Ta-Ching Chen

Long-term outcome of foveolar internal limiting membrane nonpeeling for myopic traction maculopathy.

Purpose: To investigate the long-term results of a novel technique to preserve the foveolar cone without peeling off the foveolar internal limiting membrane (ILM) during myopic traction maculopathy surgery. Methods: Nineteen patients (19 eyes) were retrospectively studied and divided into 2 groups by the extent of ILM peeled and followed for more than 3 years. Group 1: foveolar ILM nonpeeling group (FN) (12 eyes) and Group 2: total peeling of foveal ILM group (TP) (7 eyes). A donut-shaped ILM was peeled off, leaving a 400-&mgr;m diameter ILM over foveola with a sharp margin in FN group. Results: Macular hole was developed in 2 of the 7 eyes (28.6%) in the TP group and none in the FN group. Long-term central fovea thickness thinning and decrease of vision were found in the TP group, but not in the FN group (P < 0.05). Inner segment/outer segment line recovered in 75% of the 12 eyes in the FN group, but in only 14.3% of the 7 eyes in the TP group. Conclusion: Preservation of the foveolar cone by foveola nonpeeling surgery correlates with better anatomical and visual results than total peel, prevents long-term foveolar retinal thinning, and successfully saves the fovea from macular hole formation.

Intravitreal expansile gas in the treatment of early macular hole: reappraisal.

Purpose: To study the effects of intravitreal injection (IVI) of expansile gas for early macular holes (EMH). Methods: Prospective interventional case series. Twelve eyes of 12 patients with EMH (stage 2) underwent IVI of perfluoropropane 0.2 ml followed by 5 days’ facedown positioning. Results: Six cases (50%) achieved vitreous-macula separation. Three cases (25%) had hole closure with vision improvement; one of them developed rhegmatogenous retinal detachment (RRD) and hole re-opening. Another case with persistent hole also developed RRD. Seven of the 9 cases without hole closure and the one where the hole re-opened had vitrectomy, all resulting in hole closure and vision improvement. Duration of symptoms had borderline significance for hole closure (p = 0.11) and subsequent visual improvement (p = 0.03). Conclusion: With its low success rate, IVI of gas may not be a good option for EMH. Complications include retinal detachment. The procedure seems to not affect hole closure with subsequent vitrectomy.

Recurrence of corneal neovascularization associated with lipid deposition after subconjunctival injection of bevacizumab.

Purpose: To report 7 cases of recurrent corneal neovascularization (NV) and lipid deposition after subconjunctival injection of bevacizumab for the treatment of corneal NV–induced lipid keratopathy. Methods: We conducted a prospective interventional case series that included 20 eyes of chronic lipid keratopathy that received bevacizumab injection for the treatment of corneal NV and lipid deposition, including 7 eyes with recurrent corneal NV and lipid deposition after ceasing treatment. Repeated subconjunctival injections of bevacizumab were performed in 5 patients with recurrence. Penetrating keratoplasty was performed in 1 patient who had severely recurrent lipid deposition. Clinical presentation of corneal NV and lipid deposition, best-corrected visual acuity, and complications after treatments were recorded. Results: Bevacizumab inhibited corneal NV and lipid depositions in 19 patients. Seven of the 20 patients (35%) had different patterns of recurrence of corneal NV/lipid deposition 6 to 15 months after discontinuing treatment. Five of the 7 patients in whom corneal NV/lipid deposition was recurrent received another course of repeated bevacizumab treatments. Three eyes had partial response to the second course of treatment. Two eyes had too short re-treatment course to have conclusions. One patient who received penetrating keratoplasty had successful result after surgery. Conclusions: Corneal NV and lipid deposition may recur after ceasing the subconjunctival bevacizumab injections for lipid keratopathy. Some patients respond at least partially to repeated injections.

