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Editors Selection IGR 18-2
Perimetry: Visual field indices and ability to drive
Comment by Chris Johnson on:
50973 Practical landmarks for visual field disability in glaucoma, Saunders LJ; Russell RA; Crabb DP, British Journal of Ophthalmology, 2012; 96: 1185-1189
Saunders and colleagues have described a procedure for determining a person's legal fitness to drive by combining visual field information from the two eyes. Several models were evaluated for a large visual-field data set from glaucoma patients (more than 5,000 eyes of more than 2,600 patients). The mean-deviation (MD) visual-field index, a measure that is often used to determine the overall severity and whose changes over time can provide an estimate of the rate of visual field alterations, was used as the main outcome measure. It was determined that the better eye MD provided the strongest relationship with a patient's legal fitness to drive, using visual field criteria that had been previously established by this group as a criterion.
The better eye MD provided the strongest relationship with a patient's legal fitness to drive
There are several benefits to be derived from this investigation: (1) As stated in the title of the paper, this is a practical method for clinicians to implement when evaluating the ability of a glaucoma patient to safely drive an automobile; (2) This procedure is quite simple and can be conducted in a clinical setting in a minimal amount of time; (3) It is evidence-based from analysis of existing visual field data rather than being based on expert opinion. Disadvantages include: (1) Only a small portion (24 degrees radius) of the entire visual field has been utilized for analysis; (2) Decisions are based on test results rather than actual driving performance; (3) Only glaucoma patients were evaluated, patients with neuro-ophthalmologic or retinal disease (most glaucomatous visual field defects do not overlap between the two eyes) were excluded; (4) Individual differences in compensation strategies while driving were not considered.
In summary, these findings provide a rational basis and a good starting point for evidence-based decision making for quality-oflife issues and activities of daily living, and they provide a strong foundation on which to base much needed future work in this area.
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