Risk factors for excessive postoperative exo-drift after unilateral lateral rectus muscle recession and medial rectus muscle resection for intermittent exotropia.

BACKGROUND: To detect significant factors associated with excessive postoperative exo-drift in young patients with intermittent exotropia who had undergone unilateral lateral rectus muscle recession and medial rectus muscle resection. METHODS: We retrospectively examined the records of 64 consecutive patients < 18 years old who underwent surgery between April 2004 and December 2011. We sought risk factors for excessive postoperative exo-drift among patients' demographic and clinical characteristics using univariate and multivariable linear regression analysis. RESULTS: Younger patients (P = 0.007), and those with larger preoperative exo-deviation at distance (P = 0.033), a lower incidence of peripheral fusion at distance (P = 0.021) or a greater postoperative initial eso-deviation (P = 0.001), were significantly more likely to have an excessive postoperative exo-drift (> 20 prism diopters). Univariate analysis revealed significant associations between excessive postoperative exo-drift and age at surgery (P = 0.004), preoperative exo-deviation at distance (P = 0.017) and postoperative initial eso-deviation at distance (P < 0.001). Multivariable linear regression analysis showed that postoperative initial eso-deviation at distance (P = 0.008) was significantly associated with postoperative exo-drift. CONCLUSIONS: Postoperative exodrift in unilateral RR is predicted by the initial postoperative eso-deviation, which may offset the overcorrection. However, the exo-drift is greater in cases with a large preoperative exo-deviation and/or at a younger age, and should be followed carefully.

Formulas to Estimate Appropriate Surgical Amounts of Unilateral Recession-Resection in Intermittent Exotropia with Distance-Near Disparity.

The purpose of this study was to derive new formulas to provide an optimal surgical procedure and optimal amount of recession-resection (RR) surgery in intermittent exotropia (IXT) with a disparity in angle of deviation depending on the fixation distance. The records of 117 consecutive patients with IXT who underwent RR surgery between March 2008 and December 2011 at Okayama University Hospital were retrospectively examined. Multivariable linear regression analysis was performed using the observed corrective angle of deviation at distance or near fixation as the dependent variable, and amounts of lateral rectus muscle (LR) recession (mm) and medial rectus muscle (MR) resection, and age at surgery (years) as independent variables. Two simultaneous formulas were derived: corrective angle of deviation at distance fixation (°)=1.8×recession (mm)+1.6× resection (mm)+0.15×age (years)-6.6, and corrective angle at near fixation (°)=1.5×recession (mm)+1.7× resection (mm)+0.18×age (years)-3.8. Comparisons of coefficient values of the formulas between distance and near fixation revealed that LR recession was more affected by the corrective angle in distance than near fixation. MR resection was more affected at near than distance fixation. We found that our new formulas estimated the appropriate amount of unilateral RR surgery.

Magnetic resonance imaging findings of age-related distance esotropia in Japanese patients with high myopia.

PURPOSE: This study aimed to investigate the characteristics of the extraocular muscles and the orbital connective tissue pulleys in Japanese patients with age-related distance esotropia (ARDE) and high myopia using magnetic resonance imaging (MRI). METHODS: This was a retrospective case-series study. High-resolution coronal MRI scans of 12 orbits were obtained in 6 patients with ARDE and high myopia (age range: 51-69 years). We analyzed the images to determine the positions of the rectus muscle pulleys relative to the center of the globe, the integrity of the lateral rectus-superior rectus muscle (LR-SR) band, and the LR angle (the angle between the major axis of the LR and the vertical plane). RESULTS: The distance esotropia ranged from 4 to 25∆, and 3 cases exhibited vertical deviations. The mean (±standard deviation (SD)) axial length was 28.5 (± 1.6) mm. The mean positions of the medial rectus muscle pulley and LR pulley were 1.3 mm inferior and 1.4 mm inferior, respectively, to those seen in the normal control group in our previous study (P = 0.002 and P = 0.05, respectively). All 12 orbits had abnormal elongated LR-SR bands, and 8 orbits (67%) displayed ruptured LR-SR bands. The LR angle (mean±SD; 18.8° ± 8.5°) increased significantly with the inferior displacement of the LR pulley (R2 = 0.77, P = 0.0002). CONCLUSIONS: Inferior displacement of the LR pulley and abnormal LR-SR bands were seen in Japanese ARDE patients with high myopia, as was found in ARDE patients without high myopia. The LR angle might be useful for judging the degree of LR pulley displacement.