In vivo thermal evaluation of a subretinal prosthesis using an integrated resistance temperature detector

Abstract. The temperature rise from the operation of implanted biomedical devices should be kept within a safe limit to prevent thermal damage or any undesirable thermal effects. To evaluate the temperature rise from the operation of an implanted high-density microelectrodes array (MEA) on a flex in the subretinal space, we directly integrated resistance temperature detectors into this retinal MEA device in the same micro fabrication. We surgically implanted this MEA device in the subretinal space of a rabbit model and measured the temperature rise in vivo. The measured temperature rise is consistent with the calculated values from the finite element method. Experiment showed the temperature versus power dissipation of the MEA device had a slope of 0.84°C/(mW·mm−2). To ensure the temperature rise is within 1.0°C, the maximum power dissipation on the retinal implant should be kept within 1.2  mW·mm−2.

Vitreomacular Changes after Intravitreal Gas Injection for Idiopathic Impending or Early Macular Hole: An Optical Coherence Tomography Study

Purpose: To study the early changes of vitreomacular microstructure by optical coherence tomography (OCT) after intravitreal gas injection for the treatment of idiopathic impending or early full-thickness macular hole (FTMH). Methods: A retrospective, interventional case series. Results: A total of 21 eyes were included. In the impending macular hole, 8/8 achieved vitreomacular traction (VMT) release, while a macular hole developed in 1 case. On postoperative day 1, the vitreomacular configuration by OCT showed either a flattening (n = 3) or elevation (n = 1) pattern. In early FTMH, vitreomacular separation was achieved in 10/13 cases, but macular hole closure was only observed in 3 cases. On postoperative day 1, only flattening of the vitreomacular configuration was observed (n = 5). Enlargement of the macular hole was found in 4 cases. Conclusions: VMT separation can be achieved with intravitreal gas injection by mechanically stretching the posterior vitreous cortex, causing either flattening or steepening of the vitreomacular configuration. However, it did not always result in macular hole closure.

Update on ocular myasthenia gravis in Taiwan

Myasthenia gravis (MG) is an autoimmune disease involving the neuromuscular junction. Autoantibodies to the acetylcholine receptor or, less frequently, to muscle-specific kinase, attack against the postsynaptic junctional proteins, resulting in fluctuating and variable weakness of muscles. Extraocular, levator palpebrae superioris, and orbicularis oculi muscles are particularly susceptible. The majority of patients with MG present with purely ocular symptoms including ptosis and diplopia initially. About half of these patients progress to generalized disease within 2 years. The prevalence of MG in Taiwan is 140 per million with male to female ratio of 0.7. The incidence rate is higher in the elderly. Several immune-related diseases such as lymphoid malignancy, diabetes, and thyroid diseases are associated with MG in the national population-based studies in Taiwan. Ice pack test, rest test, Tensilon/neostigmine test, circulating antibody measurement, and electrophysiological studies are useful diagnostic tools with variable sensitivity and specificity. For the patients with ocular MG, acetylcholinesterase inhibitors are usually the first-line treatment. Corticosteroids and immunosuppressant could provide better disease control and may reduce the risk of conversion to generalized form although there is still some controversy. A thymectomy is also beneficial for ocular MG, especially in refractory cases. The correction of ptosis and strabismus surgery could improve the visual outcome but should be performed only in stable disease.

Vascular hypoperfusion in acute optic neuritis is a potentially new neurovascular model for demyelinating diseases

