Age-related macular degeneration, AMD, is the commonest cause of legal blindness in the industrialised world. Epidemiological data suggest that in Denmark more than 80,000 persons suffer impaired vision in at least one eye, because of AMD. More than 4000 are legally blind owing to this disease. AMD has two major phenotypes: wet and dry. Most severe visual losses are caused by wet AMD, where new blood vessels form under the macula. A new treatment of this condition is now available. Photodynamic therapy with verteporfin has been investigated in a double-blind, randomised clinical trial with more than 600 patients. This study has been scrutinised by a Cochrane review, which has recommended criteria for the treatment. For eyes meeting these inclusion criteria, photodynamic therapy can reduce the occurrence of moderate and severe visual loss over a two-year period by more than 60%. It is estimated that around 1000 eyes in Denmark will meet the inclusion criteria for photodynamic therapy.
Age-related macular degeneration (AMD) is a common macular disease affecting elderly people in the Western world. It is characterised by the appearance of drusen in the macula, accompanied by choroidal neovascularisation (CNV) or geographic atrophy. The disease is more common in Caucasian individuals than in pigmented races. In predominantly Caucasian populations, the age-standardised prevalence of AMD in at least one eye is 7760 cases per million. The age-standardised cumulated 1-year incidence of AMD in at least one eye is 1051 cases per million individuals. AMD is the most important single cause of blindness among Caucasian individuals in developed countries. Blindness resulting from AMD rarely occurs before age 70, and most cases occur after age 80. The age-standardised 1-year incidence of legal blindness resulting from AMD is 212 cases per million. Two-thirds of AMD cases have CNV (exudative cases); the remainder has only geographic atrophy. In cross-sectional population-based studies about 45% of eyes with AMD have visual acuity reduced to 20/200 or worse. This is true both for exudative AMD and pure geographic atrophy. Age and genetic predisposition are known risk factors for AMD. Smoking is probably also a risk factor. Preventive strategies using macular laser photocoagulation are under investigation, but their efficacy in preventing visual loss is as yet unproven. There is no treatment with proven efficacy for geographic atrophy. Optimal treatment for exudative AMD requires a fluorescein angiographic study and a physician capable of interpreting it. For CNV not involving the foveal centre, the only evidence-based treatment is laser photocoagulation. For AMD cases with subfoveal CNV, good visual acuity, and predominantly classic fluorescence pattern on fluorescein angiography, photodynamic therapy with verteporfin is the treatment of choice. Photodynamic therapy is also effective in eyes with pure occult CNV and evidence of recent disease progression. For new subfoveal CNV with poor vision and recurrent CNV, laser photocoagulation can be considered.
Current methods of treatment for retinopathy of prematurity, using laser photocoagulation, require surgeons to assume awkward standing positions, which can result in occupational injury. A new infant surgical table was designed for improving this surgical procedure. To quantify its benefits, an ergonomic comparison of the standard and modified procedures was carried out, using specialized checklists, Nordic Musculoskeletal Questionnaires, and analysis of videotaped procedures using an Ovako Working Posture Analysing System method. Analysis of the typical laser photocoagulation procedure revealed a high risk for cumulative trauma disorders. The majority of the risk factors were lowered considerably with use of the new table. Improvement was largely due to the new table allowing seated postures during surgery, relieving muscular stress on the back, shoulders and legs. This study demonstrates risk reduction through engineering design of new medical devices, and illustrates how combining different assessment approaches can help evaluate ergonomic impact of medical technologies.
PURPOSE: To assess retinochoroidal overexpression of heat shock proteins (HSP-70) induced by a transpupillary laser irradiation below the photocoagulation threshold. METHODS: Four pigmented rabbits were anesthetized and TTT was performed on the right eye using a 810nm diode laser (Iridis, Quantel-Medical, France) adapted on slit lamp (spot size: 1.3 mm, duration: 60 seconds; power 92-150 mW). Series of laser impacts were aimed at the posterior pole of the retina. Left eyes were used as control. Twenty-four hours after laser irradiation, a histological study was done on chorioretinal layers. Tissue samples were fixed in formalin and embedded in paraffin. A monoclonal antibody was used to detect HSP-70 immunoreactivity (mouse IgGl, SPA-810, Stress Gen, Canada), followed by a biotinylated goat antimouse antibody (Dako, Denmark), revealed by the avidin-biotin complex (Vectastain kit, Vector, USA) and the AEC chromogen. Retinal structures were further identified by HES coloration. RESULTS: The photocoagulation threshold was obtained for laser power at 150 mW. Under this threshold, HSP-70 immunostaining was the strongest for power 127 mW with a staining of some choroidal cells, including capillary endothelial cells. No HSP-70 immunoreactivity was observed on the retina. For the laser power 107 mW, HSP-70 reactivity was observed only in occasional choroidal cells. For the laser power 92 mW, as for nonirradiated eyes, no HSP-70 immunoreactivity was detected. CONCLUSIONS: Transpupillary 810 nm laser irradiation under the photocoagulation threshold induces choroidal HSP overexpression. This study concludes that choroidal HSP overexpression can be induced during TTT.