Foveal Structural Analysis of Amblyopic Eyes with Two Types of Fixation Behavior by Spectral-Domain Optical Coherence Tomography.

We used spectral-domain optical coherence tomography (SD-OCT) to compare the foveal and parafoveal structures of 19 subjects aged 16-58 years (8 men, 11 women): 6 amblyopic patients with eccentric fixation, 5 amblyopic patients with central fixation, and 8 visually normal controls. We obtained foveal horizontal line scans using SD-OCT on all of the patients and controls. The total and layer thicknesses at foveal areas were analyzed. The mean (SD) ages of individuals in the eccentric fixation, central fixation, and control groups were 43.0 (13.9), 42.2 (16.3), and 38.5 (15.5) years, respectively. We observed no significant differences in the foveal or parafoveal retinal thicknesses at 500 and 1,500 µm from the foveal center among the 3 groups or between the amblyopic and fellow eyes. No significant differences were observed in the thickness of the ganglion cell complex layer or outer retinal layer at 500 and 1,500 µm from the foveal center among the three groups or between the two eyes. Overall, our SD-OCT analyses revealed no characteristic structural change in foveal regions in amblyopic eyes irrespective of the fixation behavior.

Twist Knot: A New Sliding Noose in Adjustable Suture Strabismus Surgery.

To permit noose movement without fraying the sutures following strabismus surgery, we designed a new sliding noose, the "twist knot" and investigated its advantages and disadvantages. We measured the tensile strength required to move the twist knot in a tightly tied state (134±19 gf) and in a loosened state (21±7 gf), and that required to move the conventional sliding noose in a tightly tied state (48±14 gf), and used the Kruskal-Wallis test to compare them. A significant difference was observed among the three tensile strengths (p<0.001). The twist knot technique allowed easy sliding without the multifilament braided suture becoming frayed and a knot to be firmly fixed without slipping. However, if the 2 strings of the pole sutures exit from the sclera at 2 widely separated positions, the sliding noose may become slack. Therefore, the distance between the pole sutures should be small. The simple twist knot technique was found to be an effective approach following adjustable surgery of strabismus.

Congenital Multiple Ocular Motor Nerve Palsy Complicated by Splitting of the Lateral Rectus Muscle.

We report a case of congenital multiple ocular motor nerve palsy combined with splitting of the lateral rectus muscle (LR). A 59-year-old Japanese female was investigated for worsening esotropia after corrective surgery. She presented with left hypertropia (35Δ) and esotropia (45-50Δ). Orbital magnetic resonance imaging (MRI) showed reduced belly sizes in the superior rectus, inferior rectus, and superior oblique muscles and splitting of the LR, extending from the origin to the belly, in the left eye. Splitting of the LR belly was detected on MRI in a case of congenital multiple ocular motor nerve palsy.

Predictive factors for corrective effect of inferior rectus recession for congenital superior oblique palsy.

