The effect of phenylephrine and pilocarpine on pupil size and aqueous flare intensity in patients with diabetes mellitus.
OBJECTIVE
The aqueous flare intensity and pupillary size were studied before and after instillation of 10% phenylephrine and 4% pilocarpine in eyes with diabetes mellitus (DM).


METHODS
Twenty-three patients with DM type I were compared with 30 age-matched controls, and 25 patients with DM type II were compared with 30 age-matched controls. Patients with DM were divided into two groups: 1) with mild-moderate nonproliferative diabetic retinopathy (NPDR), and 2) with advanced diabetic retinopathy (DR) which includes moderate-severe, severe NPDR and proliferative DR. The aqueous flare intensity and the horizontal diameter of the pupil were measured before and 60 minutes after topical instillation of 10% phenylephrine and 60 min after topical administration of 4% pilocarpine.


RESULTS
Degree of induced mydriasis after phenylephrine instillation was not significantly different between diabetic groups and controls. Significantly less pronounced miosis was observed after stimulation of cholinergic receptors by pilocarpine in eyes with mild-moderate NPDR with DM type II and in eyes with advanced DR with DM type I and type II when compared to controls (p<0.05). Phenylephrine decreased flare intensity in all groups without a significant difference between groups. Pilocarpine instillation increased flare intensity in all groups as compared to flare intensity before any treatment. Also, a significantly smaller increase in flare intensity in eyes with advanced retinopathy in both DM type I and type II was found when compared to controls (p<0.05).


CONCLUSIONS
Pharmacological response to cholinergic stimulation on pupil size and flare intensity is weaker in advanced stages of DR.
St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.
A
A
Zaczek
C
C
Zetterström
D000287:Administration, Topical; D000328:Adult; D000368:Aged; D001082:Aqueous Humor / Q000378:metabolism*; D003920:Diabetes Mellitus / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018721:Muscarinic Agonists / Q000008:administration & dosage; D009184:Mydriatics / Q000008:administration & dosage; D009883:Ophthalmic Solutions; D010656:Phenylephrine / Q000008:administration & dosage*; D010862:Pilocarpine / Q000008:administration & dosage*; D011680:Pupil / Q000187:drug effects*; D011681:Pupil Disorders / Q000378:metabolism*
D005136:Eye Proteins; D018721:Muscarinic Agonists; D009184:Mydriatics; D009883:Ophthalmic Solutions; D010862:Pilocarpine; D010656:Phenylephrine