A Prototype of a Stereoacuity Test Using a Head-Mounted Display

Purpose@#To evaluate the test-retest reliability of a contour-based stereoacuity test using a head-mounted display (HMD) and compare it with other stereotests. @*Methods@#Thirty-two healthy adults aged 23-47 years were recruited from a tertiary hospital between August 2017 and July 2018. Two separate contour-based circles (crossed disparity: 135-1,350 arcsecs) were generated on a high-resolution phone display (Galaxy S7; Samsung, Seoul, Korea) using an HMD (Galaxy Gear VR). Two images were independently projected to each eye as graded circles with a random dot background. The results of the new HMD stereotest were compared to those of the standard Randot and TNO stereotests. The test-retest reliability was assessed using the Bland-Altman plot and Cohen’s kappa statistics. @*Results@#Among the 32 study participants, 17 (53%) were males and the mean age was 30.1 ± 4.8 years (range: 23-47). The mean stereoacuity was 160.3 ± 53.5 arcsecs in the first HMD stereotest (HMD1), 28.4 ± 12.5 arcsecs in the Randot stereotest, 96.1 ± 83.5 arcsecs in the TNO stereotest, and 143.3 ± 47.7 arcsecs in the second HMD stereotest (HMD2). The Bland-Altman plot showed a mean difference of 0.042 (-0.189 to +0.272, 95% limits of agreement) between HMD1 and HMD2. The reliability analysis showed an intraclass correlation coefficient of 0.499 (p = 0.022) and agreement of 81.25% in Cohen’s kappa statistics (Cohen’s kappa index = 0.119, p = 0.017). @*Conclusions@#The HMD stereotest without monocular cues showed fair test-retest reliability and reproducibility. Further studies using a high resolution display are needed to confirm the validity of the HMD stereotest.

Accuracy of the Hand-held Wavefront Aberrometer in Measurement of Refractive Error

Purpose@#To compare refractive error measured by hand-held wavefront aberrometers with postcycloplegic autorefraction (AR) and cycloplegic refraction (CR). @*Methods@#The medical records of patients who received refractive measurements using the wavefront aberrometer, postcycloplegic AR, and CR between January 2014 and January 2016 were retrospectively analyzed. The mean differences, 95% confidence intervals, and limits of agreement (LOA) were calculated for the refractive vector components (M, J0, and J45). @*Results@#Fifty-one patients (9.0 ± 5.5 years, male 41.2%) were enrolled in this study, and only the right eye of each was included. Refractive errors ranged from -9.25 to +7.25 diopters (D) for spherical equivalent (median, 0.75 D). The M component was not significantly different among the three methods (p = 0.080). However, the J0 vector component was significantly different (p < 0.001). After post hoc analysis, the wavefront aberrometer obtained more positive values for J0 compared to the other methods. The J45 component was not significantly different among the three methods (p = 0.143). The mean difference between the wavefront aberrometer and postcycloplegic AR was -0.115 D (LOA, -1.578 to 1.348 D) for M, 0.239 D (LOA, -0.371 to 0.850 D) for J0, and -0.015 D (LOA, -0.768 to 0.738 D) for J45. The mean difference between the wavefront aberrometer and CR was -0.220 D (LOA, -1.790 to 1.350 D) for M, 0.300 D (LOA, -0.526 to 1.127 D) for J0, and -0.079 D (-0.662 to 0.504 D) for J45. @*Conclusions@#The wavefront aberrometer showed good agreement with postcycloplegic AR and CR in spherical equivalents, but tended to produce slightly myopic results. The wavefront aberrometer also overestimated with-the-rule astigmatism. Therefore, we recommend that the device be used for estimations of refractive error, which may be useful for patients who have postural difficulties, live in undeveloped countries, or are bedridden.

