Macular Degeneration: Hsu J

Hsu J. · Retina Service, Wills Eye Institute, Philadelphia, PA 19107, USA. · Curr Opin Ophthalmol. · Pubmed #17435432 No free full text.

Abstract: PURPOSE OF REVIEW: New pharmacotherapies for posterior segment diseases of the eye have been recently introduced which use novel drug delivery methods. The various current and potential future methods will be discussed. RECENT FINDINGS: Drug delivery systems have been developed which can provide controlled release of drug for potentially long periods of time. Ideal candidates for these devices are chronic conditions that require repeated local administration of drug, such as noninfectious intermediate or posterior uveitis, neovascular age-related macular degeneration, and persistent macular edema due to diabetic retinopathy or venous occlusive disease. Recently, Retisert (Bausch & Lomb, Rochester, New York, USA), a nonbiodegradable fluocinolone acetonide implant, was approved for use in noninfectious uveitis affecting the posterior segment and is currently in clinical trials for the treatment of macular edema. A biodegradable dexamethasone implant is currently in clinical trials for the treatment of uveitis and diabetic macular edema. SUMMARY: With the development of therapeutic agents that require repeated administration comes a need for new strategies to improve safety and maximize efficacy. Novel drug delivery systems involving nonbiodegradable or biodegradable implants, microparticulates or nanoparticulates, liposomes, or transscleral iontophoresis may provide the solution.

Hsu J, Maguire MG, Fine SL. · Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia 19104, USA. · Can J Ophthalmol. · Pubmed #15947802 links to  free full text

Abstract: BACKGROUND: Age-related macular degeneration (AMD) is the most common cause of severe and irreversible vision loss among people 50 years of age or older in many Western countries. Most of the available treatments for AMD are intended for the late stage, specifically for choroidal neovascularization (CNV). Effective preventive treatments could have an even greater impact on the vision of the millions of people at risk for vision loss from AMD. Drusen are typically the earliest lesions seen in patients with AMD and precede the development of CNV. In 1973, Gass noted the disappearance of drusen in eyes that received laser photocoagulation, which led to the hypothesis that laser-induced drusen reduction could alter the natural course of AMD. METHODS: We reviewed relevant articles found through a search of MEDLINE through February 2005 by means of the following key words, alone or in combination: drusen, laser, photocoagulation, age-related macular degeneration, macula and choroidal neovascularization. RESULTS: Reports ranging from individual cases and case series to randomized controlled pilot studies have described various laser treatment protocols and their effects on eyes with high-risk drusen but no neovascular changes. These reports provide evidence that laser photocoagulation can induce drusen reduction. Although some investigators have reported a corresponding improvement in visual function, others have found no change or even worsening. The results in several of the larger randomized controlled studies suggest that CNV may occur at an increased rate in laser-treated eyes with high-risk drusen in patients who have neovascular AMD in the other eye. The long-term effects of laser treatment in patients with high-risk drusen in both eyes and no neovascular changes have yet to be determined. INTERPRETATION: The outcome of clinical trials such as the Prophylactic Treatment of Age-Related Macular Degeneration and the Complications of Age-Related Macular Degeneration Prevention Trial will help to determine the role of laser prophylaxis in patients with AMD.

Chen E, Hsu J, Park CH. · Retina Service, Wills Eye Institute, Philadelphia, Pennsylvania, USA. · Ophthalmic Surg Lasers Imaging. · Pubmed #19205502 No free full text.

Abstract: A 58-year-old woman with non-proliferative diabetic retinopathy presented with decreased visual acuity from chronic macular edema. She had undergone multiple treatments previously, including focal laser treatment and intravitreal triamcinolone acetonide. Within 2 days of treatment with intravitreal bevacizumab, the patient noted a significant decrease in visual acuity. Fluorescein angiogram demonstrated an enlargement of the foveal avascular zone and persistent late leakage following intravitreal bevacizumab; optical coherence tomography performed before and after treatment revealed persistent cystoid macular edema. The use of intravitreal bevacizumab in chronic, refractory diabetic macular edema may cause acute visual acuity loss by disrupting an already fragile vascular perfusion status, leading to macular ischemia.

