Bilateral cataract surgery with intraocular lens implant in a captive western lowland gorilla

A-scan biometry, phacoemulsification, and foldable intraocular lens implantation in a young orangutan (Pongo pygmaeus)

Background:

Cataracts are the major cause of visual impairment in animals which can be curable by surgical treatment. Phacoemulsification is the standard technique for cataract treatment that is applied to almost all species with a high success rate.

Case Description:

A 2-year-old intact female orangutan (Pongo pygmaeus) was presented for the study having bilateral opacity of the lenses, for 2 weeks. Ophthalmic examination revealed mature cataract OU. Ocular biometry measurements using A-scan ultrasonography for appropriate intraocular lens (IOL) refractive power calculation were carried out. Electroretinography was applied to ensure retinal function is intact. The orangutan underwent phacoemulsification OU and +24 diopter IOL implantation OS to restore vision. IOL implantation was not carried out OD because of a posterior capsular tear. Retinoscopy after 3 weeks postoperatively revealed +2.0 diopters OS. The outcome of the cataract surgery was successful during 3 years follow-up. The orangutan lived with other orangutans and was alert with normal behavior such as catching food, climbing trees, and swinging hand over hand from one branch to another.

Conclusion:

Cataract surgery with phacoemulsification OU and adjusted IOL implantation OD was successful with few complications in this orangutan. Vision was restored with normal behavior, even though an adjusted IOL was inserted in only one eye.