Biomedical subjects

Ling Yeung

Publications and source records attributed to Ling Yeung.

9 recordsLinked to original sources

PubMed2006

Central corneal iron deposition after myopic laser-assisted in situ keratomileusis.

PURPOSE: To describe central corneal iron deposition after myopic laser-assisted in situ keratomileusis (LASIK). METHODS: Patients visiting our outpatient clinics between February 2003 and January 2004 and displaying post-LASIK corneal iron deposits were retrospectively enrolled in the study. RESULTS: Forty-two eyes of 24 patients developed corneal iron deposition after myopic LASIK surgery. All eyes displayed a small, spotty iron deposit located in the center of the corneal flap. The median interval between LASIK and diagnosis of corneal iron deposition was 22.5 months. The spherical equivalents of achieved correction ranged from 4.00 D to 17.50 D. CONCLUSION: Spotty corneal iron deposition can develop in the center of the corneal flap after myopic LASIK surgery. Because it is asymptomatic, the condition may have been hitherto underestimated in patient populations.

Adult↗

PubMed2005

Severe vitreous hemorrhage associated with closed-globe injury.

BACKGROUND: The presence of marked vitreous hemorrhage is associated with poor visual prognosis in ocular trauma involving the posterior segment. The purpose of this study was to investigate the clinical features, prognostic factors, and visual outcomes in such eyes after closed-globe injury. METHODS: Retrospective chart review of patients with severe vitreous hemorrhage after closed-globe injury between January 2000 and December 2002. RESULTS: The study included 33 eyes in 32 patients with a mean age of 41.5 (range, 3-78 years) and a median follow-up period of 12 (range, 3-50 months). Presenting visual acuity was between 4/200, and there was light perception in 32 eyes (97%) and no light perception in one eye (3%). Fifteen eyes (45%) had one or more posterior segment pathologies beneath the vitreous hemorrhage. There were retinal tears in six eyes (18%), retinal detachment in six (18%), submacular hemorrhage in six (15%), choroidal rupture in three (9%), macular pucker in three (9%), retinal dialysis in one (3%), macular hole in one (3%), and retinal vessels occlusion in one (3%). Seven eyes (21%) had final visual acuity 20/40 or better, and 18 eyes (54%) had less than 20/200. Poor prognostic factors included presenting visual acuity of light perception or lower (p=0.032), hyphema (p=0.007), traumatic cataract (p=0.027), and age 55 years or younger (p=0.039). The most common cause of poor visual outcome was macular scar. CONCLUSION: The visual prognosis of severe vitreous hemorrhage after closed-globe injury was guarded. This was frequently associated with various anterior and posterior segment pathologies. In order to provide early visual rehabilitation and management of any potentially treatable posterior pathology, early vitrectomy may be considered.

Adolescent↗

PubMed2005

Selective staining of the internal limiting membrane using the sequential intraoperative instillation of whole blood followed by indocyanine green dye.

PURPOSE: To reduce the retention of indocyanine green (ICG) on the retina by selectively staining the internal limiting membrane (ILM) with whole blood during ICG-assisted ILM peeling. DESIGN: Interventional, non-comparative, prospective case series. METHODS: Autologous whole blood was applied to cover the macular area and selectively removed to expose the area needed to be stained. ICG solution (1 mg/ml) diluted in glucose 5% was used to selectively stain the macular area. The stained ILM was removed completely. RESULTS: We studied 22 patients with macular holes, eight with macular pucker and four with diabetic macular edemas. The ILM was selectively stained successfully by ICG with whole blood. One month after surgery, we found no autofluorescence in the posterior pole by infrared-sensitive camera. CONCLUSIONS: Autologous whole blood can help to achieve the goal of selectively staining ILM, further reducing the retention of ICG. It may further reduce ICG toxic effects.

Adult↗

PubMed2005

Prevention of indocyanine green toxicity on retinal pigment epithelium with whole blood in stain-assisted macular hole surgery.

