Interventions for strabismic amblyopia.

BACKGROUND: Amblyopia is reduced visual acuity in one or both eyes in the absence of any demonstrable abnormality of the visual pathway. It is not immediately resolved by the correction of refractive error. Strabismus develops in approximately 5% to 8% of the general population. The aim of treatment for amblyopia is to obtain the best possible level of vision in the amblyopic eye. Different treatment options were examined within the review. OBJECTIVES: By reviewing available evidence we wanted to establish the most effective treatment for strabismic amblyopia. In particular this review aimed to examine the impact of conventional occlusion therapy for strabismic amblyopia and analyse the role of partial occlusion and optical penalisation for strabismic amblyopia. SEARCH STRATEGY: We searched CENTRAL, MEDLINE, EMBASE and LILACS in October 2007. There were no language or date restrictions in the electronic searches for trials. SELECTION CRITERIA: We included randomised controlled trials (RCTs) for the treatment of strabismic amblyopia including participants of any age. DATA COLLECTION AND ANALYSIS: Two authors working independently extracted and entered data into Review Manager 4.2 using the double data entry facility to check for errors. MAIN RESULTS: We included two RCTs. The studies reported mean logMAR visual acuity achieved. Mean difference in visual acuity was calculated. When comparing conventional part-time occlusion (with any necessary glasses), PEDIG 2006 reported this treatment was more beneficial than glasses alone for strabismic amblyopia. Mean difference between groups was -0.18 (statistically significant 95% CI -0.32 to -0.04). Supplementing occlusion therapy with near activities may produce a better visual outcome compared to non-near activities after four weeks of treatment (PEDIG 2005). Mean difference between groups was -0.17 (95% CI -0.53 to 0.19). However, this data is from a pilot study and the full data set will be added to updates of the review when available. AUTHORS' CONCLUSIONS: Occlusion, whilst wearing necessary refractive correction, appears to be more effective than refractive correction alone in the treatment of strabismic amblyopia. Combining occlusion and refractive correction with near activities may be more effective than occlusion and refractive correction alone. Further study of the role of near activities is necessary before a more definitive conclusion can be made. Results of a full trial are expected within the coming year. No RCTs were found that assessed the role of either partial occlusion or optical penalisation to refractive correction for strabismic amblyopia.

Association between polymorphisms of the GPX1 gene and second primary tumours after index squamous cell cancer of the head and neck.

We investigated the association between genetic polymorphisms in GPX1 gene amongst patients who had index squamous cell carcinoma (SCCHN) and a second primary tumour (SPT) after a primary SCCHN in a case-control study. GPX1 genotypes were determined for 61 patients with SPT and for 259 control subjects by a PCR technique using a fluorescent-labelled primer. Analysis was by an ABI automated fluorescent sequencer. The associations between specific genotypes and the development of SPT were examined by logistic regression. A significant difference was found between the control group and the SPT cases in allele frequencies of GPX1 ALA( *)6 and ALA( *)7 (p(trend)=0.04). These results suggest that polymorphisms in the GPX1 gene may be a marker for SPT development and further studies are indicated.

A pvdf membrane hydrophone for operation in the range 0.5 Mhz to 15 Mhz.

A new form of hydrophone for measuring the spatial and temporal distributions of pressure within the fields from medical ultrasonic equipment is described. The device comprises an acoustically transparent plastic membrane with a small, central region activated to provide a freely-suspended piezoelectric element. This form of detector offers several advantages over conventional hydrophone probes employing ceramic elements, in particular a flat frequency response. The performance characteristics of a prototype membrane hydrophone and some possible developments and applications are described.

Frequency determination of visible laser light by interferometric comparison with upconverted CO(2) laser radiation.

A servocontrolled 1-m plane-parallel Fabry-Perot interferometer has been developed at NPL for the precise intercomparison of laser wavelengths. This instrument has been used to measure the wavelength ratio of a 679-nm radiation and that from a 633-nm iodine-stabilized He-Ne laser, achieving an accuracy of 2.9 parts in 10(11). The 679-nm light was derived from a stabilized CO(2) laser radiation by upconversion, and the wavelength of this 9.3-microm laser radiation can be calculated from the visible wavelength result. Frequency measurements on the same CO(2) laser radiation have already been made in this laboratory, so that the experiment reported here leads to a precise value for the speed of light in vacuum and to the value of 473, 612, 380.5 +/- 0.3 MHz for the absolute frequency of the visible radiation from a He-Ne laser stabilized to component d of (127)I(2).