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.ope

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

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.ope

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

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

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

Intraoperative Adjustment in Strabismus Surgery under Topical Anesthesia

We evaluated the one-stage intraoperative adjustment strabismus surgery with adjustable suture under topical anesthesia. Medical records of the patients who had intraoperative adjustment surgery under topical anesthesia for horizontal or vertical strabismus in our hospital from March 1997 to March 2003 with follow-up of 6 months were analyzed retrospectively. Of the 71 patients, 48 patients had exotropia, 16 had esotropia, and 7 had hyper- or hypotropia. The overall success rates were 85.9% at 1 week, 83% at 1 month, 78.9% at 3 months, and 76.1% at 6 months after surgery. The procedure was not stopped in any patients, and no serious intra-operative or postoperative complications were noted. Intraoperative adjustment strabismus surgery under topical anesthesia is a simple, well-tolerated and effective procedure

Correlation between bilateral lateral rectus muscle recession and myopic progression in children with intermittent exotropia

Abstract Although several studies have reported about the relationship between the surgical correction of intermittent exotropia and myopic progression, it remains unclear, unlike the relationship between esotropia and hyperopia. Thus, this retrospective case control study evaluated the impact of bilateral lateral rectus recession in intermittent exotropia on myopic progression. This study included 388 patients with intermittent exotropia. The refractive errors and degree of exodeviation at each follow up period were analyzed. The rate of myopic progression was −0.46 ± 0.62 diopter (D)/year in patients who underwent surgery and −0.58 ± 0.78 D/year in patients who did not, with no significant difference between them (p = 0.254). Patients who had recurrences of more than 10 prism diopters were compared with patients who did not have. The rate of myopic progression was −0.57 ± 0.72 D/year in the recurrent group and −0.44 ± 0.61 D/year in the non-recurrent group, with no significant difference between them (p = 0.237). Patients with fast myopic progression had more recurrence than patients with slow progression (p = 0.042). Moreover, recurrence had a positive correlation with fast myopic progression (OR = 2.537, p = 0.021). Conclusively, the surgical correction of intermittent exotropia did not influence myopic progression