The benefit of treatment during the criticial period in children with infantile nystagmus syndrome

e4 012 Illuminated microcatheter-assisted 360-trabeculotomy for refractory juvenile open angle glaucoma and glaucoma post childhood cataract removal. Jennifer B. Dao, Sharon F. Freedman Purpose: Juvenile open-angle glaucoma (JOAG) and glaucoma post-childhood cataract removal (GPCC) prove challenging to manage, frequently requiring surgical intervention. Angle surgery, more often successful in primary infantile glaucoma, has some reported success in these cases. Purpose: to evaluate 360-degree trabeculotomy, facilitated by microcatheter, for medically-refractory JOAG and GPCC. Methods: On-going, multicenter study of all 360-degree trabeculotomy for JOAG and GPCC using iTrack catheter (2 surgeons/2 sites since 2008). Success5 intraocular pressure(IOP) 5 22 mmHg with . 20% reduction, without disease progression and without oral glaucoma medications or additional glaucoma surgery. One eye per subject analyzed. All cases had gonioscopically open angles preoperatively. Results: Included to date from one site are 28 eyes status/post iTrack-facilitated 360-degree trabeculotomy; 8 JOAG (mean age 16.7 years at diagnosis); 14 GPCC (mean age 20 months at diagnosis). Incomplete cannulation/opening of Schlemm canal occurred intraoperatively in 1 JOAG and 3 GPCC cases. At most recent follow-up, 6 of 7(86%) JOAG and 8 of 11(72%) GPCC cases were successful. Of successful cases, preoperative vs. final IOP decreased in both groups (31.1  8.1 vs 12.1  2.8 mm Hg for JOAG, P \ 0.0008, after mean 10 months; 33.1  3.4 vs 17.3  4.6 mm Hg for GPCC, P \ 0.0001, after mean 13 months). Preoperative versus final mean #glaucoma medications decreased for both groups(JOAG: 4.3 vs 2.8, P \ 0.098; and GPCC: 3.1 vs 1.8, P \ 0.02.) When the surgery failed, it did so within 2 months in all (n 5 4)cases. Complications included vitreous hemorrhage(2 GPCC eyes/one vitrectomy) and transient choroidal effusion(1 GPCC eye). Discussion: ITrack-facilitated 360-degree trabeculotomy shows early promise for initial surgical treatment of medically-refractory JOAG and GPCC, with low complication rates and without loss of remaining surgical options. Conclusions: Continuing study of this technique for JOAG and GPCC will include larger sample size with longer follow-op and may identify predictive factors for long-term success. 013 Revised guidelines for reporting results from studies of preschool vision screening. Sean P. Donahue, Robert Arnold, Jim Ruben, David Silbert, Brian Arthur, Dan Neely Purpose: In 2003, the AAPOS Vision Screening Committee proposed criteria for automated preschool vision screening. Subsequent studies and the advent of newer devices produced the need to update these criteria. Methods: Review of recent literature from epidemiologic and natural history studies, RCTs of amblyopia treatment, and field studies of screening technologies. Results: The prevalence of amblyopia risk factors (ARF) is higher than previously suspected; many young children with low magnitude ARFs dont develop amblyopia, and those who do often respond to spectacles alone. High magnitude ARFs increase likelihood of amblyopia. While depth increases with age, amblyopia remains treatable until 60 months with decline in effectiveness after age 5. USPSTF guidelines allow photoscreening for children over 36 months. Some technologies directly detect amblyopia rather than ARFs. Discussion: Age-based criteria for ARF detection using photoscreening is prudent: referral criteria for such instruments should produce high specificity for ARF detection in young children and high

