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ISRCTN
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ISRCTN77268814
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ClinicalTrials.gov identifier
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Public title
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Randomised Controlled Trial of Efficacy of Optometric Interventions
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Scientific title
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Acronym
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N/A
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Serial number at source
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M0003074909
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Study hypothesis
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Optometrists usually prescribe interventions (spectacles, contact lenses or orthoptics) if the intervention improves visual acuity, or if it is believed that it will resolve symptoms. For optometric interventions that are prescribed for symptomatic relief, clinical tests of visual acuity (VA) often do not indicate significant improvement with the intervention.
Visual problems which cause symptoms but do not impair static VA might affect performance on dynamic tasks. Refractive errors and heterophoria are best described as continuous variables and the decision as to when to prescribe an intervention is based on clinical signs whose sensitivity and specificity for detecting symptoms is often, at best, under researched.
The objectively validated Wilkins Rate Of Reading Test will be used to assess the benefit of interventions. This test uses simple words and is relatively independent of reading skill and does not assess linguistic or semantic factors. The results are very dependent on dynamic visual skills and require sustained binocular single vision and clear vision.
The aims of the research
1. In conditions where optical corrections may be prescribed but not improve VA (e.g. decompensated heterophoria): to investigate whether optical corrections influence performance at the Wilkins Rate of Reading test.
2. In conditions where optical corrections may be prescribed and improve VA (e.g. astigmatism): to investigate whether optical corrections influence performance at the Wilkins Rate of Reading test.
3. In both (1) and (2), to investigate the relationship between the severity of the optometric anomalies and the magnitude of any improvement in the Rate of Reading.
4. If the Wilkins Rate of Reading Test does prove to be a useful tool for exploring any benefit from the ¿borderline¿ optometric interventions, to investigate the inter-relationships between the Wilkins Rate of Reading Test result, symptoms and conventional clinical test results.
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Lay summary
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Ethics approval
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Not provided at time of registration
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Study design
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Randomised controlled trial
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Countries of recruitment
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United Kingdom
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Disease/condition/study domain
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Eye Diseases: Vision disorders
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Participants - inclusion criteria
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Subjects meeting the following criteria will be selected, regardless of whether they have any existing refractive correction. All subjects meeting the criteria will be invited to participate.
1. Hypermetropes of age <40years with either retinoscopy or subjective refraction in the better eye in the range +0.75 to +1.50D
2. Patients aged 40-45 years with a subjective near correction in the range +0.50 to +1.50D
3. Astigmats of any age with astigmatism (subjectively) in the better eye in the range 0.50 to 1.50DC
4. Patients of any age with horizontal heterophoria that may be decompensated
5. Patients of any age with a vertical heterophoria either on the Mallett unit or dissociation test of >0.5^
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Participants - exclusion criteria
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No specific patient exclusion criteria
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Anticipated start date
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01/07/1998
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Anticipated end date
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31/03/2008
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Status of trial
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Completed |
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Patient information material
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Target number of participants
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Not provided at time of registration
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Interventions
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Subjects will be invited to return on the research day. They will then be tested four times with the rate of reading test, twice with the appropriate intervention A and twice with the control lens (B). The order of testing will be ABBA or BAAB (randomly) to control for practice effects. The interventions and controls for the five groups identified are summarised.
Hypermetropes will be tested with subjective refractive correction (A) and size lenses to give similar magnification (B)
Astigmats will be tested with subjective cylindrical correction (A) and best vision sphere (B)
Horizontal heterophorias will be tested with aligning prism from Mallett unit (A) and size lenses for exophoria or plano for esophoria as appropriate (B)
Vertical heterophorias will be tested with larger of aligning prism/dissociated heterophoria (A) and plano trial lenses (B)
Early presbyopes will be tested with near refractive correction (A) and size lenses (B).
Clinical data will be obtained using standard testing protocols on all subjects, and a selection from VA, cover test, foveal suppression, dissociated heterophoria, fusional reserves, Randot circles, fixation disparity. Detailed symptom questionnaires designed for each group will be used.
Subjects will be assessed from patients routinely attending the practice for eye examinations.
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Primary outcome measure(s)
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Process measure: does prescribing optometric correction for marginal refractive and orthoptic anomalies benefit patients in terms of improved performance on the Wilkins Rate of Reading test?
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Secondary outcome measure(s)
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Not provided at time of registration
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Sources of funding
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City Eye Clinic (EYENET) (UK), NHS R&D Support Funding
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Trial website
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Publications
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2006 results on http://www.ncbi.nlm.nih.gov/pubmed/17040419
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Contact name
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Prof
Bruce
Evans
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Address
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23 Shenfield Rd
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City/town
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Brentwood
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Zip/Postcode
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CM15 8AG
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Country
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United Kingdom
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Tel
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+44 (0)1277 211164
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Fax
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+44
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Email
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bruce.evans@virgin.net
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Sponsor
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Record Provided by the NHSTCT Register - 2005 Update - Department of Health (UK)
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Address
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The Department of Health
Richmond House
79 Whitehall
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City/town
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London
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Zip/Postcode
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SW1A 2NL
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Country
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United Kingdom
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Tel
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+44 (0)20 7307 2622
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Fax
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+44 (0)20 7307 2623
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Email
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dhmail@doh.gsi.org.uk
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Sponsor website:
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http://www.dh.gov.uk/Home/fs/en
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Date applied
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30/09/2005
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Last edited
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10/09/2008
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Date ISRCTN assigned
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30/09/2005
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