an adaptation to genetically determined abnormal visual pathways linked to reduced pigmentation.
• Abducens nerve abnormalities or mechanical restrictions of the medial rectus muscles were considered as differential diagnoses.
• Further research into the genetics of vision in white tigers could inform conservation and veterinary care strategies.