AIM: To determine if intravitreal microimplants containing triamcinolone acetonide (TAAC) inhibit experimental fibrovascular proliferation (FVP) induced by laser trauma in a rat as a model of choroidal neovascular membranes (CNVMs). METHODS: 20 anaesthetised male Brown Norway rats received a series of eight krypton red laser lesions per eye (647 nm, 0.05 s, 50 micro m, 150 mW). Three types of sterilised TAAC microimplant designs were evaluated: implant A consisting of 8.62% TAAC/20% polyvinyl alcohol (PVA) matrix (by dry weight); implant B consisting of 3.62% TAAC/20% PVA matrix; and implant C consisting of a dual 8.62% TAAC/20% PVA matrix design combined with a central core (0.5 mm) of compressed TAAC to extend the implant release time. For each animal studied, one eye received one of the three aforementioned TAAC implant designs, while the fellow eye received a control implant consisting of PVA but without TAAC. The animals were sacrificed at day 35 and ocular tissues were processed for histological analysis. Serial histological specimens were methodically assessed in a masked fashion to analyse each laser lesion for the presence or absence of FVP; maximum FVP thickness for each lesion was measured from the choriocapillaris. RESULTS: All three types of TAAC implants inhibited FVP relative to controls in a statistically significant fashion. In the eyes that received implant A (n = 8), the mean thickness of the recovered lesions (n = 36) measured 32 (SD 22) micro m, compared to 52 (30) micro m (p
Two hundred and ninety-six patients with diabetic retinopathy (DR) were examined: conservative therapy and laser coagulation of the retina were applied in 120 and 176 of them, respectively. The ecological situation in the residence region and its impact on the morbidity and immune status of DR patients were analyzed. The comfort degree of the environment and the level of anthropogenic contamination affect the morbidity and immunogram results. Immune-correctors, i.e. T-activin, sodium nucleinate and laser blood irradiation (LBI), were used within treatment schemes in DR. Laser coagulation of the retina is advisable to assign in combination with sodium nucleinate and LBI in the aftercare of patients concurrently with complex therapy; T-activin is used, within conservative therapy, to correct the unfavorable ecological impact exerted on patient's body.
PURPOSE: Choroidal neovascularization (CNV) plays an important role in pathogenesis of age-related macular degeneration (AMD), ocular histoplasmosis syndrome (OHS) and so on. However, mechanisms of CNV formation are not fully understood. The aim of this study is to investigate the correlation between expressions of CD105 and vascular endothelial growth factor (VEGF) in experimental laser-induced CNV in rats. METHODS: CNV model was established by 532 nm laser photocoagulation in Brown-Norway rats. The expression of CD105 and VEGF in CNV was observed by immunohistochemistry at 3, 7, 14, 21, 28 and 56 days after laser photocoagulation. The image analysis was performed with the professional software of Image-Pro Plus. RESULTS: Fluorescein angiography showed fluorescein leakage in CNV from days 7 to 56 after photocoagulation. VEGF expression was mainly observed in vascular endothelial cells, ganglion cells, inner nuclear layers and retinal pigment epithelial cells in normal retina and vascular endothelial cells in normal choroid of the rats. On day 3 after photocoagulation, VEGF began to express in laser-induced lesions. VEGF was strongly expressed in CNV after 7 days (P 0.05). CD105 was initially presented in CNV at 7 days and obviously expressed at 14 days after photocoagulation (P 0.05). There was notablely direct correlation between CD105-positive-microvessel density and positively semiquantitative scoring of VEGF in the CNV (r = 0.989, P
Age-related macular degeneration (AMD) is characterized by loss of central vision and is the leading cause of blindness among persons over the age of 50 years in Canada. The wet form of AMD has 3 subtypes-occult, minimally classic, and predominantly classic. Photodynamic therapy (PDT) with verteporfin is indicated only for the category of predominantly classic wet AMD. Currently, there are no treatments available for the other AMD subtypes. Pegaptanib sodium was the first pharmacologic therapy approved in Canada for the treatment of subfoveal wet AMD regardless of subtype.
The aim of this study was to examine the cost-effectiveness of pegaptanib versus PDT with verteporfin and versus standard care for the treatment of subfoveal wet AMD in patients aged 65 years in Canada.
A Markov model based on visual acuity in the better-seeing eye was developed. Clinical efficacy was taken from the clinical trials. Costs of treatment, comorbidities (eg, depression, fractures, need for assisted living), vision rehabilitation, visual aids, and adverse events were considered. Costs, utilities, and mortality were estimated from data from the available published literature. Costs were reported in 2004 Canadian dollars, and costs and outcomes were discounted at 3% per annum. Lifetime costs, quality-adjusted life-years (QALYs), and vision years gained (VYGs) were estimated. Sensitivity analyses were performed to determine model robustness.
Patients who received pegaptanib experienced more QALYs gained (4.17) and VYGs (3.83) compared with patients who received PDT (3.87 and 3.01, respectively) or standard care (3.96 and 3.26). Mean total costs per patient were greater in patients who received pegaptanib compared to those who received PDT or standard care ($20,016 vs $15,345 or $7669, respectively). The incremental cost per QALY in patients receiving pegaptanib compared to those receiving PDT was $49,052 and $59,039 for patients receiving pegaptanib versus standard care. The incremental cost per VYG was $20,401 and $21,559 with pegaptanib versus PDT and standard care, respectively. Sensitivity analyses found that the model was relatively robust to changes in various model parameters.
The results of this analysis suggest that in Canada, pegaptanib is a cost-effective treatment for subfoveal wet AMD in elderly patients, regardless of lesion subtype, compared to PDT with verteporfin and to standard care.