Refractive Outcomes of 4-Year-old Children after Intravitreal Anti-vascular Endothelial Growth Factor versus Laser Photocoagulation for Retinopathy of Prematurity

PURPOSE: To compare long-term refractive outcomes associated with intravitreal anti-vascular endothelial growth factor (VEGF) versus laser photocoagulation treatment for retinopathy of prematurity (ROP). METHODS: A total of 52 eyes from 27 ROP patients treated at two tertiary referral-based hospitals from August 2006 to December 2013 were reviewed. The primary outcome was refractive error measured at the age of 4 years, accounting for within-patient inter-eye correlation. Secondary outcomes included the recurrence rate and treatment complications. RESULTS: The mean age at refraction was 4.7 ± 0.3 years in the laser group (n = 30) and 4.4 ± 0.3 years in the anti-VEGF group (n = 22). No significant differences were noted in gestational age, birthweight, post-menstrual age at treatment, or ROP stage/zone distribution between groups. Mean spherical equivalent was also not significantly different (−1.0 diopters in the laser group and −0.3 diopters in the injection group, p = 0.603). Clustered regression analysis revealed that only gestational age was significantly correlated with mean spherical equivalent (p < 0.001; 95% confidence interval, −0.007 to −0.002). Recurrence was noted in four eyes (13.3%) in the laser group, but this difference was not significant (p = 0.128). There were no major systemic complications reported in either group. CONCLUSIONS: Treatment type, whether laser or anti-VEGF injection, does not appear to influence long-term refractive outcomes in ROP. Concern regarding refractive outcomes should not be the most important factor when selecting ROP treatment modality.

Surgical Management of Concurrent Strabismus and Face Turn in Patients with Infantile Nystagmus

PURPOSE: To investigate the effect of adjusted Kestenbaum surgery in patients with idiopathic infantile nystagmus who were affected by both strabismus and face turn. METHODS: This retrospective consecutive case series included 12 patients with infantile nystagmus who had face turn and strabismus. All patients underwent adjusted Kestenbaum surgery between 1996 and 2014, and primary outcome measures were the postoperative degree of face turn and strabismus. RESULTS: All patients had jerky nystagmus with compensatory face turn and strabismus. Of the 12 patients, eight patients were exotropes and four patients were esotropes. The mean age at surgery was 12.5 ± 10.7 years (range, 2–36 years). The mean postoperative follow-up was 17.8 ± 12.0 months (range, 7–43 months). Surgery was successful in eight (66.7%) out of 12 patients. Improvement of anomalous head posture was satisfactory in all patients, but an angle of deviation within 10 prism diopters was not achieved in four patients. CONCLUSIONS: Adjusted Kestenbaum surgery simultaneously improved both ocular misalignment and face turn with one-stage surgery. Two or three rectus muscles surgery can be considered in these patients because it is not only simpler than four muscles surgery but also can preserve one or two rectus muscles.

Strabismus Surgical Outcomes in Patients with Tonic and Accommodative Convergence Excess Esotropia

PURPOSE: To investigate the surgical outcomes of augmented bilateral medial rectus (BMR) recession in patients with low accommodative convergence/accommodation (AC/A) ratio tonic convergence excess esotropia (ET) compared to high AC/A ratio convergence excess ET. METHODS: This study included patients with esodeviation ≥10 prism diopter at near than at distance fixation who underwent BMR recession. The medical records of all esotropic patients with convergence excess who underwent strabismus surgery were reviewed. Six patients with tonic convergence excess and 10 patients with a high AC/A ratio met the study inclusion criteria. A successful outcome was defined as a near or distance angle of deviation ≤8 prism diopter and a ≤10 prism diopter difference between the two at the final recorded visit. RESULTS: The mean age at surgery was 5.9 ± 1.6 years in the tonic convergence excess ET group and 7.3 ± 2.9 years in the high AC/A ET group (p = 0.301). The average length of the postoperative follow-up was 2.7 years (range, 0.6–8.4 years) in the tonic convergence excess ET group and 4.0 years (range, 0.6–8.4 years) in the high AC/A ET group (p = 0.426). Near-distance disparities were reduced in all patients with tonic convergence excess ET within 10 prism diopter postoperatively, but in only 6 of 10 patients in the high AC/A ET group. Five of 6 patients (83.3%) had successful outcomes in tonic convergence excess ET group; 5 of 10 patients (50%) had successful outcomes in the high AC/A ET group. CONCLUSIONS: In our series, five patients (83%) obtained successful results in the tonic convergence excess ET group compared with 50% in the high AC/A ET group. Augmented BMR recession can be safely performed in esotropic patients with tonic convergence excess.

