Which Premature Infants Need Eye Exams?

Patient Presentation
An 81-day-old former 28 week gestation female came to the resident continuity clinic after her neonatal intensive care unit stay. She had required ventilation for almost 4 weeks and currently was on 1/2 L/minute of supplemental oxygen. She had slowly worked up on her oral feeding and was currently taking ~45-50 ml every 2-3 hours of 24 kcal/ounce premature infant formula. Her parents reported that she was still slow to eat but was continuing to improve as she grew. She had gained 16 grams/day since discharge 2 days previously. She was being followed for Zone III retinopathy of prematurity (peripherally) bilaterally.

The pertinent physical exam showed a small infant with a weight of 2.713 grams (3-10%), 45 cm length (50%) and head circumference 32 cm (10-50%). Percentiles are for the Fenton premature infant growth chart. She was alert and responsive with good tone. Her oxygen canula was in place. The examination was as expected for a former premature infant who was now 39-40 weeks corrected gestational age.

The diagnosis of a former premature infant was made. The following week she was to see ophthalmology and return to clinic for another followup appointment. The attending pediatrician said to the resident, “You probably know more about which babies get eye exams than I do. I’m not sure when they get them, but I know they need them and I help the families to followup.” The family already had a visiting nurse and oxygen therapy already coming to their home, and her neonatal infant followup appointment was already scheduled.

Retinopathy of prematurity (ROP) is a developmental problem. Term infants have full vascularization of the retina and therefore cannot have ROP. Premature infants however do not have full vascularization (which proceeds from the periphery to the central retinal area) and therefore may have abnormal and excessive vascularization. It affects premature infants primarily < 31 weeks gestation. Although the mechanism of ROP is not completely understood, increased oxygen levels are a risk factor. Additionally there is data which shows growth factors such as vascular endothelial growth factor (VEGF) are increase,d resulting in abnormal vascularization. Prevention is the best treatment for ROP which includes lower oxygen saturation targets (current targets are in the low 90s%) and proper parenteral nutrition. With cryo- and laser therapy, the outcomes for premature infants with lower rates of any ROP and especially severe ROP have dramatically improved. ROP treatment depends on the location and extent of the disease, and type of disease. Location closer to the macula, more retinal area involved and “plus” disease (i.e. which has abnormal dilation and tortuosity of the retinal blood vessels) all have worse prognoses.

Ablative treatment with laser or cryotherapy or use of anti-VEGF medications (anti-vascular endothelial growth factor) are the usual treatments.

Learning Point
According to the American Academy of Pediatrics (AAP) the following infants should be screened for ROP:

  • All infants with
    • Birth weight of < 1500 grams, OR
    • Gestation age < or = 30 weeks
  • Selected infants
    • Birth weight 1500 – 2000 grams, OR
    • Gestational age > 30 weeks
    • AND are believed to be at risk for ROP (“…infants with hypotension requiring inotropic support, infants who received oxygen supplementation for more than a few days, or infants who received oxygen without saturation monitoring” as determined by the neonatologist or attending pediatrician.

Examinations should be done by an ophthalmologist with pupillary dilation. With advanced ROP, pupillary dilation may be poor so care should be taken if considering using multiple drops to achieve dilation. First examination should occur around 31-34 weeks corrected gestational age depending on initial gestational age. “One examination is sufficient only if it unequivocally reveals the retina to be fully vascularized in both eyes.” Followup examination is determined by the classification of the infants findings. Primary health care providers can support these infants and families by ensuring appropriate followup has been scheduled and assisting families in going to their appointments.

Questions for Further Discussion
1. What are the best growth charts to use? A review can be found here
2. How long do you follow late premature infants for? A review can be found here
3. What are risk factors for bronchopulmonary dysplasia? A review can be found here

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for these topics: Premature Babies and Retinal Disorders.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Fang JL, Sorita A, Carey WA, Colby CE, Murad MH, Alahdab F. Interventions To Prevent Retinopathy of Prematurity: A Meta-analysis. Pediatrics. 2016;137(4). doi:10.1542/peds.2015-3387

Fierson WM, American Academy of Pediatrics Section on Ophthalmology, American Academy of Ophthalmology, American Association for Pediatric Ophthalmology and Strabismus, American Association of Certified Orthoptists. Screening Examination of Premature Infants for Retinopathy of Prematurity. Pediatrics. 2018;142(6). doi:10.1542/peds.2018-3061

Higgins RD. Oxygen Saturation and Retinopathy of Prematurity. Clin Perinatol. 2019;46(3):593-599. doi:10.1016/j.clp.2019.05.008

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa