Magnetic resonance imaging (MRI) in dissociated strabismus complex (DSC) demonstrated generalized hypertrophy of extraocular muscles (EOMs)

Volume 20 Number 4 / August 2016 correlate with birth anthropometric measurements, VA, refraction or RNFL thickness in neither the MLP nor the control group when adjusted for age and gender. Discussion: We report decreased P100 VEP amplitudes in the MLP group. The physiological background for the differences found are not clear but since the RNFL thickness is similar it is probably not due to retinal morphological differences but may suggest differences in optic nerve or visual cortex properties. Conclusions: Our study suggests that moderate premature birth may have a significant effect on visual evoked potential without clear retinal structural changes. Further studies are needed to better understand the association between this findings and visual functions in preterm children. 151 Magnetic resonance imaging (MRI) in dissociated strabismus complex (DSC) demonstrated generalized hypertrophy of extraocular muscles (EOMs). Ghada Z. Rajab, Joseph L. Demer Introduction: DSC is a poorly understood cause of strabismus that includes dissociated vertical (DVD) and dissociated horizontal (DHD) deviations. We employed MRI to evaluate the EOMs in patients with DSC. Methods: We prospectively studied five patients with DSC aged 12-42 (mean, 25) years, and 15 age-matched, orthotropic control subjects. All patients had DVD, and 3 of these also had DHD. We employed high resolution, surface coil MRI with thin, 2-mm slices and central target fixation. The volumes of the rectus and superior oblique muscles in the region 12 mm posterior to 4 mm anterior to the globe-optic nerve junction were measured in quasi-coronal sections in central gaze. Results: Patients with DSC exhibited statistically significant generalized volume increase of all rectus and superior oblique muscles ranging from 8.6% for lateral rectus to 22% for superior oblique (P \ 0.05). There were no structural or innervational abnormalities of EOMs in affected orbits. Discussion: DSC is composed of various combinations of sursumduction, excycloduction, and abduction that do not conform to Hering's law. Although consequent enlargement of the superior and lateral rectus muscles might have been anticipated in DSC, instead we found generalized enlargement of all rectus and the superior oblique EOMs. Generalized hypertrophy may be related to abnormal discharge patterns of motor neurons innervating the EOMs previously demonstrated in monkeys with DSC, and is consistent with similar changes in both agonist and antagonist EOMs in experimentally induced strabismus in monkeys. Conclusions: DSC is associated with generalized EOM hypertrophy in the absence of other orbital abnormalities. 152 Anatomic indices following photorefractive keratectomy in children 5+ years after surgery. Radha Ram, Terry Kang, Mitchell P. Weikert, Lingkun Kong, David K. Coats, Evelyn A. Paysse Introduction: Photorefractive keratectomy (PRK) can reduce refractive error and improve visual acuity in children with refractive error associated with amblyopia. The purpose of this study was to evaluate long-term corneal indices in children treated with PRK. Methods: This prospective interventional case series evaluated long-term anatomic outcomes in children with anisometropic or isoametropic amblyopia after PRK at a single hospital. Main outcome measures were 5+ years postoperative indices of corneal thickness, corneal curvature, presence of corneal haze, and presence of keratectasia.

Journal of AAPOS

e41 Results: Seven eyes in 5 subjects to date were included. Four subjects had high myopia and one had high hyperopic astigmatism. Mean age at surgery was 6.2 years (range, 3-9 years). Mean follow-up was 6.2 years (range, 5-8 years). Mean preoperative spherical equivalent was 11.25 D (range, 13.00 D to 7.25 D) in the myopic group and +5.62 D (range, +5.25 to +6.00 D) in the hyperopic group. At last examination, mean postoperativeerative spherical equivalent was 3.20 D (range, 6.75 D to +1.25 D) in the myopic and +2.50 D in the hyperopic groups. Mean corneal thickness was 573 um immediately before PRK, 441um immediately after PRK, and 525 um (range, 473–610 um) at lfinal examination. No subject had corneal haze or topographic evidence of keratectasia. Discussion: Nothing has been reported on the long-term effect of PRK on the cornea of children. We found that refractive error correction was persistent and corneal thickness and topography remained stable. No corneal haze or keratectasia was found. Conclusions: PRK does not appear to increase the risk of keratectasia in appropriately selected children. 153 Lateral rectus extirpation and denervation for treatment of paretic exotropia. Anvesh C. Reddy, David G. Morrison, Sean P. Donahue Introduction: Paretic exotropia presents a management dilemma given the presence of unopposed contraction of the still innervated lateral rectus. Standard recess/resect procedures have limited efficacy as the paretic medial rectus cannot function against a nonparetic lateral rectus. Disinsertion of the lateral rectus with reattachment to the periosteum of the lateral orbital wall decreases unopposed abduction and preserves the muscle, but is complex and is still prone to deviation recurrence. We report a series of patient who underwent lateral rectus extirpation and denervation (LRED) for paretic exotropia caused by third nerve palsy or other disease. Methods: Retrospective case series of patients undergoing LRED between June 1, 2013 and September 30, 2015 at Vanderbilt University. Results: 12 eyes of 10 patients with paretic exotropia were operated upon (N 5 12); 8 had cranial nerve III palsy (1 bilateral), 1 with sensory exotropia, 1 with epithelioid sarcoma overlying the medial rectus, 1 with Duane type 3, and 1 following iatrogenic medial rectus transection. One patient did not follow-up and was excluded from results (N - 1). Abduction decreased from 0.6 to 2.4. Adduction improved from 4.0 to 2.8 Exotropic deviation in primary improved from 42 to 8.9 and 42 to 8.4D at distance and near respectively. Head position was grossly unchanged. Discussion: LRED offers an alternative treatment of paretic exotropia, eliminates the risk of LR reattachment, and is less technically challenging than periosteal fixation. Conclusions: LRED improves distance and near exotropia and increases adduction. Abduction remains surprisingly well-preserved. 154 Correlation between serum insulin-like growth factor and postnatal weight in premature infants. Julia E. Reid, James Shaffer, Gui-shuang Ying, Anne K. Jensen, Gil Binenbaum Introduction: Weights are used as surrogates for serum insulin-likegrowth-factor-1 (IGF-1) in ROP prediction, despite limited published data demonstrating correlation in premature infants. We evaluated the association between postnatal serum IGF-1 and weight in a cohort of premature infants at risk for ROP. Methods: Prospective cohort study of 74 infants with birth weight \1251 g at 3 hospitals. Weekly IGF-1 assays and daily weights were collected. Correlation between IGF-1 and weights was assessed with Pearsons coefficient (r . +0.7 very strong, +0.4 to