Visual impairment registration: evaluation of agreement among ophthalmologists

To evaluate consistency among consultant ophthalmologists in registration of visual impairment of patients with glaucoma who had a significant visual field component to their visual loss.

Thirty UK NHS consultant ophthalmologists were asked to grade data sets comprising both visual acuity and visual fields as severely sight impaired, partially sight impaired, or neither. To assess intra-consultant agreement, a group of graders agreed to repeat the process.

Kappa for inter-consultant agreement (n=30) for meeting the eligibility criteria for visual impairment registration was 0.232 (95% CI 0.142-0.345), the corresponding inter-class correlation score was 0.2 (95% CI 0.172 to 0.344). Kappa for intra-consultant agreement (n=16) ranged from 0.007 to 0.9118.

When presented with the clinical data necessary to decide whether patients with severe visual field loss are eligible for vision impairment registration, there is very poor intra- and inter-observer agreement among consultant ophthalmologists with regard to eligibility. The poor agreement indicates that these criteria are open to significant subjective interpretation that may be a source of either under- or over-registration of visual impairment in this group of patients in the UK. This inconsistency will affect the access of visually impaired glaucoma patients to support services and may result in inaccurate recording of the prevalence of registerable visual disability among glaucoma patients with severe visual field loss. More objective criteria with less potential for misclassification should be introduced.