• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.363-369
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• 2014

Purpose: Three-dimensional (3D) displays are very useful in many fields, but induce physical discomforts in some people. This study is to assess symptom type and severity of asthenopia with their habitual distance corrective spectacle (HDCS) and their binocular vision corrective spectacle lenses (BVCSL) in people who feel physical discomforts. Methods: 35 adult subjects (ages $32.2{\pm}4.4$ yrs) were pre-screened out of 98 individuals to have the highest symptom/asthenopia scores following 65 minutes of 3D television viewing with HDCS. These 35 individuals were then retested symptom/asthenopia scores during they watched 3D television for 65 minutes at a distance of 2.7 m with wearing BVCSL of horizontal, vertical or base down yoked prisms. A 4-point symptom-rating scale questionnaire (0=no symptom and 3=severe) was used to assess 11 symptoms (e.g., blur, diplopia, etc.) related to visual fatigue/visual discomfort. Distance and near lateral phoria were measured using Howell phoria card and vertical phoria were measured using Maddox rod. Symptoms induced by watching 3D TV were compared between wearing HDCS and BVCSL. Results: Asthenopia in watching 3D TV with wearing BVCS was significantly lower than wearing HDCS at 5, 25, 45, and 65 minutes (all p < 0.001, paired t-tests). In only refractive error power correction power group, all asthenopia was not significantly different between HDCS and BVCSL (all $p{\geq}0.05$, paired t-tests). In prism correction groups for binocular imbalance, symptoms of asthenopia, however, was significantly lower for when wearing BVCSL than when wearing HDCS (all p < 0.05). Conclusions: Correction of phoria/vergence-based binocular vision imbalance can reduce asthenopia during 3D television viewing. An individual with binocular vision imbalance need corrected/compensated glasses with appropriate prisms prior to prolonged viewing of 3D television displays to reduce asthenopia/visual fatigue.

• Journal of The Korean Ophthalmological Society
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• v.59 no.11
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• pp.1087-1090
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• 2018

Purpose: To report a case of trochlear nerve palsy caused by quadrigeminal cistern lipoma located in the dorsal midbrain. Case summary: A 65-year-old male visited our clinic for intermittent vertical diplopia over 2-year period. Symptoms of diplopia had worsened over the past two weeks. He had no previous medical history except having had diabetes for 1 month. The best-corrected visual acuity was 20/25 in the right eye and 20/20 in the left eye. Pupillary examination was not remarkable. Extraocular examination showed 4 prism diopters (PD) left hypertropia at distant gaze and 4 PD exotropia at near gaze, with adduction elevation of the left eye. The Bielschowsky head tilt test revealed 6 PD left hypertropia on the left gaze and orthotropia on the right tilt. Fundus examination showed excyclotorsion of the right eye and incyclotorsion of the left eye. Brain magnetic resonance imaging revealed quadrigeminal cistern lipoma. Prism glasses were prescribed to alleviate diplopia, and we followed up the lesions without further treatment. Conclusions: Trochlear nerve palsy can be caused by quadrigeminal cistern lipoma; however, it is uncommon for this condition to be caused by a compressive lesion. Prompt neuroimaging can be helpful to rule out the causes of this condition in patients with atypical symptoms.

• Journal of The Korean Ophthalmological Society
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• v.59 no.12
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• pp.1195-1200
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• 2018

Purpose: To report a case of anterior segment ischemia after superior and inferior rectus muscle surgery in a patient with superior rectus muscle enlargement. This is the first report in the Republic of Korea of anterior segment ischemia after two rectus muscles surgery. Case summary: An 80-year-old male was referred to our clinic with a 3 years history of diplopia. The patient had 30 prism diopters right eye hypertropia in the primary position and downgaze limitation. The orbital computed tomography scan revealed enlargement of the right superior rectus muscle. He underwent right superior rectus recession and inferior rectus resection. On postoperative day 2, slit lamp examination revealed diffuse corneal edema, Descemet's membrane folding, an aqueous flare and a dilated pupil. Treatment with 45 mg oral steroid was initiated, and 1% prednisolone acetate and 0.5% Levofloxacin eye drops were administered. At postoperative 1 month, the patient was orthophoric in the primary position, and there was no corneal edema, pupil abnormality or aqueous flare. Conclusions: Base on the present case, the possibility of anterior segment ischemia should be considered after even two muscles surgery, and older patients with vertical muscle surgery should be considered more carefully.