Surgical Management of Superior Oblique Muscle Palsy in Hypertropia 16 Prism Diopters or More

PURPOSE: Isolated inferior oblique weakening procedure is an effective treatment for patients with superior oblique muscle palsy who had up to 15 prism diopters (PD) of vertical deviation in the primary position, but 2-muscle surgery is needed for patients with larger deviations. Herein, we report the surgical results of simultaneous 2-extraocular muscle surgery for large primary position hypertropia 16 PD or more caused by superior oblique palsy. METHODS: This study was a retrospective review of the records of patients who presented with central gaze hypertropia 16 PD or more and underwent simultaneous 2-extraocular muscle surgery between January 2003 and June 2014 in Severance Hospital. The patients were divided into 3 groups: 43 patients who underwent inferior oblique (IO) myectomy and contralateral inferior rectus (IR) recession (Group 1), 10 patients who underwent IO myectomy and superior rectus (SR) recession (Group 2), and 8 patients who underwent SR recession and contralateral IR recession (Group 3). Criteria for success included correction of head posture and a primary position alignment within 5 PD of vertical deviation. RESULTS: Mean preoperative alignment at primary gaze was 25.5 ± 7.1 PD (range, 16-60 PD) compared to the postoperative value of -1.3 ± 6.8 PD (range, -20~25 PD) (p < 0.001). Surgery was successful in 49 (80%) patients. Nine (15%) patients were overcorrected and the other 3 (5%) patients were undercorrected. Success rate was the highest in subjects who underwent IO myectomy and contralateral IR recession. Among the 24 patients who did not receive combined horizontal muscle surgery, horizontal deviations decreased from 10.4 ± 2.7 PD to 1.5 ± 5.5 PD (p < 0.001) CONCLUSIONS: Two-muscle surgery can be effective in patients with large hypertropia 16 PD or more. Additionally, horizontal deviations are more likely to be resolved with vertical muscle surgery alone. However, IO myectomy combined with ipsilateral SR recession can cause overcorrection postoperatively, so surgical dose should be reduced when performing weakening procedure of two elevators in one eye.

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 (Spearman's 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.

Changes in the Accommodation-convergence Relationship after the Artisan Phakic Intraocular Lens Implantation for Myopic Patients

PURPOSE: To evaluate the change of accommodation-convergence parameters after implantation of Artisan phakic intraocular lens (PIOL). METHODS: Prospective study for the patients with the Artisan PIOL implantation was performed. A total of 37 patients (3 males and 34 females) enrolled the study. Preoperatively, convergence amplitude, the stimulus accommodative convergence per unit of accommodation (AC/A) ratio and the near point of convergence (NPC) were evaluated. After the Artisan PIOL implantation, the identical evaluations were repeated at 1 week, 1, 3, and 6 months after the surgery. RESULTS: Mean age was 24.3 +/- 4.8 years old, and preoperative refractive error was -8.92 +/- 4.13 diopters (D). After the implantation, mean refractive errors significantly decreased to within +/-1.00 D, and noticeable complications were not found. The convergence amplitude and the stimulus AC/A ratio increased 1 month after the surgery, but progressively stabilized afterward to near preoperative values. NPC didn't show any significant change over follow-up period up to 6 months. CONCLUSIONS: These results regarding implantation of the Artisan PIOL revealed the increase of accommodation-convergence relationship within first 1 month after the surgery, but progressive stabilization was noted during follow-up periods.

Perception of 3-Dimensional (3D) Image after Successful Exotropia Surgery

PURPOSE: To investigate the perception of 3-dimensional (3D) image after successful exotropia surgery and compare with Titmus stereo test. METHODS: A total of 23 children who underwent surgery for intermittent exotropia and 28 normal children were evaluated with a 3D laptop computer and Titmus stereo test. RESULTS: The mean minimal 3D scene depth level was 38.26 +/- 19.69 in the exotropia group and 33.21 +/- 16.11 in the normal group with no significant difference (p = 0.319). The mean stereoacuity was 60.97 +/- 34.23 arc sec in the exotropia group and 76.69 +/- 93.81 arc sec in the normal group with no significant difference (p = 0.444). The mean minimal 3D scene depth and mean stereoacuity showed statistically significant positive correlation in both the exotropia group (p = 0.024) and normal group (p = 0.026). CONCLUSIONS: After a successful exotropia surgery, patients can normally perceive 3D images. Better 3D image perception can be predicted if a previously established stereo test shows good results.

