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T. Wright, G. Mirabella, E. Lakhani, M. Wilson, C. Gerth, P. Glazer, S. Boyd, C. A. Westall; Oculo-Visual Effects of Type 1 Diabetes in an Adolescent Population: Preliminary Results. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5022. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To merge global measures of visual function with localised measures of retinal function to develop a model able to predict risk factors for retinopathy.
Ongoing longitudinal, prospective study. Psychophysical and electrophysiological testing was performed on 36 subjects, mean age 15.6 years who have had type 1 diabetes for at least 5 years plus 20 age matched controls. All underwent ophthalmalogical examination, visual acuity (VA), colour vision and contrast sensitivity (CS) testing. Blood glucose was monitored and controlled. Chromatic visual evoked potentials (VEPs) were recorded. Localised retinal function was tested using 2 multifocal electroretinography (mfERG) paradigms. For the standard paradigm (103 Hexagons) a template stretching analysis was used to define normal ranges of amplitude and timing per hexagon allowing calculation of numbers of abnormal hexagons per recording. A slow-flash (sf) mfERG paradigm (61 Hexagons) was used to isolate OPs. A peak picking algorithm was used to measure timing and amplitude of the dominant peak and total number of abnormal hexagons in each recording.
Subjects with diabetes showed no significant differences in VA (mean 0.02, sd 0.1 logMar), CS (mean 1.74, sd 0.16) from controls. Colour vision was within normal limits for both populations. The short wavelength VEP (sVEP) showed increasing latency as relative contrast decreased, the subjects showed greater rate of regression than controls population (group mean controls = -1.8 ms/% contrast, subjects -2.3 ms/% contrast). Standard mfERGs showed no significant differences in the mean number of abnormal hexagons between the two groups for either timing (controls 4 ±7 subjects 5.5 ±8) or amplitude (controls 0.5 ±0.8; subjects 0.5 ±1.2 ). Only subjects in the diabetic population had retinal areas with reduced OP amplitudes (mean 0.44 ±0.7 p<0.01).
sVEP and sfmfERG detected differences between the populations. It remains to be seen if these tests can predict diabetic retinopathy.
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