Brian G. Mohney

Common forms of childhood exotropia

OBJECTIVE To determine the most common forms of childhood exotropia. DESIGN Retrospective, consecutive, observational case series. PARTICIPANTS All exotropic children (with >/=10 prism diopters) younger than 19 years from a predominantly rural Appalachian region evaluated from August 1, 1995 through July 31, 2001. METHODS Demographic and clinical data were collected on all patients. MAIN OUTCOME MEASURES The relative proportion of the various forms of childhood exotropia. RESULTS Two hundred thirty-five consecutive children without prior surgical treatment were evaluated for exotropia. Of the 235 study children, the specific forms of exotropia diagnosed and numbers were as follows: intermittent exotropia, 112 (47.7%); exotropia associated with congenital or acquired abnormalities of the central nervous system (CNS), 50 (21.3%); convergence insufficiency, 27 (11.5%); sensory exotropia, 24 (10.2%); paralytic exotropia, 5 (2.1%); congenital exotropia, 4 (1.7%); neonatal exotropia that resolved after 4 months of age, 3 (1.3%), whereas the remaining 10 (4.3%) had an undetermined form of exodeviation. CONCLUSIONS Intermittent exotropia was the most common form of divergent strabismus in this population. Exotropia associated with an abnormal CNS, convergence insufficiency, and sensory exotropia were also relatively common, whereas the congenital, paralytic, and late-resolving neonatal forms were uncommon.

Randomized clinical trial of treatments for symptomatic convergence insufficiency in children

OBJECTIVE To compare home-based pencil push-ups (HBPP), home-based computer vergence/accommodative therapy and pencil push-ups (HBCVAT+), office-based vergence/accommodative therapy with home reinforcement (OBVAT), and office-based placebo therapy with home reinforcement (OBPT) as treatments for symptomatic convergence insufficiency. METHODS In a randomized clinical trial, 221 children aged 9 to 17 years with symptomatic convergence insufficiency were assigned to 1 of 4 treatments. MAIN OUTCOME MEASURES Convergence Insufficiency Symptom Survey score after 12 weeks of treatment. Secondary outcomes were near point of convergence and positive fusional vergence at near. RESULTS After 12 weeks of treatment, the OBVAT groups mean Convergence Insufficiency Symptom Survey score (15.1) was statistically significantly lower than those of 21.3, 24.7, and 21.9 in the HBCVAT+, HBPP, and OBPT groups, respectively (P < .001). The OBVAT group also demonstrated a significantly improved near point of convergence and positive fusional vergence at near compared with the other groups (P <or= .005 for all comparisons). A successful or improved outcome was found in 73%, 43%, 33%, and 35% of patients in the OBVAT, HBPP, HBCVAT+, and OBPT groups, respectively. CONCLUSIONS Twelve weeks of OBVAT results in a significantly greater improvement in symptoms and clinical measures of near point of convergence and positive fusional vergence and a greater percentage of patients reaching the predetermined criteria of success compared with HBPP, HBCVAT+, and OBPT. Application to Clinical Practice Office-based vergence accommodative therapy is an effective treatment for children with symptomatic convergence insufficiency. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00338611.

Postoperative outcomes in children with intermittent exotropia from a population-based cohort.

PURPOSE To describe the long-term surgical outcomes in a population-based cohort of children with intermittent exotropia. METHODS The medical records of all children (<19 years) who were diagnosed with intermittent exotropia as residents of Olmsted County Minnesota, from January 1, 1975, through December 31, 1994, and managed with surgery were retrospectively reviewed. RESULTS Of 184 patients with intermittent exotropia, 61 (33%) underwent surgery at a mean age of 7.6 years (range, 3.2 to 23 years). Twelve of the 61 children (19.7%) underwent a second surgery (10 for recurrent exotropia and 2 for consecutive esotropia), and no patient received 3 or more surgeries during a mean follow-up of 10 years from the first surgery. The final postoperative measurements were recorded in 56 of 61 patients (92%) at a mean of 7.4 years (range, 0 to 18 years) after the first surgery: 31 of the 56 (55%) were within 9(Delta) of orthotropia at distance and 25 of 55 (45%) had better than 60 seconds of stereopsis. The Kaplan-Meier rate of developing >/=10(Delta) of misalignment after the first surgery was 54% by 5 years, 76% by 10 years, and 86% by 15 years. CONCLUSIONS In this population-based study of surgery in children with intermittent exotropia, although only 1 in 5 received a second surgery, after a mean follow-up of 8 years, approximately half were successfully aligned and 45% had high-grade stereopsis.