PURPOSE: To examine whether whole blood prevents indocyanine green (ICG) toxicity on in vitro retinal pigment epithelium (RPE) and prevents RPE staining in ICG-assisted macular hole (MH) surgery. DESIGN: In vitro study and prospective case series. PARTICIPANTS: In vitro study and 20 patients who underwent ICG-assisted MH surgery (20 eyes). METHODS: In the in vitro study, cultured human RPE cells were covered with balanced saline solution (BSS), heparinized whole blood, plasma, or packed red blood cells, then exposed to various concentrations of ICG. One cohort was incubated in the dark; the other cohort was exposed to light. Indocyanine green toxicity was evaluated by mitochondrial dehydrogenase assay. In the clinical study, a prospective noncomparative review of 20 consecutive patients (20 eyes) with stage 3 to stage 4 MH who underwent surgery with ICG to stain the internal limiting membrane (ILM) was performed. Indocyanine green solution (0.5 mg/ml) was used to stain the ILM after autologous whole blood covered the macular hole area. Postoperative staining of ICG on RPE was detected by an infrared-sensitive camera. MAIN OUTCOME MEASURES: Cultured human RPE cell viability, macular hole closure rate, median visual acuity preoperatively and postoperatively, postoperative ICG staining, and retinal changes. RESULTS: Cultured human RPE cells covered by whole blood or plasma showed no decrease of mitochondrial dehydrogenase even in 5.0 mg/ml concentration of ICG for 20 minutes with or without light exposure. Conversely, those exposed to ICG and covered with BSS demonstrated a significant decrease of mitochondrial dehydrogenase after incubation in 5, 2.5, and 1.0 mg/ml for 20 minutes in the dark and in 5 to 0.05 mg/ml with light. Clinically, no postoperative staining on RPE was detected. No atrophic RPE changes or other retinal changes were observed in the previous MH area that was covered by autologous whole blood in all 20 eyes on average follow-up of 10.6 months. The hole closed in 19 eyes (95%) on first surgery. Visual acuity improved in 17 eyes (85%) on most recent follow-up. CONCLUSIONS: Whole blood prevents ICG toxicity in RPE cell culture and prevents staining of RPE in surgery of MH when the ILM is stained with ICG.

Adult↗

PubMed2005

Pediatric rhegmatogenous retinal detachment in East Asians.

PURPOSE: To describe clinical features, predisposing factors, and surgical outcomes of retinal detachment in different age groups in a pediatric population. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: A total of 296 eyes from 278 children younger than 18 years of age underwent the first surgical procedure for rhegmatogenous retinal detachment between 1983 and 2003. They were divided into 3 age groups: 38 eyes in group 1 (0-10 years), 107 eyes in group 2 (11-15 years), and 151 eyes in group 3 (16-18 years). METHODS: Predisposing factors for retinal detachment were classified into 4 categories: (1) high myopia, (2) trauma, (3) congenital or developmental structural ocular abnormalities, and (4) previous intraocular surgery. MAIN OUTCOME MEASUREMENTS: Visual acuity and retinal reattachment. RESULTS: The mean age of the patients was 14.6 years; 73.7% were boys. The mean follow-up period was 51 months. At least 1 predisposing factor could be identified in 282 (95%) of study eyes. High myopia was most common in 111 eyes (38%). Thirty-one percent of eyes experienced trauma, 17% had structural abnormalities, and 5% underwent previous intraocular surgery. Macular involvement was found in 237 eyes (80%). The initial surgery was scleral buckling alone in 224 eyes (76%). Retinal reattachment was achieved in 214 eyes (72%) after the first operation and in 250 eyes (85%) at the end of intervention. Features seen in patients with a poor surgical outcome included congenital anomaly (P<0.001), previous intraocular surgery (P = 0.007), proliferative vitreoretinopathy grade C or worse (P<0.001), macula off (P = 0.001), total retinal detachment (P<0.001), and use of silicone oil (P<0.001). CONCLUSIONS: Myopia is one of the important predisposing factors of pediatric retinal detachment in East Asians. The predisposing factors, clinical features, timing of diagnosis, and frequency of proliferative vitreoretinopathy of retinal detachment are somewhat different in the 3 age groups considered. Because of higher proportions of congenital anomaly, total retinal detachment, proliferative vitreoretinopathy, and a low success rate with poor postoperative compliance, patients in group 1 experienced the lowest final reattachment rate and the worst visual recovery.

Adolescent↗

PubMed2005

Quantitative grading of preretinal neovascularization in adult rats.

