Resident and fellow participation in strabismus surgery: effect of level of training and number of assistants on operative time and cost.

OBJECTIVE: To investigate the effect of the level of training and number of assistants on operative time for uncomplicated, 2-muscle, horizontal strabismus surgery at an academic institution. DESIGN: Comparative case series. PARTICIPANTS: A total of 993 children and adults between the ages of 6 months and 75 years. METHODS: Retrospective chart review of strabismus surgeries performed between July 1, 2008, and December 31, 2012, by any of 3 attending surgeons assisted by a resident in the postgraduate year 3 (PGY3), fellow in the postgraduate year 5 (PGY5), or both. MAIN OUTCOME MEASURES: Operative time (minutes) and associated operative cost (dollars). RESULTS: There were 373 cases with 1 assistant and 44 cases with 2 assistants. Of all cases with 1 assistant, there were 200 cases with a PGY3 assistant an average operative time of 62.5 minutes (standard deviation [SD], 15.1) and 173 cases with a PGY5 assistant an average operative time of 59.0 minutes (SD, 14.7); the difference of 3.5 minutes was statistically significant (P = 0.02). The average operative time for all cases with 2 assistants (both PGY3 and PGY5) was 10.6 minutes longer than all cases with 1 assistant (P = 0.0002). No statistically significant variation in operative times was demonstrated when comparing cases with a PGY3 (P = 0.29) and PGY5 (P = 0.44) assistant in their respective first and last halves of the academic year, but operative times within individual quarters of the academic year were significant for PGY3 (P = 0.03) but not for PGY5 (P = 0.24) assistant cases. Operative times were significantly different for individual PGY3 (P = 0.03) but not PGY5 (P = 0.22) assistant cases. Cost per PGY3 assistant per year for additional operative time is $3141.95. CONCLUSIONS: Operative time in strabismus surgery increased with PGY3 participation and further increased with both assistants over either assistant alone. Operative times earlier in the year did not vary from those later in the year for PGY3 or PGY5 assistants. The difference in quarterly and individual PGY3 but not PGY5 assistant operative times suggests that efficiency in strabismus surgery varies by assistants with less experience or interest.

AAPOS uniform guidelines for instrument-based pediatric vision screen validation 2021.

BACKGROUND: As instrument-based pediatric vision screening technology has evolved, the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) has developed uniform guidelines (2003, updated 2013) to inform the development of devices that can detect specified target levels of amblyopia risk factors (ARFs) and visually significant refractive error. Clinical experience with the established guidelines has revealed an apparent high level of over-referral for non-amblyopic, symmetric astigmatism, prompting the current revision. METHODS: The revised guidelines reflect the expert consensus of the AAPOS Vision Screening and Research Committees. RESULTS: For studies of automated screening devices, AAPOS in 2021 recommends that the gold-standard confirmatory comprehensive examination failure levels include anisometropia >1.25 D and hyperopia >4.0 D. Astigmatism >3.0 D in any meridian and myopia < -3 D should be detected in children <48 months, whereas astigmatism >1.75 D and myopia < -2 D should be detected after 48 months. Any media opacity >1 mm and manifest strabismus of >8Δ should also be identified. Along with performance in detecting ARFs and refractive error, validation studies should also report screening instrument performance with regard to presence or absence of amblyopia. Instrument receiver operating characteristic curves and Bland-Altman analysis are suggested to improve comparability of validation studies. CONCLUSIONS: Examination failure criteria have been simplified and the threshold for symmetric astigmatism raised compared to the 2013 guidelines, whereas the threshold for amblyogenic anisometropia has been decreased. After age 4 years, lower magnitudes of symmetric astigmatism and myopia are also targeted despite a low risk of amblyopia, because they can influence school performance and may warrant consideration of myopia prevention therapy.

Prevalence and characteristics of abnormal head posture in children with Down syndrome: a 20-year retrospective, descriptive review.

