Self-Reported Findings of the Korean Intermittent Exotropia Multicenter Study Questionnaire.

PURPOSE: To determine subjective symptoms and medical history of patients with intermittent exotropia in a large study population. METHODS: The Korean Intermittent Exotropia Multicenter Study (KIEMS) is a nationwide, observational, cross-sectional, multicenter study conducted by the Korean Association for Pediatric Ophthalmology and Strabismus including 5,385 patients with intermittent exotropia. Subjective symptoms and medical history of patients with intermittent exotropia were extracted by a comprehensive survey based on a self-administered questionnaire according to the study protocol of the KIEMS. RESULTS: The mean age of symptom onset was 5.5 years. The most common symptom reported in patients with intermittent exotropia was photophobia (52.1%), followed by diplopia at near fixation (7.3%) and distance fixation (6.2%). Preterm birth was found in 8.8%, and 4.1% had perinatal complications. A family history of strabismus was present in 14.9%, and 5.5% of patients had a family member who underwent strabismus surgery. CONCLUSIONS: The KIEMS is one of the largest clinical studies on intermittent exotropia. Intermittent exotropia frequently caused photophobia and diplopia, and patients with a family history was not uncommon.

Longitudinal analysis of refraction and ocular biometrics in preschool children with early-onset high myopia.

We investigated changes in refraction and ocular biometrics in preschool children with early-onset high myopia. Sixty eyes of 60 children with a mean follow-up time of 58.5 months were included in this study. At baseline, mean age of children was 55.6 ± 13.1 months, mean spherical equivalent (SE) was - 8.59 ± 2.66 D, and 25.64 ± 1.16 mm for axial length (AL). The total annual rate of myopic progression and axial elongation were - 0.37 ± 0.39 D/year and 0.33 ± 0.18 mm/year, respectively. During follow-up period, there was a trend toward less myopic progression and axial elongation over time. Of the total participants, 24 children (40%) were in the myopia progression group and the remaining 36 children (60%) were in the myopia stability group. In multiple linear regression analysis, baseline SE and AL were independently associated with myopic progression, while age, sex, and baseline AL-to-CR ratio were not related to myopic progression. According to the model, more myopic SE (ß = - 0.186, P = 0.035) and longer AL (ß = - 0.391, P = 0.008) at baseline were significantly associated with myopic progression. Myopia progression in preschoolers with high myopia tended to be relatively modest, with 60% of subjects exhibited myopic stability. Higher myopic SE, and longer AL at baseline were associated with myopic progression in preschool children with high myopia.

Diagnostic performance of the Spot vision photoscreener for the detection of exodeviation in preschool-aged children.

PURPOSE: To evaluate the diagnostic performance of the Welch Allyn Spot Vision photoscreener in preschool children for detecting exotropia, the most prevalent type of strabismus among Asian children. METHODS: Children aged 3-6 years were screened using the Spot Vision photoscreener and then underwent a complete ophthalmologic examination on the same day. A child with exodeviation ≥8 Δ in the primary position using the cover-uncover test and the alternate prism cover test was confirmed to have exotropia. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the photoscreener in detecting exotropia were calculated. Subgroup analyses were performed according to the angle of deviation (≥25 Δ vs. <25 Δ) and fusional control (good/fair vs. poor). RESULTS: Two hundred and ten children were included in this study. Among 80 exotropia-confirmed children, 23 needed referrals for exodeviation (screening-positive) and 57 were proven to be screening-negatives with the photoscreener. The overall sensitivity, specificity, PPV and NPV of the photoscreener for detecting exotropia were 28.8%, 95.4%, 79.3% and 68.5%, respectively. The positive and negative likelihood ratios were 6.26 and 0.75, respectively. Compared with the 57 children with false-negatives (71.3%), those with true-positive results with the photoscreener had significantly larger angles of exodeviation (p = 0.02) and a higher proportion of poor fusional control (p = 0.004). The photoscreener had low sensitivity even in detecting exotropia ≥25 Δ or those with poor fusional control (35.2% and 43.6%, respectively). Approximately 65% (42 out of 64) of the children with a significant exodeviation which needed strabismus surgery were not identified by the Spot Vision Photoscreener. CONCLUSIONS: The Spot Vision photoscreener has low sensitivity for detecting exodeviation. It should not be used alone for assessing exotropia in preschool-aged children.

