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screening for diabetic retinopathy is a highly costeffective health initiative and blindness caused by diabetes is lower in populations where a diabetic eye screening programme is established 1 , 2 , 3 .
there is a global increase in the incidence of type 1 diabetes mellitus in children 4 , particularly in those aged under 5 years 5 .
young children face long prepubertal years of hyperglycaemia , with prepubertal , pubertal and postpubertal years contributing 6 , 7 to an increased risk of development of microvascular complications of diabetic retinopathy . in 20132014 , it was reported 8 that there were 26 687 young persons under 25 with diabetes in england and wales .
annual screening for diabetic retinopathy is recommended in england , scotland , wales and northern ireland for all those with diabetes aged 12 and above .
this was a pragmatic policy decision taken in 20022003 because the youngest person reported with sightthreatening diabetic retinopathy in the literature at that time was aged 11.3 years 9 .
we report on the relationships between age at diagnosis of diabetes , diabetic retinopathy levels at first screen at either 12 or 13 years of age , and time to development of sightthreatening diabetic retinopathy after first screen .
we recruited data for the four nations study 10 from seven diabetic retinopathy screening programmes : the wholenation programmes in wales , scotland and northern ireland and four local english programmes ( brighton , derbyshire , leeds and staffordshire ) . for the present study , one english programme was excluded because no data were available for age at diagnosis of diabetes .
data for all children referred to the eye screening programme , grading results at first screen , and age in years at diagnosis of diabetes were extracted from the screening programme databases .
the inclusion criteria were all children aged 12 and 13 years , who attended their first annual digital photographic screening in the uk . there are very few exclusion criteria , such as when a child is terminally ill . in the english nhs
diabetic eye screening programme all images are allocated a retinopathy ( r ) grade and a maculopathy ( m ) grade on the basis of the absence , presence and severity of features of diabetic retinopathy found during qualityassured grading of the retinal images .
a mapping exercise was undertaken between the english , scottish and etdrs grading criteria 10 , 11 , 12 .
referable or sightthreatening diabetic retinopathy was identified by the presence of features of moderate to severe nonproliferative , proliferative diabetic retinopathy or maculopathy in at least one eye .
children with images of either or both eyes that could not be assessed were excluded from these analyses .
screening data from both eyes were combined to provide four possible categories of children : 
 no diabetic retinopathy ( r1m0 ) in both eyes;mild nonproliferative diabetic retinopathy ( r1m0 ) in one eye;mild nonproliferative diabetic retinopathy ( r1m0 ) in both eyes;referable diabetic retinopathy ( r2 or m1 ) or fasttrack proliferative diabetic retinopathy ( r3 )  the referable diabetic retinopathy group including the fasttrack proliferative diabetic retinopathy is referred to as sightthreatening diabetic retinopathy in this article . 
 
no diabetic retinopathy ( r1m0 ) in both eyes ; mild nonproliferative diabetic retinopathy ( r1m0 ) in one eye ; mild nonproliferative diabetic retinopathy ( r1m0 ) in both eyes ; referable diabetic retinopathy ( r2 or m1 ) or fasttrack proliferative diabetic retinopathy ( r3 )  the referable diabetic retinopathy group including the fasttrack proliferative diabetic retinopathy is referred to as sightthreatening diabetic retinopathy in this article . for survival analyses of time to diabetic retinopathy in children who had at least two retinal screenings , followup was censored at the time of second screening .
kaplan  meier survival curves of time to diabetic retinopathy were plotted , stratified by duration of diabetic retinopathy at first screening .
cox proportional hazards models estimated the hazard ratio for diabetic retinopathy in children by duration of diabetes at first screening .
in total , 2125 children received their first screening at the age of 12 or 13 years .
the results of the baseline screen of 2125 children at the age of 12 or 13 years are shown in table 1 .
o the children diagnosed under the age of 2 years , 20.1% had signs of any retinopathy compared with 6.3% of those diagnosed at the age of 10 years .
results of the baseline screen at the age of 12 years or 13 years * three children were reported as having referable retinopathy at first screening .
the first was diagnosed with diabetes at the age of 8 years in 2000 , first screened in november 2005 at age 13 years , and approximately annually thereafter until 2012 .
referable diabetic retinopathy was recorded at the first screening , followed by referable diabetic retinopathy in 2007 , 2009 , 2011 and 2012 with possible preproliferative changes ( r2 ) , but mild nonproliferative diabetic retinopathy ( npdr ) in both eyes in 2008.the second was diagnosed with diabetes at the age of 10 years in 2004 , and first screened in november 2007 and again in 2012 .
referable retinopathy ( maculopathy  a blot haemorrhage or exudate < 1 disc diameter from the foveal centre ) was reported in 2007 , but only mild npdr in one eye was found in 2012.the third was diagnosed with diabetes at the age of 11 years in 2005 , and screened in 2006 , 2009 , 2010 and 2011 .
the screening result in 2006 reported  proliferative retinopathy but subsequent screening reported no diabetic retinopathy in 2009 and mild npdr in one eye in 2010 and 2011 . 