PURPOSE: To identify preoperative factors associated with the surgical corrective effect of contralateral inferior rectus recession (IRR) for vertical deviation in patients with congenital superior oblique palsy (SOP). METHODS: This retrospective study included 20 treatment-naïve patients with unilateral congenital SOP (age range, 6-79 years) who underwent contralateral IRR according to our basic policy to select IRR for paretic eye fixation. The corrective effect (°/mm) of IRR was defined as the difference in the vertical deviation at the primary gaze position between before and 6-18 months after surgery per distance of recession. We also measured the preoperative vertical deviation at primary and secondary gaze positions, and vertical deviation with head-tilting, and calculated the difference in vertical deviation between these positions. We analyzed the correlation between the corrective effect of IRR and these study parameters. RESULTS: The mean corrective effect of IRR was 2.4 ± 1.6°/mm, which had a significant correlation with preoperative differences in vertical deviation between the primary gaze position and the downward (P = 0.004, r = -0.61) and contralateral gaze positions (P = 0.03, r = -0.48); and the presence of preoperative stereopsis (P = 0.02, r = -0.51). After excluding a statistical outlier, the correlation between the corrective effect and the difference between the primary and contralateral gaze positions was no longer significant (P = 0.07), while the other two relationships remained significant. CONCLUSIONS: Our findings suggest that preoperative differences in vertical deviation between the primary and downward gaze positions and the presence of preoperative stereopsis are important considerations prior to performing IRR for congenital SOP, particularly with paretic eye fixation.

Differences in the Stability and Amount of Postoperative Exodrift with Age after Unilateral Lateral Rectus Muscle Recession and Medial Rectus Muscle Resection of Intermittent Exotropia.

We investigated variances in the stability and amount of postoperative exodrift among age groups of intermittent exotropia (XPT) patients who underwent unilateral lateral rectus muscle recession and medial rectus muscle resection. We analyzed the cases of 110 consecutive patients who underwent the surgery in 2004-2011, dividing the patients into groups by their age at surgery: <10, 10-19, and ≥20 years. We performed a regression analysis (dependent variable: postoperative exodrift (°); independent variable: number of days post-surgery) using the formula of curve lines. When the tangent line slope was = 0.01 (°/days) for each group, we defined the numbers of days until alignment became stable as the 'stable days.' We evaluated the between-group differences in the amount of exodrift calculated for the stable days. The coefficients and coefficients of determination for the fitting curves were: <10 year group: f(x)=12.2 (1-e-0.0183x) (r2=0.588, p<0.05); 10-19 year group: f(x)=10.0 (1-e-0.0178x) (r2=0.453, p<0.05); ≥20 year group: f(x)=3.40 (1-e-0.0382x) (r2=0.217, p<0.05). There were 389 , 388, and 153 stable days, and the estimated postoperative exodrift with long-term follow-up was 11.5±3.7°, 9.3±4.4°, and 4.1±3.6° for the < 10 year, 10-19 year, and ≥ 20 year groups, respectively (≥20 year vs. other 2 groups, p<0.05). Longer periods and more postoperative exodrift were associated with younger age at surgery. The postoperative evaluation was approx. ≥ 1 year post-surgery in patients aged < 20. These findings may contribute to evaluating XPT's success rate and prognoses.

Quantitative Analysis of the Effects of a Bangerter Filter on Gross Stereopsis in Experimental Models of Reduced Visual Acuity.

Although a 0.3 Bangerter filter, which reduces visual acuity, is frequently used for treating moderate amblyopia, the effects on gross stereopsis are not well known. This study quantitatively evaluated whether gross stereopsis is degraded by a Bangerter filter. Seven healthy subjects (median age: 29 years) participated in this psychophysical study. Targets with crossed disparities of 1°, 2°, 3°, 4°, and 5° were randomly presented on a three-dimensional television display. The subjects indicated the point at which the targets popped out from the television screen (matching method). The distance from the screen to the point was defined as the degree of stereopsis. This experiment was performed with and without a 0.3 Bangerter filter. The corrected monocular visual acuities were decreased to about 20/63 by the filter in all subjects. No significant difference was observed for any of the disparities (1°-5°), between the degree of stereopsis visualized with and without filters for either the dominant or the non-dominant eye. The degree of stereopsis was not degraded by the reduced visual acuity induced by the use of 0.3 Bangerter filters. In this regard, the use of 0.3 Bangerter filters may be considered safer than occlusion eye patches for the patients with normal binocular vision.

