Practical landmarks for visual field disability in glaucoma.
OBJECTIVE
To assess whether mean deviation (MD) from automated perimetry is related to the visual field (VF) component for legal fitness to drive (LFTD) in glaucoma patients.


METHODS
Monocular 24-2 VFs of 2604 patients with bilateral VF damage were retrospectively investigated. Integrated visual fields were calculated and used as a surrogate to assess LFTD according to current UK driving licence criteria. The better eye MD (BEMD), worse eye MD (WEMD) and a measure utilising MD of both eyes were compared, to assess respective diagnostic capabilities to predict LFTD (using the integrated visual field surrogate test as the gold standard) and a 'Probability of Failure' (PoF) for various defect levels was calculated.


RESULTS
BEMD appears to be a good predictor of the VF component for a patient's LFTD (receiver operating characteristic area under the curve: 96.2%); MDs from both eyes offered no significant extra diagnostic power (area under the curve: 96.4%). PoF for BEMD thresholds of ≤-10 dB and ≤-14 dB were 70 (95% CI 66% to 74%) and 92% (87% to 95%), respectively.


CONCLUSIONS
There is a strong relationship between BEMD and a patient's LFTD. PoF values for LFTD associated with readily available MD values provide practical landmarks for VF disability in glaucoma.
Department of Optometry and Visual Science, City University London, Northampton Square, London, UK.
Luke J
LJ
Saunders
Richard A
RA
Russell
David P
DP
Crabb
D000368:Aged; D059925:Anatomic Landmarks / Q000473:pathology*; D004185:Disability Evaluation; D005260:Female; D005901:Glaucoma / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011237:Predictive Value of Tests; D012372:ROC Curve; D012015:Reference Standards; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014787:Vision Tests; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests / Q000379:methods* / Q000592:standards; D014794:Visual Fields / Q000502:physiology*