Determination of Ophthalmic Parameters and Ocular Morphology in Ring-Necked Parakeets (Psittacula krameri) - Veterinary Ophthalmology Original Report Open Access

Sep 29, 2026

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Purpose: Determine normal ophthalmic test values and describe ocular morphology in ring-necked parakeets (Psittacula krameri). Materials and Methods: Thirty-three captive birds were examined using tear test (EAPPTT), intraocular pressure, corneal touch threshold, central corneal thickness, palpebral and corneal diameters, ocular ultrasonography, and corneoconjunctival microbiota; iris coloration was assessed in seven juveniles and two macerated skulls were examined. Results: Reported reference values covered EAPPTT, IOP, CTT, CCT, diameters, ultrasonographic biometry, and predominance of gram-positive bacteria. Conclusion: Findings support diagnosis and define normal anatomic features for this species.

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Abstract

Introduction

Materials and Methods

Results

Conclusion

Veterinary Ophthalmology ORIGINAL REPORT OPEN ACCESS Determination of Ophthalmic Parameters and Ocular Morphology in Ring-Necked Parakeets (Psittacula krameri) Fernanda Taques Wendt1 | Fabiano Montiani-Ferreira1 | Cecília Capacchi Dall’agnol1 | Franz Riegler Mello1 | Thiago Francisco Costa Solak1 | Breno Castello-Branco Beirão2 | Marcello Machado3 | Rogério Ribas Lange1 1Department of Veterinary Medicine, Federal University of Paraná (UFPR), Brazil | 2Department of Basic Pathology, Laboratory of Compared Immunology, Federal University of Paraná (UFPR), Brazil | 3Department of Anatomy, Federal University of Paraná (UFPR), Brazil Correspondence: Fernanda Taques Wendt ([vet.fernandatw@gmail.com](vet.fernandatw@gmail.com)) Received: 14 October 2024 | Revised: 9 May 2025 | Accepted: 11 May 2025 Funding: This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. Keywords: endodontic absorbent paper points | esthesiometry | intraocular pressure | ocular ultrasonography | Psittacula krameri | ring-necked parakeet ABSTRACT Purpose: To determine normal ophthalmic test values and to describe the ocular morphology of ring-necked parakeets (Psittacula krameri) . Materials and Methods: 33 captive birds were examined, although not all tests were conducted on each bird. The tests included endodontic absorbent paper point tear test (EAPPTT), intraocular pressure (IOP), corneal touch threshold (CTT), central corneal thickness (CCT), palpebral and corneal diameters, ocular ultrasonography, and corneoconjunctival microbiota. The iris coloration of seven young parakeets was evaluated, and two macerated skulls were described. Results: Normal values obtained were: EAPPTT: 7.57 ± 1.95 mm/min; IOP: 12.47 ± 1.51 mmHg; CTT: 2.46 ± 0.5 mm; CCT: 0.12 ± 0.006 mm; palpebral diameter: 8.04 ± 0.49 mm,; corneal diameter: 6.41 ± 0.49 mm. In ocular ultrasonography, the dimensions in the sagittal plane were: axial globe length (AGL): 0.94 ± 0.02 cm; vitreous chamber depth (VCD): 0.47 ± 0.02 cm; lens axial length (LAL): 0.32 ± 0.01 cm; anterior chamber depth (ACD): 0.1 ± 0.01 cm; pecten width (PW): 0.12 ± 0.02 cm, and pecten length (PL): 0.42 ± 0.04 cm. In the dorsal plane: AGL: 0.93 ± 0.03 cm; VCD: 0.47 ± 0.02 cm; LAL: 0.32 ± 0.03 cm; ACD: 0.1 ± 0.01 cm; PW: 0.32 ± 0.04 cm, and PL: 0.35 ± 0.03 cm. Microbiota analysis identified predominantly gram-positive bacteria, with Staphylococcus sp. being the most common (47.5%). Anatomical evaluation of skulls revealed a large lacrimal process extending to the zygomatic process, and the margins of the processes intersect but do not fuse. Young parakeets exhibit a brownish iris that gradually turns blue by 60 days of age. Conclusion: These findings may contribute to the diagnosis of ophthalmic conditions in this species and provide insight into normal anatomical features. 1 | Introduction The Order Psittaciformes includes approximately 400 species, many of which are popular pets worldwide. The ring-necked parakeet (Psittacula krameri) belongs to the genus Psittacula. It is a medium-sized bird, approximately 40 cm long, anda distinctive feature of this species is its large, curved, reddish-colored upper beak. Males of the species have a black ring around their neck, indicating sexual maturity, which is reached at around three years old [1, 2] . These birds attract attention from breeders because of their variety of color mutations and their intelligence in learning tricks and sounds, which makes them highly interactive. This species is native to India and sub-Saharan Africa, and according to the IUCN This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2025 The Author(s). Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists. Veterinary Opht

FAQs

What was the study purpose regarding ring-necked parakeets’ eyes?

To establish normal ophthalmic test values and to describe ocular morphology in ring-necked parakeets (Psittacula krameri).

Which ophthalmic tests and imaging methods were used?

The study included EAPPTT tear testing, intraocular pressure measurement, corneal touch threshold, central corneal thickness, palpebral and corneal diameters, and ocular ultrasonography, along with evaluation of corneoconjunctival microbiota.

What did the results show about reference values and microbiota?

The study reported normal reference ranges for ophthalmic tests and ultrasonographic dimensions, and microbiota analysis identified predominantly gram-positive bacteria, with Staphylococcus sp. as the most common.

Sep 29, 2026

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