Jee Ho Chang

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.

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.

Computed Tomographic Angiogram of an Anterior Communicating Artery Aneurysm Causing Acute Retrobulbar Optic Neuropathy: A Case Report

Three-dimensional computed tomographic (3D-CT) angiography is a widespread imaging modality for intracranial vascular lesions. However, 3D-CT angiograms of an anterior communicating artery aneurysm associated with acute retrobulbar optic neuropathy have not been previously described. We present 3D-CT angiograms of an aneurysm of the anterior communicating artery that caused subarachnoid hemorrhage and vision loss in a 39-year old man. The 3D-CT angiograms were consistent with findings identified directly during surgery.

Study for Analysis of the Multifocal Visual Evoked Potential

Purpose To introduce the clinical utility of the absolute value of the reconstructed waveform method in the analysis of multifocal visual evoked potential (mfVEP). Methods The mfVEP with 4-channel recording was performed using RETIscan® on 10 eyes of 10 normal subjects. Amplitudes were obtained from ring-shaped 6 areas and 4 sectors. The best visual evoked potential (VEP) response method and the absolute value of the reconstructed waveform method were compared in terms of analysis of the amplitudes. In order to assess the false positive rate of the examination, stimuli were administered with one-half of the cathode ray tube (CRT) monitor completely covered and the results were compared using 2 methods. Results The amplitudes in 6 areas and 4 sectors analyzed with the best VEP response method and the absolute value of the reconstructed waveform method showed no statistical difference (p > 0.05). The amplitude in the stimuli-blocked area of the absolute value of the reconstructed waveform method was smaller than that of the best VEP response method (p < 0.05) and the amplitude of the stimuli area showed no substantial difference between two methods (p > 0.05). Conclusions The absolute value of the reconstructed waveform method has similar reproducibility and lower level of false positives relative to the best VEP response method. Therefore, it can be considered as a useful method in the analysis of the mfVEP.

Changes in Corneal and Conjunctival Sensitivity, Tear Film Stability, and Tear Secretion After Strabismus Surgery

PURPOSE Some patients complain of a foreign body sensation, a burning sensation, or dryness after strabismus surgery. We prospectively investigated the changes in corneal and conjunctival sensitivity, tear film stability, and tear secretion after strabismus surgery. PATIENTS AND METHODS Corneal and conjunctival sensitivity were assessed with an esthesiometer, tear film breakup time was measured, and the Schirmer test was performed prospectively (preoperatively and 1 week, 1 month, and 3 months postoperatively) in 83 patients (124 eyes) who underwent strabismus surgery at our institution. RESULTS There were no significant changes in corneal sensitivity, tear film stability, or tear secretion after strabismus surgery (P > .05). Conjunctival sensitivity decreased significantly after strabismus surgery (P < .05). CONCLUSION Discomfort and dryness after strabismus surgery do not seem to be related to changes in corneal sensitivity, tear film stability, or tear secretion.