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. 2025 May 28:47:e001125.
doi: 10.29374/2527-2179.bjvm001125. eCollection 2025.

Evaluation of the lacrimal and nasolacrimal system in dogs treated at a veterinary ophthalmology service

Lucas de Souza Viana  1 , Diego Neves Vianna  1 , Camila Cristina Rio Preto Martins de Sousa  2 , Suzana de Souza Lima  1 , Bruno Alberigi  3
Affiliations

Evaluation of the lacrimal and nasolacrimal system in dogs treated at a veterinary ophthalmology service

Lucas de Souza Viana et al. Braz J Vet Med. .

Abstract
in English, Portuguese

In routine veterinary medicine, the lacrimal and nasolacrimal systems are associated with several ophthalmopathies. Understanding its physiology and improving specific diagnostic tests will help establish an assertive approach and avoid lacrimal and nasolacrimal disorders that cause damage to the ocular surface. This prospective study was conducted on 43 dogs treated at the Veterinary Ophthalmology Service and approved by the Ethics Committee for the Use of Animals under protocol number 5154141022. The study's objective of this study was to evaluate lacrimal and nasolacrimal system findings in dogs treated byat an ophthalmology service, determine the frequency of lacrimal and nasolacrimal system disorders, and correlate the diagnosed changes with the patient's main complaint. All dogs underwent a complete ophthalmic examination, emphasizing the lacrimal and nasolacrimal tests: the Schirmer tear test, tear film break-up test, tear crystallization test, and Jones test. The findings of these tests correlated with those of the ocular surface and the general condition of the dogs. Statistical analyses were performed using the Shapiro-Wilk test, Pearson's chi-square test, and Student's t test. The Student's t test revealed that dogs with normal tear crystallization test scores had a significantly higher score (25.5 ± 4.94) than dogs with altered tear crystallization test scores (15.35 ± 6.64) (t (40) = 2.121, p = 0.004). Our findings suggest that quantitative and qualitative tear tests should be performed together and their interpretation depends on several factors, including ocular and systemic disorders.

Na rotina da medicina veterinária, os sistemas lacrimal e nasolacrimal estão associados a diversas oftalmopatias. Compreender sua fisiologia e aprimorar testes diagnósticos específicos auxiliará no estabelecimento de uma abordagem assertiva e na prevenção de distúrbios lacrimais e nasolacrimais que causam danos à superfície ocular. Este estudo prospectivo foi realizado em 43 cães atendidos no Serviço de Oftalmologia Veterinária, com aprovação do Comitê de Ética no Uso de Animais sob o protocolo número 5154141022. O objetivo do estudo foi avaliar as alterações no sistema lacrimal e nasolacrimal em cães atendidos em um serviço de oftalmologia, determinar a frequência de distúrbios nesses sistemas e correlacionar as alterações diagnosticadas com a queixa principal do paciente. Todos os cães foram submetidos a um exame oftálmico completo, com ênfase nos testes lacrimais e nasolacrimais: teste de Schirmer, teste de ruptura do filme lacrimal, teste de cristalização da lágrima e teste de Jones. Os achados desses testes foram correlacionados com a avaliação da superfície ocular e a condição geral dos cães. As análises estatísticas foram realizadas utilizando o teste de Shapiro–Wilk, o teste do qui-quadrado de Pearson e o teste t de Student. O teste t de Student revelou que cães com cristalização lacrimal normal apresentaram uma pontuação significativamente maior (25,5 ± 4,94) do que cães com cristalização lacrimal alterada (15,35 ± 6,64) (t(40) = 2,121, p = 0,004). Nossos resultados sugerem que os testes quantitativos e qualitativos da lágrima devem ser realizados em conjunto, e sua interpretação depende de vários fatores, incluindo alterações oculares e sistêmicas.

Keywords: ocular surface; precorneal tear film; tear crystallization; tear production.

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Conflict of interest statement

Conflict of interests: LSV, DNV, CCRPMS, SSL and BA - No conflict of interest.

Figures

Figure 1
Figure 1. Simplified methodology of the tear crystallization test. Tear collection (A), placement on a slide for drying (B), and subsequent microscopic evaluation (C).
Figure 2
Figure 2. Microscopic images of tear crystallization patterns: types I (A), II (B), III (C), and IV (D).
Figure 3
Figure 3. Main complaints for ophthalmic care in dogs.
See this image and copyright information in PMC

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