Sir,

There are ~1.2 million people with learning disability (LD) in the United Kingdom with one in ten people with LD estimated to have a visual impairment.1 Life expectancy in LD is increasing1, 2 with anticipated rise in the numbers presenting for cataract surgery. Assessing vision in this group of patients can be a challenge, which becomes a barrier to accessing surgery. We have developed Visual Symptoms in Learning Disability (VSLD) questionnaire as a novel tool to document vision-related signs and symptoms in patients with LD to establish visual function and facilitate decision making in patients who cannot perform traditional acuity methods. Here we share our prospective case series of 10 patients with LD undergoing cataract surgery, in which the questionnaire was applied and validated.

Methods

VSLD questionnaire was designed by pooling 50 questions from published visual function and social function tools, patient interest groups (RNIB, SeeAbility), patient advocates and learning disability facilitators. Statements were reviewed by health professionals and combined, reworded or omitted to leave 10 core statements (Table 1). The developed VSLD questionnaire was administered by specialists orthoptists, ophthalmologist or LD health facilitation nurse to 10 patients referred for cataract surgery. The responder was encouraged to report difficulty regardless whether they consider that vision was a factor in their ability to perform the task, to avoid bias of diagnostic overshadowing.

Table 1 Visual Symptoms in Learning Disability questionnaire
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Results

Nine out of 10 patients experienced an improvement in vision and VSLD score (Figure 1). VSLD improvement correlated with improvement in estimated visual acuity. The patient with a static VSLD score had undergone second eye surgery (pre-operative visual acuity 1.2 RE, 0.0 LE). Interestingly, even in those patients in whom problems with functioning were not thought to be directly related to vision, an improvement had been noted post-operatively, which gives us confidence in using the questionnaire as a way of avoiding diagnostic overshadowing bias.

Figure 1
figure 1

VSLD score comparing pre- and post-cataract surgery visual function for 10 patients with LD. VSLD, Visual Symptoms in Learning Disability.

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Discussion

We have previously discussed methods of applying reasonable adjustments in order to facilitate cataract surgery in people with LD.3, 4 Traditional measures of visual function to demonstrate cost effectiveness of cataract surgery such as VF-14 questionnaire5 refer to tasks which may not be relevant to adults with moderate and severe LD. In order to demonstrate utility of cataract surgery in patients with LD, one would strive to demonstrate improvement in functioning, but no assessment tool previously existed for this purpose. VSLD questionnaire will support the patient and healthcare team in decision-making process about cataract surgery in this challenging patient group, as well as providing an alternative way to audit cataract success in the absence of visual acuity.