Hsu J, Kaiser RS, Sivalingam A, Abraham P, Fineman MS, Samuel MA, Vander JF, Regillo CD, Ho AC. · Retina Service, Wills Eye Hospital, Philadelphia, Pennsylvania 19107, USA. · Retina. · Pubmed #18040237 No free full text.

Abstract: PURPOSE: To describe the effects of intravitreal bevacizumab in eyes with macular edema resulting from central retinal vein occlusions (CRVO). METHODS: Retrospective consecutive case series of patients diagnosed with macular edema from CRVO who received intravitreal bevacizumab. RESULTS: Thirty eyes of 29 patients with an average age of 72 years (range, 54-87 years) had intravitreal bevacizumab injections. Mean follow-up was 18.1 weeks. Initial mean visual acuity was 20/394. At the 1- and 2-month follow-up, mean visual acuity improved to 20/237 (n = 26, P = 0.04) and 20/187 (n = 21, P = 0.008), respectively. At the 3- and 4-month follow-up, visual acuity improved from 20/228 to 20/157 (n = 15, P = 0.05) and from 20/313 to 20/213 (n = 11, P = 0.03), respectively. No significant changes in visual acuity were found after 4 months though the number of patients in this group was small. Duration of treatment effect following an injection appears to be limited to 2 months for most patients. No ocular or systemic adverse reactions were noted. CONCLUSIONS: The visual benefits of intravitreal bevacizumab for macular edema due to CRVO are apparent early but are not sustained without repeated injections. Larger clinical studies with long-term follow-up will be necessary to better elicit the best regimen for this therapy.

Shah CP, Hsu J, Garg SJ, Fischer DH, Kaiser R. · Retina Service of Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA. · Am J Ophthalmol. · Pubmed #17157598 No free full text.

Abstract: PURPOSE: To report two cases of a retinal pigment epithelial (RPE) tear after intravitreal bevacizumab injection for exudative age-related macular degeneration (AMD). DESIGN: Observational case series. METHODS: Two patients presented with occult choroidal neovascularization secondary to AMD. Both patients received intravitreal bevacizumab injections. RESULTS: The first patient developed a RPE tear shortly after a third intravitreal bevacizumab injection. The second patient developed a RPE tear 10 days after a second intravitreal bevacizumab injection. CONCLUSIONS: Although RPE tears may occur spontaneously as part of the natural history of exudative AMD, patients may develop visually devastating RPE tears after repeat intravitreal bevacizumab injection. Further studies are needed to determine the incidence of RPE tears after intravitreal bevacizumab injections.

Ibarra MS, Hsu J, Mirza N, Wu IH, Ying GS, Mainster MA, Tolentino MJ. · Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. · Invest Ophthalmol Vis Sci. · Pubmed #15452076 links to  free full text

Abstract: PURPOSE: To study the risk of adverse events in transpupillary thermotherapy (TTT) for age-related macular degeneration by measuring how laser-induced retinal temperature increase is affected experimentally by subretinal blood, choroidal blood flow, and chorioretinal pigmentation. METHODS: An ultrafine thermocouple technique was developed to measure retinal temperature increase during TTT in albino and pigmented rabbit eyes. TTT was performed with 60-second, 0.78-mm spot size, 810-nm infrared diode laser exposures with power settings ranging from 50 to 950 mW. Intraretinal and subretinal temperature increases were measured in pigmented and albino rabbits, with or without subretinal blood and choroidal blood flow. RESULTS: Threshold power settings for visible lesions in albino and pigmented rabbits were 950 and 90 mW, respectively, corresponding to retinal temperature increases of 11.8 degrees C and 5.28 degrees C, respectively. Power settings required to produce threshold lesions in albino rabbits caused retinal temperature increases in pigmented rabbits that were five times higher than in the albino rabbits. Temperature increases in albino rabbits were 1.5 times higher with subretinal blood than without it. Choroidal blood flow generally did not affect measured retinal temperature increases. CONCLUSIONS: The results confirm prior theoretical recommendations that clinicians should consider decreasing TTT power settings in darkly pigmented eyes and proceed with caution in those with subretinal hemorrhage or pigment clumping.