 
the first was diagnosed with diabetes at the age of 8 years in 2000 , first screened in november 2005 at age 13 years , and approximately annually thereafter until 2012 .
referable diabetic retinopathy was recorded at the first screening , followed by referable diabetic retinopathy in 2007 , 2009 , 2011 and 2012 with possible preproliferative changes ( r2 ) , but mild nonproliferative diabetic retinopathy ( npdr ) in both eyes in 2008 .
the second was diagnosed with diabetes at the age of 10 years in 2004 , and first screened in november 2007 and again in 2012 .
referable retinopathy ( maculopathy  a blot haemorrhage or exudate < 1 disc diameter from the foveal centre ) was reported in 2007 , but only mild npdr in one eye was found in 2012 .
the third was diagnosed with diabetes at the age of 11 years in 2005 , and screened in 2006 , 2009 , 2010 and 2011 .
the screening result in 2006 reported  proliferative retinopathy but subsequent screening reported no diabetic retinopathy in 2009 and mild npdr in one eye in 2010 and 2011 .
followup data were available for 1703 children who had baseline gradable images and at least one subsequent set of images .
of these 1703 children , the median age at diagnosis of diabetes was 8 years with an interquartile range ( iqr ) of 511 years ; 52% of these children were male . at baseline , 1531 ( 89.9% )
children were graded as having no retinopathy , 129 ( 7.6% ) were graded as having mild npdr in one eye and 43 ( 2.5% ) were graded as having mild npdr in both eyes . of the 1703 children with subsequent images , 16 had a valid screening result at first screen that was not gradable at the second screen but had at least one subsequent gradable image .
of the 129 children with mild npdr in one eye at first screen , 88 ( 68.2% ) were graded as no diabetic retinopathy , 26 ( 20.2% ) as mild npdr in one eye and 15 ( 11.6% ) as mild npdr in both eyes at the second screen .
of the 43 children with mild npdr in both eyes at first screen , 18 ( 41.9% ) were graded as no diabetic retinopathy , 12 ( 27.9% ) as mild npdr in one eye and 13(30.3% ) as mild npdr both eyes at the second screen ( chisquared for trend = 146 , p < 0.0001 ) . during subsequent followup visits ,
25 children were graded as having sightthreatening or referable diabetic retinopathy , three of whom were graded as having proliferative diabetic retinopathy .
figure 1 shows the time to sightthreatening diabetic retinopathy from baseline screen at 12 or 13 years by age of diagnosis of diabetes in these 25 children .
the median time from baseline to sightthreatening diabetic retinopathy was 3.1 years with an iqr of 1.74.1 years .
time to sightthreatening diabetic retinopathy from baseline screen at 12 or 13 years by age of diagnosis of diabetes .
the red line represents children diagnosed with diabetes at 5 , 6 or 7 years .
the green line represents children diagnosed with diabetes at 8 , 9 or 10 years .
the results of the cox proportional hazards model analysis show that those with longer duration of diabetes at baseline screening episode at age 12 or 13 years were at higher risk of progression to referable diabetic retinopathy with a hazard ratio of 1.36 per year [ 95% ci ( 95% ci ) , 1.20 to 1.53 ) .
since 2002 , the uk national screening committee , the sign guideline 13 and the nice guidelines 14 , 15 have recommended annual digital photographic screening for all children over the age of 12 years and adults with diabetes , with evidence from studies 16 , 17 demonstrating that one and twofield digital photographic screening could show sensitivities of > 85% against a reference standard of an ophthalmologists examination or sevenfield stereophotography .
specificities of 8595% were also achieved for mydriatic photography 16 , 17 and for staged mydriasis 18 .
the american academy of ophthalmology 19 recommends annual ophthalmic examinations beginning 35 years after the diagnosis of type 1 diabetes mellitus .
the international diabetes federation / international society for pediatric and adolescent diabetes guideline 20 recommends examination for diabetic retinopathy in type 1 diabetes from age 11 years and after two years diabetes duration , and from diagnosis in type 2 diabetes .
it found that , although 10% of children have some retinopathy at baseline screening at the age of 1213 years , only three children ( 0.17% ) were graded as having sightthreatening diabetic retinopathy .
of the three we identified , it seems likely that none required treatment because only one case was consistently diagnosed as sightthreatening and this was preproliferative diabetic retinopathy which does not normally require laser treatment . in those diagnosed with diabetes in early childhood , the rate of retinopathy was significantly higher than for those diagnosed later on .
the low prevalence and incidence rates in this large cohort of children suggest that earlier screening for sightthreatening diabetic retinopathy is not necessary in this age group . there may be value in detecting diabetic retinopathy at a mild stage , but only if it could be shown that closer followup in this atrisk group could reduce the progression rate and the development of complications in these children .
funding was received from the nhs diabetic eye screening programme & scottish diabetes retinal screening programme .
gl , mb , ml , cj and bf all commented on the drafts of the paper .
peter scanlon is the guarantor of this work and , as such , had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis .
abstractaimsto investigate the relationships between age at diagnosis of diabetes , age at diabetic eye screening and severity of diabetic retinopathy at first and subsequent screenings in children aged 12 or 13 years.methodsdata were extracted from four english screening programmes and from the scottish , welsh and northern irish programmes on all children with diabetes invited for their first and subsequent screening episodes from the age of 12 years . 
 retinopathy levels at first and subsequent screens , time from diagnosis of diabetes to first screening and age at diagnosis in years were calculated.resultsdata were available for 2125 children with diabetes screened for the first time at age 12 or 13 years . in those diagnosed with diabetes at 2 years of age or less , the proportion with retinopathy in one or both eyes was 20% and 11% , respectively , decreasing to 8% and 2% in those diagnosed between 2 and 12 years ( p < 0.0001 ) . 
 only three children ( aged 8 , 10 and 11 years at diagnosis of diabetes ) had images graded with referable retinopathy and , of these , two had nonreferable diabetic retinopathy at all subsequent screenings . 
 of 1703 children with subsequent images , 25 were graded with referable diabetic retinopathy over a mean followup of 3.1 years , an incidence rate of 4.7 ( 95% confidence interval , 3.17.0 ) per 1000 per year.conclusionsin this large cohort of children , the low prevalence and incidence rates of referable diabetic retinopathy suggest that screening earlier than age 12 is not necessary .