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

PURPOSE: To investigate the role of focal adhesion kinase (FAK) in transforming growth factor (TGF)-beta-induced myofibroblast transdifferentiation of human Tenon's fibroblasts. METHODS: Primary cultured human Tenon's fibroblasts were exposed to TGF-beta1 for up to 48 hours. The mRNA levels of FAK, alpha smooth muscle actin (alphaSMA), and beta-actin were determined by quantitative real time reverse transcription polymerase chain reaction. The protein levels of collagen type I, FAK, phospho-FAK, alphaSMA, and beta-actin were determined by Western immunoblots. After the small interfering RNA targeting FAK (siRNA(FAK)) molecules were delivered into the cells, the expressions of alphaSMA proteins were determined by Western immunoblots. RESULTS: In human Tenon's fibroblasts, TGF-beta1 significantly increased the mRNA and protein expressions of alphaSMA. However, when the action of FAK was inhibited using siRNAFAK, the TGF-beta1-induced expression of alphaSMA was attenuated. CONCLUSIONS: Our data suggest that FAK may be associated with the TGF-beta1-induced transdifferentiation of human Tenon's fibroblasts to myofibroblasts, which is the essential step of subconjunctival fibrosis.

Recession-Resection Surgery Augmented with Botulinum Toxin A Chemodenervation for Paralytic Horizontal Strabismus

In this case series study, we assessed the effects of recession-resection surgery augmented with botulinum toxin A chemodenervation for patients with chronic paralytic horizontal strabismus. In addition, we compared these effects with those of full tendon transposition (FTT) augmented with posterior intermuscular suture (PIMS). Ten patients who underwent strabismus surgery due to paralytic horizontal strabismus were retrospectively reviewed. They received a recession-resection surgery augmented with botulinum toxin A chemodenervation (type I surgery) or a FTT augmented with PIMS (type II surgery). The preoperative angle of deviation (AOD) and postoperative improvement in AOD were compared according to the type of procedure. The preoperative AOD was 60.00 +/- 28.50 prism diopters (PD) for type I surgery and 68.00 +/- 27.06 PD for type II (p = 0.421). Improvement in AOD was 53.20 +/- 25.01 PD for type I surgery and 44.20 +/- 18.74 PD for type II (p = 0.548). Recession-resection surgery augmented with botulinum toxin A chemodenervation is a concise and effective procedure for treating paralytic horizontal strabismus.

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.

Unilateral Recession-Resection Surgery with Inferior Displacement Combined with Augmented Anterior Transposition of Inferior Oblique Muscle

We report the effects of unilateral recession-resection surgery of the horizontal recti muscles with inferior displacement and augmented anterior transposition of the inferior oblique muscle with a posterior intermuscular suture in a patient with large exotropia and considerable hypertropia.

Pattern Visual Evoked Potential as a Predictor of Occlusion Therapy for Amblyopia

PURPOSE: This study was conducted to investigate the role of the pattern visual evoked potential (pVEP) as a predictor of occlusion therapy for patients with strabismic, anisometropic, and isometropic amblyopia. The secondary aim was to compare the characteristics of pVEP between strabismic and anisometropic amblyopia. METHODS: This retrospective comparative case series included 120 patients who had received occlusion therapy or a glasses prescription for correction of strabismic, anisometropic, and isometropic amblyopia (20 patients had strabismic amblyopia, 41 patients had anisometropic amblyopia, and 59 patients had isometropic amblyopia). For each patient, the value of the P100 latency on pVEP at the time of the initial diagnosis of amblyopia was collected. Subsequently, the P100 latency was compared according to types of amblyopia. Fifty of 120 patients (7 patients with strabismic amblyopia, 21 patients with anisometropic amblyopia, and 22 patients with isometropic amblyopia) who were followed-up for longer than 6 months were divided into two groups based on the value of their P100 latency (Group 1, P100 latency 120 msec or less; Group 2, P100 latency longer than 120 msec.) The amount of visual improvement after occlusion therapy or glasses was compared between two study groups. RESULTS: The mean P100 latency was 119.7+/-25.2 msec in eyes with strabismic amblyopia and 111.9+/-17.8 msec in eyes with non-strabismic (anisometropic or isometropic) amblyopia (p=0.213). In Group 1, the mean visual improvement after occlusion therapy or glasses was 3.69+/-2.14 lines on Dr. Hahn's standard test chart; in Group 2, the mean improvement was 2.27+/-2.21 lines (p=0.023). CONCLUSIONS: The P100 latency on pVEP at the time of initial diagnosis was significantly related to the visual improvement after occlusion therapy or glasses in patients with strabismic, anisometropic, and isometropic amblyopia. Therefore, it was presumed that patients with a delayed P100 latency might have less visual improvement after occlusion therapy or glasses. In addition, there was no apparent difference in P100 latency between patients with strabismic and non-strabismic (anisometropic or isometropic) amblyopia.

