Purpose: To develop a nomogram based on age and disease type for sclerotomy placement in pars plana vitrectomy for infants and children with congenital and acquired vitreoretinopathies. Design: A retrospective, single-center, single-surgeon comparative case series. Participants: A total of 171 eyes of 93 patients ranging in age from a postmenstrual age (PMA) of 34 weeks to a chronological age of 23 years with congenital and acquired vitreoretinopathies. Methods: The corneal white-to-white diameter and the distance between the ora serrata and surgical limbus (ora-limbus distance) in the nasal, temporal, inferior, and superior quadrants were measured externally in vivo under general anesthesia prior to planned pars plana vitrectomy or laser procedure. The average ora-limbus distance of the quadrants was calculated for each eye (mean ora-limbus distance); and mean ora-limbus distance was evaluated as a function of age and compared among age-matched subjects from control and disease groups. Results were used to create a nomogram for safe sclerotomy placement based on age and disease type. Main Outcome Measures: The main outcome measure was distance (millimeters) from the ora serrata to the surgical limbus; a secondary measurement was corneal white-to-white distance (millimeters). Results: Among all subjects, the ora-limbus distance was greatest in the superior quadrant, followed by the temporal, inferior, and nasal quadrants. A positive logarithmic relationship between ora-limbus distance and age was demonstrated in all groups. Whereas age-adjusted mean ora-limbus distances were similar among the familial exudative vitreoretinopathy and control groups, growth trends differed in patients with coloboma, persistent fetal vasculature, Stickler syndrome and/or myopia, and retinopathy of prematurity (ROP). In ROP, when subjects <12 months of age were considered separately, a negative correlation was found between the ora-limbus distance and PMA, with infants of lesser gestational age exhibiting greater restriction in ora-limbus distance. Conclusions: Placement of sclerotomies for pars plana vitrectomy in children requires consideration of ocular development in congenital and acquired vitreoretinopathies; we present an age-based nomogram for sclerotomy placement in infants and children based on analyses of ora-limbus distance in several pediatric ocular conditions.
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