Disorders of the Retina and Vitreous

Figure 25-1 Schematic of the retina of the right and left eyes, showing the area of zones I (red), II (yellow), and III (green), as well as clock-hours, which are used to describe the location of retinopathy of prematurity (ROP).

Figure 25-2 Stage 1 ROP. The demarcation line has no height. (Courtesy of Daniel Weaver, MD.)

Figure 25-3 Stage 2 ROP. The demarcation line has height and width, creating a ridge. (Courtesy of Andrea Molinari, MD.)

Figure 25-4 Stage 3 ROP. Ridge with extraretinal fibrovascular proliferation. (Reproduced with permission from Lueder GT. Pediatric

Practice Ophthalmology. New York: McGraw-Hill; 2011:232.)

dilation and tortuosity that is abnormal but less than that seen in the standard photograph (Fig 25-7). Aggressive posterior ROP is a severe form of ROP found in some babies with zone I disease (Fig 25- 8). The Cryotherapy for Retinopathy of Prematurity (CRYO-ROP) trial defined threshold disease as 5 contiguous or 8 total clock-hours of stage 3 in zone I or II with plus disease. The Early Treatment for Retinopathy of Prematurity (ETROP) trial further classified ROP into type 1 and type 2 disease to delineate which babies would benefit from treatment before the development of threshold disease (Table 25-3).

Committee for Classification of Retinopathy of Prematurity. An international classification of retinopathy of prematurity. Arch Ophthalmol. 1984;102(8):1130–1134.

Figure 25-6 Plus disease. (Reproduced with permission from Lueder GT. Pediatric Practice Ophthalmology. New York: McGraw-Hill; 2011:231.)

Figure 25-7 Pre–plus disease. (Courtesy of Daniel Weaver, MD.)

Figure 25-8 Aggressive posterior ROP in an infant born at 31 weeks’ gestation and weighing 1375 g. (Courtesy of Gregg T.

Lueder, MD.)

Table 25-3

Risk factors for development of ROP

Gestational age and weight at birth, 2 of the strongest risk factors for ROP, are inversely correlated with the development of ROP: smaller babies and those born at an earlier gestational age are at higher risk. The incidence of ROP requiring treatment is lower among African American than non–African American babies.

Use of supplemental oxygen is a risk factor, as shown in the 1960s when ROP markedly decreased (and death and cerebral palsy markedly increased) with the severe limitation of oxygen for premature infants. However, the exact role that oxygen plays is still not well understood. Despite many studies, the optimal amount of supplemental oxygen to give to premature infants to promote normal

development and limit ROP remains elusive. Even though some studies have shown that maintaining oxygen saturation levels at a lower level than was customary prior to 34 weeks’ corrected age can lower the incidence of ROP, it is unclear whether the benefit is significant enough to warrant the systemic risks to the infant. Low early levels of IGF-I are associated with slower-than-expected weight gain and more severe ROP. The weight, IGF-I, neonatal ROP (WINROP) algorithm (Premacure AB, Uppsala, Sweden) is a surveillance system that identifies babies at high risk for development of type 1 ROP. This algorithm—which uses the gestational age, serum IGF-I levels, and tracking of the infant’s weight gain—may allow for targeted, cost-effective screening of infants at high risk for severe ROP.

International Committee for the Classification of Retinopathy of Prematurity. The International Classification of Retinopathy of Prematurity revisited. Arch Ophthalmol. 2005;123(7):991–999.

Löfqvist C, Hansen-Pupp I, Andersson E, et al. Validation of a new retinopathy of prematurity screening method monitoring longitudinal postnatal weight and insulinlike growth factor I. Arch Ophthalmol. 2009;127(5):622–627.

Diagnosis

Dilated fundus examinations should be performed to screen for ROP in infants who were born at a gestational age of 30 weeks or earlier or had a birth weight of less than 1500 g. They should also be performed in premature infants with an unstable course if the pediatrician believes that the child is at high risk for ROP. The first examination should be done at 4 weeks’ chronologic (postnatal) age or at a corrected gestational age of 30–31 weeks, whichever is later (but not later than 6 weeks’ chronologic age). Current recommendations can be found on the website of the American Academy of Pediatrics (http://pediatrics.aappublications.org/content/131/1/189.full.pdf+html?sid=1db1246f-7f4 d-48d9-8692-17301d5808d8).

Cyclomydril (0.2% cyclopentolate and 1.0% phenylephrine) is recommended for the examination of premature infants. Alternatively, tropicamide 0.5% or 1.0% and phenylephrine 2.5% can be used. Sterile instruments should be used to examine the infant. A nurse should be present for examinations in the neonatal intensive care unit because the infant may experience apnea and bradycardia during examination. If an examination must be postponed, the postponement and medical reason should be documented in the patient’s medical record. Follow-up examinations should be performed according to Table 25-4.

Table 25-4

Currently, the incidence of ROP is rising in developing countries, echoing the epidemic that occurred in the United States and the United Kingdom in the 1940s and early 1950s. Affected infants in developing countries are larger and of older gestational age than infants in the United States in whom ROP develops, suggesting that screening criteria for ROP should be modified in developing countries.

Digital retinal photography is highly accurate for detecting clinically significant ROP. Therefore, telemedicine involving retinal image–based screening has been used in underserved areas to identify infants at high risk of requiring treatment.

Chiang MF, Melia M, Buffenn AN, et al. Detection of clinically significant retinopathy of prematurity using wide-angle digital retinal photography: a report by the American Academy of Ophthalmology. Ophthalmology. 2012;119(6):1272–1280. Epub 2012 Apr 27.

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. 2013;131(1):189–195.

Treatment

Treatment guidelines have been created based on the results of several multicenter ROP trials. These guidelines indicate which level of disease requires treatment to decrease the risk of adverse visual sequelae. In the CRYO-ROP trial, cryotherapy applied to the avascular peripheral retina at threshold resulted in a 50% lower rate of retinal detachment compared with observation. In later studies, laser therapy was used following the same guidelines as those in the CRYO-ROP trial; it was shown to be equally effective in inducing regression of the new vessels and more effective in preventing adverse visual sequelae (Fig 25-9). More recently, the ETROP trial found that earlier treatment in high-risk eyes classified as type 1 resulted in better structural and visual outcomes than conventional treatment at threshold. Laser treatment is strongly recommended for any eye with type 1 ROP. Eyes with type 2 ROP should be closely observed for progression to type 1 disease.