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.

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.

Eye Movements Recording with Video-oculography (VOG)

The measurement of eye movements in three dimensions is an important tool to investigate the human oculomotor system. When compared with the conventional electro-nystagmography (ENG) and scleral search coil system (SSCS), the video-oculography (VOG) has a higher accuracy and is a more comfortable and reliable method for the 3D-measurement of human eye movements.

Morphological Changes in Extraocular Muscle of Rabbit Eye Produced by Subtenon's Botulinum A Toxin Chemodenervation

PURPOSE: Currently, when injecting botulinum a toxin into the extraocular muscle, EMG (Electromyography) is used for accurate location. In this study, we examined the effects of subtenon botulinum toxin injection without EMG guidance by quantifying the morphological changes of the extraocular muscle fibers in rabbits. METHODS: Using 10 New Zealand white rabbits, 10 units of botulinum a toxin in 0.1 ml of normal saline was injected into the subtenon space of the superior rectus muscles, 5 mm from the muscle insertion in right eyes. As a control, 0.1 ml of normal saline was injected into the subtenon space of the superior rectus muscles in left eyes. At 3 weeks after injections, the bilateral superior rectus muscles of each rabbit were carefully dissected from the globe. Cross-sections of 5 micrometer thickness were obtained at the site, 5 mm from the insertion of each superior rectus muscle. Sections were stained with Masson's trichrome and observed by light microscopy. Using Image-Pro Plus software, the diameter of the orbital layer myofibers was measured and statistical analysis was done using the Kruskal-Wallis test. RESULTS: The average diameter of the orbital layer fiber cells after botulinum toxin injection was 11.5+/-2.26 micrometer at 3 weeks, whereas that of the control was 14.4+/-3.77 micrometer. The difference was statistically significant (p<0.01). CONCLUSIONS: The diameter of myofibers in the orbital layer was reduced after subtenon botulinum a toxin injection. Further studies on the duration of botulium toxin in subtenon space and the change in the size of myofibers depending on the dosage of botulinum toxin will be necessary.

Calcium Uptake and Release through Sarcoplasmic Reticulum in the Inferior Oblique Muscles of Patients with Inferior Oblique Overaction

We characterized and compared the characteristics of Ca2+ movements through the sarcoplasmic reticulum of inferior oblique muscles in the various conditions including primary inferior oblique overaction (IOOA), secondary IOOA, and controls, so as to further understand the pathogenesis of primary IOOA. Of 15 specimens obtained through inferior oblique myectomy, six were from primary IOOA, 6 from secondary IOOA, and the remaining 3 were controls from enucleated eyes. Ryanodine binding assays were performed, and Ca2+ uptake rates, calsequestrins and SERCA levels were determined. Ryanodine bindings and sarcoplasmic reticulum Ca2+ uptake rates were significantly decreased in primary IOOA (p < 0.05). Western blot analysis conducted to quantify calsequestrins and SERCA, found no significant difference between primary IOOA, secondary IOOA, and the controls. Increased intracellular Ca2+ concentration due to reduced sarcoplasmic reticulum Ca2+ uptake may play a role in primary IOOA.

Full Tendon Transposition Augmented with Posterior Intermuscular Suture and Recession-Resection Surgery

PURPOSE: To report an effect of the full tendon transposition augmented with posterior intermuscular suture and recession-resection surgery, for the patient with monocular elevation deficiency (MED) and large exotropia. METHODS: Interventional case report. Full tendon transposition augmented with posterior intermuscular suture and recession-resection surgery was performed for a 26-year-old male patient had monocular elevation deficiency (MED) and large exotropia. RESULTS: Preoperative angle of deviation was 56 prism diopters (PD) hypotropia and 45 PD right exotropia, compared with 18 PD left hypertropia and 10 PD right esotropia postoperatively. Essotropia persisted after 2.5 years, however, and so the right medial rectus was recessed after removal of the previous posterior intermuscular suture. At a three-year follow-up after the second surgery, alignment was straight in the primary position at near and far distances. CONCLUSIONS: Full tendon transposition augmented with posterior intermuscular suture and recession-resection surgery was effective for a patient with MED associated with significant horizontal deviation, and a second operation was easily performed when overcorrection occurred.