Abstract
Purpose: :
Evaluate and compare obtained mydriasis with Phenylephrine 10% associated with Tropicamide 1%, in type 2 diabetics and non-diabetics.
Methods: :
A total of 50 patients scheduled for fundus examination were dilated with Phenylephrine 10% associated with Tropicamide 1%. Group 0 consisted in 20 type 2 diabetic patients and group 1 consisted in 30 non-diabetic patients. Drugs were applied with a 5 minutes interval and a drop of proximetacain 0,5% was instilled in each eye 1 minute before initiating mydriatic drugs.Patients were instructed to close eyelids after instillation and to keep eyes closed for at least 30 seconds. In both groups, pupil diameter was measured 60 minutes after eyedrops instilation. Patients aged 18 years or older were included in our study. Exclusion criteria were chronic use of topic pilocarpine, pseudophakic eyes, presence of synechiae, previous intraocular eye surgery and rubeosis. For statistical analysis we used the Mann-Whitney test, assuming values of p<0.05 as statistically significant.
Results: :
Both groups were similar regarding age (p=0.06). Mean pupil diameter in group 0 was 8.57 and 8.73 in group 1. There was no statistic difference between both groups (p=0.44). Pupil diameter was greater than 7 mm in all patients (100%).
Conclusions: :
Although there are few studies regarding this issue, there is a belief that mydriasis is poorer in diabetics when compared to non-diabetic patients 1,2. In diabetic patients, we find edema and vesiculation of the pigmented epithelium of iris and ciliary body, and glicogenous degeneration of the tissues that affects iris stroma and sphincter and dilator muscles. However, these are not proved to cause mydriasis differences2. Also, pupil in diabetics is less reactive, especially to mydriatics, probably due to neuropathy that affects autonomic nervous system3. Optimal mydriasis is necessary to allow adequate fundus examination, with at least 6.0 mm pupil diameter. To achieve this goal, a combination of tropicamide and phenylephrine is frequently used4,5. Preinstillation of topical anesthetics6 eliminated the difference in absorption of drugs due to burning or discomfort. In our study, all patients had pupil diameter greater than 7.0 mm, and there was no statistically significant difference in the amount of pupillary dilation between both groups. So, when appropriate drug combination is used7,8, diabetics can achieve mydriasis as satisfactory as non-diabetic patients, allowing adequate fundus examination and/or retinopathy treatment.
Keywords: diabetes • pupil • drug toxicity/drug effects