Related Experiment Video
Updated: May 19, 2026
Inducement and Evaluation of a Murine Model of Experimental Myopia
Published on: January 22, 2019
A randomized controlled trial to determine the lowest effective dose for adequate mydriasis in premature infants
G Vike Vicente1, Monisha Bahri, Judith J Palafoutas
1Eye Doctors of Washington, Chevy Chase, Maryland, USA. Vvicente@edow.com
Insights
One drop of mydriatic solution effectively dilated pupils in premature infants for retinopathy of prematurity screening. This finding suggests that fewer eye drops may be sufficient for adequate retinal examinations in neonates.
Area of Science:
- Ophthalmology
- Neonatology
- Pediatric Medicine
Background:
- Retinopathy of prematurity (ROP) screening is crucial for premature infants.
- Current neonatal intensive care unit (NICU) protocols often use multiple eye drops for mydriasis.
- Optimizing mydriatic protocols can improve efficiency and infant comfort.
Purpose of the Study:
- To compare the mydriatic efficacy of varying numbers of eye drops for retinal examinations in premature infants.
- To determine the minimum effective number of drops for adequate pupil dilation.
Main Methods:
- Pilot study involving preterm infants (<32 weeks gestational age) undergoing ROP screening.
- Randomized comparison of 0, 1, or 2 drops in the test eye versus 3 drops in the reference eye.
- Pupil size measured at multiple time points after instillation of cyclopentolate 0.2% and phenylephrine 1%.
Main Results:
- No significant difference in mean pupil size between 1-, 2-, and 3-drop groups at 90 and 120 minutes.
- Retinal examinations were completed by 90 minutes in all infants who received 1 drop.
- The 0-drop group showed no change in pupil size from baseline.
Conclusions:
- One or two drops of the mydriatic solution achieved effective and sustained mydriasis up to 120 minutes.
- A single drop may be sufficient for timely retinal examinations in most premature infants.
- Further research is warranted to explore factors like iris color and ROP severity.
Purpose:
To compare the mydriatic efficacy of different numbers of eye drops for retinal examination of premature infants.
Methods:
This pilot study enrolled preterm infants born at <32 weeks' gestational age who were scheduled for retinopathy of prematurity screening examinations. In all study group assignments, the right (treatment reference group) eye received 3 eye drops per current neonatal intensive care unit protocol, whereas the left (test) eye was randomized at each examination to receive either: 0, 1, or 2 drops. Pupils were dilated with the use of a cyclopentolate 0.2% and phenylephrine 1% ophthalmic solution. Pupil size (in mm) was measured by a single examiner at 0 (baseline), 45, 90, and 120 minutes after instillation. Retinal examination occurred at the first opportunity to adequately visualize the peripheral retina. Comparison of the means was calculated using paired t test, t test, or analysis of variance, as appropriate.
Results:
A total of 64 eye examinations were performed on 15 enrolled infants (mean gestational age, 28.7 ± 2.6 weeks, 53% white; 40% male). No significant differences existed in mean pupil size between the 1-, 2- and 3-drop groups at baseline, 90 minutes, and 120 minutes. All 1-drop group eyes could be examined by 90 minutes. The 0-drop group maintained baseline size.
Conclusions:
Effective mydriasis was achieved in the test eye with 1 or 2 drops and was sustained to 120 minutes. Therefore, retinal examinations could be completed by 90 minutes in most infants with the use of 1 drop. A larger study is needed to determine the effect of iris color and severity of ROP on these findings.