Effects of vertical muscle surgery on differences in the orientation of Listing's plane in patients with superior oblique palsy.

BACKGROUND: Although scleral search coils are widely and accurately used for the measurement of Listing's plane in both eyes, they require specialized equipment and are invasive. In this study, we describe a convenient and less invasive method that uses a synoptometer to analyze the differences in orientation of Listing's plane (difLP), and the effects of vertical muscle surgery on the difLP tilt in patients with superior oblique palsy (SOP). METHODS: Seventeen patients with unilateral congenital SOP (CSOP) and four patients with unilateral acquired SOP (ASOP) who had not undergone any strabismus surgeries were examined. Cyclodeviations of 13 vertical and horizontal gaze points within 30° were measured with a synoptometer, and the difLP tilts in the yaw and pitch planes were analyzed before and after vertical muscle surgery. RESULTS: The difLP tilt in the CSOP patients was significantly tilted nasally (p = 0.02) and forward on the lower side (p = 0.001), whereas that in ASOP patients tended to tilt temporally (p = 0.15). Ipsilateral inferior oblique recession (IOR) performed in seven CSOP patients tended to improve the difLP tilt in both the yaw (p = 0.07) and pitch (p = 0.09) planes, whereas contralateral inferior rectus recession (IRR) performed in three CSOP patients significantly improved the difLP tilt in the pitch plane (p = 0.015). The mean excyclodeviations in the 13 gaze points were significantly improved with both procedures (p < 0.0001 for both). CONCLUSIONS: The difLP tilt in the SOP patients could be analyzed with a convenient and less invasive method using a synoptometer, and dissimilar difLP tilts were confirmed in the ASOP and CSOP patients. The results of this study suggest that both IOR and IRR are reasonable treatments for improving the difLP tilt in CSOP patients. IOR should be selected for patients with a steep preoperative difLP tilt to the nasal side, whereas IRR should be selected for patients with a gentle preoperative difLP tilt.

[Viewing 3D stereoscopic images in children and adults with and without strabismus: multicenter study in Japan].

PURPOSE: To investigate the ability of patients with strabismus and/or amblyopia to see 3D images. METHODS: A questionnaire survey conducted for children aged 6 to 19 years and adults aged 20 to 39 years on their experience of viewing 3D images (movies, motion attractions, television, games), asking whether they could see stereoscopically, with or without adverse effects. A retrospective investigation of ophthalmological examinations was followed. RESULTS: Of 507 cases, 342 had had the experience of veiwing 3D images. In 212 (62%) cases of strabismus and/or amblyopia, stereopsis was lacking in 17 to 18% of the subjects for movies, in 6 to 7% for attractions, in 32% in children and 50% in adults for television and 23% in children and 17% in adults for games. Adults complained of a higher rate of adverse effects, 65% for movies and 75% for games, as compared with 34% for movies and 26% for games in children(p < 0.01). The lack of stereopsis for games and movies was higher in the subgroup of Fly (-) and convergence insufficiency (p < 0.05). CONCLUSIONS: Since many patients with strabismus and/or amblyopia found some difficulty in stereoscopic viewing, precise examinations for stereopsis and convergence are needed to assess individual aptitude for 3D viewing.

Phenotype-phenotype and genotype-phenotype correlations in patients with idiopathic superior oblique muscle palsy.