PURPOSE: To characterize the abnormal head posture (AHP) in children with Down syndrome (DS). The study had 3 aims: to estimate the prevalence of AHP, to describe the distribution of different causes for AHP, and to evaluate the long-term outcomes of AHP in children with DS evaluated at the University of Iowa Hospitals and Clinics between 1989 and 2009. DESIGN: Retrospective chart review. PARTICIPANTS: Two hundred fifty-nine patient records. METHODS: The study data were analyzed using chi-square tests (the Fisher exact test when appropriate) to describe the relationship between the outcome of interest and each study covariate. A predictive logistic regression model for AHP was constructed including all the significant covariates. MAIN OUTCOME MEASURES: Abnormal head posture. RESULTS: Over the study period, 259 records of patients with DS were identified. Of these, 64 (24.7%) patients had AHP. The most frequent cause of AHP was incomitant strabismus in 17 (26.6%) of 64 patients. The second most frequent cause of AHP was nystagmus, in 14 (21.8%) of 64 patients. For a substantial number of patients with AHP, the cause could not be determined. They represented 12 (18.8%) of all the patients with AHP in this study and 12 (4.6%) of all patients with DS examined. When compared with patients with AHP from a determined cause, this subgroup has a statistically significantly (P = 0.027, Fisher exact test) higher percentage of atlantoaxial instability. In the study population, 9 (14.1%) of 64 patients with AHP had more than 1 cause for AHP. Refractive errors, ptosis, unilateral hearing loss, and neck and spine musculoskeletal abnormalities were responsible for AHP in a small percentage of patients. Of all the patients with AHP, 23 (35.9%) improved their head posture with treatment (glasses or surgery). An additional 6 (9.4%) patients improved their posture spontaneously, over time and without treatment. CONCLUSIONS: The prevalence of AHP in the children with DS evaluated was 24.7%. From this analysis, having strabismus of any kind and particularly incomitant strabismus, nystagmus, or both is highly correlated with the development of an AHP. Almost 19% of DS patients with AHP had no definitive cause that could be determined.

A novel 4p16.3 microduplication distal to WHSC1 and WHSC2 characterized by oligonucleotide array with new phenotypic features.

Larger imbalances on chromosome 4p in the form of deletions associated with Wolf-Hirschhorn syndrome (WHS) and duplications of chromosome 4p have a defined clinical phenotype. The critical region for both these clinical disorders has been narrowed based on the genotype-phenotype correlations. However, cryptic rearrangements in this region have been reported infrequently. We report on a male patient with a microduplication of chromosome 4p, who presents with findings of macrocephaly, irregular iris pigmentation-heterochromia, and preserved linear growth in addition to overlapping features of trisomy 4p such as seizures, delayed psychomotor development, and dysmorphic features including prominent glabella, low-set ears, and short neck. Using a high-density oligonucleotide microarray, we have identified a novel submicroscopic duplication involving dosage sensitive genes TACC3, FGFR3, and LETM1. The microduplication did not involve WHSC1 and WHSC2 which are considered in the critical region for WHS and trisomy 4p. This patient's presentation and genomic findings help further delineate clinical significance of re-arrangements in the 4p16 region without the involvement of WHS critical region.

Diffuse anterior retinoblastoma without retinal involvement.

PURPOSE: To present a unique case of an 8.5-year-old child with unilateral, anterior, pseudouveitis. He was found to have unilateral, invasive, small blue cell tumor of the anterior segment that was diagnosed as diffuse infiltrating retinoblastoma despite lack of retinal involvement on fundus examination or histopathologic analysis. DESIGN: Interventional case report. PARTICIPANTS: One patient. INTERVENTION: The patient was treated with topical prednisolone acetate 1% and oral prednisone with no improvement in anterior chamber reaction. The patient underwent fine-needle aspiration biopsy (FNAB) of anterior chamber fluid, the results of which were consistent with a primitive neuroectodermal neoplasm, either retinoblastoma or medulloepithelioma. Retinoblastoma was favored strongly, and the patient underwent enucleation followed by chemotherapy with vincristine, carboplatin, and etoposide, and radiation to the eye socket of 4140 cGy total was performed. MAIN OUTCOME MEASURES: The patient is alive and tumor free with follow-up of 5 years. RESULTS: Microscopic examination demonstrated cells similar to those seen on the FNAB infiltrating the iris stroma, trabecular meshwork, Schlemm's canal, and the inner portion of sclera in the region of the angle. No calcifications were identified. Serial sections of the entire globe were performed to determine the origin of the tumor. No retinal involvement was identified, and tumor was not seen to arise from the ciliary epithelium. Immunohistochemistry demonstrated positive staining with synaptophysin and negative staining with leukocyte common antigen and CD34. CONCLUSIONS: This patient represents a case of diffuse anterior retinoblastoma with lack of obvious retinal involvement. Morphologic features typical of medulloepithelioma were not found on pathologic analysis. Although the patient lacked a retinal focus, he is alive at 5 years without evidence of recurrence of tumor.

Nine-year results of a volunteer lay network photoscreening program of 147 809 children using a photoscreener in Iowa.

