A Case of Superior Oblique Palsy without Brown Syndrome Induced by a Dog Bite.

BACKGROUND Pseudo-Brown syndrome is characterized by dysfunction of the superior oblique tendon-trochlear complex. Canine tooth syndrome, which involves superior oblique palsy with pseudo-Brown syndrome, results from damage to the trochlear and superior oblique tendon from dog bites around the eye. This report describes a variant of canine tooth syndrome without pseudo-Brown syndrome following a dog bite around the left upper eyelid. In this case, magnetic resonance imaging (MRI) facilitated early diagnosis and therapeutic intervention. CASE REPORT A 19-year-old man presented with torsional diplopia following a dog bite around the left upper eyelid and forehead. Five days after the injury, an alternate prism cover test revealed 6 prism diopters (Δ) exotropia and 5Δ left hypertropia. Ocular motility showed no significant limitation in elevation or depression during adduction. MRI performed on the same day showed a high-signal area extending from the superior oblique tendon to the trochlear region and the superior oblique muscle belly of the left eye. A diagnosis of canine tooth syndrome without pseudo-Brown syndrome was made and oral steroids were administered. Ocular alignment did not improve, so left inferior oblique myotomy was performed 7 months after the injury. The patient's cyclovertical diplopia resolved postoperatively. CONCLUSIONS Dog bites around the eye can result in abnormalities of the extraocular muscles. Early MRI may be useful for diagnosis and determining treatment strategies. This report has highlighted the importance of rapid assessment and management of patients with dog bites involving the eye.

Changes in Optic Nerve Head Blood Flow During Horizontal Ocular Duction.

Purpose: In this study, we aimed to compare blood flow changes in the optic nerve head (ONH) during horizontal ocular duction among normal, primary open-angle glaucoma (POAG), and normal-tension glaucoma (NTG) eyes. Methods: In this cross-sectional study, we included 90 eyes from 90 participants (30 control eyes, 30 POAG eyes, and 30 NTG eyes). ONH blood flow was measured with laser speckle flowgraphy using an external fixation light to induce central gaze, abduction, and adduction at 30 degrees for each eye. The mean blur rate (MBR) of the entire ONH area (MA), vascular region (MV), and tissue region (MT), and the change ratio were analyzed. The change ratio was defined as abduction or adduction value/central gaze value. Results: In the control group, MA significantly decreased during adduction (22.9 ± 3.7) compared with that during central gaze (23.6 ± 3.9, P < 0.05). In the POAG group, MA (adduction = 17.4 ± 3.8 and abduction = 17.3 ± 3.6) and MV (adduction = 37.9 ± 5.6 and abduction = 38.0 ± 5.6) significantly decreased during adduction and abduction compared with those during central gaze (18.0 ± 4.1 and 39.5 ± 6.3, respectively, P < 0.05). In the NTG group, MA significantly decreased during adduction (17.4 ± 4.2) compared with that during central gaze (18.1 ± 4.6) and abduction (18.1 ± 4.8, P < 0.05). The change ratio did not differ between the glaucoma and control groups. Conclusions: ONH blood flow decreased during horizontal ocular duction regardless of normal or glaucoma states; however, the change ratio was comparable between the normal and glaucoma groups.

Clinical presentations of acquired comitant esotropia in 5-35 years old Japanese and digital device usage: a multicenter registry data analysis study.

PURPOSE: To describe clinical presentations of acquired comitant esotropia and digital device use in children, adolescents, and young adults without neurological problems. STUDY DESIGN: Multicenter prospective observational study. METHODS: Patients with acquired comitant esotropia, without intracranial diseases aged 5-35 years at the time of visit, who were seen at pre-registered facilities within 1 year of onset were enrolled. The duration from the onset of symptoms and the time of digital device usage approximately 1 month before onset and their lifestyles were surveyed. Visual acuity, cycloplegic refraction, and strabismus angles were measured. Data were analyzed in three age groups (Child: 5-12 years, Adolescent: 13-18 years, and Young adult: 19-35 years). RESULTS: Between November 2019 and December 2021, 218 patients were enrolled from 55 facilities, and 194 patients (including 62 children, 69 adolescents, and 63 young adults) were analyzed. The child group spent the least amount of time using digital devices (children: 159; adolescents: 210; young adults: 267 min/work day, p < 0.05; (mean time in the same order below) 229, 338, 314 min/holiday, p < 0.05) and had the largest strabismus angle (mean strabismus angle at near: 30, 22, 18 PD, p < 0.01; at far: 28, 26, 21 PD, p<0.05). CONCLUSION: The clinical features of acquired comitant esotropia and hand-held digital device usage differed between children aged ≤ 12 years and older patients. This report gives the current clinical characteristics of young patients with acquired esotropia and digital device usage.

