Background It is currently unknown which of the two devices most commonly used in equine ophthalmology for intraocular pressure (IOP) estimation demonstrates the lowest inter‐user and intra‐user variation. Objectives To assess the inter‐user and intra‐user variation of two tonometers in sedated and unsedated horses. Study design Randomised masked cross‐over trial. Methods Four examiners used the rebound (ICare® TonoVet) and applanation (TonoPen®) tonometers to measure the intraocular pressure (IOP) in triplicate in 10 normal horses before and after sedation with xylazine. For inter‐user variation, coefficient of variation (CV) values were calculated from the mean of each examiner for each condition combination. For intra‐user variation, CV values were calculated from the individual measurements of each examiner for each condition combination. CV values were also assessed in relation to other variables using ANOVA. Results The rebound tonometer was found to have lower inter‐user (15.4% vs 21.7%, P = .01) and intra‐user (9.1% vs 16.1%, P < .0001) variation in unsedated horses and lower intra‐user (8.4% vs 14.7%, P < .0001) variation in sedated horses than the applanation tonometer. Both instruments had similar inter‐user variation in sedated horses. For the rebound tonometer, sedation did not affect inter‐user or intra‐user variation, but for the applanation tonometer inter‐user variation was lowest while horses were sedated (16.0% vs 21.7%, P = .03). No other variable assessed was found to have an effect on IOP. Main limitations No animals with ocular disease were included in this study. Conclusions The rebound tonometer may be the preferred instrument to minimise intra‐user and inter‐user variation for IOP measurement in unsedated horses. The rebound tonometer is also likely to be the preferred instrument to minimise intra‐user variation in sedated horses. If the applanation tonometer is used to perform IOP measurement in horses, it is recommended that this is performed while horses are sedated to minimise inter‐user variation for this instrument.

Summary Gastric ulcers are common in horses. The purpose of this study was to test the effect of a commercially available supplement, SmartGut® Ultra pellets (SmGU) on gastric ulcer scores and gastric juice pH after omeprazole treatment in stall‐confined horses. Eight Thoroughbred horses were studied in a 2‐period, 2‐treatment crossover design, where the SmGU (40 g, twice daily) was mixed in grain feed. Horses were stall‐confined and treated with the supplement or control for 6 weeks, consisting of 2 weeks (Days 1–14) omeprazole treatment, 2 weeks (Days 14–28) following discontinuation of omeprazole treatment, one week (Days 28–35) alternating feed deprivation to induce or worsen existing ulcers and a one week (Days 35–42) recovery period. Gastroscopy was performed and gastric juice pH measured on Days 0, 14, 28, 35 and 42. Gastric ulcer lesion number (NGN) and severity (NGS) scores were assigned to each horse by an investigator (F.M.A.) masked to treatment. On Day 0 before treatment, mean NGN and NGS scores and gastric juice pH were not different (P>0.05) between treatment groups. By Day 14, mean NGN and NGS scores decreased (P<0.05) in both treatment groups. By Days 28 and 35, mean NGN score significantly increased in the untreated control horses but not the SmGU‐treated horses. By Day 42, mean NGN and NGS scores were not different in either group and were significantly lower than Day 0. Mean gastric juice pH was higher in both groups on Day 14 as a result of omeprazole treatment when compared with other days. SmartGut® Ultra supplement added to the feed prevented the worsening of gastric ulcer number 2 weeks after omeprazole treatment, without altering the gastric juice pH. Supplementation with SmGU might aid in protection of the nonglandular stomach from recurrence of ulcers after omeprazole treatment in stall‐confined horses undergoing intermittent feeding.

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Objectives Feline herpesvirus-1 (FHV-1) is a prevalent cause of ocular disease in cats and limited topical options for treatment currently exist. The first objective of this study was to confirm the efficacy of ganciclovir against FHV-1 in vitro. The second objective was to assess the safety and ocular tolerability of topically applied ganciclovir eye gel (GEG) in healthy cats. Methods FHV-1 was used to infect tissue culture wells covered in maximally confluent Crandall–Rees feline kidney cells prior to the addition of three molarities of ganciclovir (8.9 µM, 17.8 µM and 89 µM) before being incubated for 48 h. Ganciclovir efficacy in vitro was then assessed using standard plaque reduction assay. Commercially available GEG (0.15%) was applied q8h to one randomly chosen eye of four healthy cats for 7 days. Commercially available lubricating eye gel (LEG) was applied to the opposite eye q8h. Complete blood counts (CBC), blood chemistry panels (CHEM) and urinalysis (UA) were performed on all cats before and after the study period. Ocular lesions were assessed daily using a standardized scheme. Results Ganciclovir led to a significant reduction in FHV-1 plaque number, area and diameter at all tested molarities in vitro. The highest molarity assessed (89 µM) caused a 100% reduction in viral plaque number. There was no significant difference in lesion scores between eyes receiving GEG and LEG. Animals remained healthy throughout the study period with CBC, CHEM and UA showing no clinically significant alterations. Conclusions and relevance Based on the in vitro results, ganciclovir appears to be effective against FHV-1 in vitro. When applied q8h as a commercial 0.15% gel to a small group of cats with normal eyes, this medication was well tolerated. Taken together, these data suggest this medication warrants further investigation in cats with ocular disease caused by FHV-1.

Objective Porcine models of ocular disease are becoming increasingly utilized. A recently commercialized ocular tonometer, the Reichert Tono‐Vera® Vet, has not been evaluated for use in pigs. The purpose of this study was to calibrate this device for use in porcine eyes and to determine which settings are most appropriate for use in pigs. Procedure The anterior chambers of five freshly enucleated normal porcine eyes were cannulated then connected to a reservoir of balanced salt solution and a physiologic monitor. Triplicate measurements were obtained with the four available settings: dog, cat, horse, and rabbit at intraocular pressures ranging from 5– to 80 mmHg. Bland–Altman analysis was utilized to determine bias and 95% limits of agreement for each setting. Results There was a strong positive linear regression trend for all settings (dog r2 = 0.986, horse r2 = 0.947, cat r2 = 0.977, and rabbit r2 = 0.982). The linear regression equations for the dog, horse, cat, and rabbit setting were y = 1.0168x – 2.6128, y = 0.8743x – 3.4959, y = 0.9394x – 7.3188, and y = 1.1082x – 3.4077. The average bias and 95% limits of agreement for dog, horse, cat, and rabbit settings were − 2.00, −8.32, −9.58, and 0.57 mmHg, and (−7.52, 3.53), (−19.00, 2.37), (−16.66, −2.50), and (−7.79, 8.93), in mmHg. Conclusion The Tono‐Vera® Vet dog setting was most accurate and precise setting compared to true intraocular pressures. This setting is likely to be appropriate for in vivo use in pigs, with the appropriate correction formula applied.