PURPOSE: To present the largest cohort of preschool children screened by the MTI PhotoScreener over a 9-year period from a single, statewide vision screening effort. DESIGN: Cross-sectional study. PARTICIPANTS: We included 147,809 children screened between May 1, 2000, and April 30, 2009 by a photoscreening program. METHODS: Retrospective review of results from the Iowa photoscreening program using the MTI PhotoScreener. The photographs were taken by volunteers from local Lions clubs and sent to the University of Iowa for interpretation. Children who failed the photoscreening were referred to local eye care professionals, who preformed a comprehensive eye evaluation and forwarded the results to the Iowa KidSight program. MAIN OUTCOME MEASURES: Number of screenings, referral rate, positive predictive value (PPV), follow-up rate, and associated costs per year are described. RESULTS: Over the 9 years of the continuously operating program, 147,809 children underwent photoscreens to detect amblyopic risk factors at 9746 sites. Because of abnormal photoscreen results, 6247 children (4.2%) were referred. Of the children, 24.3% were evaluated by local ophthalmologists and 76.7% were seen by local optometrists. Between 2000 and 2009, the follow-up rate ranged from a low of 36.1% to a high of 89.5%, with an overall program follow-up rate after the addition of the follow-up coordinator of 81.3%. The overall PPV of the MTI PhotoScreener was 94.2%. Taking into account overall operating budget including salaries and associated costs, the cost of screening 1 child has been reduced to $US9 per child. CONCLUSIONS: The addition of a part-time follow-up coordinator to the photoscreening program produced 89.5% follow-up rate when screening 147,809 children for amblyopia risk factors over a 9-year period.

Pediatric ophthalmology attire: should we wear a white coat?

The purpose of this study was to determine if patients and their families in a pediatric ophthalmology and adult strabismus clinic have a preference regarding physician and staffattire. Patients and/or parents were invited to complete a three-question survey. Respondents were queried based on three types of attire preference: white coat, professional clothing without white coat, or casual attire without white coat. Two hundred twenty-seven patients participated. Of the patients queried, no preference for any one style of physician attire was found. These results do not support previous studies indicating significant preference for white coats.

Presentation of TRPM1-Associated Congenital Stationary Night Blindness in Children.

Importance: Congenital stationary night blindness (CSNB) implies a stable condition, with the major symptom being nyctalopia present at birth. Pediatric clinical presentation and the course of different genetic subtypes of CSNB have not, to our knowledge, been well described in the era of molecular genetic diagnosis. Objective: To describe the presentation and longitudinal clinical characteristics of pediatric patients with molecularly confirmed TRPM1-associated complete CSNB (cCSNB). Design, Setting, Participants: This study was conducted at the University of Iowa from January 1, 1990, to July 1, 2015, and was a retrospective, longitudinal case series of 7 children (5 [71.4%] female) with TRPM1-associated cCSNB followed up for a mean (SD) of 11.1 (2.8) years. Main Outcomes and Measures: History, ophthalmologic examination findings, full-field electroretinogram (ffERG) results, full-field stimulus threshold testing results, Goldmann visual field results, optical coherence tomography results, and molecular genetic results were evaluated. Presenting symptoms and signs, the correlation of refractive error with electroretinography, and clinical evolution were analyzed. Results: Seven patients (5 [71.4%] female) presented early in childhood with strabismus (n = 6 [86%]), myopia (n = 5 [71%]), and/or nystagmus (n = 3 [43%]). The mean (SD) age at presentation was 8 (4) months and for receiving a diagnosis by ffERG was 7.3 years, with molecular diagnosis at 9.7 years. The mean (SD) length of follow-up was 11 (2.8) years. The best-corrected visual acuity at the most recent visit averaged 20/30 in the better-seeing eye (range, 20/20-20/60). The mean (SD) initial refraction was -2.80 (4.42) diopters (D) and the mean refraction at the most recent visit was -8.75 (3.53) D (range, -4.00 to -13.75 D), with the greatest rate of myopic shift before age 5 years. Full-field electroretinogram results were electronegative, consistent with cCSNB, without a significant change in amplitude over time. No patient or parent noted night blindness at presentation; however, subjective nyctalopia was eventually reported in 5 of 7 patients (71%). The full-field stimulus threshold testing results were moderately subnormal (-29.7 [3.8] dB; normal -59.8 [4.0] dB). Goldmann visual field results were significant for full I-4e, but constricted I-2e isopter. Eight different mutations or rare variants in TRPM1 predicted to be pathogenic were detected, with 3 novel variants. Conclusions and Relevance: Children with TRPM1-associated cCSNB presented before school age with progressive myopia as well as strabismus and nystagmus (but not nyctalopia), with stable, electronegative ffERG results, mildly subnormal full-field stimulus threshold testing results, and a constricted I2e isopter on perimetry. These findings suggest that ffERG and cCSNB genetic testing should be considered for children who present with early-onset myopia, especially in the presence of strabismus and/or nystagmus, and that TRPM1-associated cCSNB is a channelopathy that may present without complaints of night blindness in childhood.

