Medical Care
Although oxygen therapy has been blamed for ROP progression in the past, many physicians believe that maximizing the oxygen saturation in these critical babies will induce regression in prethreshold disease. STOP-ROP (Supplemental Therapeutic Oxygen for Prethreshold Retinopathy Of Prematurity), a multicentered national study, found that no benefit was achieved by keeping the oxygen saturation above 95%. However, higher oxygen saturation levels were not found to worsen the disease in prethreshold babies.
Because ROP progresses sequentially, and timely treatment can reduce the risk for visual loss, at-risk preterm infants must be examined at proper times and intervals. A January 2013 policy statement from the American Academy of Pediatrics on screening for ROP provides screening recommendations, including descriptions of the following [5] :
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Criteria for screening
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Equipment and methods for retinal examinations for ROP
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Examiner qualifications and reporting criteria
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Timing of the first retinal examination, based on the infant’s postmenstrual age (gestational age at birth plus chronologic age)
There appears to be a lower incidence of very high myopia (≥8.00 diopters) when ROP is treated with intravitreal bevacizumab compared with conventional lasers, [19, 20] on the basis of results from the Bevacizumab Eliminates the Angiogenic Threat for ROP (BEAT-ROP) Cooperative Group study, which randomized 109 children (211 eyes) as infants to intravitreal bevacizumab or conventional laser treatment and then compared refractive outcomes at age 2.5 years. Moreover, myopia in the laser group was linked to greater numbers of laser applications, with an increase of -0.14 D for every 100 laser applications. [20]
Among infants with zone I ROP, very high myopia developed in 2 of 52 eyes (3.8%) in the bevacizumab group and 18 of 35 eyes (51.4%) in the laser group (P < .001); among those with zone II posterior ROP, very high myopia developed in 1 of 58 eyes (1.7%) in the bevacizumab group and in 24 of 66 eyes (36.4%) in the laser group (P < .001). [19, 20]
Surgical Care
Cryotherapy was the original mode of treatment (since the 1970s). The procedure may be completed with general or topical anesthesia. It involves approximately 50 applications of a freezing probe under direct visualization with cryo applications to the avascular retina anterior to the fibrovascular ridge. The stress of the procedure may require assisted ventilation after the procedure. The most common complications include intraocular hemorrhage, conjunctival hematoma, conjunctival laceration, and bradycardia.
Laser surgery (eg, xenon, argon, diode) has been shown to be as effective as cryotherapy for ROP. The systemic adverse effects are significantly less, the ocular tissues are less traumatized, posterior zone 1 disease is treated easily, general anesthesia is not necessary, and, as many studies show, there is less incidence of late complications. Complications include corneal haze, burns of the iris, cataracts, and intraocular hemorrhages.
The use of diode laser therapy in extremely preterm infants with ROP appears not only to halt disease progression but also leads to good visual outcomes for most of these infants, thereby apparently offering similar structural and visual outcomes to those of low and very low birth weight infants with this condition. [21, 22]
Scleral buckling surgery and/or vitrectomy is usually performed for stages 4 and 5. Some surgeons recommend surgery for stage 4A, while others do not think surgery should be performed because of the risks and unproven benefit. Although some surgeons advocate surgery for stage 5, the surgeon with the most experience (ST Charles, MD, personal communication) no longer recommends surgery because of the poor anatomical and visual prognosis.
According to the largest reported case series in the world, lens-sparing vitrectomy to correct early degrees of retinal detachment results in excellent lens clarity and vision in the majority of infants with retinopathy of prematurity. Success rates for retinal reattachment with a single surgery were approximately 89% for infants with stage 4A retinopathy. Success rates for stage 4B retinopathy were 60%. The procedure was less successful in infants with stage 5 retinopathy, with an 18% success rate. [23]
Consultations
An ophthalmology consultation is essential in a premature infant born weighing less than 1500 g and/or younger than 32 weeks' gestation (as defined by the attending neonatologist). Also, selected infants with a birth weight of 1500-2000 g or a gestational age of more than 32 weeks with an unstable clinical course, including those requiring cardiorespiratory support and who are believed by their attending pediatrician or neonatologist to be at high risk, should have retinal screening examinations performed after pupillary dilation using binocular indirect ophthalmoscopy to detect ROP. One examination is sufficient only if it unequivocally shows the retina to be fully vascularized in each eye. The ophthalmologist chosen should be one with the most experience in screening or treating this disease. A review of two randomized crossover trials performed in single centers found that the application of topical proparacaine 30 seconds before the evaluation brings about a reduction in pain scores, particularly at the moment of speculum insertion. [24]
An ophthalmologist experienced in this modality should perform laser or cryotherapy surgery.
Scleral buckle surgery and vitrectomy techniques in these small eyes should be left in the hands of experienced surgeons.
Practitioners involved in the ophthalmologic care of premature infants should be aware that the retinal findings that require strong consideration of ablative treatment were revised according to the Early Treatment for Retinopathy of Prematurity Randomized Trial study. The finding of threshold ROP, as defined in the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity, may no longer be the preferred time of intervention.
Treatment may also be initiated for the following retinal findings:
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Zone 1 ROP - Any stage, with plus disease
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Zone 1 ROP - Stage 3, with no plus disease
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Zone 2 ROP - Stage 2 or 3, with plus disease
The number of clock hours of disease may no longer be the determining factor in recommending ablative treatment. Treatment should generally be accomplished, when possible, within 72 hours of determination of treatable disease to minimize the risk of retinal detachment.
Diet
Vitamin E is not recommended in infants who weigh less than 1500 g.
Prevention
The Light-ROP study evaluated the role of light in stimulating the development of ROP. Patients were either exposed to normal light conditions in the nursery or shielded from ambient light conditions. There was no difference in the number of patients developing ROP in either group.
In infants at risk for ROP, early administration of high-dose intramuscular vitamin A improves retinal function at 36 weeks’ postmenstrual age.
Long-Term Monitoring
Any premature infant should continue to be monitored until active disease has subsided.
Since 20% of premature babies develop strabismus and refractive errors, a pediatric ophthalmologist should screen them every 6 months, until age 3 years.
Up to 10% of premature babies may develop glaucoma in later years. Eye examinations should be a part of their annual examinations.
Transfer
Transfer the infant to a NICU that can handle the disease and the required surgical intervention if necessary.
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Retinopathy of prematurity consultation form and fundus drawing.
