Objective:To assess the visual acuity of eyes successfully treated with 3-port lens-sparing vitrectomy for stage 4 retinopathy of prematurity.Methods:Of 102 consecutive eyes achieving at least posterior pole reattachment,30 eyes of 26 patients were tested by Teller or Allen acuity measurements and were subsequently converted to logarithm of the minimum angle of resolution(logMAR).Visual outcomes were also examined as either favorable or unfavorable(Snellen equivalent >20/200).Results:Seventy-two eyes were not tested because of either inability to performtesting(age or neurologic sequelae related to prematurity)or loss of follow-up.Of those tested,mean± SD logMAR visual acuity for the stage 4A and stage 4B groups was 0.51± 0.09(Snellen approximate 20/62)and 1.03± 0.19(Snellen approximate 20/200),respectively(odds ratio,0.39;95% confidence interval,0.24-0.64;P=.001).Of those eyes assessed by Teller measurements,10 of 10 stage 4A eyes and 3(37.5%)of 8 stage 4B eyes had favorable outcomes;among eyes assessed with Allen measurements,4 of 4 stage 4A eyes and 0 of 8 stage 4B eyes had favorable outcomes.Conclusions:The majority of eyes were not tested.Among eyes tested after successful 3-port lens-sparing vitrectomy,some eyes treated prior to macular detachment may be associated with a more favorable outcome and improved maintenance of functional visual acuity. Objective: To assess the visual acuity of eyes successfully treated with 3-port lens-sparing vitrectomy for stage 4 retinopathy of prematurity. Methods: Of 102 consecutive eyes achieving at least posterior pole reattachment, 30 eyes of 26 patients were tested by Teller or Allen acuity measurements and were succeeded to logarithm of the minimum angle of resolution (logMAR) .Visual outcomes were also examined as either favorable or unfavorable (Snellen equivalent> 20/200) .Results: Seventy-two eyes were not tested because of either in inability to perform testing (age or neurologic sequelae related to prematurity) or loss of follow-up. Of those tested, mean ± SD logMAR visual acuity for the stage 4A and stage 4B groups was 0.51 ± 0.09 (Snellen approximate 20/62) and 1.03 ± 0.19 (Snellen approximate 20/200), respectively (odds ratio, 0.39; 95% confidence interval, 0.24-0.64; P = .001) .Of those eyes assessed by Teller measurements, 10 of 10 stages 4A eyes and 3 (37.5% of 8 stage 4B eyes had favorable outcom es; among eyes assessed with Allen measurements, 4 of 4 stage 4A eyes and 0 of 8 stage 4B eyes had favorable outcomess.Conclusions: The majority of eyes were not tested. Amorphous eyes tested succeeded 3-port lens-sparing vitrectomy, some eyes treated prior to macular detachment may be associated with a more favorable outcome and improved maintenance of functional visual acuity.