Purpose Optic neuritis is highly correlated with multiple sclerosis and is a major cause of acute visual loss and long-term neuronal degeneration. Primary cerebral hypoperfusion has been reported in brain demyelinating diseases. This study investigated whether peripapillary perfusion is changed in patients with acute optic neuritis (AON). Methods This three-year cohort study was conducted from September 1 2012, to August 31, 2015. Two hundred and forty-one patients with non-glaucomatous acute optic neuropathy were screened, and 42 non-highly myopic patients who had suffered their first episode of unilaterally idiopathic AON were studied. All cases received spectral-domain optical coherence tomography (OCT) examination, general survey, and standard corticosteroid therapy. OCT images were analyzed using a customized MATLAB program for measuring peripapillary choroidal thickness (PCT). Multivariate regression models were constructed to identify factors that are significantly related to peripapillary perfusion. Results Decreased PCT was found in eyes experiencing AON combined with disc swelling (the ratio of lesion eye PCT/fellow eye PCT was 0.87 ± 0.08; range, from 0.75 to 1.00). In comparison to the healthy fellow eyes, approximately every 26% increase in the thickness of the retinal nerve fiber layer due to axonal swelling was associated with a 10% decreased thickness of PCT. Thinner PCT is also correlated with poorer trough vision, which may lead to poorer final vision. These findings were obvious in patients with optic papillitis but not in patients with retrobulbar neuritis. Conclusions Peripapillary vascular hypoperfusion was found in patients experiencing AON combined with disc swelling. These findings are unlike those for other ocular inflammatory diseases but are consistent with cerebral hypoperfusion, which is found in brain demyelinating diseases; thus, these findings may represent a new neurovascular model in this field.

Surgical result of pterygium extended removal followed by fibrin glue-assisted amniotic membrane transplantation.

BACKGROUND/PURPOSE To report the recurrence rate and cosmetic results of conjunctival wound edge and caruncle, and complications after pterygium extended removal followed by fibrin glue-assisted amniotic membrane transplantation. METHODS A prospective interventional cohort study enrolled 57 (58 eyes) patients undergoing pterygium extended removal followed by fibrin glue-assisted amniotic membrane transplantation. All patients received postoperative follow-up for at least 12 months. Recurrence rate was graded from 1 to 4, and cosmetic results of conjunctival edge and caruncle were graded from 1 to 5. RESULTS The cohort included 48 eyes with nasal pterygium, 5 eyes with temporal pterygium, and 5 eyes with double pterygium. There were 81.0% (n=47), 0% (n=0), 12% (n=7), and 7% (n=4) of eyes with Grades 1-4 recurrence, respectively. The cosmetic results of conjunctival wound edge and caruncle in cases with nasal pterygium showed 59.3% (n=32), 14.8% (n=8), 9.3% (n=5), 16.6% (n=9), and 0% (n=0) of eyes with Grades 1-5 morphology, respectively. Overall, 5.1% (n=3), 3.4% (n=2), 3.4% (n=2), 3.4% (n=2), 1.7% (n=1), 6.9% (n=4), and 1.7% (n=1) of patients suffered from postoperative pyogenic granuloma, transient diplopia, permanent motility restriction, steroid glaucoma, fat prolapse, subamniotic membrane hemorrhage, and early detachment of amniotic membrane, respectively. CONCLUSION Pterygium extended removal followed by fibrin glue-assisted amniotic membrane transplantation results in low recurrence, satisfactory cosmetic results and a low incidence of additional complications.

Acute Total Keratolysis of Trichophyton Fungal Keratitis-Case Report

Objectives: To report a case of Trichophyton fungal keratitis with acute total keratolysis. Method: Interventional case report. Results: The 25-year-old woman has been suffering from decreased vision, pain, and photophobia in her right eye for 1 month. Slit lamp biomicroscopy revealed dense, feathery-like infiltrate in the central cornea with mild melting. Ring-shaped infiltrate was also noted in peripheral cornea. Grams stain of the corneal scraping revealed filamentary hyphaes. Cultures of the corneal scraping revealed Trichophyton spp. Despite medication of topical Natamycin and oral Itraconazole, total melting of the whole cornea with anterior bulging out of lens/iris was found. Emergent transplantation of conjunctival flap and temporary tarsorrhaphy were performed to prevent loss of intraocular contents. The conjunctival flap remained in place three months after surgery. Fungal ulcer was considered to be cured after the operation. Conclusions: Acute total keratolysis can be found in patient with Trichophyton fungal keratolysis. The aggressive nature of the infection was difficult to treat by medical treatment. Counjunctival flaps offered a useful emergent therapeutic modality when therapeutic keratoplasty can not be performed.