Analysis of Facial Features of Patients With Sagging Eye Syndrome and Intermittent Exotropia Compared to Controls.

PURPOSE: To compare the facial features of patients with sagging eye syndrome (SES) and other ophthalmic diseases, and to evaluate the diagnostic usefulness of facial features for SES. DESIGN: Retrospective cross-section study. METHODS: We evaluated frontal facial photographs of patients >60 years of age with SES and intermittent exotropia (IXT), and control patients who visited the ophthalmology outpatient clinics of 2 institutions between June 2020 and December 2021. Three ophthalmologists evaluated each eye for sunken upper eyelid, blepharoptosis, and baggy lower eyelid, using a scoring scale. The average scores for each parameter among the 3 groups were analyzed. Patients with glaucoma, visual acuity <16/20, SES with a vertical strabismus angle of ≥6 Δ, IXT that could not be maintained in the phoria position during photography, a history of previous oculoplastic or ophthalmic surgery, and use prostaglandin analogs for cosmetic purposes were excluded. RESULTS: A total of 86 patients were included: 23 with SES, 28 with IXT, and 35 in the control group. All were Japanese. In all, 45 patients were male and 41 were female. The mean age was 72.7 ± 7.4 years. The sunken upper eyelid scores were significantly higher in the SES group than in the control and IXT groups (P < .001), whereas the baggy lower eyelid scores were significantly higher in the IXT group than in the control group (P < .05). CONCLUSIONS: Age-related orbital connective tissue degeneration may manifest as SES in the upper eyelid and as IXT in the lower eyelid.

Agreement in the detection of chiasmal and postchiasmal visual field defects between imo binocular random single-eye test and Humphrey monocular test.

PURPOSE: To compare the ability of imo binocular random single-eye test (BRSET) to detect visual field (VF) defects due to chiasmal and postchiasmal lesions (C/PCLs) with a Humphrey Field Analyzer (HFA) monocular test. STUDY DESIGN: Prospective multicenter study METHODS: This study enrolled 40 patients with C/PCLs and measured their VFs using both imo BRSET and HFA monocular test. The VFs were classified into three groups using the cluster criterion: 1) bitemporal group, 2) homonymous group, and 3) others. The agreement and correlation of VF results between imo and HFA were analyzed using the Bland-Altman plot and Spearman correlation coefficient. RESULTS: The VFs of 34 patients were analyzed and classified. There were 13 patients in the bitemporal, 6 in the homonymous, and 15 in the others group. BRSET showed a significantly shorter test duration than HFA. The imo systematically yielded a lower sensitivity than HFA. The average sensitivity at each test location correlated well between the perimeters in all groups, with the correlation coefficients ranging from 0.89 to 0.98. Bland-Altman plots showed wider limits of agreement in the affected quadrants compared to the unaffected quadrants in the bitemporal and homonymous groups. The fixation loss rate did not differ between the perimeters, but there were significant differences in the false positive and false negative rates between perimeters. CONCLUSION: BRSET detected VF defects due to C/PCLs as accurately as the HFA monocular test with a shorter test duration.

Comparison of subjective cyclofusion ranges and objective ocular torsion in normal participants according to age.

PURPOSE: To investigate the relationship between subjective cyclofusion ranges and objective ocular torsion in normal participants according to age. METHODS: This cross-sectional study included 120 participants aged ≥ 20 years with no ocular diseases. The subjective cyclofusion ranges were measured centrifugally and centripetally in the direction of excyclotorsion and incyclotorsion, respectively, concurrently with rotational diplopia production by rotation using synoptophore. Disc fovea angle (DFA) was defined as the angle formed by two lines: a line passing through the center of the optic nerve papilla and fovea and a horizontal line passing through the center of gravity of the optic papilla using fundus photographs. RESULTS: The participants were aged 49.1 ± 17.7 years. The total cyclofusion centrifugal (sum of extorsion and intorsion) and centripetal ranges were 10.9 ± 2.2° and 7.2 ± 1.8°, respectively, both of which decreased in participants in their 60 s and 70 s (p < 0.01). The DFA was - 7.0 ± 3.4° in the right eye (- : excyclo, + : incyclo) and - 8.0 ± 3.2° in the left, which was associated with age (p < 0.001). The correlation between the DFA and centrifugal (r = - 0.13, p = 0.16) and centripetal (r = - 0.002, p = 0.99) cyclofusion ranges of extorsion was not significantly different. The centrifugal (r = 0.37, p < 0.001) and centripetal (r = 0.40, p < 0.001) cyclofusion ranges of intorsion were positively correlated. CONCLUSION: Subjective cyclofusion ranges decreased in both extorsion and intorsion in the elderly. Objective ocular torsion showed excyclotorsion with age. When strabismus surgery is performed in elderly patients with torsional strabismus, the decrease in subjective cyclofusion ranges should be considered.

