Ian Murdoch

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PURPOSE To determine the sensitivity to change and specificity achieved when published test-retest variability (TRV) data are used to determine whether measured changes in ETDRS logarithm of the minimum angle of resolution (logMAR) visual acuity reflect true clinical change or are attributable to measurement error alone. METHODS Various degrees of change(More)
In conclusion, when an observation by its nature involves two eyes, as for blindness, statistical analyses should be conducted on individuals rather than eyes and between eye correlation is not a problem. In other circumstances, if information on only one eye per individual is used in the analysis there is a potential "waste" of information leading to less(More)
PURPOSE To determine the effect of optical defocus on the test-retest variability (TRV) of visual acuity measurements in normal subjects. METHODS Normal subjects underwent repeated visual acuity measurement with optical defocus of 0, 0.50, and 1.00 D. All measurements were taken using the Early Treatment Diabetic Retinopathy Study (ETDRS) version of the(More)
During a field trial of ivermectin in Kaduna State, 6831 people age 5 years and above, living in 34 mesoendemic onchocercal communities in Kaduna State, northern Nigeria, were examined for ocular disease. Visual function assessments included tests of visual acuity and visual fields. A total of 185 individuals (2.7%) were bilaterally blind by acuity criteria(More)
The safety and efficacy of ivermectin in the prevention of blindness from onchocerciasis have been established in many studies that have addressed the drug's effects on the front of the eye. We undertook a study with sufficient statistical power to detect an effect on optic nerve disease (OND), probably the main cause of blindness in the disorder. The trial(More)
Telemedicine technologies and services allow today's ophthalmic clinicians to remotely diagnose, manage and monitor several ophthalmic conditions from a distance. But is this the case for glaucomas? There has been a proliferation of telemedicine friendly devices in recent years that improves the capabilities of the clinician in managing glaucomas. The(More)
OBJECTIVE To evaluate whether beta radiation may offer a practical method of improving surgical success for glaucoma drainage surgery in South Africa. DESIGN Double blind, randomised controlled trial. SETTING Three public hospitals in South Africa. PARTICIPANTS 450 black Africans with primary glaucoma. INTERVENTIONS Trabeculectomy with 1000 cGy beta(More)
Reported are the results of a study of onchocerciasis in communities mesoendemic for savanna onchocerciasis in Kaduna State, northern Nigeria. The study involved 6831 individuals aged > or = 5 years who underwent an extensive screening examination for visual function including Friedmann field analysis. A total of 185 (2.7%) were bilaterally blind by acuity(More)
BACKGROUND Binocular infrared pupillometry allows an estimate of the relative afferent pupillary defect (RAPD), designated the pupillometric RAPD (pRAPD). We calibrated the pRAPD of a commercially available pupillometer against neutral density filters (NDFs) of known attenuation. The performance of the pupillometer using its own proprietary algorithm is(More)
INTRODUCTION In an African setting surgery is generally accepted as the treatment of first choice for glaucoma. A problem with trabeculectomy surgery for the glaucomas is the frequent co-existence and exacerbation of cataract. We report a randomized controlled trial to compare the use of beta radiation with 5FU in combined cataract and glaucoma surgery. (More)