Sueng- Han

Supermaximal Recession and Resection in Large-Angle Sensory Exotropia

In cases of extropia with an exodeviation angle over 50 prism diopter (PD), a 3- or 4-muscle surgery is a rational option. But, in patients with sensory exotropia, there is usually a strong preference for a monocular procedure to avoid surgery on the single seeing eye. Thus, we confined surgery to visually poor eyes, and performed a medial rectus muscle resection with a mean of 10.3 mm (range, 9-11 mm) and a lateral rectus muscle recession with a mean of 12.8 mm (range, 10-14 mm) in 4 adult sensory exotropia patients who had a mean deviation of 82.3 PD (range, 75-90 PD). The mean postoperative angle of exodeviation was 2.0 PD (range, ortho-8 PD). The limitation on abduction was not disfiguring. Other expected disfigurements, such as narrowing of the palpebral fissure or enophthalmos, were not conspicuous. The mean follow-up period was 4.5 months (range, 3-7 months). In large-angle sensory exotropia, instead of additive surgery on the seeing eye, supermaximal medial rectus resection and lateral rectus recession only on the visually poor eye is a clinically feasible surgical option.

Inadvertent scleral perforation after strabismus surgery: incidence and association with refractive error

BACKGROUND Inadvertent scleral perforation is a rare but serious complication of extraocular muscle surgery for strabismus. We evaluated the incidence of unwanted scleral penetration after strabismus surgery and its association with refractive error. METHODS This cross-sectional noncomparative case series comprised 453 eyes from 236 patients who underwent strabismus surgery. After dilation, each patient had fundus examination using indirect binocular ophthalmoscope. Chorioretinal scars around the suture area, which presumed the previous scleral perforation, were detected. We assessed whether the presence of these scars was related to the degree of preoperative refractive error. RESULTS Mean postoperative follow-up was 52.44 (SD 30.07) months. Overall incidence of inadvertent penetration of the sclera was 1.77%. A total of 8 eyes (6 patients) showed chorioretinal scars, and all were myopic. Of these, 3 eyes were classified as mild myopia, 3 as moderate myopia, and the other 2 as severe myopia. The relationship between inadvertent scleral penetration and degrees of refractive error was weak but statistically significant (p = 0.001). INTERPRETATION Inadvertent scleral perforation after strabismus surgery seems to be associated with myopic refractive error.

Ophthalmological manifestations in patients with Leigh syndrome

Background To describe the ophthalmological manifestations in patients with childhood onset Leigh syndrome (LS) and investigate the correlation between genotypes and phenotypes in patients with LS. Methods Childhood onset LS was clinically and enzymatically confirmed in a total of 63 patients. Among them, 44 patients who underwent ophthalmologic consultation were included in this study. Patients with LS underwent genotyping for the whole genome of mitochondrial DNA and SURF1 mutations. The clinical demographic and ophthalmologic phenotypes were compared between the good prognosis group and the poor prognosis group. Results Strabismus (40.9%) was the most frequently observed ophthalmologic manifestation, followed by pigmentary retinopathy (22.5%), optic atrophy (22.5%), ptosis (15.9%), and nystagmus (13.6%). Thirteen patients were exotropes and five patients were esotropes. The mean exodeviation was 29.6±12.5 prism dioptres (PD) and the mean esodeviation was 24.0±8.9 PD. All patients with esotropia reported disease onset at <1 year old. Among 26 patients older than 4 years, eight (30.8%) patients had better than 0.4 in the best eye was noted. Eyelid ptosis was a main presenting sign in four patients (9.1%). Among these patients, two patients had m.13513G>A mutation in the MT-ND5 gene. Age at onset was 2.47±2.06 years in the good prognosis group and 0.92±0.98 years in the poor prognosis group (p=0.002). Serum lactate peak concentration was 3.23±1.36 mmol/L in the good prognosis group and 4.54±2.31 mmol/L in the poor prognosis group (p=0.051). Conclusions LS is a group of mitochondrial disorders with variable ophthalmologic manifestations, the most frequent being strabismus in this study. Ptosis could be an initial sign in patients with LS and these patients can be easily misdiagnosed as having juvenile myasthenia gravis.

