Although screening exams for retinopathy of prematurity (ROP) prevent blindness they are physiologically stressful for infants. The investigators postulate that photosensitivity during mydriasis contributes to post-examination stress and that reducing light stimulation with a phototherapy mask can make infants more comfortable. The objective of this study is to determine the effect of a phototherapy mask worn during mydriasis on infant stress in the 12 hour period following ROP screening.

Retinopathy of Prematurity (ROP) is a disorder of retinal vascular development of the low birthweight preterm infant that may lead to blindness if untreated. The long term visual acuity of infants with ROP detected by screening examination can be improved by peripheral retinal ablation therapy or injection of anti-VEGF agents.

The screening examination for retinopathy of prematurity involves dilation with mydriatic eye drops, insertion of a lid speculum to retract the eyelids, and depression of the sclera to visualize the retina. These exams are routinely performed in Neonatal Intensive Care Units (NICUs) to facilitate early detection of ROP and guide treatment to prevent retinal detachment and blindness. However, infants undergoing this examination have shown elevations in heart rate, blood pressure, and desaturations at the time of the examination, and in the hours following. The frequency of apneic events experienced by these infants is increased in the 24-48 hour period after an examination.

Several studies have looked at the pain response to mydriatic drops and speculum insertion as well as the systemic effects of the mydriatic drops. However, the cause of apneic events in the later post-examination period is unknown. The investigators postulate that photosensitivity related to mydriasis is distressing for infants in the period before and after the ROP exam, potentially contributing to stressful events, including apnea.

The investigators propose to test this hypothesis by conducting a dual-centre, prospective parallel group trial with balanced randomization (1:1), applying a phototherapy mask (Biliband, Natus, Pleasanton, California, USA) to cover the eyes of the infant after the instillation of mydriatic drops, leaving the mask on for 4 hours, the typical duration of mydriasis following a drop of cyclopentolate. The investigators expect that this intervention will result in a significant reduction in the number of stressful events following an examination, and may reduce the amount of distress experienced by infants. Infants requiring ROP screening will be automatically identified as part of routine hospital protocols. Participants will be recruited from the NICUs at St. Michael's Hospital and Sunnybrook Health Sciences Hospital in Toronto, Ontario, Canada.

The investigators predict that infants that have had their eyes shielded from environmental light while dilated are less likely to experience distressful events in the 12 hour period following ROP screening. If this study shows decreased rates of distress using this therapy, it would be a very simple addition to current practice and be of benefit for premature infants undergoing an uncomfortable exam.

Inclusion Criteria:

• Infant with birthweight of ≤1500 g or less or a gestational age of ≤ 32 weeks with no prior ROP screening. Examinations will be performed starting at either 4 weeks chronological age or 31 weeks post menstrual age, whichever is later.

Exclusion Criteria:

• Pre-existing corneal abrasion/ulcers, ocular malformations that prevent dilation, and known neurological abnormalities that could affect response to pain.
• Anticipation of transfer to another institution.
• Prior ROP screening