Detection of early-stage age related macular degeneration with a compact rarebit test

Department of Ophthalmology, Academic Medical Center, University of Amsterdam, P.O. Box 22700, Amsterdam, NL-1100 DE, The Netherlands
The British journal of ophthalmology (Impact Factor: 2.98). 08/2012; 96(10):1354-5. DOI: 10.1136/bjophthalmol-2012-301735
Source: PubMed
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Available from: Ton G van Leeuwen, Nov 04, 2014
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    ABSTRACT: OBJECTIVE: Rapid assessments of vision commonly rely on visual acuity testing alone. Although well suited for uncovering optical defects, visual acuity tests may fail to detect dysfunction of the neural substrate. There is a need for a rapid companion test sensitive to neural damage. DESIGN: Evaluation of diagnostic tests. PARTICIPANTS AND CONTROLS: Forty-seven patients with optic nerve or visual pathway lesions of low to moderate severities and 30 normal subjects. METHODS: A new computer-based quick test of neurovisual integrity was developed using segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented on a dark background. MAIN OUTCOME MEASURES: The test variable was the number of rarebits per segment; digit size was fixed. The test task was to call out verbally all digits that were seen during an 8-second presentation sequence. Test outcomes were contrasted with the results of an optotype acuity test and automated perimetry. RESULTS: All subjects easily grasped the test task. The normal subjects read, on average, 5.6 (±0.5 standard deviation) of the 6 digits contained in the test sequence, whereas the patients averaged 3.3±1.8 digits. The numbers of digits read correlated modestly with the acuity and perimetry results. Analysis of receiver operating characteristic curves indicated that the multiple rarebit test provided the best discrimination. CONCLUSIONS: The multiple rarebit test seemed to be highly capable of detecting neurovisual dysfunction. Its simplicity and uniquely short duration indicate a useful role in screening settings. The test is available free on the Internet. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.
    No preview · Article · Apr 2013 · Ophthalmology
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    ABSTRACT: PurposeEvaluation of a new personal-computer-based vision test aimed for rapid and accurate assessment of macular conditions such as age-related macular degeneration (AMD).Methods The new test depends on segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented against a dark background. Digit size was fixed at 40 × 50 min of arc. Digit positions were varied at random within a 4.6 × 3.5-degree test field. There were no fixation demands. The number of rarebits per digit segment could be varied between 3 (the minimum needed for veridical perception) and 128, in 11 preset steps. The test task was to find the smallest rarebit number required to recognize the test digits. Thirty-seven patients with various stages of AMD and 25 control subjects participated in the evaluation, which also included a standard acuity test.ResultsAnalysis of receiver operating characteristics indicated significantly better discrimination by the rarebit test. Rarebit numbers >16 appeared to reliably indicate the presence of oedema.Conclusion The rarebit test appeared well suited for fine grading of vision in AMD. The simple set-up and the lack of fixation demands made for practicable examinations of short durations. The test is available for free on the Internet.
    No preview · Article · Jan 2015 · Acta ophthalmologica
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    ABSTRACT: Purpose. There is a need for efficient self-tests of vision in patients with neovascular age-related macula degeneration. A new tablet/smartphone application aiming to meet this need is described and its performance is assessed in a longitudinal pilot study. Materials and Methods. The new MultiBit Test (MBT) employs segmented digits defined by rarebits, that is, receptive field-size bright dots briefly presented against a dark background. The number of rarebits per digit segment was varied in a cyclic fashion, in preset steps. There were no fixation demands. Twenty-eight patients with neovascular AMD of varying severity were monitored for an average of 30 weeks. Test scores were evaluated on an individual basis, by contrasting observed trends with the clinical status recorded at independently scheduled clinical examinations. Results. Serial plots of MBT results revealed gradual improvement after successful antineovascular treatment. Recurrences were signalled by gradual deteriorations of results. Test results remained stable during clinically stable time intervals. MBT results agreed well with clinical assessments whereas an acuity test performed at chance level. The MBT was well accepted by all subjects. Conclusions. The MBT appears to have a good potential for effective self-testing of vision in AMD and merits large-scale studies. Exploration of MBT performance with other forms of macula conditions may be worthwhile.
    Full-text · Article · Jun 2015 · Journal of Ophthalmology