VISUAL-FIELDS MEASURED WITH DOUBLE-ARC PERIMETRY IN EYES WITH THRESHOLD RETINOPATHY OF PREMATURITY FROM THE CRYOTHERAPY FOR RETINOPATHY OF PREMATURITY TRIAL

Purpose: To measure monocular visual field extent in very-low birth we ight children in whom severe (threshold) acute-phase retinopathy of pr ematurity (ROP) developed in one or both eyes, and who had random assi gnment of eyes to cryotherapy or no cryotherapy. A control group of ve ry-low birth weight children in whom ROP did not develop also was test ed. Methods: There were 78 children in the severe ROP group from 5 of 23 centers in the randomized trial of cryotherapy for ROP (CRYO-ROP). The comparison cohort consisted of 75 study participants in whom ROP d id not develop. All subjects had birth weights of less than 1251 g. At the 5 1/2-year study examination, visual field size was measured usin g double-are kinetic perimetry. Testers were masked to treatment statu s of each eye. Four meridia were tested: superotemporal (ST), inferote mporal (IT), inferonasal (IN), and superonasal (SN). Target size was 6 degrees. Results: When blind eyes were assigned a score of 0 degrees, the no-ROP, treated, and control eyes had an average visual field ext ent of 62 degrees, 35 degrees, 27 degrees at ST; 73 degrees, 42 degree s, 35 degrees at IT; 51 degrees, 30 degrees, 21 degrees IN; and 50 deg rees, 26 degrees, 22 degrees at SN, respectively, Among 25 children wh o had bilateral threshold ROP and measurable fields in each eye, value s for treated and control eyes were 59 versus 62 at ST, 69 versus 80 a t IT, 44 versus 49 at IN, and 41 versus 48 at SN, respectively. Conclu sions: Overall, visual fields in eyes that reached threshold ROP were smaller than those of eyes that did not develop ROP, When only pairs o f sighted eyes were considered, visual fields in the treated eyes were 6.4 degrees smaller than those of control eyes. Therefore, it appears that a small loss of peripheral field occurs when cryotherapy prevent s the development of retinal detachment.