Volume 16 Number 1 / February 2012 sensitivity to detect amblyopia in older children. Refractive screening for ARFs for ages 12-30 mos should detect astigmatism .2.50 D, hyperopia .4.5 D, and anisometropia .2.0 D; screening of children 3148 mos should detect astigmatism .2.50 D, hyperopia .4.0 D, and anisometropia .2.0 D. For children over 49 mos original criteria should be used (astigmatism .1.5 D, anisometropia .1.5 D, hyperopia .3.5 D). Visually significant media opacities and manifest (not intermittent) strabismus should be detected at all ages. Instruments that detect amblyopia should report results using amblyopia presence as gold standard. Conclusions: New AAPOS VSC guidelines will improve reporting of results and comparison of technologies. 014 Measurement of corneal hysteresis, corneal resistance factor and intraocular pressure using the Ocular Response Analyzer in children. Marc F. Comaratta, Victor Neamtu, Airaj F. Fasiuddin Purpose: To compare intraocular pressure measurements obtained by iCare rebound tonometry to the corneal compensated (IOPcc) and Goldmann-correlated (IOPg) measurements obtained by the Ocular Response Analyzer (ORA). To evaluate differences in corneal hysteresis (CH) and corneal resistance factor (CRF) according to age, race, gender and refractive error. Methods: Reichert ORA measurements of CH, CRF, IOPcc, and IOPg were obtained from patients ages 3-17. Intraocular pressure was measured using iCare rebound tonometry and cycloplegic refraction was performed. Data was analyzed to correlate iCare tonometry with the ORA measurements of IOPcc and IOPg. The effects of age, race, gender, and refractive error on CH and CRF were examined. Results: 79 patients and 152 eyes were included in this study. Analysis using Lins concordance class correlation (CCC) indicated moderate agreement between iCare tonometry and the ORA measurements among all subjects, and good correlation in older age groups. Analysis of CH by age group showed significant differences between ages 3-6 compared to 7-10 and 11-14 (P 5 0.0030 and 0.0045, respectively). Mean CH values were lower in black versus white children (P 5 0.0008). Differences in mean CRF between ages 3-6 and 11-14 (P 5 0.0030) and between black and white populations (P 5 0.0065) were identified. Analysis by gender and refractive error showed no significant difference in mean CH or CRF among these groups. Conclusions: The non-contact measurement calculated by ORA shows reasonable correlation with iCare rebound tonometry in patients ages 3-17. Mean CRF values are lower in children ages 3-6 than older age groups. Both CRF and CH values are lower for black versus white children. 015 The benefit of treatment during the criticial period in children with infantile nystagmus syndrome. Joost Felius, David R. Stager, Sr., Reed M. Jost Background/Purpose: Improvements in both ocular motor and sensory function in patients with infantile nystagmus syndrome (INS) have been reported after 4-muscle surgery. Here we tested the hypotheses that improvements in eye movement control lead to improvements in visual acuity in idiopathic INS but not necessarily in INS associated with afferent defects, and that visual acuity improvements are larger for children in the critical period for acuity development than for older children. Methods: Eye movement recordings and binocular grating acuity were assessed in 31 patients (age 5.1  3.8 years) before and after 4-horizonal rectus surgery. Nystagmus was quantified using the

Journal of AAPOS

Volume 16 Number 1 / February 2012 Nystagmus Optimal Fixation Function (NOFF), a measure of foveation time that is feasible in children. Post-operative changes were evaluated by group: INS with albinism (n 5 15), idiopathic INS \6 years of age (n510), and idiopathic INS $6 years of age (n 5 6). Results: There was a significant overall improvement in eye movement outcome (mean change in NOFF, 0.8 logit units [range, 0-2.2]; P \ 0.001), which did not differ among groups (P 5 0.6). Visual acuity improved in the combined idiopathic INS groups (mean change, 0.11  0.15 logMAR; P 5 0.013), in the younger idiopathic group ( 0.17  0.14 logMAR; P 5 0.014) but not in the other groups. In the younger idiopathic group, visual acuity change correlated with the improvement in NOFF (P 5 0.039). Discussion: During the critical period, 4-muscle surgery results in both improved ocular motor stability and improved visual acuity in idiopathic INS. Conclusions: Younger patients may experience a larger functional benefit from nystagmus surgery due to remaining plasticity in the visual system. 016 Visual field measurement in infants and young children with neurological disorders using saccadic vector optokinetic perimetry (SVOP). Brian W. Fleck, Ian Murray, Harry Brash, Robert Minns Purpose: To demonstrate detailed visual field measurement sequentially in infants and young children with visual pathway abnormalities using saccadic vector optokinetic Perimetry (SVOP). Methods: SVOP uses a noncontact eye tracking device to monitor infants and young childrens eye movements in response to suprathreshold visual stimuli presented within the visual field. It makes use of reflex foveation saccades. Custom developed software determines if each stimulus has been seen. Initial and sequential visual field plots were obtained on 7 infants and young children (mean age 47  10 months) from a larger cohort of children with visual field defects from optic pathway tumors, following pyogenic meningitis, periventricular leucomalacia, and Non Accidental Head Injury. Results were compared with findings from clinical assessment, and automated and manual perimetry methods where possible. Repeatability of SVOP was statistically assessed. Results: There was good agreement on the "side" of the field defect between SVOP and clinical assessment but little agreement on the extent of the defect. Standard adult automated and kinetic perimetry testing proved not possible under 5 years. "Moderate" agreement was obtained on repeatability testing of SVOP (k 5 0.56  0.26). Sequential SVOP measurements (over a maximum of 36 months) generally showed a gradual reduction in the extent of the field defects following a previous insult, or following treatment. Discussion: SVOP provided a quantified visual field measurement in infants and children under 5 years where currently only the "side" of the defect could be determined by clinical assessment. Sequential SVOP testing was of particular benefit for children with visual pathway tumours undergoing treatment. Conclusions: SVOP provides a method of visual field testing in infants and young children. The technique will open up new areas of study of visual pathway abnormailities in these patients. 017 The effect of horizontal rectus muscle surgery on distance– near incomitance. A. Paula Grigorian, Brita Deacon, R. Scott Lowery, Katherine J. Fray, Shawn L. Brown, Paul H. Phillips Purpose: Determine the effect of horizontal rectus muscle surgery on distance-near incomitance. Methods: Prospective evaluation of patients who had horizontal rectus muscle surgery between 12/09 and 9/11. Prism and alternate

