Symmetry of Disease in Retinopathy of Prematurity
Anne K. Jensen, MD; Gui-shuang Ying, PhD; Graham Quinn, MD, MSCE; Lauren A. Tomlinson, BS; Gil Binenbaum, MD, MSCE; G-ROP Study Group
The Children’s Hospital of Philadelphia
Introduction: Correlation of retinopathy of prematurity (ROP) between eyes has been reported in high-risk populations. We sought to evaluate inter-eye symmetry for ROP in a broad-risk cohort representative of infants undergoing ROP screening.
Methods: Retrospective cohort study of infants undergoing ROP examinations from 29 hospitals between 2006-2012 (The G-ROP Study). Primary outcomes were symmetry for type (type 1, 2, not 1 or 2, no ROP), highest stage of ROP, and disease course of asymmetric fellow eyes when one eye developed type 1.
Results: 7483 infants were studied. 94% of right and left eyes were symmetric for type. 93% of eyes were symmetric for highest stage. 378/459 (82%) infants developed type 1 in both eyes together. In 44 infants, one eye had type 1 and the fellow eye was treated simultaneously for type 2. All 37 remaining fellow eyes had ROP: 8 developed type 1 and were treated (6 within 2 weeks, all within 4 weeks); 4 developed type 2 and regressed; and 25 developed ROP less than type 1 or 2 and regressed.
Discussion: This large, broad-risk cohort is representative of infants receiving ROP screening. When asymmetric for type 1, nearly all type 2 eyes were treated along with the more severe eye, so it is not possible to know what proportion would have progressed to type 1.
Conclusion: ROP is a highly symmetric disease between eyes with respect to the presence and severity of disease. When type 1 ROP develops in only one eye, the risk of progression to type 1 in the fellow eye is very low if it has not occurred within 4 weeks.
References: Quinn GE, Dobson V, Biglan A, Evans J, Plotsky D, Hardy RJ. Correlation of retinopathy of prematurity in fellow eyes in the CRYO-ROP Study. ARCH OPHTHALMOL 113:469-73, 1995.