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Updated: May 16, 2026
A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
The pain response to mydriatic eyedrops in preterm infants
A M Cohen1, N Cook, M C Harris
1Divisions of Neonatology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
Insights
Mydriatic eyedrops cause significant pain in premature infants undergoing retinopathy of prematurity (ROP) screening. One-third of infants showed pain responses, necessitating supportive measures during ROP exams.
Area of Science:
- Neonatal care
- Ophthalmology
- Pain management
Background:
- Retinopathy of prematurity (ROP) screening requires mydriatic eyedrops.
- Infant pain responses to these drops are not well understood.
- Older patients experience burning and stinging, but infant responses differ.
Purpose of the Study:
- To assess infant pain responses to mydriatic eyedrops.
- To evaluate physiological and behavioral pain indicators.
- To inform pain management strategies during ROP examinations.
Main Methods:
- Vital signs and video monitoring captured infant responses.
- Premature Infant Pain Profile (PIPP) scores were assessed before and after eyedrop instillation.
- Two masked observers graded PIPP scores.
Main Results:
- Mean PIPP scores increased significantly after mydriatic eyedrop administration (P=0.01).
- Thirty-five percent of infants exhibited moderate to severe pain post-instillation (PIPP ≥7).
- One infant experienced severe pain (PIPP >12).
Conclusions:
- Mydriatic eyedrops induce a clinically relevant pain response in a substantial proportion of premature infants.
- Non-pharmacological interventions are recommended for all infants undergoing ROP screening.
- Further research is needed to identify predictive factors for pain response.
Objective:
Evaluate physiological and behavioral pain responses of premature infants following instillation of mydriatic eyedrops for retinopathy of prematurity (ROP) examinations. While burning and stinging occurs in older patients, the infant pain response is not well characterized.
Study Design:
Vital sign and video monitor recorded infant responses before, during and after mydriatic (tropicamide 1%, phenylephrine 2.5%) administration upon first ROP exam. Two masked observers graded Premature Infant Pain Profile (PIPP) scores immediately before and following eyedrop administration. Scores <7 indicate no/minimal pain, 7 to 12 slight/moderate, >12 severe.
Result:
Twenty infants had mean premydriatic PIPP score 3.6 (s.d. 1.6), mean postmydriatic score 5.7 (s.d. 3.4), mean change 2.1 (s.d. 3.4) (P=0.01). One (5%) had premydriatic PIPP score ≥7, seven (35%) post scores ≥7 (P=0.07) with one >12.
Conclusion:
Mydriatic drops cause a clinically significant pain response in one-third of infants. Non-pharmacological supportive measures are recommended for all infants until predictive factors are defined.