Ocular biometric changes following unilateral cataract surgery in children.

PURPOSE: To analyze ocular biometric changes following unilateral cataract surgery in children. METHODS: A total of 57 children aged under 13 years who underwent unilateral cataract surgery were analyzed. Groups were classified according to their age at surgery: group I (age <3), II (3≤ age <6), III (6≤ age <9), and IV (age ≥9). The myopic shift, axial growth, and corneal curvature changes were compared between the pseudophakic eyes and the fellow phakic eyes. RESULTS: During 7.81 ± 4.39 years, the overall myopic shift (D) and the rate of myopic shift (D/year) were significantly higher at -3.25 ± 3.21 D and -0.45 ± 0.44 D/year in the pseudophakic eyes than -1.78 ± 2.10 D and -0.22 ± 0.29 D/year in the fellow phakic eyes (P = 0.01, 0.004). Group I (-1.14 ± 0.66 vs -0.02 ± 0.45 D/year) and group II (-0.63 ± 0.37 vs -0.31 ± 0.29 D/year) showed significantly higher rate of myopic shift in the pseudophakic eyes than in the phakic eyes. The rate of myopic shift in the pseudophakic eyes decreased in the older age groups (P = 0.001). There was no significant between-eye difference in the changes in axial length and keratometric values postoperatively. CONCLUSION: Following unilateral cataract surgery, a significant postoperative myopic shift was noticed in the pseudophakic eyes compared to the fellow phakic eyes in groups under 6 years old. Postoperative myopic shift and the resultant anisometropia should be considered when selecting the optimal power of IOL in young children requiring unilateral cataract surgery.

Variability in Plus Disease Diagnosis using Single and Serial Images.

PURPOSE: To assess changes in retinopathy of prematurity (ROP) diagnosis in single and serial retinal images. DESIGN: Cohort study. PARTICIPANTS: Cases of ROP recruited from the Imaging and Informatics in Retinopathy of Prematurity (i-ROP) consortium evaluated by 7 graders. METHODS: Seven ophthalmologists reviewed both single and 3 consecutive serial retinal images from 15 cases with ROP, and severity was assigned as plus, preplus, or none. Imaging data were acquired during routine ROP screening from 2011 to 2015, and a reference standard diagnosis was established for each image. A secondary analysis was performed using the i-ROP deep learning system to assign a vascular severity score (VSS) to each image, ranging from 1 to 9, with 9 being the most severe disease. This score has been previously demonstrated to correlate with the International Classification of ROP. Mean plus disease severity was calculated by averaging 14 labels per image in serial and single images to decrease noise. MAIN OUTCOME MEASURES: Grading severity of ROP as defined by plus, preplus, or no ROP. RESULTS: Assessment of serial retinal images changed the grading severity for > 50% of the graders, although there was wide variability. Cohen's kappa ranged from 0.29 to 1.0, which showed a wide range of agreement from slight to perfect by each grader. Changes in the grading of serial retinal images were noted more commonly in cases of preplus disease. The mean severity in cases with a diagnosis of plus disease and no disease did not change between single and serial images. The ROP VSS demonstrated good correlation with the range of expert classifications of plus disease and overall agreement with the mode class (P = 0.001). The VSS correlated with mean plus disease severity by expert diagnosis (correlation coefficient, 0.89). The more aggressive graders tended to be influenced by serial images to increase the severity of their grading. The VSS also demonstrated agreement with disease progression across serial images, which progressed to preplus and plus disease. CONCLUSIONS: Clinicians demonstrated variability in ROP diagnosis when presented with both single and serial images. The use of deep learning as a quantitative assessment of plus disease has the potential to standardize ROP diagnosis and treatment.

Clinical features of premature twin babies with intersibling asymmetry of retinopathy of prematurity severity.