The convergence insufficiency treatment trial: Design, methods, and baseline data

Objective: This report describes the design and methodology of the Convergence Insufficiency Treatment Trial (CITT), the first large-scale, placebo-controlled, randomized clinical trial evaluating treatments for convergence insufficiency (CI) in children. We also report the clinical and demographic characteristics of patients. Methods: We prospectively randomized children 9 to 17 years of age to one of four treatment groups: 1) home-based pencil push-ups, 2) home-based computer vergence/accommodative therapy and pencil push-ups, 3) office-based vergence/accommodative therapy with home reinforcement, 4) office-based placebo therapy. Outcome data on the Convergence Insufficiency Symptom Survey (CISS) score (primary outcome), near point of convergence (NPC), and positive fusional vergence were collected after 12 weeks of active treatment and again at 6 and 12 months posttreatment. Results: The CITT enrolled 221 children with symptomatic CI with a mean age of 12.0 years (SD = +2.3). The clinical profile of the cohort at baseline was 9Δ exophoria at near (+/− 4.4) and 2Δ exophoria (+/−2.8) at distance, CISS score = 30 (+/−9.0), NPC = 14 cm (+/− 7.5), and near positive fusional vergence break = 13 Δ (+/− 4.6). There were no statistically significant nor clinically relevant differences between treatment groups with respect to baseline characteristics (p > 0.05).Conclusion: Hallmark features of the study design include formal definitions of conditions and outcomes, standardized diagnostic and treatment protocols, a placebo treatment arm, masked outcome examinations, and the CISS score outcome measure. The baseline data reported herein define the clinical profile of those enrolled into the CITT.

INTRAOCULAR USE OF RITUXIMAB

PurposeTo evaluate the toxicity of 1 mg of intraocular rituximab and to present a small case-series of patients treated with intravitreal rituximab.MethodsRituximab (1 mg/0.1 ml) was injected in the vitreous of one eye of three Dutch-belted rabbits. Two animals were injected with balanced salt solution as controls. At 1 month the rabbits were killed and the eyes examined by light microscopy. Three patients (five eyes) with intraocular lymphoma were also treated with a 1 mg injection of rituximab.ResultsThe treated rabbit eyes and the control eyes showed no light microscopic evidence of ocular toxicity at 1 month following injection. The five human eyes of three patients have shown no evidence of intraocular toxicity with a median follow-up time of 3.6 months (range 2.0–6.4 months). One patient received a total of four injections in the right eye and three injections in the left eye.ConclusionIntravitreal rituximab at a dose of 1 mg does not appear to cause toxicity in rabbit eyes and in the five eyes of three patients.

Validity of the convergence insufficiency symptom survey: a confirmatory study.

Purpose. The objectives of the present study were to evaluate whether investigator bias influenced the Convergence Insufficiency Symptom Survey (CISS) scores of children with normal binocular vision (NBV) in our original validation study, reevaluate the usefulness of the cutoff score of 16, and reexamine the validity of the CISS. Methods. Six clinical sites participating in the Convergence Insufficiency Treatment Trial (CITT) enrolled 46 children 9 to <18 years with NBV. Examiners masked to the child’s binocular vision status administered the CISS. The mean CISS score was compared with that from the children with NBV in the original, unmasked CISS study and also to that of the 221 symptomatic convergence insufficiency (CI) children enrolled in the CITT. Results. The mean (±standard deviation) CISS score for 46 subjects with NBV was 10.4 (±8.1). This was comparable with our prior unmasked NBV study (mean = 8.1 (±6.2); p = 0.11) but was significantly different from that of the CITT CI group (mean = 29.8 ± 9.0; p < 0.001). Eighty-three percent of these NBV subjects scored <16 on the CISS, which is not statistically different from the 87.5% found in the original unmasked study (p = 0.49). Conclusions. Examiner bias did not affect the CISS scores for subjects with NBV in our prior study. The CISS continues to be a valid instrument for quantifying symptoms in 9 to <18-year-old children. These results also confirm the validity of a cut-point of ≥16 in distinguishing children with symptomatic CI from those with NBV.

An Office-Based Scale for Assessing Control in Intermittent Exotropia

Introduction. Although intermittent exotropia may deteriorate with time, there are no widely accepted criteria for measuring progression in this disorder. The purpose of this study was to prospectively evaluate a new scale for assessing the level of control in children with intermittent exotropia. Methods. Thirty consecutive pediatric patients (< 14 years) with intermittent exotropia were prospectively evaluated from July 1, 2004 through June 30, 2005 using a new scale to assess the level of control for both distance and near fixation. The distance score (0 to 5) was combined with the near score (0 to 5) to yield an overall control score from 0 to 10. Results. The 30 patients were examined at a median age of 72 months (range, 15 months to 13 years). The level of control at distance was worse than or equal to the near level of control in all 30 patients. The control scores ranged from 0 to 5 for distance and 0 to 4 for near, with an overall control score ranging from 0 to 8 (median of 3). Conclusions. This new scale for assessing control in children with intermittent exotropia can be easily applied in the office setting and characterizes the wide range of control in this disorder.

