Clinical comparison of tear film breakup time measurements in normal dogs using three different methods of fluorescein solution administration

Abstract

Objective To evaluate whether the method of fluorescein administration affects the results of tear film breakup time (TFBUT) measurement in normal dogs. Animals studied Thirty‐seven client and hospital staff owned dogs over 1 year of age with no known comorbidities or administration of systemic or topical ophthalmic medications. Procedures A prospective randomized three‐way crossover study was conducted. All dogs received an abbreviated ophthalmic examination to rule out ocular surface disease. Using a 30‐min washout interval period, each dog's right eye was received: (a) direct application of fluorescein stain strip with one drop of sterile eyewash, (b) direct application of fluorescein stain strip with two drops of sterile eyewash, or (c) application of one drop from a premade fluorescein solution (dilution of one strip in 0.3 mL sterile eyewash). Eyes were assessed using the cobalt blue filter of a slit lamp biomicroscope. TFBUT measurements were summarized as means ± standard deviation. The methods were compared using mixed model analysis of variance. All analyses were performed using sas version 9.4. Results Thirty‐seven dogs met the inclusion criteria. Mean TFBUT ± standard deviation (SD) for the three described methods were: (a) 16.58s ± 6.9, (b) 15.98s ± 7.1, and (c) 16.43s ± 8.1. No differences between fluorescein stain application techniques were observed (p = .92). Conclusion The technique of fluorescein solution administration did not affect TFBUT measurement in this population of healthy dogs.

Tear film breakup time and Schirmer tear test in normal dogs: Effects of age, sex, reproductive status, skull type, and nasolacrimal duct patency

“…In the current study, the authors used diluted fluorescein sodium. A recently published study reported no difference in mean TBUT between different methods of fluorescein sodium application 12 . By reviewing the literature, mean TBUT values for normal dogs have also been reported to be 5.9–8.6 s, 13 which was similar to the findings of the present study.…”

“…This study was conducted on 19 different dog breeds including Pomeranian (7), English Cocker Spaniel (7), Shih Tzu (24), Yorkshire Terrier (1), West Highland White Terrier (12), Maltese (1), Japanese Spitz (3), English Bulldog (2), Dachshund (1), Miniature Poodle (1), Chihuahua (3), Pekingese (9), Chow chow (1), Japanese Akita (1), Pug (3), King Charles Cavalier Spaniel (1), Golden Retriever (3), French Bulldog (1), and German Shepherd (1).…”

An eye on the Shih Tzu dog: Ophthalmic examination findings and ocular surface diagnostics

“…Although the quantity of tear secretion is adequate in Shih Tzu dogs, the quality of tear film appears to be compromised in this breed. Tear film breakup time, a subjective measurement of tear quality, was much lower in the present study of Shih Tzu dogs (mean 5.3 s) compared with normative data from previous studies (mean ranges from 16.0 to 21.5 s) 43–45 . This important finding could be explained by three main factors: breed‐related conformation, low conjunctival goblet cell density (reduced pre‐ocular mucins) 16 and meibomian gland dysfunction (altered tear film lipids) 12,46 .…”

“…Tear film breakup time, a subjective measurement of tear quality, was much lower in the present study of Shih Tzu dogs (mean 5.3 s) compared with normative data from previous studies (mean ranges from 16.0 to 21.5 s). [43][44][45] This important finding could be explained by three main factors: breed-related conformation, low conjunctival goblet cell density (reduced pre-ocular mucins) 16 and meibomian gland dysfunction (altered tear film lipids). 12,46 First, several anatomical features of Shih Tzu eyes (e.g., exophthalmos, macropalpebral fissure, and lagophthalmos) promote tear film evaporation owing to excessive exposure of the ocular surface.…”

A review of diagnostic tests for qualitative and quantitative tear film deficiency in dogs

“…In humans, it is generally recommended to apply a minimal amount of fluorescein to improve test reliability 80 . In dogs, however, TFBUT values were relatively similar whether one or two drops of fluorescein were applied to the ocular surface, 81 a species difference that is likely due to larger tear volume in dogs compared to humans 82 …”