Effect of 0.15% sodium hyaluronate on tear film breakup time in healthy anesthetized cats

OBJECTIVES

This study aimed to evaluate the effect of 0.15% sodium hyaluronate (SH) on tear film breakup time (TFBT) in healthy anesthetized cats.

PROCEDURES

Forty cats undergoing elective surgery were enrolled. TFBT was assessed before anesthesia to obtain baseline values. As a preanesthetic medication, cats received midazolam, tramadol, and cetamine combined in the same syringe. For anesthetic induction and maintenance, propofol and isoflurane were used. After a 15 min stabilization period to achieve the surgical anesthetic plane, one eye was treated with one drop of SH, while the other eye received saline and served as a control. TFBT was measured at the end of the general anesthesia (T40) and 35 (T75) and 80 min (T120) after the termination of the anesthesia. TFBT values were compared between the control and SH-treated eyes; both values were also compared with the baseline values (p < .05).

RESULTS

In the control eyes, TFBT significantly decreased from baseline at all time points (p < .001), while in SH-treated eyes, TFBT significantly increased from baseline only at T40 (p < .0001). In SH-treated eyes, TFBT was significantly higher than that in the control eyes at all time points (p < .001).

CONCLUSIONS

In healthy cats, TFBT decreases significantly after 40 min of general anesthesia, and one drop of 0.15% sodium hyaluronate was able to maintain the stability of the tear film for up to 75 min in treated eyes. However, the isolated effect of each drug used in our anesthetic protocol on TFBT should be executed in further studies.

Artificial tears potpourri: a literature review

Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived.