How much blame can be placed on laser photocoagulation for failure to attain driving standards?

Abstract

One hundred consecutive patients who underwent bilateral pan-retinal photocoagulation (PRP) for proliferative diabetic retinopathy were assessed in accordance with the UK Driver and Vehicle Licensing Agency (DVLA) guidelines. Visual acuity was documented, and visual fields were assessed using the Esterman test. Among the 30% of patients who failed to reach the visual standards required for a driving licence, three groups were identified: those who failed to attain either the required binocular visual acuity (n = 4), or visual fields (n = 9), or both (n = 17). Previous studies reveal a large variation in DVLA field test failure following PRP treatment for proliferative diabetic retinopathy. Our results show a 19% failure rate solely attributable to treatment, which is at the lower end of previously reported studies (20-80%). The reasons for this discrepancy are discussed. We conclude that modern treatment procedures for proliferative diabetic retinopathy may be undertaken with the knowledge that in the majority of cases a patient's driving licence is unlikely to be revoked.

Effects of conventional argon panretinal laser photocoagulation on retinal nerve fibre layer and driving visual fields in diabetic retinopathy

“…They advocated routine use of a 200-mm spot for primary PRP in PDR to achieve regression of PDR and maintenance of driving visual fields. Similar recommendations were reported by Mackie et al, 8 after 19% of patients studied were found to fail the DVLA standards. We used a 100-ms pulse duration, 300-mm spot, and low laser power.…”

“…The extent of visual field loss has been attributed to higher laser power intensity and greater retinal laser coverage. 8,9 In this study, an increase in mean threshold sensitivity was observed in a majority of the patients, and such increases were also present for the untreated central 101. Our laser technique was modelled on ETDRS guidelines but used lower power than did the EDTRS and Henricsson and Heijl studies, which may have contributed to significant functional benefits.…”

“…Some centres use 500 mm as a standard laser strategy rather than our current laser strategy of 300 mm; however, there are risks of 16.5% expansion rate with large laser spots and increased risks of people failing driving fields using a 500-mm spot size. [7][8][9] Although laser powers appear lower than those of the published literature, standard pulse duration was used to ensure ETDRS burn intensity. No natural history data are available for RNFL changes in PDR.…”

“…7 After ETDRS protocol PRP, between 12 and 30% of patients may fail DVLA binocular visual field testing. 8,9 Vision testing and driving field assessment are requested locally by the DVLA to assess the patient's fitness to drive after self-declaration of bilateral laser photocoagulation, which may be repeated as required with further PRP.…”

How good are we at assessing driving visual fields in diabetics?

“…Both the present and a previous chairman emphasise that the recommendations should not be applied in an unduly restrictive manner. 4,8 Although fields that are found difficult to assess may be referred to the Visual Standards Sub-Committee, the majority of fields are not examined in this way. It is possible that variation in assessment may deprive some patients of their licence to drive whilst allowing others to continue despite having inadequate visual field.…”