The effects of interocular differences in retinal illuminance on vision and binocularity

BackgroundIt is known that binocular function is affected by interocular differences in retinal image size, shape, clarity, and illumination. The present study was performed to systematically examine the effects of interocular differences in retinal illuminance on monocular visual acuity, fusion, and stereopsis.MethodsFifty adults with normal binocularity and a best-corrected visual acuity of 20/20 or better were enrolled. We examined best-corrected visual acuity, fusion, and stereoacuity as monocular retinal illuminance was gradually reduced by increasing neutral density filters from 0.2 neutral density (ND; 63% transmission) to 3.0 ND (0.1% transmission) in increments of 0.2 ND. We measured the smallest size of fusion slide by major amblyoscope, and evaluated stereoacuity with the Titmus test and the Lang test.ResultsThe best-corrected visual acuity began to decrease significantly when the value of the neutral density filter reached 2.0 ND (1% transmission; p<0.01). The level of fusion decreased significantly when monocular retinal illuminance was reduced to 2.0 ND (p<0.01). Stereoacuity began to decline significantly when the value of the neutral density filter was 1.4 ND (4% transmission) with the Titmus test and 1.6 ND (2.5% transmission) with the Lang test.ConclusionsA binocularly conducted Titmus test was the most sensitive to the presence of monocularly induced retinal illuminance deterioration.

Role of Heat Shock Protein 47 in Transdifferentiation of Human Tenon's Fibroblasts to Myofibroblasts

BackgroundHeat shock protein 47 (Hsp47) is a well-known molecular chaperone in collagen synthesis and maturation. The aim of this study is to investigate its putative role in the transdifferentiation of Tenon’s fibroblasts to myofibroblasts.MethodsPrimary cultured human Tenon’s fibroblasts were exposed to transforming growth factor-β1 (TGF-β1) for up to 48 hours. The mRNA levels of Hsp47 and α smooth muscle actin (αSMA) were determined by quantitative real time RT-PCR. After delivery of small interfering RNA (siRNA) molecules targeting Hsp47 into the cells, the expression of Hsp47 and αSMA proteins was determined by western immunoblotting.ResultsTGF-β1 increased the mRNA expressions of both Hsp47 and αSMA in human Tenon’s fibroblasts, as determined by quantitative real time RT-PCR. However, it induced the protein expression of only αSMA but not Hsp47, as determined by western immunoblots. When siRNAs specific for Hsp47 were introduced into those cells, the TGF-β1-induced expression of αSMA was significantly attenuated on western immunoblots; after 48 hours of exposure to TGF-β1, the relative densities of immunobands were 11.58 for the TGF-β1 only group and 2.75 for the siRNA treatment group, compared with the no treatment control group (p < 0.001).ConclusionsOur data suggest that Hsp47 may be related to the TGF-β1-induced transdifferentiation of human Tenon’s fibroblasts to myofibroblasts.

The Role of Focal Adhesion Kinase in the TGF-β-Induced Myofibroblast Transdifferentiation of Human Tenon's Fibroblasts

Purpose To investigate the role of focal adhesion kinase (FAK) in transforming growth factor (TGF)-β-induced myofibroblast transdifferentiation of human Tenons fibroblasts. Methods Primary cultured human Tenons fibroblasts were exposed to TGF-β1 for up to 48 hours. The mRNA levels of FAK, α smooth muscle actin (αSMA), and β-actin were determined by quantitative real time reverse transcription polymerase chain reaction. The protein levels of collagen type I, FAK, phospho-FAK, αSMA, and β-actin were determined by Western immunoblots. After the small interfering RNA targeting FAK (siRNAFAK) molecules were delivered into the cells, the expressions of αSMA proteins were determined by Western immunoblots. Results In human Tenons fibroblasts, TGF-β1 significantly increased the mRNA and protein expressions of αSMA. However, when the action of FAK was inhibited using siRNAFAK, the TGF-β1-induced expression of αSMA was attenuated. Conclusions Our data suggest that FAK may be associated with the TGF-β1-induced transdifferentiation of human Tenons fibroblasts to myofibroblasts, which is the essential step of subconjunctival fibrosis.

