Comparison of two eyelid speculums and their effect on intraocular pressure in clinically normal cats.

Objectives: The present study was undertaken to determine the possible effects of the placement two different types of eyelid speculum on intraocular pressure (IOP) measurement in clinically normal cats.
Methods: Thirty healthy cats were divided randomly into two groups of 15, group B (Barraquer wire speculum) and group W (Williams eye speculum). All cats were sedated with intramuscular medetomidine (Dorbene vet; 100 μg/kg) then placed in right lateral recumbency, and IOP was recorded in the left eye using a Tono-Pen Vet tonometer without and with an eyelid speculum in place in both groups.
Results: The without-speculum IOPs for cats in group B and group W were 13.8 ± 3.0 mmHg and 13.2 ± 3.6 mmHg, respectively, and did not differ significantly. A significant increase in IOP (19.8 ± 3.7 mmHg) was observed in group W in with-speculum measurements in comparison to the without-speculum values ( P <0.001).There was no significant difference between with- and without-speculum IOP values (13.8 ± 2.7 mmHg) in group B ( P  = 1.0).
Conclusions and Relevance: The Barraquer wire speculum has no effect on IOP compared with the Williams eye speculum in normal cats, and may be an appropriate choice in cats for intraocular surgeries that cannot tolerate acute increases in IOP.