Biomedical subjects

Ko-Jen Yang

Publications and source records attributed to Ko-Jen Yang.

8 recordsLinked to original sources

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

Retinopathy of prematurity: an evaluation in the Keelung area of Taiwan over a 10-year period.

BACKGROUND: We report on the experience of retinopathy of prematurity (ROP) at Chang Gang Memorial Hospital (CGMH), Keelung, Taiwan over a 10-year period. METHODS: A retrospective review was made of data of all premature infants with a diagnosis of ROP at Keelung CGMH between 1994 and 2003. Data on certain characteristics including gender, gestational age (GA), birth body weight (BBW), stage of ROP, and treatment modalities were collected and analyzed. RESULTS: Among the 458 infants screened for ROP, 148 eyes of 74 premature infants were diagnosed as having ROP. Threshold ROP occurred in 24 eyes of 12 infants. The average BBW and GA were significantly lower in the threshold than in the non-threshold ROP group (p < 0.05). According to medical records of the 24 eyes of the 12 patients receiving transscleral cryotherapy, anatomical success was attained in 13 (81.3%) of 16 eyes. CONCLUSIONS: This review found low GA and BBW to be major risk factors for ROP. This review shows that transscleral cryotherapy for treating threshold ROP achieved anatomical success in about 80% of eyes. However, myopia, amblyopia, and strabismus remain major sequelae. Laser therapy is now believed to be less damaging to ocular structures and just as effective as cryotherapy in treating ROP.

Birth Weight↗

PubMed2005

Choroidal detachment after filtering surgery.

BACKGROUND: The purpose of this study is to report the treatment and outcome of eight cases of choroidal detachment, which occurred several days to many years after trabeculectomy. METHODS: This is a retrospective study of eight cases of choroidal detachment after trabeculectomy with or without cataract extraction reviewed at CGMH, Keelung, from 2002 to 2004. One eye with idiopathic scleromalacia with chronic uveitis and secondary glaucoma, five eyes with primary open angle glaucoma and two eyes with chronic angle closure glaucoma after trabeculectomy were reported. Six of the eight cases developed acute onset choroidal detachment within two weeks after surgery. The other two cases suffered from choroidal detachment many years after trabeculectomy for different reasons. Regarding the types of operation, combined glaucoma and cataract surgery was performed in five cases and intraoperative application of adjunctive mitomycin C was used in two cases. Decrease in vision acuity and varying degrees of eye pain with a flat or shallow chamber were noted in all cases. Associated hypotony was found in six of the eight cases. The treatment included topical cycloplegic corticosteroid and oral corticosteroid. RESULTS: Choroidal detachments were improved or complete resolution obtained after medical treatment for about three weeks to one month in all cases. But persistent poor control of intraocular pressure was found in two cases. Ultrasonography was used as a reliable tool to confirm the diagnosis and resolution of choroidal etachment in cases of blurred fundus examination and synechiae miotic pupil. CONCLUSIONS: Choroidal detachment is one of the complications after trabeculectomy. The diagnosis of choroidal detachment can be confirmed most reliably by ultrasonography. Medical therapy is effective for resolution.

Adult↗

PubMed2004

Efficacy and safety of phacoemulsification with intraocular lens implantation under topical anesthesia.

BACKGROUND: To eliminate complications of peribulbar and retrobulbar anesthesia and to achieve efficacy and safety for topical anesthesia with cataract surgery. METHODS: We performed clear corneal phacoemulsification with foldable intraocular lens (IOL) implantation under topical anesthesia using preservative-free 2% lidocaine drops, without intracameral anesthetic supplementation. The exclusion criteria were anxiety, small pupil, baseline endothelial count 1500 cells/mm2, uncontrolled glaucoma, other ocular entities affecting corneal endothelium, and allergy to the relevant medications. We used a specular microscope to evaluate the effect on the endothelium and employed a 10-point visual analog pain scale to assess the discomfort experienced during the operation. RESULTS: Totally, 29 eyes of 29 patients were enrolled in this series. The mean age was 71.5 +/- 8.5 years. Twenty-three of 29 (79.3%) cases achieved a best-corrected visual acuity (BCVA) equal to 20/40 or better at an interval of 3 months postoperatively. Most patients (86.5%) felt mild or no pain during surgery. Pre- and postoperative endothelial counts were 2072.6 +/- 104 and 1927.4 +/- 196 cell/mm2, respectively. One in 29 cases developed vitreous loss due to involuntary eye movements intraoperatively. CONCLUSIONS: Topical anesthesia with preservative-free 2% lidocaine drops is an effective and safe modality for clear corneal phacoemulsification with IOL implantation. On the other hand, for patients with small pupil or those who are anxious, the procedure may be time-consuming, and it is challenging for physicians to perform cataract surgery merely using topical anesthesia.