Real Stereopsis Test Using a Three-Dimensional Display with Tridef Software

Purpose To investigate horizontal image disparity in three-dimensional (3-D) perception using 3-D animations in normal control patients and patients with intermittent exotropia, anisometropic amblyopia, and partially accommodative esotropia. Materials and Methods A total of 133 subjects were included. Stereopsis was measured using the Titmus Stereo test (Stereo Optical Inc., Chicago, IL, USA) and a 3-D stereopsis test with a 15 inch 3-D display laptop, adjusting 3-D parameters of 0 mm horizontal disparity to 15 mm horizontal disparity. Results When compared with normal controls, the average threshold of the 3-D stereopsis test was significantly reduced for esotropia patients (p<0.001) and for anisometric amblyopia patients (p<0.001), compared to normal controls. No significant difference was observed between normal controls and intermittent exotropia patients (p=0.082). The 3-D stereopsis test was correlated with the Titmus Stereo test (Spearmans rho=0.690, p<0.001). Mean difference in stereoacuity was 1.323 log seconds of arc (95% limits of agreement: 0.486 to 2.112), and 125 (92.5%) patients were within the limits of agreement. Conclusion This study demonstrated that a 3-D stereopsis test with animation is highly correlated with the Titmus Stereo test; nevertheless, 3-D stereopsis with animations generates more image disparities than the conventional Titmus Stereo test. The 3-D stereopsis test is highly predictive for estimating real stereopsis in a 3-D movie theater.

Outcomes of 6 Hour Part-time Occlusion Treatment Combined with Near Activities for Unilateral Amblyopia

Purpose To evaluate the outcome of the part-time occlusion therapy with near activities in monocular amblyopic patients according to gender, age, severity of amblyopia, and the cause of amblyopia. Methods Fifty eight patients who were prescribed part-time occlusion therapy with near activity from July 1998 to October 2004, were included in this retrospective study. All patients were divided into groups by gender, age, severity of amblyopia, and the cause of amblyopia. Main outcome measures were best corrected visual acuity, line improvement, and success rate. Results At the end of patch therapy, visual acuity improved from baseline by an average of 3.2±2.5 lines (0.33±0.26 log MAR), and follow-up period was 19.71±14.61 months (1.62±1.20 years). At the last follow-up, visual acuity improved from baseline by an average of 3.7±2.4 lines (0.38±0.26 log MAR), and follow-up period was 37.41±25.83 months (3.08±2.12 years). The success rate was 86% (50 patients) at the end of patch therapy. In 44 patients out of 50 patients (88%), the visual acuity was maintained. While 43 patients out of 47 patients who were less than 7 years old (91%) achieved success, 7 patients out of 11 patients 7 years or older (64%) achieved success (p=0.035). Conclusions Six-hour part-time occlusion treatment combined with near activities appears to be favorable in treating 58 children during follow-up of mean 3.08 years. The significant factor was the age at initial treatment.

Contrast Sensitivity Function of Sound Eye after Occlusion Therapy in the Amblyopic Children

To verify the changes of mesopic and photopic contrast sensitivity function of sound eye whose visual acuity was kept the same after occlusion therapy in the amblyopic children. Fourteen sound eyes of amblyopic children (mean; 7.67 years; S.D., 1.50 years) who kept their visual acuity the same after the occlusion therapy were tested. The children had 6 hours of part-time patch therapy for 3 months prior to this examination. Among 14 amblyopic children, 8 were anisometric and 6 were strabismic amblyopes. Using the visual capacity analyzer which measures the minimal contrast level at from low to high spatial frequencies, the contrast sensitivity of sound eye was measured, under both photopic and mesopic condition, before and after 3 months of occlusion therapy. Comparing the contrast sensitivity of sound eye after the occlusion therapy to that before the occlusion, there was no statistical difference in photopic condition. When it comes to mesopic condition, the contrast sensitivity decreased at the intermediate spatial frequency level (3-13 c.p.d, p=0.028) after the occlusion therapy. The occlusion caused statistically significant decrease in mesopic contrast sensitivity, when the visual acuity was not changed after the occlusion therapy. It may indicate that mesopic contrast sensitivity can be considered as a useful tool for early detection of hidden occlusion amblyopia.

Transient neonatal myasthenia gravis due to a mother with ocular onset of anti-muscle specific kinase myasthenia gravis

We describe a 27-year-old pregnant female with new onset of conjugate gaze deficit during the third trimester of pregnancy. Repetitive nerve stimulation tests, neostigmine tests, and acetylcholine receptor antibody assays were all negative. The patient delivered a normal healthy baby at a local clinic via cesarean section. The baby became hypotonic and had respiratory failure several minutes after birth. The result of acetylcholine receptor antibody was negative in the neonate. The neonate became healthy spontaneously and was extubated after 21 days of ventilation care. Two months after delivery, the mother developed ptosis and generalized symptoms and subsequent workup revealed she was muscle specific kinase (MuSK) antibody positive. The neonate was presumed to have an anti-MuSK-mediated transient neonatal myasthenia gravis. Although MuSK antibody testing is rarely indicated in ocular myasthenia gravis, MuSK antibody testing is necessary in pregnant women who are presumed ocular myasthenia gravis to warn occurrence of transient neonatal myasthenia gravis.