Earlier detection of diabetic retinopathy possible in children

Screening programmes could catch diabetic retinopathy earlier if they began screening 6 years after diabetes is diagnosed, researchers said.

However, the study by researchers at Heartlands Hospital in Birmingham, UK, found that no sight-threatening diabetic retinopathy emerged in children younger than 12. They published their finding in the journal Eye.

Current UK guidelines of the National Health Service (NHS) Diabetic Eye Screening Programme call for screening for diabetic retinopathy to begin at age 12.

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That threshold was established in 2005 when the screening programme started because of a report finding that the youngest person to have sight-threatening diabetic retinopathy was nearly 12 years old.

However, other studies have shown that a small percentage of patients develop diabetic retinopathy at a younger age. 

As an audit of the programme, the Birmingham researchers retrospectively analysed diabetic retinopathy in 143 patients aged 12 years or younger registered with the Birmingham, Solihull, and Black Country Diabetic Eye Screening Programme.

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55% of the patients were boys and 98% had diabetes mellitus type 1. The mean age at first diabetic eye screen was 10.7 years, and they ranged in age from 7 years and  4 months to 12 years 11 months. Some of these patients were younger than 12 years because they were referred for screening from local hospital paediatric diabetes departments based on their age of diagnosis and diabetes duration.

The mean duration of diabetes at the first screen was 5 years.

Accredited optometrists and screeners performed the screening in optometry practices and hospitals.

They used Snellen notation to measure best corrected visual acuity. With a digital fundus camera, they took two 45° images (one macula-centred and one optic disc-centred) through dilated pupils in each eye.

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They performed grading according to English national grading definitions and NHS Diabetic Eye Screening Programme guidelines.

The researchers used the screening database to establish the patients’ date of birth and age of first diabetic eye screen, as well as visual acuity and screening result.

They considered the presence of any diabetic retinopathy as a screen-positive result.

Patient screening

The patients had a mean visual acuity of 6/5 in their best eyes. Eight patients had visual acuities of 6/12 or worse in at least one eye, with ambylopia, optic atrophy, longstanding poor visual acuity, and refractive problems recorded as causes.  

Twelve patients (8.4%) screened positive for diabetic retinopathy. All were found to have mild non-proliferative diabetic retinopathy without maculopathy in at least one eye. The retinopathy did not seem to threaten the vision of any of these patients.

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The researchers divided these patients into two groups: the 72 who were younger than 12 years and the 70 who were 12 years old. They found seven patients (9.6%) in the group younger than 12 years and five (7.1%) in the 12-year-old group who screened positive, but the difference was not statistically significant.

On the other hand, they found a significant difference in diabetes duration between those who presented with diabetic retinopathy and those who didn’t. The mean duration of diabetes diagnosis in those with diabetic retinopathy was 7.3 years (range 6–11 years) compared with 4.8 years (range 1 month–11 years) in those without diabetic retinopathy.

No patient who had a diabetes diagnosis duration of less than 6 years had diabetic retinopathy. This finding fit into the pattern established by previous research.

The results also confirmed previous findings that patients younger than 12 years can develop diabetic retinopathy. And the finding that none of the patients’ sight was threatened by their diabetic retinopathy also agreed with previous studies.

So at what age should patients be screened for diabetic retinopathy?

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That depends on the mission of the screening programme, the Birmingham researchers wrote. “If it is to detect STDR [sight-threatening diabetic retinopathy], then our data support 12 years of age to be the right age as demonstrated in our population.”

But screening programmes might have other goals, they write.

“If it is important to identify first detection of development of diabetic retinopathy, for example, to review diabetes medical management, then ideally diabetic retinopathy screening should start 6 years after the onset of childhood diabetes.”

Since the NHS screening programme set a goal of detecting sight-threatening disease, 12 years of age still makes sense as the threshold, they decided.

But they acknowledged some limitations to their study. First, it was limited to a population living in the United Kingdom. Since the screeners did not accurately record ethnicity, it could not be used in this analysis.

Also the patients younger than 12 were referred by paediatric diabetologists on the basis of the duration of diagnosis, whereas the 12-year-olds were referred because of their age, creating the risk of selection bias.

However, they concluded that their research supports the current NHS guidelines.

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