Aged↗

PubMed2002

Posttraumatic neovascularization in a cataractous crystalline lens.

A 73-year-old woman presented with a dense traumatic cataract and intralens angiogenesis. Slitlamp examination showed abundant blood vessels in the lens stroma. Microscopic examination confirmed the presence of blood cells in the lumen. The angiogenesis represented an ingrowth into the lens from posterior synechias. Pathologic angiogenesis is frequently seen in the retina, vitreous, iris, and cornea but is rarely seen in the crystalline lens. This is the first well-documented case of angiogenesis in the lens stroma.

Aged↗

PubMed2002

Sub-tenon anesthesia for segmental scleral buckling and assessment of postoperative pain.

BACKGROUND: To evaluate the safety and efficacy of sub-Tenon anesthesia for segmental scleral buckling. METHODS: Thirty-two patients diagnosed with rhegmatogenous retinal detachment were treated with segmental scleral buckling under sub-Tenon anesthesia. After topical anesthesia, a buttonhole was made through the conjuntiva and Tenon's capsule 4 mm posterior to the limbus. Four milliliters of anesthetic solution was then delivered into the posterior sub-Tenon space using a blunt cannula. The buckling procedure was done immediately after the completion of anesthesia. We evaluated akinesia and recorded the pain with a visual analogue scale after surgery. RESULTS: There were no anesthesia related complications. Twenty-two patients (69%) reported no pain during surgery. Nine patients (28%) felt pain during surgery. However, the pain was tolerable and the surgeries were finished smoothly with or without a supplemental anesthetic solution. One patient (3%) experienced uncomfortable pain and needed an additional retrobulbar block. Five patients (16%) retained complete eye movement 5 min after anesthesia, and only 4 patients (13%) experienced total akinesia. At the end of the surgery, 16 patients (50%) had total akinesia and 2 patients (6%) retained complete eye movement. CONCLUSIONS: Sub-Tenon anesthesia is efficient and safe in segmental scleral buckling. It can prevent the complications of peribulbar or retrobulbar anesthesia and is a good alternative to both methods of anesthesia, especially in highly myopic eyes.

Adolescent↗

PubMed2002

Surgical removal of the internal limiting membrane for the treatment of a macular hole.

BACKGROUND: To evaluate the efficacy of internal limiting membrane (ILM) peeling in the treatment of a macular hole. METHODS: The ocular evaluation included Snellen visual acuity, a slit-lamp examination, indirect ophthalmoscopy, and contact lens biomicroscopy. The macular holes were confirmed using a Watzke-Allen slit beam test. Surgery consisted of a standard 3-port vitrectomy under local anesthesia. The vitreous was removed, and the macular ILM was peeled by creating a small opening and a tear in the ILM with a bent 22-gauge needle around the inner margin of the vascular arcade. The ILM flap was then grasped with end-gripping forceps, and a circular capsulorrhesis maneuver was initiated. Next, gas-fluid exchange and internal tamponade with 10% C3F8 were performed, followed by postoperative face-down positioning. RESULTS: Thirty-six eyes in 36 patients with idiopathic macular holes from stages 2 to 4 were included. The average follow-up time was 8.9 months. The holes were completely closed in 33 eyes (92%), and visual acuity was improved in 26 eyes (72%). Ten eyes were pseudophakic, 24 of the 26 phakic eyes had an increased density of the cataract after surgery, which was not detected in 2 cases. One of the patients had vitreous hemorrhage and hyphema; no retinal detachment or retinal tear was found in this study. CONCLUSION: Surgery for macular holes using ILM peeling has a high anatomical and functional success rate.

Adult↗

PubMedDate not supplied

Unambiguous comparison of juvenile and senile rhegmatogenous retinal detachment.

BACKGROUND AND OBJECTIVE: To investigate whether age is a prognostic factor in rhegmatogenous retinal detachment (RRD). PATIENTS AND METHODS: The patient population was divided into two groups according to age at onset of RRD (juvenile R RD = younger than18 years and senile RRD = 65 years and older). The juvenile RRD group consisted of 35 patients and the senile RRD group consisted of 39 patients. RESULTS: There were statistically higher incidences of male patients, trauma, subretinal fibrosis, and myopia in the juvenile RRD group compared withthe senile RRD group. In addition, there were statistical differences in the break characteristics, extent of RRD, and severity of proliferative vitreoretinopathy between the juvenile and senile RRD groups. However, no statistical differences were evident in the final retinal reattachment rate (88.6% vs 94.9%; P = .413) or the final visual outcome (P = .902) between juvenile RRD and senile RRD. CONCLUSION: Clinical characteristics between juvenile and senile RRD are different. Although delayed diagnosis is common, the final surgical outcome in juvenile RRD is as promising as in senile RRD.

Adolescent↗