Use of a Supplemental Oxygen Protocol to Suppress Progression of Retinopathy of Prematurity.

Purpose: To compare progression of retinopathy of prematurity (ROP) before and after institution of an oxygen therapy protocol to inhibit active proliferation and progression of ROP in premature infants. Methods: A retrospective cohort study was performed of premature infants undergoing ROP screening before (cohort A) and after (cohort B) implementation of an oxygen therapy protocol to inhibit further progression for those with stage 2 ROP or worse. Statistical analysis with χ2, Fisher's exact test, or Wilcoxon rank sum test was performed; and logistic regression models were created to determine the odds ratio of cohort B developing ROP progression beyond stage 2, compared to cohort A, adjusting for other risk factors for ROP. Results: In cohort A, without oxygen therapy protocol (2002-2007), 44% (54/122) of infants progressed beyond stage 2, compared to 23% (24/103) of infants after protocol implementation (cohort B, 2008-2012) (P = 0.001). No significant differences between cohort A and B were found for gestational age, birth weight, survival, sepsis, bronchopulmonary dysplasia, oxygen at discharge, or need for diuretics. Infants with stage 2 ROP in cohort B, with oxygen therapy protocol, had significantly decreased risk of ROP beyond stage 2 (odds ratio 0.37, 95% confidence interval 0.20-0.67; P = 0.0013), compared to cohort A, correcting for differences in birth weight and necrotizing enterocolitis. Conclusions: Progression from stage 2 to stage 3 ROP in premature infants was significantly decreased after implementation of an oxygen therapy protocol, without a corresponding increase in pulmonary morbidity. This study suggests that appropriate oxygen therapy may play a role in inhibiting progression of stage 2 ROP, potentially decreasing the risk of lifelong visual loss in this vulnerable population.

Validity of a layperson-administered Web-based vision screening test.

PURPOSE: To determine the sensitivity and specificity of the Web-based vision-screening test (WBT) VisionForKids.org when administered by an untrained layperson in a controlled environment. METHODS: Visual acuities were obtained by an untrained layperson using the WBT under observation and by an ophthalmic professional using the Electronic Visual Acuity (EVA) Tester. Subjects were randomized to which method was used first. Subjects were considered to have failed by the following criteria: in children <48 months, 20/50 vision; in children between 48 and 59 months, 20/40 or worse; in children ≥60 months, 20/30 or worse. The results of the vision examinations by the WBT and the EVA Tester were compared; sensitivity and specificity of the WBT and the correlation coefficient to detect normal and abnormal vision compared to EVA testing were determined. RESULTS: Visual acuities were obtained on 203 children between ages 3 and 12 years (average age, 7.4 years). Sensitivity of the WBT was 78.7% (95% CI, 66.0%-87.7%), specificity was 89.4% (95% CI, 82.9%-93.8%). The correlation coefficient of EVA testing with the WBT was 0.89 (P < 0.001). CONCLUSIONS: This layperson-administered WBT, VisionForKids.org, is valid for identifying amblyopia in a controlled environment, making it possible for cost-effective and easily accessible vision screening to be performed by laypersons.

Description and validation of a structured simulation curriculum for strabismus surgery.

PURPOSE: To describe and validate a Web-based structured simulation curriculum of strabismus surgery for residents in training using noncadaveric eye models. METHODS: A pre- and posttest of cognitive skills, objective wet laboratory structured assessment of technique, and summative global evaluation form were implemented as part of a systematic ophthalmology wet lab (OWL) curriculum. Strabismus techniques were taught using a structured simulation method on noncadaveric models of eyes. Likert scale questionnaires were administered to assess the comfort level with strabismus surgery of residents before and after participation in the wet laboratory. Statistical analysis was performed using the paired t test. RESULTS: Seven residents participated in the curriculum. Average test scores improved from 65% to 91% (P = 0.0002). Resident comfort level improved from an average score (assessed by Likert scale of 1-5) with standard deviation of 2.6 ± 1.0 to 4.3 ± 0.5 for passing scleral sutures (P = 0.0008), of 2.6 ± 0.5 to 4.3 ± 0.5 for isolating and suturing muscles (P = 0.00004), and of 2.7 ± 1.0 to 4.6 ± 0.5 for comfort with naming instruments (P = 0.0007). CONCLUSIONS: In this study of 7 residents, knowledge and comfort level with strabismus surgery statistically improved with a structured simulation curriculum.