New device for taking nine-directional ocular photographs: "9Gaze" application.

This study compared the time required to produce nine-directional ocular photographs using the conventional method to that using the newly devised 9Gaze application. In total, 20 healthy adults, 10 adult patients with strabismus, and 10 pediatric patients with amblyopia or strabismus had their ocular photographs taken using a digital camera with PowerPoint 2010, and with an iPad, and iPod touch with 9Gaze. Photographs of 10 healthy patients were taken by orthoptists with <1 year of experience, and the other participants had theirs taken by those with >1 year of experience. The required time was compared between the three devices in all patients and the two orthoptist groups in 20 healthy adults (>1 year and <1 year of experience). The required times were significantly different between the devices: 515.5 ± 187.0 sec with the digital camera, 117.4 ± 17.8 sec with the iPad, and 76.3 ± 14.1 sec with the iPod touch. The required time with the digital camera was significantly different between the two orthoptist groups (404.7 ± 150.8 vs. 626.3 ± 154.2 sec, P=0.007). The use of the 9Gaze application shortened the recording time required. Furthermore, 9Gaze can be used without considering the years of experience of the examiner.

Sagging eye syndrome.

The pulley is the functional origin of the extraocular muscles and prevents their dislocation from the muscle cone. The pulley degenerates with age and may progress to cause the sagging eye syndrome (SES). Divergence paralysis, a type of distance esotropia, occurs when the lateral rectus muscle pulley and lateral rectus-superior rectus (LR-SR) band show degenerated symmetry OU. Cyclovertical strabismus of a small angle occurs when the lateral rectus muscle pulley and LR-SR band show degenerated asymmetry OU. Patients with SES have distinctive features, such as baggy eyelids, deep superior sulcus deformity, and aponeurotic ptosis. SES is the leading cause of non-paralytic diplopia, and its rate increases with age, with 60% of the patients being women. One-third of the cases of SES are distance esotropia of 9Δ on average, and two-third of the cases are small-angle hypertropia of 4Δ on average. Diplopia is cured with surgery, and each case needs to be differentiated from the heavy eye syndrome for diagnosis and treatment.

Characterization of the position of the extraocular muscles and orbit in acquired esotropia both at distance and near using orbital magnetic resonance imaging.

PURPOSE: Age-related distance esotropia (ARDE) involves acquired esotropia at distance and phoria at near. However, distance-independent esotropia (DIE) exists esotropia both at distance and near. Thus, we examined the orbital magnetic resonance imaging (MRI) findings for DIE to assess differences in its characteristics. METHODS: This study was a retrospective case-control study. We evaluated the efficacy of the standard coronal MRI in patients with acquired esotropia and control patients with optic neuritis. Cases with strabismus in the control group were excluded. DIE was defined as having esotropia both at distance and near, and an angle of more than 10 prism diopters at near. The condition of the lateral rectus-superior rectus band, position of rectus muscles, and the volume ratio of the globe to the whole orbit (G/WO) were examined. RESULTS: The DIE group consisted of 12 eyes of 6 patients (77.3±7.7 years); ARDE group, 38 eyes of 19 patients (73.1±6.8 years); and control group, 34 eyes of 17 patients (70.9±4.3 years). The ratio of abnormality of the lateral rectus-superior rectus bands was higher in the DIE and ARDE groups than in the control group (p<0.01). The vertical angle of the lateral rectus deviated downwards in the control (-7.5±5.1°), ARDE (-12.2±9.1°), and DIE groups (-18.8±5.7°) (p<0.05). The tilting angle of the lateral rectus was tilted temporally in the control (-12.2±9.1°), ARDE (-20.0±8.6°) and DIE groups (-28.6±5.4°) (p<0.01). G/WO was higher in the DIE (0.28±0.01) and ARDE groups (0.27±0.02) compared to the control (0.25±0.03) group (p<0.01). CONCLUSION: In comparison with the ARDE and control groups, the DIE group presented with abnormalities of the lateral rectus-superior rectus band, malposition of the lateral rectus, and differences in the G/WO. The DIE group showed a more severe form of ARDE.