Journal of AAPOS

e5 cover testing was performed at distance and near before and after .45minutes of monocular occlusion at the preoperative and postoperative examinations. The change in distance-near incomitance was calculated. The choice of strabismus surgery was at the surgeons discretion. Muscle fibrosis/paralysis were excluded. Results: Of 23 patients included, 7 had medial rectus recessions, 5 a recess/resect procedure, 9 lateral rectus recessions and 2 medial rectus resections. One week after surgery, the change in distancenear incomitance was clinically insignificant in all patients, (\5D in 19 patients,\8D in all). Sixteen of 17 patients that had measurements .2 months postoperatively had reduced distance-near incomitance prior to occlusion. In seven of these, distance–near incomitance increased after supressing the fusion. Nine patients maintained it, indicating that muscle/anatomic changes reduced distance–near incomitance. Discussion: Our study prospectively isolated the mechanical effect of strabismus surgery on distance–near incomitance by eliminating the effect of fusional vergence with monocular occlusion. Regardless of surgical choice, strabismus surgery did not alter distance– near incomitance at the one week postoperatively. Most patients had a reduction in distance–near incomitance two months after surgery from fusional vergence, muscle/anatomic changes, or both. Conclusions: Horizontal rectus muscle surgery does not have a clinically significant effect on distance-near incomitance. It is not necessary to consider distance–near incomitance when choosing between medial rectus and lateral rectus muscle surgery. 018 Analysis of prediction error of intraocular lens (IOL) power calculation formulae in children aged less than two years. Ramesh Kekunnaya, Amit Gupta, Virender Sachdeva, Harsha L. Rao, Omprakash Vempati Purpose: Most of the published studies have compared different intraocular lens (IOL) power calculation formulae in children older than two years. Children less than two years form a small subset of most such studies. Purpose of our study is to assess the accuracy of different IOL power calculation formulae in children less than two years. Methods: We retrospectively analyzed records of 84 children (124 eyes) with congenital cataract in children (\ 2 years age) who underwent primary IOL implantation. Data was analyzed for prediction error (PE) using the four commonly used IOL power calculation formulae. We calculated the absolute (PE) with each of the formulae and formula that gave least variability was determined. The formula, which gave the best PE, was determined. Results: Mean age at surgery was 11.7 + 6.2 months. Absolute PE was found to be 2.27  1.69 D with SRK II, 3.23  2.24 D with SRK T, 3.62  2.42 D with Holladay and 4.61  3.12 D with Hoffer Q. The number of eyes with absolute PE within 0.5 D was 27 (21.1%) with SRK II, 8 (6.3%) with SRK T, 12 (9.4%) with Holladay and 5 (3.9%) with Hoffer Q. Comparison between different formulae showed that the absolute PE with SRK II formula was significantly better than others (P \ 0.001). PE with SRK II formula was not affected by age (P 5 0.31), keratometry (P 5 0.32) and axial length (P 5 0.27). Axial length influenced the absolute PE with Holladay (P 5 0.05) and Hoffer Q formulae (P 5 0.002). Mean Keratometry influenced PE (P 5 0.03) with SRK T formula. Discussion: In the existing literature there are conflicting reports of accuracy of various IOL power calculation formulae in children. In children with short eyes Hoffer Q is presumed to be most accurate though there are reports contrary to it as well. Our study is the largest