Effect of once daily topical 0.3% naltrexone on tear parameters and corneal sensitivity in dogs with uncontrolled keratoconjunctivitis sicca: a double‐masked randomized placebo‐controlled clinical trial

Abstract

Objective To determine the effect of once daily topical 0.3% naltrexone (NTX) on tear production, tear film breakup time (TFBUT), and corneal sensitivity in dogs with uncontrolled keratoconjunctivitis sicca (KCS). Animals studied Sixteen dogs with uncontrolled KCS. Procedures A randomized placebo-controlled trial was performed in 16 dogs with topical 0.3% NTX once daily or topical saline solution drops once daily. A baseline was obtained at week 0 for tear production (Schirmer tear test 1 and 2-STT1, STT2), TFBUT, and corneal sensitivity. STT1, STT2, and TFBUT were then subsequently measured at weeks 1, 2, and 4 while on NTX or saline drops. Corneal sensitivity measures were repeated at week 4. The drops were subsequently discontinued and all parameters rechecked at week 5. Results There was no statistically significant difference in tear parameters or corneal sensitivity between the NTX-treated and the saline-treated groups. Conclusion Topical 0.3% NTX given as a once daily dose over 4 weeks did not alter tear production, tear film stability, or corneal sensitivity in dogs with uncontrolled KCS.

Effect of 0.15% sodium hialuronate and 0.5% carboxymethylcellulose on tear film breakup time in healthy dogs and in dogs with keratoconjunctivitis sicca

“…Although values of such parameter decreased in accordance with the disease severity, statistical significance was only observed between the eyes graded as mild and severe. Considering the 32 eyes with KCS, TFBUT values (5.93 seconds, range 2.10 to 11.2 seconds) were similar to those reported in another research (6.2 to 7 seconds) conducted in dogs with KCS (Chen and Powell, 2015). In the study of Chen and Powell (2015), STT values ranged from 0 to 13mm/minute, but authors did not separate the eyes with KCS in different categories.…”

“…Considering the 32 eyes with KCS, TFBUT values (5.93 seconds, range 2.10 to 11.2 seconds) were similar to those reported in another research (6.2 to 7 seconds) conducted in dogs with KCS (Chen and Powell, 2015). In the study of Chen and Powell (2015), STT values ranged from 0 to 13mm/minute, but authors did not separate the eyes with KCS in different categories. In diabetic dogs with qualitative KCS, TFBUT was 6.55 seconds, also similar with the ones observed in our study (Cullen et al, 2005).…”

Dry-eye syndrome in Shih Tzu dog: Ocular surface clinical and morphological aspects in the different stages of keratoconjunctivitis sicca

“…Furthermore, TBUT values in Shih Tzu dogs for each stage were similar to those described by Madruga et al (2018) in a study that evaluated dogs of different breeds with mild, moderate, and severe KCS. Moreover, dogs with KCS, regardless of the stage, have TBUT values ranging from 5.93 to 11 s (Oria et al 2013, Chen & Poweel 2015, Dos Santos et al 2019.…”

Opioids and Ocular Surface Pathology: A Literature Review of New Treatments Horizons

“…According to these results, preclinical reports in animals demonstrated that continuous suppressions of receptors with NTX applied topically resulted in reversal of dry eye and re-establishing the corneal sensitivity in diabetic animals without effect in normal ones [ 109 , 110 ]. Additionally, LDN (1–5 mg/daily) has been effective and well-tolerated for alleviating refractory neuropathic pain in diabetic patients [ 108 , 111 ].…”