Evelyn A. Paysse

To enhance the safety and efficacy of surgical treatment of strabismus, we sought to measure and determine the ultrasound biomicroscopy (UBM) profile of scleral tunnels created with needles commonly used during strabismus surgery, to determine which needles are less likely to create the complication of scleral perforation. Adult cadaver eyes were secured in a styrofoam head. Intraocular pressure was maintained between 15 and 21 mm Hg. Then S14, S24, S28 and TG100 needles were used to create scleral tunnels simulating those created during routine strabismus surgery. Ten scleral tunnels were created with each needle type at 3 different sites on the globe, for a total of 120 passes. The thickness of the sclera and the maximum depth and length of each scleral tunnel were measured using UBM. The mean tunnel depth below the scleral surface (+/- SD) was 0.43 +/-0.11 mm, 0.37 +/-0.09, 0.40 +/-0.08 and 0.34 +/-0.07 mm, for the S14, S24, S28 and TG100 needles, respectively (P=0.002, One way ANOVA). For both the S14 and S28 needles, there was a "statistically significant" P 0.05) linear trend of an increase in the depth of the pass as the length of the pass increased (P=0.01 for the S14 and P=0.02 for the S28 {Pearson Correlation 2 tailed test}). A similar trend was found with the S24 needle but the trend was not "statistically significant" (P=0.35). No such trend was found with the TG100 needle. Needle design had a definite impact on the characteristics of scleral tunnels created to simulate those made during strabismus surgery and may influence needle selection by the surgeon for different or various surgical circumstances, but the differences were not such as to predicate for or against the general use of any of these four needles for strabismus surgery.

Correct diagnosis and analysis of an abnormal head posture (AHP) is critical in the clinical assessment of patients with strabismus and nystagmus. This study was performed to evaluate the accuracy and precision of clinicians estimating the degree of face turns and head tilts. Experimental simulation study. Two normal volunteers and 4 pediatric and 1 general ophthalmologists. Using a cervical range of motion (CROM) device, single axis head position (chin up, chin down, right and left face turn, and head tilts) were modeled, and clinical estimates of the amount of deviation were estimated by the four ophthalmologists. Each of the 4 examiners estimated 108 single axis AHPs in a randomized and masked pattern. Accuracy of clinical estimation of AHP, intra- and inter- observer variability, and variability in terms of head position. The examiners tended to overestimate the AHPs by an average of 5 degrees (P less than 0.001). Two "right" positions (right head tilt and face turn) were the worst. The average error was 10 +/-8 degrees for the right tilt and turn positions, while the error for all other positions, excluding these two, averaged 0 +/-10 degrees (P = 0.0001). Clinical estimation of an AHP by ophthalmologists is in part remarkably accurate, even if imprecise, but some positions, notably right head tilt and right face turn in this study, were significantly overestimated. Objective methods of measuring AHPs such as the CROM may be preferable for these RHT and RFT AHPs and when maximum precision is needed for tracking changing AHPs or deviations.

To describe a protocol for treating children with photorefractive keratectomy (PRK) under general anesthesia and to review intraoperative and postoperative complications. Institutional academic practice. Nine patients between 3 years and 9 years of age were treated with PRK under general anesthesia for anisometropia with unilateral high myopia or high hyperopia and amblyopia of the affected eye. Induction of anesthesia and the surgical procedure were carried out in separate rooms. The laser beam was centered on the entrance pupil, and eye position was monitored throughout the procedure. Specific precautions were taken before and during the procedure to prevent unwanted effects of inhalational anesthetic agents on laser performance. All children did well, with no anesthesia-related or treatment-related complications. Our protocol for PRK under general anesthesia was effective and efficient in children who were unable to cooperate for the procedure using local anesthesia. It can be adapted for laser in situ keratomileusis and other refractive surgical procedures in children and uncooperative adults.

Case Report from JAMA Ophthalmology — Congenital Toxoplasmosis With Unusual Retinal Findings

To document the rate of healing of the corneal epithelial defect created by photorefractive keratectomy (PRK) and the degree of discomfort experienced by children treated with PRK. Baylor College of Medicine, Texas Children's Hospital, Houston, Texas, USA. Ten patients between 3 and 10 years of age were treated with PRK for severe anisometropia. All had anisometropic amblyopia refractory to conventional therapy with glasses or contact lenses and occlusion therapy. The size of the corneal epithelial defect was documented daily until the defect healed completely. Postoperative discomfort was documented daily using a pain-assessment scale until the epithelial defect healed completely. Two children were treated with PRK for hyperopic anisometropia; the rest were treated for myopic anisometropia. Cumulatively, the corneal epithelium had healed completely by day 3 in 6 patients (60%), by day 4 in 9 patients (90%), and by day 5 in all patients. The mean healing time was 3.5 days. Patients experienced mild discomfort on the day of surgery and on the first postoperative day. They had minimal pain on day 2. After day 2, no patient reported pain or other discomfort. The corneal epithelial defect created by PRK healed promptly and was associated with minimal postoperative discomfort in children treated with the protocol described.

To quantify the level of bacterial contamination of needles and sutures immediately after use in strabismus surgery. Strabismus surgery was performed on 56 eyes from 31 pediatric strabismus surgical cases. Preoperative site preparation included instillation of 5% povidone-iodine in the conjunctival fornices in all cases. A total of 124 needles and 127 sutures were cultured immediately after final scleral passage. Seventeen of the 31 cases (54.8%) produced at least one positive specimen. Nineteen per cent of the needles and 25.2% of the sutures were culture positive. The bulk of positive specimens (96.7% of needles, 91.3% of sutures) produced 3 or less colony forming units, corresponding to 7 or less total viable organisms per needle or sutures in accordance with the dilution scheme. Coagulase-negative staphylococci overwhelmingly predominated. Needles and sutures used in strabismus surgery can become contaminated during surgery despite preoperative povidone-iodine preparation. The number of viable bacterial contaminants is usually below the level known to consistently produce experimental endophthalmitis. However, a few needles and sutures carried a high contaminant load, suggesting the possibility that contaminated needles and sutures could potentially cause postoperative intraocular infection.