Registration of visual impairment due to diabetic retinopathy Table 2 Causes of certiﬁcation of visual impairment (VI) in Cambridgeshire (City, South, and Hunts), 2004–2005 Cause of visual Number of Percentage of VI Severe VI 0–15 years 15–64 years Impairment (VI) occurrences patients n = 365 ARMD Glaucoma Retinitis pigmentosa Diabetic retinopathy Visual cortex disorder Optic neuropathy Retinal detachment Cause unstated Others Total occurrences Total CVI forms 224 43 12 18 19 27 7 12 22 384 365 61.4% 11.8% 3.3% 4.9% 5.2% 7.4% 2% 3.3% 6.0% 125 27 5 13 15 18 5 6 14 228 209 99 16 7 5 4 9 2 6 8 156 156 0 0 0 0 1 3 0 4 1 9 9 2 2 7 3 5 12 2 1 7 41 41 65 + years 222 41 5 15 13 12 5 7 14 334 315 In persons of working age (16–64 years), the leading cause of VI registration was optic neuropathy followed by retinitis pigmentosa (Table 2). The speciﬁc causes of optic neuropathy were not stated in most instances on the CVI form. Most optic neuropathies were congenital or secondary to demyelination and did not include diabetic or glaucomatous optic neuropa- thy. Further studies are needed to clarify the types of optic neuropathy, by examining the patient records. A comparison of the demographic proﬁle of our study population with that of England and Wales reveals a younger age proﬁle (Table 4). There are 0.8% less persons aged 75 years and over, and 0.6% more persons in the 0–15 year age group of Cambridge city, South Cambridgeshire, and Huntingdonshire. These differences in age proﬁle may contribute to the differences observed. Three diabetic patients were of working age (16–64 years). From our study, DR does not appear to be the leading cause of CVI in the working age group in this population. This ﬁnding is contrary to that of Bunce and colleagues5 who found that DR was the leading cause of VI in the working age group in England and Wales in 1999–2000. The severe VI registration rate of 6.5 per million per year meets the national standard of 9.5 per million per year. The VI registration rate was 17.1 per million per year, and almost doubles the current national standard of 9.3 per million per year. However, new data on national VI registration has emerged from a study carried out by Bunce and colleagues5 in 1999–2000. In this study the rate of certiﬁcation of VI due to DR was 38.4 per million per year, compared to 19.9 per million per year in 1990–1991.3,6 These rates have doubled over the nine years, partly explained by increased VI registration rates during the time interval 1991–1999, an aging population, and increasing prevalence of Type 2 and Type 1 diabetes.5 Given these new ﬁgures, we recommend that the national standards of severe VI and VI registration rates be revised. A severe VI registration rate of 12 per million population per year has been reported for Fife from 1990–1999,7 and a severe VI registration rate of 10 per million Table 3 Summary of registrations of visual impairment (VI) due to diabetic retinopathy (DR) in Cambridgeshire (City, South, and Hunts) (2004–2005) Number of registrations with severe VI due to DR 5 (3.2% of severe VI registrations) Number of registrations with partial VI due to DR 13 (6.2% of partial VI registrations) Number of registrations with VI due to DR in working 0% of severe VI registrations age group (16–64 years) 1.4% of partial VI registrations Severe VI registration rate due to DR 6.5 per million population per year Partial VI registration rate due to DR 17.1 per million population per year Number of diabetics in Cambs City, South, Hunts 2005 10,842 Prevalence of diabetes 2.74% Severe VI registration rate in diabetics 230 per million diabetics per year Partial VI registration rate in diabetics 600 per million diabetics per year Clinical Ophthalmology 2009:3 77