Effect of body position, eyelid manipulation, and manual jugular compression on intraocular pressure in clinically normal cats.

Objective: To determine the effect of body position, eyelid manipulation, and manual jugular compression on intraocular pressure (IOP) in clinically normal cats.

Animal Studied: TWENTY-ONE ADULT CLIENT-OWNED DOMESTIC SHORTHAIR CATS: PROCEDURES: The IOP was measured by means of rebound tonometer. A baseline IOP was measured in all cats in ventral recumbency with normal head position (horizontal to the ground) with no pressure on the neck or eyelids. To measure the IOP in dorsal recumbency, each cat was held in the dorsal recumbency position for 5 min. Four different manipulations were used, including maximal dorsoventral extension of the eyelids, lateral eyelid extension, manual compression of the ipsilateral jugular vein, and manual compression of both jugular veins. IOP after all the manipulations was measured in ventral recumbency.

Results: Overall the mean ± SD IOP values of all eyes in ventral recumbency, dorsal recumbency, maximal dorsoventral extension of the eyelids, lateral eyelid extension, compression of the right jugular vein, compression of the left jugular vein, and compression of the both jugular veins were 16.1 ± 2.9 mmHg, 17.1 ± 5.0 mmHg, 21.7 ± 5.8 mmHg, 22.4 ± 5.6 mmHg, 15.0 ± 3.7 mmHg, 14.9 ± 3.7 mmHg, and 16.1 ± 4.6 mmHg, respectively. IOP was increased significantly in maximal dorsoventral extension of the eyelids (P = 0.001) and lateral eyelid extension (P = 0.001) compared to baseline.

Conclusions: Results of this study may be beneficial for clinicians to be aware of the effects of body position, traction, and compression of the eyelids and neck on IOP during ophthalmic examination in cats.