Characteristics of Japanese patients with Leber's hereditary optic neuropathy and idebenone trial: a prospective, interventional, non-comparative study.

PURPOSE: Leber's hereditary optic neuropathy (LHON) is a mitochondrial neuropathy that causes acute vision loss. Idebenone, a short-chain ubiquinone analog that preserves mitochondrial function is thought to suppress disease progression in early-onset LHON patients. We investigated the effects of idebenone in Japanese LHON patients. STUDY DESIGN: Prospective, interventional, non-comparative study in patients with definite LHON diagnosis, under trial registration number UMIN000017939. METHODS: Fifty-seven patients received 900 mg/day idebenone for 24 weeks. We measured baseline best-corrected visual acuity, visual fields, critical fusion frequency and retinal ganglion cell layer complex thickness; we assessed efficacy at 24 and 48 weeks, and safety throughout. RESULTS: Patients were predominantly male (91.2%) and most had an mt.11778G>A mutation (94.7%). All patients tolerated idebenone therapy well. Data from the 51 mt.11778 patients were compared with their baseline data. At 48 weeks, significant improvement in best-corrected visual acuity was observed in 17 patients (33.3%). Furthermore, 25.5% of patients showed improvements in visual fields and 33.3% in critical fusion frequency. However, retinal ganglion cell layer complex thickness was significantly reduced. Among patients who started idebenone >1 year after disease onset, visual improvement was found in 12 (38.7%). Among patients who developed LHON before 19 years of age, visual improvement was found in 11 (42.3%). CONCLUSION: Idebenone's potential and favorable safety profile were confirmed in Japanese LHON patients. However, this study had no placebo group; therefore, we need to undertake a prospective intervention study to further investigate the therapeutic effects of Idebenone in Japanese LHON patients.

Strabismus After Ahmed Glaucoma Valve Implantation.

PURPOSE: Most reports of strabismus after glaucoma drainage device implantation study larger devices and rarely note the incidence of strabismus after Ahmed glaucoma valve (AGV) implantation. It is unknown if the pattern of strabismus is similar with smaller devices. We investigated characteristics of strabismus after AGV implantation. DESIGN: Retrospective review. METHODS: Institutional study of 732 patients at our institution undergoing AGV implantation between 2013 and 2018. Rate and characteristics of strabismus were the primary outcome; age, gender, and location of AGVs were also analyzed. RESULTS: We identified 29 patients who developed new-onset strabismus postoperatively after initial AGV implantation, for 4% incidence of strabismus. Twenty-one (72%) of these had diplopia. AGVs were implanted superotemporally in 21, superonasally in 5, inferotemporally in 1, and inferonasally in 2. Three patients were esotropic, 11 were exotropic, 4 had hypertropia, 2 had hypotropia, and 9 patients had combined horizontal/vertical strabismus (esotropia/hypotropia [n = 1] or exotropia/hypertropias [n = 8]). Exotropia was the most common type of strabismus in both the superotemporal and superonasal (60%) AGV groups. Superotemporal AGVs were more commonly associated with ipsilateral hypertropia (43%) than superonasal AGVs. Treatments included strabismus surgery (n = 14), prisms (n = 6), or an occlusive lens (n = 1). DISCUSSION: In the largest single-center series of patients undergoing initial AGV implantation, the overall incidence of postoperative strabismus was 4%. This is comparable to strabismus incidence following implantation of other types of glaucoma drainage devices, even larger devices. The possibility of this complication should be discussed with patients prior to surgery.

Standard coronal orbital magnetic resonance imaging is an effective technique for diagnosing sagging eye syndrome.