Cataract surgery in children with uveitis: retrospective analysis of intraocular lens implantation with anterior optic capture.

PURPOSE: To present experience with cataract extraction in 9 eyes of 7 pediatric patients with chronic uveitis and compare the technique of anterior optic capture in 5 eyes that underwent cataract extraction without optic capture of the intraocular lens (IOL) or were left aphakic. METHODS: A retrospective review of pediatric patients with chronic uveitis undergoing cataract surgery was performed, examining the preoperative and postoperative visual acuity, immunosuppressive therapy, surgical technique, complications, subsequent procedures, and need for escalation of systemic immunosuppressive therapy. The technique of anterior optic capture is described in detail. RESULTS: Of the 9 eyes, 5 underwent cataract extraction with IOL placement with the haptics in the capsular bag and optic prolapsed through the anterior capsulorhexis. One eye underwent cataract extraction with IOL implantation in the bag. Three eyes had lensectomy without IOL placement. The eyes with anterior optic capture had no adverse outcomes and uveitis flares were controlled with topical medications and systemic immunosuppressants; the eye with IOL placement without optic capture had recurrent membranes and uveitis flares, necessitating increased systemic immunosuppression. All eyes achieved best-corrected visual acuity of 20/60 or better by 6 months following surgery and 20/30 or better at the most recent follow-up. CONCLUSIONS: The technique of cataract extraction with IOL placement and anterior prolapse of the optic through the anterior capsulorhexis shows promise to be a safe and viable option for pediatric patients with chronic uveitis treated with systemic immunotherapy.

Cryptic respiratory epithelial cyst of the lateral orbit in a 3 year old with strabismus and amblyopia.

Although choristomatous cystic orbital lesions are not uncommon in the pediatric population, these lesions rarely cause strabismus without being clinically obvious. Common choristomas, such as dermoid cysts and epidermoid cysts, usually cause vision loss through amblyopia or changes in refractive error. A 3-year-old girl with a history of esotropia and presumed lipodermoid who subsequently developed an abduction deficit and worsening of her visual acuity to 20/70 from a baseline of 20/50 is described. Magnetic resonance imaging of the orbits was performed, which showed a large cyst of the lateral orbit. On surgical removal, a developmental cyst lined with respiratory epithelium was identified and, based on its temporal location and history, characterized as a choristomatous lesion. Subsequently, the patient's visual acuity improved to 20/25 without patching. This patient had a larger than expected developmental cyst of respiratory epithelium that was originally thought to be a lipodermoid, contributing to her strabismus and amblyopia. Although orbital imaging is not routine management prior to strabismus surgery in the presence of a lipodermoid, it may be useful in cases when an abduction deficit is present or amblyopia treatment fails, because an underlying process may be responsible.

Retinal hemorrhages in intubated pediatric intensive care patients.

PURPOSE: To define the diagnoses associated with the presence of retinal hemorrhages, to clarify the association between retinal hemorrhages, cardiopulmonary resuscitation (CPR), and coagulopathy, and to describe the type of retinal hemorrhages found in intubated critically ill patients <4 years of age. METHODS: This was a prospective observational study of intubated patients <4 years of age admitted to the pediatric intensive care unit of a tertiary care center from March 2010 to May 2012. The presence and description of retinal hemorrhages was recorded along with diagnoses, international normalized ratio (INR), CPR (in minutes), and mortality. RESULTS: A total of 85 intubated, critically ill patients (37 females) were included; average patient age was 8.2 months (range, 0.1-46.8 months). Of the 85 patients, 6 (7%) had retinal hemorrhages (95% CI, 0.029-0.153). Of the 6 patients with RH, abusive head trauma (AHT) was diagnosed in 4 patients, 1 patient had direct head trauma, and 1 had CPR. There were 8 patients with CPR out of the 85. AHT was highly associated with severe multilayered retinal hemorrhages (P = 0.0001) but coagulopathy (P = 0.2671) and CPR (P = 0.5342) were not. CONCLUSIONS: Severe multilayered retinal hemorrhages were associated with AHT in this cohort of patients. Without a history of trauma, retinal hemorrhages occurred in only 1 of 85 patients; in this case the hemorrhages were mild, confined to the posterior pole, and found only in the retinal layer.