• Journal of The Korean Ophthalmological Society
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• v.58 no.11
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• pp.1260-1268
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• 2017

Purpose: Strabismus affects any age and represents various functional or non-functional eye problems. This population-based study was conducted to determine the prevalence of strabismus and nystagmus in South Korea according to various sociodemographic factors. Methods: We acquired data from the Korea National Health and Nutrition Examination Survey, a nation-wide cross-sectional survey and examinations of the non-institutionalized civilian population in South Korea (n = 30,538), conducted from July 2008 to December 2011. The prevalence of strabismus and nystagmus were verified, and associated sociodemographic factors was evaluated. Results: The overall prevalence of strabismic disorder in participants over 3 years of age was $1.4{\pm}0.1%$ (95% confidence interval [CI] 1.3-1.6%; $1.5{\pm}0.1%$ in males, $1.3{\pm}0.1%$ in females). The prevalence of exodeviation (15 or more prism diopters), esodeviation (10 or more prism diopters), vertical deviation, and other complicated strabismus and nystagmus was 1.0%, 0.2%, 0.2%, 0.1% and 0.1% respectively. The prevalence was highest in the 6 to 15-year age group ($1.9{\pm}0.3%$), and lowest in the 40 to 49 years age group ($0.8{\pm}0.1%$) (p = 0.005). There were no statistically significant differences for gender, region, residential area, household income, educational level and occupation. Conclusions: This nation-wide epidemiologic study demonstrated that the prevalence of strabismus and nystagmus according to various sociodemographic factors in South Korea was not statistically significant except for age group. Further investigations are required based on more surveys to better recognize the etiologic or risk factors that may be related to strabismus and nystagmus.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.2
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• pp.41-46
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• 2009

Purpose: Stereopsis is one of primary characteristics for assessment of binocular function. The purpose of this study was to determine the possible relationship between the degree of exophoria and stereoacuity at near. Methods: 110 exophores (male n=71, female n=39, mean $age{\pm}SD=11.30{\pm}1.47$ years) without amblyopia, strabismus, and ocular and systemic pathology were studied. Subjects were also excluded if they had visual acuity poorer than 0.8 in either eye or vertical phoria greater than 1 prism diopter. Clinical tests were performed for near phorias by von Graefe technique using a Digital Refractor (CDR-3100, Huvitz, Korea) with chart (Predio CDC-4000, Huvitz, Korea), and for stereoacuity using the Titmus fly. Results: A one-way analysis of variance revealed that mean values of the stereoacuity classified according to the degrees of the exophoria were not significantly different (p>0.05). Conclusions: Based on the result of this study, it was found that there was no relationship between the degree of exophoria and stereoacuity.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.37-42
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• 2009

Purpose: There is uncertainty if the vergence facility would provide clinically significant supplementary information to the fusional vergence measurements. The purpose of this study was to determine the relationship between vergence facility and fusional vergence in a group of symptomatic subjects. Methods: A total of 114 symptomatic subjects aged 9 to 13 years, who passed the vision screening test, participated in this study. Vergence facility was measured with 8$\Delta$ BI/8$\Delta$ BO flipper lenses and a suppression control target, the 20/30 letter line on Vectogram 9 (Bernell, USA). Near fusional vergence was measured with a single 20/30 vertical line target by Von Graefe technique. In order to avoid excessive convergence stimulation, negative fusional vergence (NFV) range (blur, break and recovery) was measured followed by positive fusional vergence (PFV) ranges (blur, break and recovery). Results: Pearson correlations were calculated and showed no correlations between vergence facility and any of fusional vergence measurements (p>0.05). Also, there were no significant differences of vergence facility measurements on the compensating vergence that passed or failed Sheard and Morgan's criterion for comfortable vision (p>0.05). Conclusions: There was no correlation between vergence facility and fusional vergence among symptomatic subjects. Hence, both vergence facility and fusional vergence should be assessed for those with binocular dysfunction in order to make an accurate diagnosis and management plan.