PURPOSE: The aim of this study was to determine the importance and efficacy of the standard coronal magnetic resonance imaging (MRI) analysis method for the correct clinical diagnosis of the sagging eye syndrome. METHODS: This retrospective study evaluated the standard coronal MRI efficacy by comparing the positions of the orbital pulleys and extraocular muscles in patients with sagging eye syndrome as well as controls. The participants included 50 patients with sagging eye syndrome (aged 73.3 ± 6.7 years) and 17 age-matched control patients (aged 70.9 ± 4.3 years) that presented optic neuritis. The participants were classified into groups of age-related distance esotropia and cyclo-vertical strabismus. Lateral rectus-superior rectus band condition, lateral rectus vertical angle, lateral rectus tilting angle, and superior rectus-lateral rectus displacement angle were examined. RESULTS: The lateral rectus-superior rectus band was more frequently disordered in the two groups than that in the control. The lateral rectus vertical and tilt angle examinations exhibited a significant difference in the age-related distance esotropia [(- 13.3 ± 10.9°, p < 0.05) and (- 24.1 ± 9.5°, p < 0.01)] and cyclo-vertical strabismus [(- 11.9 ± 6.9°, p < 0.05) and (- 20.8 ± 9.3°, p < 0.01)] groups compared with those in the control group [(- 7.5 ± 5.1°) and (- 12.2 ± 9.1°)]. The superior rectus-lateral rectus displacement angle did not present a significant difference between the patients and control groups. CONCLUSIONS: Patients with sagging eye syndrome exhibited disordered orbital pulley and extraocular muscle malposition, as determined by standard coronal magnetic resonance imaging, indicating the effectiveness of the procedure for diagnosing sagging eye syndrome.

Prevalence of Sagging Eye Syndrome in Adults with Binocular Diplopia.

PURPOSE: Sagging eye syndrome (SES), horizontal and/or vertical strabismus caused by orbital connective tissue degeneration, was first defined 10 years ago. This study investigated SES and other causes of acquired binocular diplopia in adults presenting to a single institution since the description of SES. DESIGN: Retrospective observational case series. METHODS: Medical records were reviewed of all new patients over the age of 40 who presented to the Stein Eye Institute with binocular diplopia between January 2015 and December 2018. Clinical causes of diplopia were tabulated in patients grouped by age and sex. In patients with SES, we tabulated binocular alignment, types of treatment, and surgical outcomes. RESULTS: There were 945 patients of mean age 66.5 years, of whom 514 (54.4%) were female. The most common cause of diplopia was SES (31.4%). The 297 patients with SES were older at 71.2 years (P < 0.0001) and more predominantly female at 59.9% than other patients (52.0%; P = 0.023). The relative proportion of SES patients among all diplopic patients increased with age from 4.7% under age 50 years to 60.9% over the age of 90. Age-related distance esotropia was present in 35% and cyclovertical strabismus in 65% of cases of SES. Strabismus surgery was performed in 50% of cases of SES. Mean esotropia at distance decreased from 6.9 ± 0.7Δ preoperatively to 0.3 ± 0.3Δ postoperatively. Preoperative hypertropia decreased from 3.0 ± 0.3Δ to 0.7 ± 0.2Δ postoperatively. Surgery resolved diplopia in all cases. CONCLUSIONS: It is important to recognize that SES is a very common cause of adult binocular diplopia.

Compression of the Choroid by Horizontal Duction.

Purpose: The optic nerve becomes tethered in adduction in most people, which deforms the disc. We investigated the effect of horizontal ocular duction and subject age on choroidal volume at the macular side of the optic disc. Methods: In 25 younger (18-33 years) and 15 older (50-73 years) normal subjects, the disc and the peripapillary choroid were imaged with optical coherence tomography (OCT) in central gaze and 35° adduction and abduction. The choroid temporal to the optic disc underlying the region between the Bruch's membrane opening and fovea was segmented into regions that were multiples of the disc radius for determination of local choroidal thickness. Regional volume changes from central gaze were determined in adduction and abduction. Results: In adduction, regional choroidal volume decreased by 42.4 ± 3.4 nanoliters (nL) (standard error of the mean) in younger (P < 0.0001) and 6.2 ± 2.6 nL in older (P < 0.02) subjects. Relative volume reduction in adduction was 7.5% ± 0.6% in younger (P < 0.001) and 1.3% ± 0.6% in older (P < 0.02) subjects. Volume reduction was greatest near the disc and significant up to three disc radii from it in younger and 1 radius in older subjects but was insignificant in abduction. Conclusions: Horizontal duction compresses the temporal peripapillary choroid, more in adduction than in abduction and more in younger than older subjects. This reflects duction-related peripapillary tissue deformation probably related, at least in part, to optic nerve tethering in adduction.

Correction to: Causes, background, and characteristics of binocular diplopia in the elderly.

In the original publication, the second paragraph under the heading "Results" has been mistakenly published as.

Epidemiologic and Clinical Characteristics of Optic Neuritis in Japan.