Idiopathic superior oblique muscle palsy presents, as quantitative phenotypes, vertical deviation and cyclodeviation in eye alignment on clinical testing, and superior oblique muscle hypoplasia on imaging. We determined ARIX and PHOX2B polymorphisms as genotypes, and analyzed phenotype-phenotype and genotype-phenotype correlations in 37 patients with idiopathic superior oblique muscle palsy. Vertical deviations were measured at upright position of the head and head tilt for 30° to either side, and angles of objective excyclodeviations were determined by image analysis on fundus photographs. Cross-sectional areas of the superior oblique muscle near the eye globe-optic nerve junction were measured by image analysis on coronal sections of magnetic resonance imaging to calculate the paretic-side/normal-side ratios. Among the phenotypes, the increase in vertical deviations elicited by head tilt to the paretic side, the decrease in vertical deviations elicited by head tilt to the normal side and the difference of angles of objective excyclodeviations between the paretic side and normal side were significantly correlated inversely with the paretic-side/normal-side ratios of the cross-sectional areas of the muscle (r=-0.43 with P=0.0084, r=-0.34 with P=0.038, and r=-0.43 with P=0.009, respectively, n=37, Pearson's correlation test). Fifteen patients with ARIX and/or PHOX2B polymorphisms had significantly greater paretic-side/normal-side ratios of the muscle compared with 20 patients without the polymorphisms (P=0.017, n=35, Mann-Whitney U-test). The patients with ARIX and/or PHOX2B polymorphisms had less hypoplastic superior oblique muscles.

Comparison of VF-14 scores among different ophthalmic surgical interventions.

To clarify surgical outcomes for 5 ophthalmic diseases in terms of vision-related quality of life (QOL), we sent a self-administered Visual Function Questionnaire-14 (VF-14) to patients 3 months postoperatively, and the VF-14 scores for the surgical outcome of strabismus were compared with those of patients with diabetic macular edema (DME), cataract, glaucoma, and epiretinal membrane (ERM). Test-retest repeatability of VF-14 was evaluated with Bland-Altman analysis. Of the 625 eligible patients who were referred for enrollment, 48 with comitant strabismus, 50 with incomitant strabismus, 45 with DME, 38 with cataract, 129 with glaucoma, and 73 with ERM agreed to answer. Eighty percent of subjects showed 95% limits of agreement with the VF-14 evaluated by repeated measurements. The gain by surgery for incomitant strabismus was not different from that of cataract (p = 0.5551), but it was significantly better than those of DME (p = 0.0266), comitant strabismus (p = 0.0128), ERM (p = 0.0021), glaucoma with cataract (p < 0.0001), and glaucoma alone (p < 0.0001). The surgical outcome in terms of QOL for patients with incomitant strabismus was good and comparable to that of patients with cataract surgery.

Time trade-off utility analysis for surgical intervention in comitant strabismus, glaucoma, and cataract.

The utility value was compared among 3 surgical interventions, and the validity of the time trade-off (TTO) method was evaluated by analyzing the correlations of the utility value with the results of the Visual Function Questionnaire-14 (VF-14) and other variables. The subjects were 127 patients aged 40-85 years who were surgically treated between January 2008 and March 2010, including 26 patients with glaucoma, 50 with cataracts, and 51 with comitant strabismus. The scores on VF-14 and utility values determined using TTO were calculated retrospectively. The mean value (SD) of the utility gain was 0.096 (0.105) for glaucoma, 0.101 (0.105) for comitant strabismus, and 0.167 (0.237) for unilateral and 0.245 (0.167) for bilateral cataracts, indicating significant postoperative improvements in the utility value. A significant correlation was observed between the utility value and the postoperative VF-14 scores of the bilateral cataracts, and the postoperative visual acuity of the better eye of the unilateral cataract. The mean value of the quality-adjusted life years was 2.181 for bilateral and 1.424 for unilateral cataracts, 1.132 for strabismus, and 0.870 for glaucoma with an annual discount rate of 3%. The gain of utility value was highest in bilateral cataracts, and lowest in glaucoma, and thus the TTO analysis was considered to be highly valid for cataract surgery.

Double-under muscle transposition: an effective surgical option for large-angle paralytic strabismus.

