Fig. 17.1 International classification system for ROP: location and extent of disease. Zone I is defined as a circle with radius twice the distance from the center of the optic nerve to the macular center. Zone II extends centrifugally

from the edge of zone I to the nasal ora serrata. Zone III is the residual crescent of retina anterior to zone II. The extent of disease is recorded as clock hours or as twelve 30o sectors

the posterior retinal blood vessels that is equal to or greater than that of a published retinal photograph which was selected by expert consensus [18].

guidelines for identification of severe treatmentrequiring ROP based on the classification of the disease [6, 18].

17.1.3 Examination and Treatment

Since severe ROP is treatable with laser photocoagulation or cryotherapy if diagnosed early enough, it is important to examine all infants who are at risk for ROP [24]. Screening guidelines for ROP have been established based on the natural history data and risk of disease progression [6, 18, 25]. In the United States, current published guidelines recommend screening examinations for infants with [31]:

•Birth weight of less than 1,500 g, or

•Gestational age determined by ultrasound of 30 weeks or less, or

•Birth weight between 1,500 and 2,000 g or gestational age of more than 30 weeks with an unstable clinical course, as determined by the attending neonatologist

ROP examination consists of dilated, binocu-

lar indirect ophthalmoscopy (BIO) at the neonatal intensive care unit (NICU) bedside, performed by an experienced ophthalmologist. Multicenter randomized trials, such as Cryotherapy for ROP (CRYO-ROP) and Early Treatment for ROP (ETROP) studies, have established specific

17.1.4 Limitations of Current Care

Traditional ROP screening with BIO has been extremely effective at preventing the advanced complications of disease, when implemented appropriately. However, there are several limitations to current ROP screening models. Limitations to current ROP screening models include: (1) standard examinations are logistically difficult and require significant travel time for ophthalmologists and coordination with neonatologists; (2) examinations using scleral depression are physiologically stressful for premature infants and frequently cause problems such as apnea, bradycardia, and aspiration [15];

(3) there is enormous medicolegal liability associated with ROP care; and (4) persistent variability with regard to how ROP findings are diagnosed and documented using traditional paper-based retinal sketches. Concerns have been raised about an emerging ROP “epidemic” due to a shortage of adequately trained ophthalmologists to perform ROP screening, particularly in developing nations. A recent American Academy of Ophthalmology survey showed that only half of retinal specialists and pediatric ophthalmologists