Primary peripheral retinal nonperfusion in a family with Loeys-Dietz syndrome.

Loeys-Dietz syndrome (LDS) is a connective tissue disorder associated with aggressive arterial aneurysms; rarely, it can have clinical features similar to those of Marfan syndrome, with retinal detachment, myopia, and ectopia lentis. A 19-month-old boy with history of LDS was found to have peripheral retinal nonperfusion in both eyes and a combined traction and exudative retinal detachment of the left eye. Ocular findings in the father, who also had LDS, were normal, but the patient's 34-month-old sister with LDS was also found to have less extensive peripheral retinal nonperfusion. To our knowledge, this is the first report of LDS associated with peripheral retinal nonperfusion in siblings with the same LDS mutation.

Quantitative measurement of retinal hemorrhages in suspected victims of child abuse.

PURPOSE: Child abuse is one of the leading causes of death in early childhood. The presence of retinal hemorrhages often supports the diagnosis. The purpose of this study was to determine whether the specific measurement of retinal hemorrhages when present on fundus photography correlates with other clinical findings typically seen in children suspected of having been abused. METHODS: The medical records of children with retinal hemorrhages who were suspected of being victims of abusive head trauma from June 2003 to June 2013 and who had widefield retinal photography performed were retrospectively reviewed. Data collected included hemorrhage-covered percentage (HCP) of the central retina (posterior pole or 40° circle centered on fovea) measured by ImageJ in relation to death, length of hospital stay, presence of abnormal findings on neuroimaging or skeletal survey, and definite versus possible abuse. RESULTS: Significant difference in retinal hemorrhage measured on fundus photography was found in patients with axial skeletal fracture (P = 0.016), signs of severe brain trauma on neuroimaging (P = 0.014) and definite versus possible abuse (P = 0.023). No correlation of quantitative measurement of the retinal hemorrhage to length of hospital stay, death, or the presence of skull fracture was found in this cohort. CONCLUSIONS: The quantitative measurement of total retinal hemorrhage when present on fundus photography centered on posterior pole in children suspected of having been abused correlated with some but not all findings typically seen in abused children.

Transient leopard spot corneal endothelial staining with trypan blue during cataract surgery in a child with congenital rubella syndrome.

We report the complication of corneal endothelial staining with trypan blue that limited the surgical view during cataract extraction in a 10-month-old boy. The boy had presented with a pigmentary retinopathy, microphthalmia, and a dense, white, unilateral congenital cataract. He was suspected of having, and was later diagnosed with, congenital rubella syndrome. We hypothesize that the corneal staining may have resulted from virally induced corneal endothelial damage. To our knowledge, this is the first reported case of trypan blue adversely affecting congenital cataract surgery.

Effect of occlusion amblyopia after prescribed full-time occlusion on long-term visual acuity outcomes.

PURPOSE: To investigate the incidence and characteristics of occlusion amblyopia with prescribed full-time patching and determine its effect on long-term visual acuity outcomes. METHODS: The records of patients younger than 10 years diagnosed as having amblyopia between 1970 and 2000 were retrospectively reviewed. Patients were prescribed full-time occlusion and observed until completion of therapy. RESULTS: Of 597 patients treated for amblyopia by full-time patching, 115 were diagnosed as having occlusion amblyopia (19.3%). Seventy-five percent (86 of 115) developed occlusion amblyopia during the first episode of full-time patching. Occlusion amblyopia occurred more frequently in children prescribed full-time patching at an earlier age (P = .0002), with an odds ratio of 8.56 (95% confidence interval: 2.73, 26.84) in children younger than 36 months and 2.66 (95% confidence interval: 0.96, 7.37) in children between 36 and 59 months old. Seven of the patients with occlusion amblyopia did not reverse fixation and continued to fixate with the initially amblyopic eye after treatment. Final visual acuity in these eyes with occlusion amblyopia was 20/30 or better. After cessation of treatment, the final interocular difference in visual acuity was less in patients with a history of occlusion amblyopia (P = .003). CONCLUSION: Occlusion amblyopia occurred at all ages, but the incidence decreased with increasing age. Patients who developed occlusion amblyopia with prescribed full-time occlusion had less interocular visual acuity difference than patients who did not, suggesting that development of occlusion amblyopia can indicate the potential for the development of better vision in the originally amblyopic eye.