PubMed · 13403285
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
N CABAU, J B BARON, F MONESTIER, S GUILLON. 1955. Ocular microbial flora.. https://pubmed.ncbi.nlm.nih.gov/13403285/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
BACKGROUND: Radiotherapy has been proposed as a treatment to prevent new vessel growth in people with neovascular age-related macular degeneration (AMD). OBJECTIVES: The aim of this review was to examine the effects of radiotherapy on neovascular AMD. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group trials register) on The Cochrane Library Issue 2, 2004, MEDLINE (1966 to May 2004), EMBASE (1980 to June 2004) and LILACS (Latin American and Caribbean Health Sciences Literature Database) (May 2004). We also wrote to investigators of trials included in the review to ask if they were aware of any other studies. SELECTION CRITERIA: We included all randomised controlled trials in which radiotherapy was compared to another treatment, sham treatment, low dosage irradiation or no treatment in people with subfoveal choroidal neovascularisation secondary to AMD. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted the data. Relative risks were combined using a random effects model. The percentage of the variability in effect estimates that was due to heterogeneity, rather than sampling error, was estimated using I2. MAIN RESULTS: Eleven trials randomising a total of 1078 people were included in this review. All trials used a similar method of delivering the radiotherapy treatment (external beam). Dosage ranged from 7.5 to 24 Gy. Most trials found effects (not always significant) that favoured treatment. However, there was considerable inconsistency in the results between trials (I2 > 50%). As only 11 trials were included in the review and only some of these trials provided data for each outcome our ability to determine the causes of the heterogeneity between trials was limited. Subgroup analyses did not reveal any statistically significant interactions although with small numbers of trials in each subgroup (range two to four) this was not surprising. There was some indication that trials with no sham irradiation reported a greater effect of treatment as did trials with a greater percentage of participants with classic choroidal neovascularisation. REVIEWERS' CONCLUSIONS: This review currently does not provide evidence that external beam radiotherapy is an effective treatment for neovascular AMD. If further trials are to be considered to evaluate radiotherapy in AMD then adequate masking of the control group must be considered. Given the recent evidence that most lesions are amenable to treatment with photodynamic therapy if identified at a small lesion size, trials evaluating radiotherapy against photodynamic therapy are warranted.
We provide an adjustment factor for ablation algorithms used in photorefractive laser surgery that takes into account how laser polarization in reflection losses affects the cornea. We evaluate the influence of this factor on corneal radius and asphericity after surgery, showing that it is significant for visual performance (effective visual acuity is reduced) and for the correction of eye aberrations. Our data indicate that this adjustment factor should be included in the ablation algorithms (depending on the polarization state of each laser device) that are proposed for customized corneal ablation, which need great accuracy for minimization of eye aberrations.
According to optical diffraction theory, a visual acuity of 20/3.5 is possible in human eyes with pupil diameters larger than 6 mm. This theoretical value cannot be obtained in practice - in fact visual acuity is limited by the scale of the mosaic of the retinal cones. Anatomical data and the model by Helmholtz-Hering suggest that visual acuity of humans cannot be substantially higher than 20/10. Many young adult reach this visual acuity with their normal spectacles or contact lens correction. The human eye has higher-order aberrations which can be measured with a Hartmann-Shack aberrometer. A partial correction of these aberrations is possible by means of wavefront-controlled keratectomy and customized corneal ablation. A perfect eye completely free of ocular aberrations cannot be created by customized refractive surgery as, for example chromatic aberration cannot be corrected and the strength of ocular aberrations depends on the state of accomodation and varies with time.