Keratometry, biometry, and intraocular lens power calculation in Bornean sun bears (Helarctos malayanus euryspilus).

Abstract

Background: Cataracts are a common ocular condition that affects captive sun bears, yet there is a lack of detailed case reports and ocular studies of this species.

Aim: The examinations aim to calculate the intraocular lens (IOL) power required to achieve emmetropia following cataract surgery.

Methods: Five Bornean sun bears diagnosed with cataracts at the Bornean Sun Bear Conservation Centre in Malaysia underwent ocular examination under general anesthesia. Keratometry and biometry data, including anterior chamber depth, crystalline lens thickness, and axial globe length, were collected using an automated keratometer and B-mode ultrasound. The Retzlaff, Binkhorst, Colenbrander, and Fyodorov formulas were used to estimate the required IOL power.

Results: The mean corneal keratometric power was 56.94 D, the mean axial globe length was 12.93 mm, and the mean calculated postoperative anterior chamber depth was 4.77 mm. The mean calculated IOL power was +92.96 D. Conclusion: Aphakic cataract surgery were decided following these findings showing no available commercial IOL implants for this species. These findings provide valuable baseline data for optimizing cataract surgery in Bornean sun bears.