Hee Kyung Yang

Deepening of eyelid superior sulcus during topical travoprost treatment

BackgroundTopical travoprost, a prostaglandin F2α (PGF2α) analog, has several well-known side effects, including a darkening of the eyelid and eyelash hypertrichosis, but there are no reports of a deepening of the eyelid superior sulcus associated with its use.CasesWe examined one patient with unilateral normal-tension glaucoma and another with unilateral primary open-angle glaucoma, both of whom were treated with travoprost monotherapy unilaterally for 2 years.CommentsBoth patients gradually developed a deepening of the eyelid superior sulcus with hyperpigmentation in the eyelid skin of the treated eye. The disparity between the treated eye and the fellow eye was quite visible. However, the disparity returned to normal after discontinuation of travoprost for 15 months. A deepening of the eyelid superior sulcus is more significant in Asians, who seldom have an eyelid crease or deep sulcus. One proposed mechanism is a mechanical insult to the eyelid causing levator dehiscence. A second possible mechanism is fatty degeneration and reduced collagen fibers in the levator complex caused by the PGF2α analog. However, the exact mechanism remains to be determined.ConclusionA deepening of the eyelid superior sulcus should be considered a possible complication of topical travoprost that can be reversed by discontinuation of the medication.

Accommodative Response of Integral Imaging in Near Distance

Objective evaluation results using optometric device to measure accommodative responses in viewing a real object and integral imaging are presented. From the empirical results between the real object and an integrated three-dimensional (3D) image, we find that over 73% of participants keep eyes on the real integrated 3D image instead of a display panel. The results also show the participants do not recognize a mismatch between the accommodative response and the convergence of the eye, which used to be believed as one of the major factors to cause visual fatigue in viewing near-distance integral imaging. Seventy-one normal adult subjects (23 ~ 38 years old) participated in the experiment, and accommodative response measurement results of the real integrated image show a statistically significant concordance with real objects.

Bilateral vs Unilateral Medial Rectus Resection for Recurrent Exotropia after Bilateral Lateral Rectus Recession

PURPOSE To compare outcomes after bilateral and unilateral medial rectus (BMR/UMR) resection for the treatment of recurrent exotropia after bilateral lateral rectus (BLR) muscle recession. DESIGN Retrospective, cohort study. METHODS Forty-four patients underwent BMR resection (BMR group) or UMR resection (UMR group) for recurrent constant exotropia of 25 prism diopters (PD) or less at distance after undergoing BLR muscle recession for intermittent exotropia in an institutional setting. The main outcome measures were final success rates and improvement in stereopsis and were compared between the groups. The risk factors for recurrence after reoperation also were evaluated. Secondary outcome measures were evaluated based on the drift of ocular alignment toward exodeviation after surgery (exodrift) from postoperative day 1. RESULTS Thirteen (54%) of 24 patients in the BMR group had successful outcomes, 10 (42%) had overcorrection, and 1 (4%) had undercorrection at the last follow-up examination. Sixteen (80%) of 20 patients in the UMR group had successful outcomes, 2 (10%) had undercorrection, and 2 (10%) had overcorrection. The incidence of successful outcomes at the last follow-up examination and the incidence of recurrence were not significantly different between the 2 groups, whereas the incidence of overcorrection was significantly higher in the BMR group (P = .017). CONCLUSIONS Large UMR resection is a safe and effective procedure in the treatment of small to moderate angles of recurrent exotropia after BLR muscle recession. The overcorrection rate was significantly lower after UMR resection than it was after BMR resection.

Distance stereotest using a 3-dimensional monitor for adult subjects.

PURPOSE To evaluate the validity and test-retest reliability of a contour-based 3-dimensional (3-D) monitor distance stereotest (distance 3-D stereotest) and to measure the maximum horizontal disparity that can be fused with disparity vergence for determining the largest measurable disparity of true stereopsis. DESIGN Observational case series. METHODS Sixty-four normal adult subjects (age range, 23 to 39 years) were recruited. Contour-based circles (crossed disparity, 5000 to 20 seconds of arc; Microsoft Visual Studio C(++) 6.0; Microsoft, Inc, Seattle, Washington, USA) were generated on a 3-D monitor (46-inch stereoscopic display) using polarization glasses and were presented to subjects with normal binocularity at 3 m. While the position of the stimulus changed among 4 possible locations, the subjects were instructed to press the corresponding position of the stimulus on a keypad. The results with the new distance 3-D stereotest were compared with those from the distance Randot stereotest. RESULTS The results of the distance 3-D stereotest and the distance Randot stereotests were identical in 64% and within 1 disparity level in 97% of normal adults. Scores obtained with the 2 tests showed a statistically significant correlation (r = 0.324, P = .009). The half-width of the 95% limit of agreement was 0.47 log seconds of arc (1.55 octaves) using the distance 3-D stereotest--similar to or better than that obtained with conventional distance stereotests. The maximum binocular disparity that can be fused with vergence was 1828 ± 794 seconds of arc (range, 4000 to 500). CONCLUSIONS The distance 3-D stereotest showed good concordance with the distance Randot stereotest and relatively good test-retest reliability, supporting the validity of the distance 3-D stereotest. The normative data set obtained from the present study can serve as a useful reference for quantitative assessment of a wide range of binocular sensory abnormalities.