OBJECTIVE: To report the clinical features of premature twin babies showing intersibling asymmetry in their severity of retinopathy of prematurity (ROP) and analyze risk factors associated with development of severe ROP between twin siblings with discordant ROP severity. METHODS: A retrospective study of records of 105 premature twin pairs was conducted. The criteria for discordant ROP with an intersibling difference in ROP severity were as follows: (i) two or more stages of difference in ROP between siblings, (ii) one sibling having treatment-requiring ROP and the other having no ROP or ROP that regressed spontaneously, or (iii) one sibling having aggressive posterior ROP and the other having staged or no ROP. Twin siblings were classified into two groups according to the severity of ROP (no or less ROP and more severe ROP). We examined ocular features in twins having intersibling asymmetry of ROP and analyzed perinatal risk factors for ROP. RESULTS: Of 105 twin pairs, 32 pairs (30.5%) showed intersibling asymmetry of ROP severity, and 15 pairs (14.3%) showed ROP asymmetry in terms of need for ROP treatment. The development of more severe ROP was associated with longer duration of oxygen supplementation and greater frequency of total blood and packed red blood cell transfusion (p = 0.020, p = 0.045, and p = 0.036, respectively). Longer duration of oxygen supplementation remained a statistically independent risk factor of severe ROP using multivariate logistic regression analysis. CONCLUSIONS: Ophthalmologists caring for premature infants should be aware of the variable courses and progressions of ROP between twin babies. Longer duration of oxygen supplementation and greater frequency of blood transfusions were associated with higher ROP severity in twins.

Morphological change of the posterior pole following the horizontal strabismus surgery with swept source optical coherence tomography.

Extraocular muscle movement during strabismus surgery causes changes in eyeball shape. Because extraocular muscle insertion is in front of the equator, it is thought that changes due to strabismus surgery mainly occur in the anterior segment. However, changes in the posterior segment of eye may also occur, which may also result in changes in refractive error after strabismus surgery. Using a 3-dimensional reconstruction technique (en face imaging) of the swept source optical coherence tomography, we determined and quantitatively measured the posterior polar change. The deepest interface between Bruch's membrane and the choroid could be identified as the deepest point of the eyeball (DPE), and the location of the DPE relative to the optic disc and the fovea was measured. After lateral rectus muscle recession, the DPE moved away from the fovea, but after medial rectus muscle recession, the DPE moved toward the fovea. The amount of DPE movement differed by age and preoperative refractive error. Our findings suggest that the positional shift of the rectus muscle in horizontal strabismus surgery causes a structural change in the posterior segment of the eye, and the postoperative refractive changes may be related to this shift.

Influence of coronavirus disease 2019 on myopic progression in children treated with low-concentration atropine.

PURPOSE: The outbreak of coronavirus disease 2019 (COVID-19) has caused many children to stay indoors. Increased near work and insufficient outdoor activities are considered important risk factors for myopic progression. This study aimed to compare the changes in myopic progression before and after COVID-19 in children treated with low-concentration atropine. METHODS: The records of 103 eyes of 103 children who were treated with low-concentration atropine eye drops were retrospectively reviewed. We classified children according to the concentration of atropine eye drops and children's age. The beginning of the pre-COVID-19 period was set from January 2019 to May 2019, and the endpoint was set in March 2020. The beginning of the post-COVID-19 period was set in March 2020, and the endpoint was set from January 2021 to March 2021. We evaluated the questionnaires administered to children's parents. RESULTS: A significant myopic progression was observed in the post-COVID-19 period compared to the pre-COVID-19 period in the 0.05% and 0.025% atropine groups (P < 0.001 and P = 0.020, respectively). For children aged 5 to 7 and 8 to 10 years, the axial elongations were significantly faster in the post-COVID-19 period than in the pre-COVID-19 period (P = 0.022 and P = 0.005, respectively). However, the rates of axial elongation and myopic progression were not significantly different between pre- and post-COVID-19 in children aged 11 to 15 years (P = 0.065 and P = 0.792, respectively). The average time spent using computers and smartphones and reading time were significantly increased, and the times of physical and outdoor activity were significantly decreased in the post-COVID-19 period compared to the pre-COVID-19 period. CONCLUSIONS: The rates of myopic progression have increased substantially after the spread of COVID-19 with an increase in the home confinement of children. Therefore, it is necessary to control the environmental risk factors for myopia, even in children undergoing treatment for the inhibition of myopic progression.

Change of ocular parameters in children with large cup-to-disc ratio and interocular cup-to-disc ratio asymmetry.

