Overview
Epidemiology
- Retinopathy of prematurity is the leading cause of blindness in infants.
- The incidence of the disease is:
- Directly proportional to the gestational age of the patient
- Inversely proportional to their birth weight
Risk factors
- Low birth weight
- Low gestational age
- Supplemental oxygen therapy
- Genetic predisposition
- Infections
- Congenital cardiac defects
Pathophysiology
Premature infants of low birth weight are at risk of developing hyperoxia during their care; this can lead to:
- Reactive oxygen species production → causing damage to the retina
- Abnormal vascular endothelial growth factor (VEGF) production → causing abnormal neovascularization
- Newly formed vessels are different than normal ones:
- Abnormally permeable
- Grow outside retina
- Development of abnormal fibrovascular tissue occurs and pulls the retina, causing retinal detachment.
Related videos
Classification
International classification of retinopathy uses a number of parameters to describe the disease:
- Defining which “zone” is involved
- Defining the “extent” of retinal involvement (expressed as segments on a clock)
- Defining the severity of disease, or “stage” (see table below)
- The presence or absence of “plus disease” (e.g., venous dilation and arterial tortuosity of the posterior retinal vessels)
Stages | Characteristics |
---|---|
1 | A demarcation line between the vascular and avascular retina |
2 | A demarcation line grows to occupy a volume and a ridge is formed above the plane of the retina, protruding into the vitreous. |
3 |
|
4 | Retinal detachment (partial or subtotal)
|
5 |
|
Fundus image of the right eye at 57 days after birth. Note the wide avascular retina with markedly progressed tractional changes.
Image: “Fundus image of the right eye” by Department of Pediatrics, Hamamatsu University School of Medicine. License: CC BY 3.0Presence of severe, aggressive posterior retinopathy with intense plus and minimum changes in the periphery
Image: “Presence of severe aggressive posterior ROP” by Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Kingdom of Saudi Arabia. License: CC BY 2.0Retinal images of an infant with type 1 retinopathy. A, B: Zone II stage 3 retinopathy with plus disease before treatment. C, D: Plus disease and retinopathy regressed 1 week following laser treatment.
Image: “Retinal images of an infant with type 1 ROP” by US National Library of Medicine. License: CC BY 4.0
Screening
Indication to screen
- All infants of low birth weight (< 1,500 g)
- All infants born before 30 weeks‘ gestational age
- Infants between 1,500 g and 2,000 g birth weight and born after 30 weeks’ gestation who are exposed to potential risk factors (see above)
Screening methods
- When to screen:
- For infants born between 22 and 26 weeks, when they reach 30 weeks’ corrected gestational age
- For infants ≥ 27 weeks’ gestational age, starting at 4 weeks after birth
- Follow-up exams weekly
- How to screen:
- Use indirect ophthalmoscopy or a RetCam digital camera
- The aim is to look for the features that stage retinopathy.
- Patients are classified into 2 categories:
- Infants with low risk
- Infants with proliferative retinopathy who require laser treatment
- Risk of progression is determined by:
- Weight gain
- Serum levels of insulin-like growth factor 1 (IGF-1)
- Degree of aggressiveness of the retinopathy
Management
- Early stages (stage 1 or 2 in zone I without plus disease OR stage 3 in zone II without plus disease) require close follow-up without intervention.
- Indications for treatment:
- Any stage of retinopathy in zone I with plus disease
- Stage 3 in zone I without plus disease
- Stage 2 or 3 in zone II with plus disease
- Treatment options:
- Cryotherapy: done under general anesthesia
- Indirect laser photocoagulation
- Anti-vascular endothelial growth factor drugs, such as intravitreal bevacizumab
- Vitrectomy for retinal detachment
Differential Diagnosis
The following conditions are differential diagnoses for blindness in infancy:
- Cataracts: clouding of the lens in the eye that leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble with bright lights, and trouble seeing at night. Cataracts are often noted in clinics through an asymmetric red-light reflex. Cataracts have a diverse etiology including TORCH infections, trauma, side effects of glucocorticoids, and radiation.
- Retinal detachment: the separation of the neurosensory retina from the retinal pigmented epithelium. The retina is the innermost layer of the eye, containing cones and rods that are specialized sensory organs used to detect light. Anything affecting the connection between the retina and the choroid can lead to photoreceptor ischemia and painless vision loss as a consequence.
- Retinoblastoma: the most common primary intraocular malignancy of childhood, accounting for 2% of malignant tumors in children. The condition typically presents as leukocoria (abnormal white reflection in the eye) in children under the age of 2 years. The disease may affect one or both eyes and can appear sporadically or cumulatively in families. Untreated, the condition is fatal, but with age-appropriate treatment there is a > 95% survival rate.
References
- International Committee for the Classification of Retinopathy of Prematurity. (2005). The International Classification of Retinopathy of Prematurity revisited. Arch Ophthalmol. https://pubmed.ncbi.nlm.nih.gov/16009843/
- Smith LE. (2005). IGF-1 and retinopathy of prematurity in the preterm infant. Biol Neonate. https://pubmed.ncbi.nlm.nih.gov/16210846/
- Walter M. Fierson (2018). AMERICAN ACADEMY OF PEDIATRICS Section on Ophthalmology, AMERICAN ACADEMY OF OPHTHALMOLOGY, AMERICAN ASSOCIATION FOR PEDIATRIC OPHTHALMOLOGY AND STRABISMUS, AMERICAN ASSOCIATION OF CERTIFIED ORTHOPTISTS Pediatrics. https://pediatrics.aappublications.org/content/142/6/e20183061