Nintendo Wii Remote Controllers for Head Posture Measurement: Accuracy, Validity, and Reliability of the Infrared Optical Head Tracker

PURPOSE To evaluate the accuracy, validity, and reliability of a newly developed infrared optical head tracker (IOHT) using Nintendo Wii remote controllers (WiiMote; Nintendo Co. Ltd., Kyoto, Japan) for measurement of the angle of head posture. METHODS The IOHT consists of two infrared (IR) receivers (WiiMote) that are fixed to a mechanical frame and connected to a monitoring computer via a Bluetooth communication channel and an IR beacon that consists of four IR light-emitting diodes (LEDs). With the use of the Cervical Range of Motion (CROM; Performance Attainment Associates, St. Paul, MN) as a reference, one- and three-dimensional (1- and 3-D) head postures of 20 normal adult subjects (20-37 years of age; 9 women and 11 men) were recorded with the IOHT. RESULTS In comparison with the data from the CROM, the IOHT-derived results showed high consistency. The measurements of 1- and 3-D positions of the human head with the IOHT were very close to those of the CROM. The correlation coefficients of 1- and 3-D positions between the IOHT and the CROM were more than 0.99 and 0.96 (P < 0.05, Pearsons correlation test), respectively. Reliability tests of the IOHT for the normal adult subjects for 1- and 3-D positions of the human head had 95% limits of agreement angles of approximately ±4.5° and ±8.0°, respectively. CONCLUSIONS The IOHT showed strong concordance with the CROM and relatively good test-retest reliability, thus proving its validity and reliability as a head-posture-measuring device. Considering its high performance, ease of use, and low cost, the IOHT has the potential to be widely used as a head-posture-measuring device in clinical practice.

New Clinical Grading Scales and Objective Measurement for Conjunctival Injection

PURPOSE To establish a new clinical grading scale and objective measurement method to evaluate conjunctival injection. METHODS Photographs of conjunctival injection with variable ocular diseases in 429 eyes were reviewed. Seventy-three images with concordance by three ophthalmologists were classified into a 4-step and 10-step subjective grading scale, and used as standard photographs. Each image was quantified in four ways: the relative magnitude of the redness component of each red-green-blue (RGB) pixel; two different algorithms based on the occupied area by blood vessels (K-means clustering with LAB color model and contrast-limited adaptive histogram equalization [CLAHE] algorithm); and the presence of blood vessel edges, based on the Canny edge-detection algorithm. Area under the receiver operating characteristic curves (AUCs) were calculated to summarize diagnostic accuracies of the four algorithms. RESULTS The RGB color model, K-means clustering with LAB color model, and CLAHE algorithm showed good correlation with the clinical 10-step grading scale (R = 0.741, 0.784, 0.919, respectively) and with the clinical 4-step grading scale (R = 0.645, 0.702, 0.838, respectively). The CLAHE method showed the largest AUC, best distinction power (P < 0.001, ANOVA, Bonferroni multiple comparison test), and high reproducibility (R = 0.996). CONCLUSIONS CLAHE algorithm showed the best correlation with the 10-step and 4-step subjective clinical grading scales together with high distinction power and reproducibility. CLAHE algorithm can be a useful for method for assessment of conjunctival injection.

Binocular visual acuity in intermittent exotropia: role of accommodative convergence.