PURPOSE: To describe our surgical outcomes using a novel muscle transposition procedure, or double-under muscle transposition (DUT), in the treatment of paralytic strabismus. METHODS: In this surgery, the split halves of the superior and inferior rectus muscles opposite the paralyzed muscle are disinserted, crossed under both the remaining half and the paralyzed muscle, and anchored at opposite corners of the insertion of the paralyzed muscle. The medical records of consecutive patients who underwent DUT were retrospectively reviewed. Outcome measures were angle of deviation and duction deficit. RESULTS: Seven patients were included. Diagnoses included WEBINO (n = 1), rupture of the medial rectus muscle (n = 1), and abducens nerve palsy (n = 5). DUT alone was performed in 3 patients; DUT combined with antagonist muscle recession, in 4 patients. One patient underwent the surgery bilaterally. Mean follow-up was 17 ± 18+ months (range, 7-57). Preoperative angles of distance deviation ranged from 25Δ to 142Δ in magnitude. All except a single patient had duction limitation of grade -5. The mean change in distance deviation for DUT alone for each operated eye was 60Δ ± 6Δ (53Δ-65Δ); for combined surgery, 69Δ ± 23Δ (range, 52Δ-103Δ). Final mean angle of deviation at distance was +2Δ ± 3Δ (-4Δ to 0Δ), although an additional surgery was required for large overcorrections in 2 patients. Duction limitation improved in all patients. One patient experienced a postoperative vertical deviation. CONCLUSIONS: DUT may be an alternative for patients with severely paralytic strabismus not likely to resolve with previously reported muscle transposition surgeries. Overcorrection may occur in some cases.

Glycocalyx degradation in retinal and choroidal capillary endothelium in rats with diabetes and hypertension.

Endothelial glycocalyx (GCX) has been reported as a protective factor for vascular endothelial cells (VEC) in diabetes and hypertension. However, the involvement of GCX impairment in ocular vasculopathy remains unclear. We evaluated the changes in the GCX thicknesses of the retinal and choroidal capillaries in rats with diabetes and hypertension by cationic colloidal iron staining using a transmission electron microscope. In the control group, the mean (standard error of the mean) thicknesses of retinal and choroidal GCX were 60.2 (1.5) nm and 84.3 (3.1) nm, respectively. The diabetic rats showed a significant decrease of GCX thickness in the retina, but not in the choroid, compared to controls (28.3 (0.3) nm, p<0.01 and 77.8 (1.4) nm, respectively). In the hypertensive rats, both retinal and choroidal GCX were significantly decreased compared to the control values (10.9 (0.4) nm and 13.2 (1.0) nm, respectively, both p<0.01). Moreover, we could visualize the adhesion of leukocytes and platelets on the luminal surface of VEC, at the site where the GCX was markedly degraded. These findings suggest that the GCX prevents adhesion of leukocytes and platelets to the VEC surface, and this impairment may lead to ocular vasculopathy in diabetes and hypertension.

Two cases of corneal perforation after oral administration of nonsteroidal anti-inflammatory drugs: oral NSAID-induced corneal damage.

PURPOSE: To report 2 cases of corneal perforation associated with the use of oral nonsteroidal anti-inflammatory drugs (NSAIDs). METHODS: In a 62-year-old woman and a 79-year-old woman, corneal perforation occurred after 7 days and 5 months of oral NSAIDs administration, respectively. RESULTS: After NSAIDs were discontinued, the cornea epithelialized and the anterior chamber formed within 14 and 10 days, respectively. CONCLUSIONS: It is well known that topical NSAIDs cause corneal perforation. Observations in the present cases suggest that the oral administration of NSAIDs may also cause corneal damage, and hence, medical professionals should consider the risk of damage to the cornea when administering these drugs orally.

Investigation of parent-of-origin effect in comitant strabismus using MOD score analysis.

