Ji Won Kwon

Biocompatibility of poloxamer hydrogel as an injectable intraocular lens A pilot study

Purpose: To induce irreversible gelation of poloxamer, a thermosensitive polymer hydrogel, by using a photoinitiator and ultraviolet (UV) irradiation and to verify the biocompatibility and use of poloxamer as an injectable intraocular lens (IOL) material. Setting: Department of Ophthalmology, Seoul National University College of Medicine, Seoul Artificial Eye Center, Clinical Research Institute, Seoul National University Hospital, Seoul, Korea. Methods: In 10 rabbits, endocapsular phacoemulsification was performed and a poloxamer–photoinitiator mixture was injected into the capsular bag through a small capsulorhexis site. In 1 eye, the capsulorhexis site was closed with a small plug and the entire eye was irradiated with UV light for 5 minutes. Postoperatively, poloxamer transparency and effect on the conjunctiva, cornea, iris, vitreous, and retina were observed. Results: A mixture comprising 25% poloxamer and 0.01% photoinitiator produced a poloxamer that remained transparent in the lens capsule for up to 6 months. No inflammatory response or toxicity was observed in the conjunctiva, cornea, iris, vitreous, or retina. Conclusion: Poloxamer is a potentially suitable material for an injectable IOL. Further study is needed.

Retinal Nerve Fiber Layer Defect and Cerebral Small Vessel Disease

PURPOSE To determine whether retinal nerve fiber layer defect (RNFLD) is associated with cerebral small vessel diseases (SVDs) and to identify risk factors for RNFLD. METHODS A total of 4421 Korean subjects who underwent health checkups including brain magnetic resonance imaging (MRI) and fundus photography between January 2008 and October 2009 were included in this study. Co-morbid systemic diseases including hypertension, diabetes mellitus, and stroke or ocular diseases were evaluated using detailed questionnaires and medical records. Two experienced ophthalmologists assessed RNFLD on fundus photographs, according to the definition that describes the condition as marked thinning or absence of retinal nerve fiber layer bundles. RESULTS RNFLD was detected in 238 of 4395 eligible subjects, and the estimated prevalence was 5.4%. Multivariate regression analysis results showed the prevalence of RNFLD to be significantly higher in hypertensive subjects (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.28-2.34), in those with cerebral SVD based on MRI (OR, 1.58; 95% CI, 1.17-2.12), and in male (OR, 1.47; 95% CI, 1.10-1.96) and older subjects (OR, 1.02; 95% CI, 1.00-1.03). Among the cases of cerebral SVD, white matter lesions (WMLs) were associated with RNFLD, whereas lacunar infarctions were not significantly associated with it. CONCLUSIONS The results indicate that RNFLD may be related to the presence of cerebral SVD, particularly WMLs. Furthermore, being older and male and having hypertension increase the risk of RNFLD.

Ultrasound Energy in Phacoemulsification: A Comparative Analysis of Phaco-Chop and Stop-and-Chop Techniques According to the Degree of Nuclear Density

BACKGROUND AND OBJECTIVE To evaluate the amount of ultrasound energy used, corneal endothelial cell loss, and central corneal thickness using the phaco-chop and stop-and-chop techniques for cataracts with different degrees of nuclear density. PATIENTS AND METHODS One hundred two eyes of 51 patients with bilateral senile cataract were included. Each eye was randomly assigned to have either phaco-chop or stop-and-chop nucleofractis during phacoemulsification. The groups were divided into two subgroups according to the nuclear density. The effective phacoemulsification time, endothelial cell density, and central corneal thickness were analyzed. RESULTS The mean effective phacoemulsification time was similar between the groups in moderately dense nuclei (2.17 +/- 1.33 vs 1.33 +/- 1.05 seconds; P = .41). However, the phaco-chop technique required less effective phacoemulsification time than the stop-and-chop technique in dense nuclei (3.86 +/- 4.18 vs 6.70 +/- 5.43 seconds; P = .01). The endothelial cell loss and the central corneal thickness did not vary significantly between the groups. CONCLUSION The phaco-chop technique requires lower ultrasound energy for nuclear management than the stop-and-chop technique in dense cataracts and the resulting endothelial loss was similar in both techniques.

The Epidemiology of Cosmetic Treatments for Corneal Opacities in a Korean Population

Purpose To describe etiologies and clinical characteristics of corneal opacities leading patients to seek cosmetic treatments. Methods The medical records of 401 patients who presented for cosmetic improvement in corneal opacities between May 2004 and July 2007 were retrospectively reviewed. The following parameters were analyzed: age, gender, cause of corneal opacity, time course of the corneal disease, associated diseases, prior and current cosmetic treatments, visual acuity, location and depth of the corneal opacity, and the presence of either corneal neovascularization or band keratopathy. A single practitioner examined all patients. Results The most common causes of corneal opacity were ocular trauma (203 eyes, 50.6%), retinal disease (62 eyes, 15.5%), measles (38 eyes, 9.5%), and congenital etiologies (22 eyes, 5.5%). Prior treatments included iris colored contact lenses (125 eyes, 31.1%) and corneal tattooing (34 eyes, 8.46%). A total of 321 of 401 eyes underwent cosmetic treatment for corneal opacities. The most common treatment performed after the primary visit was corneal tattooing (261 eyes, 64.92%). Conclusions This is the first study to investigate the causes and clinical characteristics of patients presenting for cosmetic treatment of corneal opacities rather than for functional improvement. Various cosmetic interventions are available for patients with corneal opacities, and these should be individualized for the needs of each patient.

One-year outcome of argon laser photocoagulation of pinguecula.

Purpose: To determine the efficacy and safety of argon laser photocoagulation of pinguecula by evaluating 1-year outcomes. Methods: Twenty-one eyes of 15 patients treated with argon laser photocoagulation (photocoagulation group) and 23 eyes of 16 patients treated with surgical excision (excision group) were retrospectively reviewed. Cosmetic outcome was evaluated by patients self-report on a 5-grade scale (excellent, good, acceptable, poor, and very poor), and evaluation of treatment outcome was based on objective findings of anterior segment photography and anterior segment optical coherence tomography. Results: Overall cosmetic results were excellent or good in 90.5% of laser-treated cases and 78.6% of surgically treated cases. There was no significant difference in cosmetic outcome (P = 0.15). Nineteen (90.5%) and 17 (63.9%) cases demonstrated complete removal of pingueculae after laser photocoagulation and surgical excision, respectively. The anatomic outcome was not significantly different between the 2 groups (P = 0.25). Subconjunctival hemorrhage and conjunctival scarring with an irregular surface occurred less frequently in the photocoagulation group than in the excision group [34.8% vs. 0% (P = 0.003) and 30.4% vs. 4.8% (P = 0.048), respectively]. Conclusions: Argon laser photocoagulation is an effective and safe method for removing a pinguecula for cosmetic purposes. The method facilitates control of the extent and depth of removal and thus minimizes conjunctival defects and other complications.

Presumed Atypical HDR Syndrome Associated With Band Keratopathy and Pigmentary Retinopathy

This report describes presumed atypical hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome associated with unexpected ocular findings. The patient had exotropia, bilateral band keratopathy, and pigmentary retinopathy, including attenuated retinal vessels and atrophy of the retinal pigment epithelium. Even though the calcific plaques were successfully removed, visual acuity in both eyes gradually decreased and electroretinography was extinguished.