PURPOSE To investigate binocular interaction of visual acuity (VA) in patients with intermittent exotropia and its relationship with accommodative responses during binocular vision. DESIGN Prospective pilot study. METHODS setting: Institutional. patient: Sixty-three patients with intermittent exotropia between 8 and 15 years of age. observation: Binocular VA and monocular VA were measured in sequence. Accommodative responses of both eyes were measured using the WAM-5500 autorefractor/keratometer (GrandSeiko) during binocular and monocular viewing conditions at 6 m. Accommodative responses during binocular vision were calculated using the difference between the refractive errors of binocular and monocular vision. main outcome measures: Binocular interactions of VA were categorized as binocular summation, equivalency, or inhibition. The prevalence of the 3 patterns of binocular interaction was investigated. Accommodative responses were correlated with differences between binocular VA and better monocular VA. RESULTS Most patients (38 patients; 60.3%) showed binocular equivalency. Binocular summation and inhibition were noted in 19 (30.2%) and 6 (9.5%) patients, respectively. Linear regression analysis revealed a significant correlation between binocular interaction and accommodative responses during binocular vision (P < .001). Accommodative responses significantly correlated with the size of exodeviation at distance (P = .010). CONCLUSIONS In patients with intermittent exotropia, binocular interaction is associated with accommodative response during binocular vision and the size of exodeviation, suggesting that accommodative convergence is a mechanism that maintains ocular alignment. Therefore, binocular interaction, especially binocular inhibition, can be a good indicator of diminishing fusional control in intermittent exotropia.

Comparison of Long-term Surgical Outcomes of 2-muscle Surgery in Children With Large-angle Exotropia: Bilateral vs Unilateral

PURPOSE To evaluate the long-term results of 2-muscle surgery in children with primary large-angle exotropia, comparing 10 mm bilateral lateral rectus recession (BLR) with unilateral lateral rectus recession-medial rectus resection (recess/resect). DESIGN Retrospective case series. METHODS Eighty-six children with exotropia of ≥40 prism diopters (PD), who underwent the 10 mm BLR (BLR group) or the unilateral recess/resect procedure (RR group) based on the largest angle measured at distance or near were included. Patients were followed-up for more than 2 years. Final successful alignment rates, stereopsis, and factors related to recurrence and overcorrection were evaluated. RESULTS At the final examination, 29 (60.4%) of 48 patients in the BLR group achieved successful alignment; 16 (33.3%) had recurrence, and 3 (6.3%) had overcorrection. In the RR group, 26 of 38 patients (68.4%) were successfully aligned, 10 (26.3%) had recurrence, and 2 (5.3%) had overcorrection. Successful alignment and recurrence rates were not significantly different in the groups (P = .371 and .640, respectively). The overcorrection rate was significantly higher in the RR group (P = .014) until 2 years after surgery, but this difference was not significant afterward (P = 1.000). In patients with an exodeviation of ≥45 PD, the recess/resect procedure showed higher successful alignment rates at the final examination (P = .006). CONCLUSIONS The long-term successful alignment rate of 2-muscle surgery in children with primary large-angle exotropia was 64%, and the overall surgical outcomes were comparable between the BLR and RR groups. However, in patients with exotropia of ≥45 PD, the unilateral recess/resect procedure resulted in more favorable long-term outcomes.

Toxicity of voriconazole on corneal endothelial cells in an animal model

Aims To determine the effect of intracamerally injected voriconazole on corneal endothelial cells in rabbit eyes. Methods Various concentrations of voriconazole (0%, 0.03%, 0.1%, 0.25%, 0.5% and 1%) were injected intracamerally in 36 eyes of 18 rabbits (six eyes for each concentration). Measurements of endothelial cell counts and central corneal thickness were performed at 30, 60, 90 and 120 min after the injection. In each group, five of six corneas were used for the live/dead cell assay; staining with alizarin red and trypan was done. In one cornea from each group, scanning electron microscopy was performed. Results There was no significant difference in endothelial cell counts and central corneal thickness among the six groups at any time points. The live/dead cell assay revealed no difference in the mean percentage of dead endothelial cells among the six groups (p=0.504). However, scanning electron microscopy revealed blurring of cell border at voriconazole concentrations ≥0.25%, indicating cell wall damage. Conclusion Intracameral injection of voriconazole did not induce a significant gross change in rabbit corneal endothelial cells up to a concentration of 1%. However, risk of microstructural damages might exist with a concentration of ≥0.25%.

Optic neuritis following Varicella zoster vaccination: Report of two cases

Two women presented at our clinic with vision blurring following Varicella zoster virus (VZV) vaccination, 3 weeks and 1 week ago. Ophthalmologic examination and magnetic resonance imaging revealed bilateral and unilateral optic neuritis, respectively. One patient had a history of optic neuritis in the fellow eye 33 years ago without recurrence since then. Both patients completely recovered after treatment with high dose intravenous methylprednisolone followed by a tapered dose of oral prednisolone. This is the first report of optic neuritis occurring in relation to VZV vaccination.