Tear fluid collection in dogs and cats using ophthalmic sponges
Objective - To compare the use of two ophthalmic sponges for tear collection in dogs and cats. Animals studied - Ten healthy dogs and 10 healthy cats.
Procedures - A strip (4x10 mm) of either cellulose or polyvinyl acetal (PVA) sponge was inserted into the ventral fornix of each eye for either 15, 30 or 60 seconds. The wetted strip was placed into a 0.2-mL tube that was first punctured at its bottom. Tears were eluted through the drainage hole into a 1.5-mL tube via centrifugation. Tear volume absorbed (VA) and tear volume recovered (VR) were calculated as the difference of the post- and pre- collection weight of the 0.2-mL tube and 1.5-mL tube, respectively. Recovery ratio (RR) was determined as the ratio between VR and VA.
Results - Ophthalmic sponges were well tolerated by all subjects. In dogs and cats, median (95% range) VA, VR and RR were: 44 μL (11-106 μL) and 16 μL (2-43 μL); 27 μL (1-84 μL) and 6 μL (0-29 μL); 64 % (7-91%) and 35% (0-86%), respectively. PVA sponges achieved significantly greater VR in cats and RR in both species. All parameters were significantly greater with a collection time of 60 vs. 30 and 15 seconds. Body weight was associated with VA and VR in dogs but not cats.
Conclusions – PVA is better than cellulose for tear collection given its superior recovery. Ophthalmic sponges could facilitate routine analysis of tear fluid in dogs and cats, although further studies are needed to evaluate the quality of tears obtained with this method.
This is the peer reviewed version of the following article: Sebbag, L., Harrington, D. M. and Mochel, J. P. (2017), Tear fluid collection in dogs and cats using ophthalmic sponges. Vet Ophthalmol., which has been published in final form at doi: 10.1111/vop.12502. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.