• A prospective, randomized study evaluated the effects of unilateral, topical 1% apraclonidine hydrochloride on conjunctival oxygen tension in 10 normal volunteers using a conjunctival oxygen monitor. Conjunctival oxygen tension and intraocular pressure were measured prior to instillation of apraclonidine, then at 1, 3, and 5 hours. Apraclonidine was found to significantly decrease conjunctival oxygen tension 76% at 1 hour compared with baseline values. At 3 hours conjunctival oxygen tension was decreased to 56% and at 5 hours to 10% of baseline. Intraocular pressure was lowered maximally at 3 hours to 40% of baseline measurements in the treated eye. The contralateral eye had a small decrease in conjunctival oxygen tension and intraocular pressure that was not statistically significant. Lid retraction and conjunctival blanching were noted to occur maximally between 1 and 3 hours. Further study is needed to determine if the apraclonidine-induced conjunctival hypoxia noted in this study has clinical significance for ocular blood flow, particularly in patients with glaucoma.
Serdahl CL, Galustian J, Lewis RA. The Effects of Apraclonidine on Conjunctival Oxygen Tension. Arch Ophthalmol. 1989;107(12):1777–1779. doi:10.1001/archopht.1989.01070020859027