PURPOSE: Comitant strabismus is a common pediatric ophthalmic disorder with both genetic and non-genetic factors contributing to its etiology. The aim of the current study is to investigate the phenomenon of a parent-of-origin effect, genomic imprinting, as a possible mode of inheritance in comitant strabismus. METHODS: We performed parametric genome-wide MOD score (model-maximized LOD score) linkage analysis, incorporating imprinting effects, for 382 microsatellite markers in a sample of 258 individuals (117 males and 141 females) from 55 Japanese families with comitant strabismus. We included individuals as affected patients if they presented with comitant esotropia or exotropia based on ophthalmic examination, history taking, or analysis of medical records. RESULTS: Significant or suggestive linkage to comitant strabismus with evidence of maternal or paternal imprinting was detected at D4S1575 (4q28.3), D7S486 (7q31.2), D11S1320 (11q24.2), D12S324 (12q24.32), and D19S420 (19q13.11). Using the MOD score approach, we found new evidence of linkage to comitant strabismus at three loci on chromosomes 6q26 (MOD(imp)=MOD(reg)=3.75), 12q24.32 (MOD(imp)=3.36), and 19q13.11 (MOD(imp)=3.79). CONCLUSIONS: The results suggest that the parent-of-origin effect may play a role in the etiology of comitant strabismus.

One-Year Outcome Predictors of Strabismus Surgery from Anterior Segment Optical Coherence Tomography with Multiple B-Scan Averaging.

Strabismologists are eager to identify preoperative or intraoperative strabismus surgery outcome predictors because of the variable effects in each patient. Conjunctival closure position recession after rectus muscle recession is effective for correcting large angle strabismus. The elasticity of the conjunctiva and Tenon's capsule is important for strabismus surgery management. In this longitudinal study, we evaluated the prognosis of conjunctiva and Tenon's capsule thickness (CTT) near the limbus 1 year after strabismus surgery with a limbal conjunctival incision using swept-source anterior segment optical coherence tomography with multiple B-scan averaging. Also, we identified preoperative and/or intraoperative parameters associated with corrective effects 1 year after surgery in 15 consecutive treatment-naïve patients with exotropia or esotropia who underwent recession and resection. The 1-year CTT was greater than the preoperative CTT on the resection side (269 ± 111 vs 183 ± 53 µm, P < 0.001) but was smaller on the recession side (137 ± 54 vs 183 ± 71 µm, P = 0.02). The corrective effect of surgery (1.6 ± 0.3°/mm) was most strongly correlated with preoperative CTT on the recession side (P = 0.005, ß = -0.73). Hence, CTT on the recession side may provide adjunctive information for strabismus treatment.

Abnormal Outer Choroidal Vasculature in Amblyopia.

PURPOSE: Several studies have indicated morphological changes in the choroid in amblyopia cases. This study investigates whether choroidal vasculature was different among amblyopic and fellow eyes in unilateral amblyopia patients and healthy eyes, using en face images acquired via swept-source optical coherence tomography (SS-OCT). DESIGN: Prospective, observational case-control study. METHODS: This study included 14 consecutive patients with unilateral amblyopia and 22 age- and axial length-matched healthy eyes. Using SS-OCT, we obtained en face images of choroidal vasculature midway through the subfoveal inner and total choroid, corresponding to the vasculature of the choriocapillaris and Sattler's layer (inner choroid) and Haller's layer (outer choroid), respectively. We analyzed the en face images of the inner and outer choroidal vascular areas in 3 × 3 mm squares adjusted from 6 × 6 mm squares, using Littmann's magnification correction, after binarization of the images as a portion of the whole area. RESULTS: The outer choroidal vascular areas were larger in both amblyopic and fellow eyes than in healthy eyes (both P < 0.001), although there were no significant differences in inner (56.35 ± 2.46% and 56.27 ± 3.75%, respectively) or outer (61.49 ± 4.95% and 61.48 ± 3.73%, respectively) choroidal vascular area between amblyopic and fellow eyes (P=0.98 and 0.91, respectively). An outer choroidal vascular area of 59% was set as an appropriate cutoff value for distinguishing patients from controls. CONCLUSIONS: The outer choroidal vascular area was larger in both amblyopic eyes and fellow eyes compared to healthy eyes. Our findings may help clarify the etiology of amblyopia.