BACKGROUND: Enlarged optic disc cupping and interocular cup-to-disc ratio (CDR) asymmetry are often important indicators of glaucoma. Clinically, we occasionally encounter children with large CDR and interocular CDR asymmetry during vision screening. This study aimed to report longitudinal change of ocular parameters in children with large cup-to-disc ratio (CDR) and interocular CDR asymmetry. METHODS: This was a retrospective, observational case series of 160 eyes of 160 children with large CDR who visited a tertiary eye center from January 2010 to June 2016. Average CDR ≥ 0.6 were considered large CDR values, and CDR asymmetry was defined as an interocular difference ratio value greater than 0.2. All included patients showed interocular pressure (IOP) < 21 mmHg at least three ophthalmic examinations conducted at total intervals of at least 30 months. RESULTS: The mean age of children included in the study was 7.14 ± 2.42 years, with a follow-up period of 54.46 ± 19.82 months. Changes in refractive error and axial length were significantly different between initial and final examination (p < 0.001). However, optic nerve head (ONH) analysis and retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (mGCIPL) thicknesses were not significantly different between initial and final examination. In interocular comparisons of patients with CDR asymmetry, changes of refractive error, axial length, ONH analysis, and RNFL and mGCIPL thickness were not significantly different between the two eyes. CONCLUSIONS: There were no significant differences in the changes of ONH analysis, and RNFL and mGCIPL thicknesses in children with large CDR, or those with interocular CDR asymmetry over the study period. Our results provide helpful information for the establishment of guidelines for managing children with large CDR and interocular CDR asymmetry.

Compressive Optic Neuropathy with a Concurrent Mutation of Leber's Hereditary Optic Neuropathy: A Case Report.

Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease that leads to acute or subacute, painless, bilateral loss of vision, caused by degeneration of retinal ganglion cells that most affects men in their second or third decade of life. We describe a woman with compressive optic neuropathy with a concurrent LHON-associated mitochondrial mutation. Temporal hemifield defect connected to central scotoma and concurrent abduction limitation are diagnostic clues in identifying chiasmal compression with craniopharyngioma. This case emphasizes an awareness of the possible coexistence of compressive and hereditary optic neuropathy.

Long term change of the optic disc and OCT parameters during myopic shift in children with large cup to disc ratio.

PURPOSE: This observational case series was to determine long term optic disc changes in eyes with large cup to disc ratio (CDR) and compare the changes induced by myopic shift during childhood with normal control eyes. METHODS: Children under 15 years of age who developed myopia with serial optic disc photographs and spectral domain (SD)-optical coherence tomography (OCT) images with a minimal interval of three years were evaluated. Children with average CDR ≥ 0.6 on SD-OCT were classified as having large CDR. The ratios of vertical disc diameter (VDD), horizontal disc diameter (HDD), and maximum peripapillary atrophy (PPA) width (PPW) were measured to quantify morphologic changes of optic discs and SD-OCT parameters, such as peripapillary retinal nerve fiber layer (RNFL) thickness and macular ganglion cell and inner plexiform layer (GCIPL) thickness were measured. RESULTS: Of the 82 eyes (82 patients) analyzed, 42 eyes had large CDR and 40 eyes were normal controls. The mean age and refractive error at initial examination were not different between groups (P = 0.33, P = 0.76, respectively). The changes in HDD/VDD and PPW/VDD ratios during follow-up showed no significant difference among the groups (P = 0.45, P = 0.62, respectively). No statistical significance was found in changes in RNFL and GCIPL thickness between the two groups (P = 0.74, P = 0.79, respectively). CONCLUSIONS: Children with enlarged CDR showed changes in optic disc morphology and RNFL/GCIPL thickness similar to normal children during myopic shift.

Genotypic and phenotypic characteristics of Korean children with childhood-onset Leber's hereditary optic neuropathy.