PURPOSE: To quantify photodynamic venous occlusion-induced preretinal neovascularization with fluorescein isothiocyanate-dextran (FITC-dextran) angiography in adult Sprague-Dawley rats. METHODS: Argon green laser was used to ablate retinal veins in the experimental group (24 rats), and applied between the vessels in the control group (10 rats) after systemic injection of rose bengal. Animals were systemically infused with FITC-dextran and killed 14 days after laser treatment. Retinal flat-mounts were observed under a fluorescence microscope. The number and area of neovascular tufts were measured. Confocal microscopy and histological study were performed to rule out possible artifacts, and to confirm FITC-dextran angiography findings. RESULTS: Out of the entire group of 34 albino rats, no preretinal neovascularization was found in the control group (total 20 eyes, 10 rats). In the experimental group (total 48 eyes, 24 rats) 43 eyes (90%) developed well demarcated neovascular tufts revealed by FITC-dextran angiography. This well demarcated boundary of neovascular tufts was reconfirmed by confocal microscopy and histological study. There were no significant differences in the number or area of neovascular tufts between the right and left eyes. CONCLUSION: FITC-dextran angiography provides a time- and labour-efficient basis for quantifying both the number and area of preretinal neovascularization induced by photodynamic venous occlusion in adult rats. This model is suitable for angiostatic study in the adult animals.

Animals↗

PubMed2005

Chorioretinal folds associated with a meningioma.

Chorioretinal folds are a rare presentation of a meningioma. We report a case of a meningioma with chorioretinal folds as its initial presentation. A 39-year-old female patient complained of progressive blurring of the right eye. A fundus examination of the right eye revealed chorioretinal folds. Magnetic resonance imaging found a tumor mass involving the right orbit and right anterior middle cranial fossa. An echo-guided biopsy confirmed the meningioma. She received surgical excision of the meningioma, and her visual acuity was stationary at 12/20 after 15 months of follow-up. We review the etiologies of chorioretinal folds and elucidate the strategies for dealing with them. Certain underling diseases associated with chorioretinal folds are lethal and require prompt management. Ophthalmologists should evaluate these patients carefully in a stepwise manner.

Adult↗

PubMed2004

Combination of adult inclusion conjunctivitis and mucosa-associated lymphoid tissue (MALT) lymphoma in a young adult.

PURPOSE: To report a patient who was diagnosed with combined adult inclusion conjunctivitis (AIC) and mucosa-associated lymphoid tissue (MALT) lymphoma. METHODS: This is a case report. RESULTS: An 18-year-old male patient presented with chronic conjunctivitis and giant follicles. Evaluation by chlamydial antigen assay was positive. Conjunctival biopsy for the immunohistochemical stain and polymerase chain reaction of the left eye showed MALT lymphoma. CONCLUSIONS: MALT lymphoma can masquerade as other ocular surface diseases. Chlamydial infection causes chronic inflammation of the conjunctiva. Both of these diseases should be considered as a differential diagnosis of refractory follicular conjunctivitis. It is worthy of further study to determine whether chronic inflammation resulting from chlamydial infection increases the risk of MALT lymphoma or it is coincidental.

Adolescent↗

PubMed2004

Polypoidal choroidal vasculopathy in Taiwan.

BACKGROUND: Polypoidal choroidal vasculopathy (PCV) has been described since the 1980s with great variations in patient data in different countries. We report the first case series in the Taiwanese population. METHODS: We reviewed the medical records of all patients diagnosed with PCV between January 2000 and October 2001 at the retina clinics of Chang Gung Memorial Hospital. RESULTS: Eight patients (9 eyes) were enrolled. Six were men. The average age was 60.9 (range, 48-72). One patient had bilateral disease. All of the 9 eyes had polypoidal lesions in the macular area; 2 eyes had peripapillary lesions. The average follow-up time was 16.5 months. One eye (1/9) improved more than 2 lines in the Snellen chart, 4 eyes (4/9) changed within 1 line, and 4 eyes (4/9) deteriorated more than 2 lines. Seven eyes (7/9) had final visual acuities worse than 20/200 and 5 eyes (5/9) developed disciform scarring. CONCLUSIONS: The prognosis of PCV among Taiwanese patients seems worse than in other ethnic groups. A high incidence of disciform scar formation and predominantly centrally located polypoid lesions seem to play an important role in the poor prognosis.

Aged↗