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Pupil dilatation after single and triple doses of mydriatic agent in preterm infants
Achara Punyawattanaporn1, Supaporn Tengtrisorn, Pasuree Sangsupawanich
1Department of Ophthalmology, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
Insights
Three drops of a cyclopentolate and phenylephrine eye drop mixture achieved significantly larger pupil dilation in preterm infants compared to a single drop. This dilation was adequate for retinopathy of prematurity screening.
Area of Science:
- Ophthalmology
- Neonatology
- Pharmacology
Background:
- Pupillary dilation is crucial for retinopathy of prematurity (ROP) screening in preterm infants.
- Optimizing mydriasis in neonates is essential for effective fundus examination.
- The combination of cyclopentolate and phenylephrine is commonly used for pupillary dilation.
Purpose of the Study:
- To compare the efficacy of a single drop versus three drops of a 0.2% cyclopentolate and 1.0% phenylephrine eye drop mixture for pupillary dilation in preterm infants.
- To determine if the achieved pupillary size is adequate for ROP screening.
Main Methods:
- Prospective comparative study involving preterm infants undergoing ROP screening.
- Baseline pupil diameter was measured after topical anesthetic (0.5% tetracaine).
- Infants were randomized to receive either a single drop (Group A) or three drops (Group B) of the mydriatic mixture at 10-minute intervals. Pupil diameter was measured at 45 and 60 minutes post-instillation.
Main Results:
- Seventy preterm infants (mean gestational age 30.49 weeks) were analyzed.
- Both groups showed similar baseline pupil diameters (p = 0.90).
- Significantly greater pupillary dilation was observed in Group B (three drops) at 45 minutes (6.02 mm vs 5.50 mm, p < 0.01) and 60 minutes (6.77 mm vs 6.13 mm, p < 0.01) compared to Group A (single drop).
Conclusions:
- Three drops of the 0.2% cyclopentolate and 1.0% phenylephrine mixture provide significantly better pupillary dilation in preterm infants than a single drop.
- A pupil diameter of ≥ 6 mm, achieved with the triple-drop regimen, is adequate for peripheral retinal examination during ROP screening.
Objective:
To compare the pupillary response to a single drop and three drops of a combination of eye drops (0.2% cyclopentolate and 1.0% phenylephrine) in preterm infants.
Design:
Prospective comparative study.
Material And Method:
Preterm infants scheduled to undergo their first retinopathy of prematurity (ROP) screening in the Neonatal Intensive Care Unit, Songklanagarind Hospital, between 1 August 2007 and 30 August 2008, were enrolled in the present study. An eyelid speculum was placed after the topical anesthetic, 0.5% tetracaine, application to measure the baseline horizontal pupil diameter with a Vernier caliper. Then each eye was randomized to either receive a drop of mixture of 0.2% cyclopentolate and 1.0% phenylephrine single dose for group A, or triple doses of 10-minute interval for group B. The pupil diameter was measured at 45 and 60 minutes after instillation and a fundus examination was performed afterward.
Results:
Seventy preterm infants, 45 males and 25 females, were included in the present study. The mean gestational age was 30.49 +/- 2.34 weeks (range of 24-36 weeks) and the mean birth weight was 1,368.00 +/- 438.99 grams (range of 640-2,850 grams). At baseline, the mean pupil diameter was 2.18 +/- 0.44 mm in group A and 2.19 +/- 0.44 mm in group B (p = 0.90). The mean pupil diameter at 45 minutes after instillation was 5.50 +/- 0.80 mm in group A and 6.02 +/- 0.56 mm in group B (p < 0.01). At 60 minutes after instillation, the mean pupil diameter was 6.13 +/- 0.82 mm in group A and 6.77 +/- 0.41 mm in group B (p < 0.01).
Conclusion:
The pupil size of preterm infants was significantly larger after three drops of the eye drop mixture (0.2% cyclopentolate and 1.0% phenylephrine) than after a single drop. However, a dilated pupil diameter > or = 6 mm was adequate for the peripheral retina examination.
