Interventions for intermittent distance exotropia: review.

PURPOSE: Management decisions in intermittent distance exotropia vary and lack well-defined clinical guidelines. We undertook a systematic review in an attempt to clarify the effects of various surgical and nonsurgical treatments and to establish the significance of factors such as age with respect to outcome. The review was undertaken in collaboration with the Cochrane Eyes and Vision Group. METHODS: Electronic and manual searches were undertaken to identify randomised controlled trials of surgical or nonsurgical treatments for intermittent distance exotropia. We also contacted researchers active in this field for information about further published or unpublished studies. There were no language restrictions. Study abstracts identified from the searches were analysed independently by the two reviewers (SR and LG) and marked for inclusion, exclusion, or consideration. Reviewer analysis was compared and full papers for appropriate studies were requested. RESULTS: No randomised controlled trials were found that met our selection criteria. CONCLUSIONS: The current literature consists mainly of retrospective reviews. These are difficult to compare and analyse due to variations in definition, intervention criteria, and outcome measures. However, there appears to be an agreement that the nonsurgical treatment is more appropriate in small-angle deviations or as a supplement to surgery. Studies supporting both early and late surgical intervention were found, so the optimal timing of surgical intervention could not be concluded. There is a need for robust clinical trials to improve the evidence base for the management of this condition.

Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening.

OBJECTIVES: To test the efficacy of treatment for unilateral visual loss detected by preschool vision screening and the extent to which effectiveness varies with initial severity. DESIGN: Randomised controlled trial of full treatment with glasses and patching, if required, compared with glasses only or no treatment. Masked assessment of best corrected acuity after one year of follow up. SETTING: Eight UK eye departments. PARTICIPANTS: 177 children aged 3-5 years with mild to moderate unilateral impairment of acuity (6/9 to 6/36) detected by screening. RESULTS: Children in the full and glasses treatment groups had incrementally better visual acuity at follow up than children who received no treatment, but the mean treatment effect between full and no treatment was equivalent to only one line on a Snellen chart (0.11 log units; 95% confidence interval 0.050 to 0.171; P < 0.0001). The effects of treatment depended on initial acuity: full treatment showed a substantial effect in the moderate acuity group (6/36 to 6/18 at recruitment) and no significant effect in the mild acuity group (6/9 to 6/12 at recruitment) (P = 0.006 for linear regression interaction term). For 64 children with moderate acuity loss the treatment effect was 0.20 log units, equivalent to one to two lines on a Snellen chart. When all children had received treatment, six months after the end of the trial, there was no significant difference in acuity between the groups. CONCLUSIONS: Treatment is worth while in children with the poorest acuity, but in children with mild (6/9 to 6/12) unilateral acuity loss there was little benefit. Delay in treatment until the age of 5 did not seem to influence effectiveness.

Effects of nonylphenol ethoxylate exposure on reproductive output and bioindicators of environmental estrogen exposure in fathead minnows Pimephales promelas.

Nonylphenol ethoxylates (NPEOs) were evaluated in the laboratory for potential effects on the reproductive physiology and fecundity of fathead minnows (Pimephales promelas). Groups of three adult male and three female fathead minnows were exposed in a continuous flow-through system to 0, 0.21, 0.65, 2.1, or 7.9 microg NPEO/L for 42 d. Rabbit anti-goldfish vitellogenin (VTG) antiserum was prepared and a competitive enzyme-linked immunosorbent assay (ELISA) was adapted for measurement of plasma VTG in fish following exposure. Plasma 17beta-estradiol (E2) and testosterone (T) were also quantified by ELISA at the end of the exposure. Neither survival nor fecundity of fathead minnows exhibited a concentration-dependent response to NPEOs. No significant differences were observed in plasma VTG concentrations among treatments for males or females. Mean plasma VTG concentrations in females ranged from 291.7 to 895.1 microg VTG/ml among treatments and did not overlap with mean concentrations measured in the plasma of males, which ranged from less than the method detection limit (0.27 microg VTG/ml) to 3.2 microg VTG/ml. Plasma E2 concentrations exhibited a significant difference between males and females within all NPEO treatments, but no differences were observed among treatments. Similarly, plasma T concentrations did not exhibit a concentration-dependent response to NPEOs.

Effects of waterborne exposure to 4-nonylphenol and nonylphenol ethoxylate on secondary sex characteristics and gonads of fathead minnows (Pimephales promelas).

Fathead minnows were exposed to 4-nonylphenol (NP) or nonylphenol ethoxylate (NPEO) to determine the effects of these weak estrogen agonists on secondary sex characteristics and gonads of sexually mature males and females during 42-day continuous-flow exposures. Neither NP nor NPEO caused statistically significant effects on tubercles or fatpad size at the concentrations tested. Exposure to 1. 1 or 3.4 micrograms NP/L caused changes in the number and size of Sertoli cells and germ cell syncytia. Necrotic aggregates of various stages of germ cells in the spermatogenic sequence were observed in the testes of males exposed to NP. Electron microscopy of the testes of NP-exposed males revealed the presence of phagocytic cells in the lumina of seminiferous tubules. The cytoplasm of some Sertoli cells was distended with myelin figures and necrotic spermatozoa. No significant effects on the stages of follicular development were observed in females exposed to NP. There were no differences in the gonads or secondary sex characteristics of males or females exposed to 5.5 micrograms NPEO/L, the greatest concentration studied. The histologic responses observed are sensitive indicators of waterborne exposure to NP at environmentally relevant concentrations, but not as sensitive as induction of plasma vitellogenin. The secondary sex characteristics were not affected by concentrations of NP or NPEO as great as 3.4 or 5.5 micrograms/L, respectively. Histologic responses occurred at concentrations that were less than the final chronic value based on survival and approximately the same as those required to cause effects on egg production. The histologic effects caused by NP were similar to, but not exactly the same as those caused by exposure of fathead minnows to 17 beta-estradiol.

Intracellular acidification is not a prerequisite for glutamate-triggered death of cultured hippocampal neurons.

Glutamate decreased intracellular pH (pHi) in cultured rat hippocampal neurons. The protonophore, FCCP (1 microM), produced an acidification comparable to that produced by glutamate. Application of glutamate to FCCP-treated cells, returned pHi to resting levels. This alkaline shift resulted from a glutamate-induced membrane depolarization that removed the driving force across the plasmalemma for H+ entry via FCCP. The endogenous protonophore, arachidonic acid (10 microM), produced pHi changes similar to those elicited by FCCP. Because application of glutamate and FCCP in combination did not change pHi, this treatment was used to determine the role of glutamate-induced acidification in neurotoxicity. FCCP (1 microM, 5 min) did not affect neuronal viability, either alone or in combination with various concentrations of glutamate, as indicated by the release of lactate dehydrogenase into the bathing medium. Thus, acidification was not the cause of glutamate-induced cell death although, it may be symptomatic of neurotoxic processes.