Variability of Stereoacuity in Intermittent Exotropia

PURPOSE Distance stereoacuity is used to monitor deterioration of intermittent exotropia (IXT), but variability of stereoacuity has not been studied rigorously. The purpose of this study was to assess the variability of stereoacuity over one day in children with IXT. DESIGN Prospective cohort study. METHODS Twelve children with IXT were recruited. Stereoacuity was assessed using the Frisby Davis Distance test and the Distance Randot test at distance, and the Frisby and Preschool Randot tests at near. Tests were repeated three or four times over the day, with at least two hours between assessments. The main outcome measure was variable stereoacuity defined as a change by two or more log levels between any two time points over the day. RESULTS Variable stereoacuity at distance was found in five (42%) of 12 patients. Four (33%) of 12 patients demonstrated variable results using the Distance Randot test, three of whom also showed variable results using the Frisby Davis Distance test. One patient had variable results using the Frisby Davis Distance test only. Nine (75%) of 12 patients completed near stereoacuity testing; two (22%) of nine showed variable near stereoacuity. Two (22%) of nine showed variable results using the Preschool Randot test, one (11%) of whom also had variable results using the Frisby test. In some cases, stereoacuity changed from measurable stereoacuity on one assessment to nil on another. CONCLUSIONS Nearly half of children with IXT show marked changes in stereoacuity over the course of a single day. When based on isolated measures, an apparent change in distance stereoacuity between visits should be interpreted with caution.

Congenital esotropia in Olmsted County, Minnesota

OBJECTIVE To determine the birth prevalence of and risk factors associated with congenital esotropia. DESIGN Population-based prevalence study with nested case-control study. PARTICIPANTS All residents of Olmsted County, Minnesota who were diagnosed with congenital esotropia and born between January 1, 1980 and December 31, 1989 (n = 47). Control subjects were chosen by selecting the next two sequential births to parents residing in Olmsted County, Minnesota (n = 94). METHODS Cases were identified through the Medical Diagnostic Index of Mayo and the Rochester Epidemiology Project. The community medical records were reviewed to confirm case status and ascertain risk factor information. MAIN OUTCOME MEASURE Birth prevalence of congenital esotropia. RESULTS Forty-seven cases were identified from 17,536 live births, for a birth prevalence of 27 per 10,000 (95% confidence interval [CI], 20-35). Congenital esotropia was associated with prematurity (odds ratio [OR], 11.5; 95% CI, 3.4-39.2), a birth weight less than 2500 grams (OR, 4.6; 95% CI, 1.7-12.9), a low Apgar score at 1 minute (OR, 4.3; 95% CI, 1.7-11.2) and at 5 minutes (OR, 6.3; 95% CI, 1.3-30.7), and a family history of strabismus (OR, 3.5; 95% CI, 1.5-8.3). CONCLUSIONS The birth prevalence of congenital esotropia in Olmsted County, Minnesota is lower than previous estimates. Prematurity, low birth weight, low Apgar scores, and a family history of strabismus are significant risk factors for congenital esotropia.

Incidence and Clinical Characteristics of Childhood Glaucoma: A Population-Based Study

OBJECTIVE To describe the incidence and clinical characteristics of childhood glaucoma in a defined population of the United States. METHODS The medical records of all pediatric patients younger than 20 years living in Olmstead County, Minnesota, from January 1, 1965, through December 31, 2004, who met diagnostic criteria for glaucoma or glaucoma suspect were reviewed. RESULTS Thirty children were diagnosed as having glaucoma during the 40-year study period. The incidence of childhood glaucoma was 2.29 (95% confidence interval, 1.47-3.12) per 100,000 residents younger than 20 years, with the following types and incidences: 19 acquired (1.46/100,000; 0.80-2.12), 6 secondary (0.45/100,000; 0.08-0.82), and 5 primary glaucoma (0.38/100,000; 0.05-0.72). The birth prevalence of primary congenital glaucoma during the 40-year period was 1 per 68 254 residents younger than 20 years or 1.46 per 100,000 (95% confidence interval, 0.03-8.16). Twenty-four individuals with glaucoma suspect were also identified, yielding an incidence of 1.9 per 100,000 residents younger than 20 years (95% confidence interval, 1.14-2.66). CONCLUSION The incidence of childhood glaucoma in this population was 2.29 per 100,000 residents younger than 20 years or 1 per 43 575 residents younger than 20 years. Acquired and secondary forms of glaucoma were the most common, whereas congenital and juvenile glaucoma were rare.