PURPOSE: We sought to identify the phenotypic and genotypic characteristics of Korean children with genetically confirmed Leber's hereditary optic neuropathy (LHON). METHODS: The medical records of 64 genetically confirmed LHON patients were reviewed. Seventeen patients aged 13 years or younger with optic atrophy with positive mitochondrial DNA (mtDNA) mutations were considered to demonstrate childhood-onset LHON. The non-childhood-onset group included 47 patients with genetically confirmed LHON who experienced disease onset later than 13 years of age. The type of mtDNA mutation, visual acuity (VA), color vision, fundus photography, retinal nerve fiber layer (RNFL) thickness, and visual field were investigated. RESULTS: Sequence analysis of the mitochondrial genome revealed five different kinds of LHON-associated mtDNA mutations among our childhood-onset patients, including m.11778G>A (58.8%), m.3496G>T (11.8%), m.3497C>T (5.9%), m.11696G>A (5.9%), and m.14502T>C (5.9%). The mean final best-corrected VA in the childhood-onset group was better than that in the non-childhood-onset group with the value of logMAR 0.29 (0.09-0.75) vs. 0.55 (0.27-1.29) (expressed as median (interquartile range); p = 0.05). Spontaneous visual recovery was observed in 35.3% of the childhood-onset group but in only 12.8% of the non-childhood-onset group (p = 0.04). Eight patients (47.1%) showed interocular asymmetry of the disease, with two presenting true unilateral involvement of the optic nerve and the other six patients demonstrating unilateral subclinical manifestations with bilateral optic atrophy. CONCLUSION: Involvement of secondary mitochondrial mutations was confirmed in patients with childhood-onset LHON. Characteristic clinical features of childhood-onset LHON included a higher proportion of subacute or insidious onset of symptoms, better VA, higher spontaneous recovery, and asymmetrical ocular involvement.

Current Management of Childhood Amblyopia.

Amblyopia is defined as the reduction of best-corrected visual acuity of one or both eyes caused by conditions that affect normal visual development. The basic strategy to treat amblyopia is to obtain a clear retinal image in each eye and correct ocular dominance through forced use of the amblyopic eye. Treatment modalities include correcting any underlying organic disease, prescribing appropriate optical correction, and providing occlusion/penalization therapy for the non-amblyopic eye. Given the success of amblyopia treatment declines with increasing age, the detection and management of amblyopia should begin as early as possible during the sensitive period for visual development. Proper management of amblyopia during childhood can reduce the overall prevalence and severity of visual loss. This study aims to provide an update for the management of childhood amblyopia to provide better visual outcomes.

Interocular difference associated with myopic progression following unilateral lateral rectus recession in early school-aged children.

PURPOSE: To compare refractive changes in operated eyes and fellow unoperated eyes following unilateral lateral rectus recession in early school-aged children. STUDY DESIGN: A retrospective case control study. METHODS: The medical records of children under ten years of age with intermittent exotropia who underwent unilateral lateral recession surgery were reviewed. The operated eyes were reviewed and the fellow unoperated eyes were used as control. The rate of myopic progression was calculated by spherical equivalent (SE) changes per year, and by the rate of refractive growth (RRG) equation. RESULTS: SE showed a myopic shift one week after surgery and in the following months, from -1.43 ± 1.84 diopters (D) at 1 week post operation to -1.57 ± 2.22 D at one year and, finally -2.95 ± 2.97 D at the average 4.62 years following surgery. However, the SE shift was not significantly different from the unoperated eye. The low myopia group (under -3.0 D) showed a significantly higher myopic change in the operated eye until one year post operation (p = 0.022). The average myopic shift ratio was -0.53 ± 0.46 D yearly in the operated eye. CONCLUSIONS: This study presents data of a large series of refractive changes secondary to lateral rectus recession, and of long-term myopia progression in Korean population.

A Mutation in ZNF143 as a Novel Candidate Gene for Endothelial Corneal Dystrophy.

Corneal dystrophies (CDs) are a diverse group of inherited disorders with a heterogeneous genetic background. Here, we report the identification of a novel ZNF143 heterozygous missense mutation in three individuals of the same family with clinical and pathological features that are consistent with endothelial CD. Ophthalmologic examination revealed diffuse corneal clouding and edema with decreased endothelial cell density. Pathological findings showed increased corneal thickness due to edema of basal epithelial cells and stroma, and abnormal metaplastic endothelium with stratified epithelium-like changes. Patients' metaplastic corneal endothelial cells expressed predominantly cytokerain 7, cytokeratin 19, and E-cadherin. Although Sanger sequencing did not detect any mutation associated with endothelial CDs, whole exome sequencing identified the ZNF143 c.937G>C p.(Asp313His) mutation as a candidate gene for our patients' endothelial CD. In-vitro functional studies demonstrated that mutant ZNF143 promoted the mesenchymal-to-epithelial transition; it upregulated the expression of genes associated with epithelialization in human corneal endothelial cells. Additionally, proinflammatory cytokine responsive genes were significantly enriched after mutant ZNF143 transfection, which may contribute to the severe phenotype of the three patients. These findings link a mutation in ZNF143 with endothelial CD for the first time.

Surgical and sensory outcomes in patients with intermittent exotropia according to preoperative refractive error.

