The consensual ophthalmotonic reaction

The consensual ophthalmotonic reaction describes the phenomenon whereby alteration of the intraocular pressure in one eye is accompanied by a corresponding pressure change in the contralateral eye. Thirteen normal and thirteen ocular hypertensive subjects received 0.5% timolol, 2% pilocarpine, 1% adrenaline, or saline uniocularly with saline to the other eye under double blind, randomised conditions. Intraocular pressure was measured by applanation tonometry at 0, 30, 60, 120, and 240 minutes. Falls in pressure were found in both treated and consensual eyes for all treatments in both subject groups. A linear relationship between the fall in pressure in the treated eye and that in the consensual eye was found for timolol and pilocarpine but not for adrenaline.