PURPOSE: To elucidate the clinical and epidemiologic characteristics of optic neuritis in Japan. DESIGN: Multicenter cross-sectional, observational cohort study. PARTICIPANTS: A total of 531 cases of unilateral or bilateral noninfectious optic neuritis identified in 33 institutions nationwide in Japan. METHODS: Serum samples from patients with optic neuritis were tested for anti-aquaporin-4 antibodies (AQP4-Abs) and anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) using a cell-based assay and were correlated with the clinical findings. MAIN OUTCOME MEASURES: Antibody positivity, clinical and radiologic characteristics, and visual outcome. RESULTS: Among 531 cases of optic neuritis, 12% were AQP4-Ab positive, 10% were MOG-Ab positive, 77% were negative for both antibodies (double-negative), and 1 case was positive for both antibodies. Pretreatment visual acuity (VA) worsened to more than a median 1.0 logarithm of the minimum angle of resolution (logMAR) in all groups. After steroid pulse therapy (combined with plasmapheresis in 32% of patients in AQP4-Ab-positive group), median VA improved to 0.4 logMAR in the AQP4-Ab-positive group, 0 logMAR in the MOG-Ab-positive group, and 0.1 logMAR in the double-negative group. The AQP4-Ab-positive group showed a high proportion of females, exhibited diverse visual field abnormalities, and demonstrated concurrent spinal cord lesions on magnetic resonance imaging (MRI) in 22% of the patients. In the MOG-Ab-positive group, although posttreatment visual outcome was good, the rates of optic disc swelling and pain with eye movement were significantly higher than those in the AQP4-Ab-positive and double-negative groups. However, most cases showed isolated optic neuritis lesions on MRI. In the double-negative group, 4% of the patients had multiple sclerosis. Multivariate logistic regression analysis of all participants identified age and presence of antibodies (MOG-Ab and AQP4-Ab) as significant factors affecting visual outcome. CONCLUSIONS: The present large-scale cohort study revealed the clinicoepidemiologic features of noninfectious optic neuritis in Japan. Anti-aquaporin-4 antibody-positive optic neuritis has poor visual outcome. In contrast, MOG-Ab positive cases manifested severe clinical findings of optic neuritis before treatment, but few showed concurrent lesions in sites other than the optic nerve and generally showed good treatment response with favorable visual outcome. These findings indicate that autoantibody measurement is useful for prompt diagnosis and proper management of optic neuritis that tends to become refractory.

Compressive Lesions of the Optic Chiasm: Subjective Symptoms and Visual Field Diagnostic Criteria.

We investigated the diagnostic ability of a new criterion (simple temporal depression) for compressive lesions of the optic chiasm. The subjects were 124 eyes with compressive lesions of the optic chiasm. The controls were 84 eyes. The Humphrey (Carl Zeiss) visual field test was used for visual field testing. The simple temporal depression index was calculated as the ratio of the sums of the thresholds for one line on the nasal side and temporal side of the vertical meridian. The result of new index was 87% sensitivity and 99% specificity. This result suggested that our new criterion will assist the diagnosis in the future.

Causes, background, and characteristics of binocular diplopia in the elderly.

PURPOSE: We evaluated the background and characteristics of elderly patients with binocular diplopia including diseases caused by abnormalities in orbital pulleys. STUDY DESIGN: Retrospective. METHODS: The participants were 236 patients aged 60 years or older who visited Kitasato University Hospital complaining of binocular diplopia. We classified strabismus by types and investigated the causes for each group. We diagnosed orbital pulley disorders using magnetic resonance imaging (MRI). Patients with orbital pulley disorders exhibited esotropia and/or vertical strabismus and did not present with cranial nerve palsy, systemic illness, or ocular injury. RESULTS: Classification of strabismus types was: exotropia (24.2%); esotropia (25.0%); vertical strabismus (30.1%), combined strabismus (20.8%). There were 50.9% cases of strabismus associated with vertical deviation. The causes of disease in each group were as follows: in the exotropia group, 50.9% convergence insufficiency exotropia, 21.1% basic exotropia; in the esotropia group: 35.6% orbital pulley disorder 33.9% sixth cranial nerve palsy; in the vertical strabismus group: 32.4% forth cranial nerve palsy, 31.0% orbital pulley disorder; in the combined strabismus group: 28.6% orbital pulley disorder, 28.6% forth cranial nerve palsy. CONCLUSIONS: About half of the elderly patients with binocular diplopia exhibited vertical deviation. In addition, binocular diplopia was often caused by orbital pulley disorders. It is the first epidemiological study focusing on orbital pulley disorders diagnosed on the basis of MRI.