BACKGROUND/OBJECTIVES: To analyze the surgical and sensory outcomes of intermittent exotropia according to refractive errors and the factors associated with surgical success. SUBJECTS/METHODS: A total of 326 children were divided into three groups according to preoperative refractive error; hyperopic eyes with SE ≥+2D (hyperopic group), eyes with SE between -1D and +2D (emmetropic group), and myopic eyes with SE ≤-1D (myopic group). The surgical outcomes and the sensory outcomes measured by near and distant stereoacuity were compared among the three groups. RESULTS: The surgical success rate in hyperopic group was significantly lower compared to myopic group at last follow-up (P = 0.012). Preoperative near stereopsis was not different among three groups, however, the distance stereopsis was significantly deteriorated in the hyperopic group compared to the other two groups (Titmus; P = 0.168, FD2; P < 0.001, DR; P = 0.048). There was postoperative improvement in both near and distant stereopsis in all three groups (Titmus; P = 0.009, FD2; P = 0.021, DR; P = 0.036) and no significant difference was found in the postoperative distant stereopsis among the three groups. CONCLUSIONS: Preoperative refractive error is a prognostic factor of surgical success in patients with intermittent exotropia. Patients with hyperopia achieved less favorable surgical outcome compared to myopic patients. The preoperative distant stereoacuity was decreased in hyperopic patients compared to myopic patients, which eventually improved after surgery and showed no significant difference at postoperative measurements.

Changes in axial length in accommodative esotropia patients with minimal hyperopic correction.

PURPOSE: To compare the changes of spherical equivalent refractive error (SER) and axial length (AL) for three years in hyperopic children with minimal undercorrection according to the presence of accommodative esotropia (AE). METHODS: A total of 67 hyperopic children were enrolled. The patients were divided into 3 groups and matched by initial age upon examination; esotropic eyes with AE (AE group), fellow eyes with AE (FE group), and right eyes without esotropia (HE group). Changes of SER and AL were serially measured every six months for three years and collected data were compared among the groups. RESULTS: All three groups underwent significant myopic shift and AL elongation during the follow-up period. However, the least amount of change was found in the AE group. The AE group (-0.96 ± 1.38D) exhibited significantly less change in SER compared to the HE group (-1.76 ± 1.11D) and the FE group (-1.57 ± 1.33D) (both p<0.001). Meanwhile, smaller changes of AL were noticeable in the AE group (0.62 ± 0.88mm) compared to the other two groups (HE 0.99 ± 0.29mm; p<0.001, FE 0.73 ± 0.65mm; p = 0.04). The SER and AL changes were not significantly different between the HE group and FE group. CONCLUSIONS: Esotropic eyes with AE patients with minimal undercorrection exhibited little negative shift of SER and AL elongation compared to not only hyperopic eyes without AE but also fellow eyes with AE.

Distant stereoacuity in children with anisometropic amblyopia.

PURPOSE: To characterize changes in distant stereoacuity using Frisby-Davis Distance test (FD2) and Distant Randot test (DR) during treatment for anisometropic amblyopia, to determine factors that influence posttreatment stereoacuity and to compare the two distant stereotests. METHODS: Fifty-eight anisometropic amblyopic patients with an interocular difference of ≥1.00 diopter who achieved the visual acuity 20/20 following amblyopia treatment were retrospectively included. Stereoacuity using FD2 and DR for distant and Titmus test for near measurement were assessed and compared at the initial, intermediate, and final visit. Multivariate regression models were used to identify factors associated with initial and final stereoacuity. RESULTS: The two distant stereotests revealed a significant improvement in distant stereoacuity after successful amblyopia treatment. Distant stereoacuity using FD2 showed the greatest improvement during the follow up period. The number of nil scores was higher in DR than FD2 at each period. In multivariate analysis, better final stereoacuity was associated with better initial amblyopic eye acuity in both distant stereotests, but not in the Titmus test. Comparing the two distant stereotests, final stereoacuity using FD2 was associated with initial stereoacuity and was moderately related with the Titmus test at each period, but final stereoacuity using DR was not. CONCLUSIONS: Distant stereoacuity measured with both FD2 and DR showed significant improvement when the visual acuity of the amblyopic eye achieved 20/20. Changes in distant stereoacuity by FD2 and DR during the amblyopia treatment were somewhat different.