Ophthalmic diagnostic tests and ocular findings in healthy adult cockatiels (Nymphicus hollandicus)

Cockatiels (Nymphicus hollandicus) are a common companion psittacine for which little ophthalmic data has been gathered. The goal of this study was to establish normal ocular parameters in healthy cockatiels and evaluate whether intraocular pressure (IOP) varies by restraint method. Twenty-five cockatiels free of ophthalmic disease underwent complete ophthalmic examination including slit-lamp biomicroscopy, indirect ophthalmoscopy, and measurement of palpebral fissure diameter, tear production by absorbent paper point tear test (PPTT) and rebound tonometry. IOP measurements were obtained with birds held in two different body positions (vertical and dorsal recumbency). Cockatiel eyes are atapetal, anangiotic, and possess robust filoplumes, brown irises, pleated pecten, and circular pupil. There was no significant difference for horizontal palpebral fissure diameter, vertical palpebral fissure diameter, PPTT or IOP when comparing dorsal to vertical recumbency. For all eyes (50 eyes from 25 cockatiels), the mean (range) of horizontal palpebral fissures was 5.45 (5.0–6.0) mm, PPTT was 9.39 (6–14) mm/15s, and IOP (both recumbencies) was 13 (8.0–24.0) mm Hg. Described data can be used to improve diagnosis and management of ocular alterations in this species.