The Children's Cataract Calculator is a unique online analytical tool that assesses a child's risk of developing cataract in later life
Why the need for a Children’s Cataract Calculator?
The aim of the Children's Cataract Calculator has been not only to raise awareness of the risks faced by children from a young age, but to also produce an individual risk prediction sound in both science and optometry. By this means, children and their parents can be made aware of the risks of developing cataract, and importantly, how to reduce them. In addition, although eye care professionals may be well aware of the risks to adults, the greater risks faced by children, particularly regarding UV light, can often be overlooked.
As a result of increased time outdoors, particularly in summer, children receive as much as three times the amount of UV exposure than adults. Other factors (although anecdotal) could be that children have a more upright posture than adults (who increasingly stoop with age) and facial bone structure which tends to less deep-set orbits, both of which would increase the light incident on the eyes. These factors are consistent with studies which suggest that 80 per cent of radiation damage is likely before the age of 20 years.
Cataract risk factors
The first thing that comes to mind as a cataract risk is increasing age. However, it is evident that some people develop cataract at a relatively early age, and others live all their lives untroubled. We live in an age where research is increasingly identifying individuals who have high or low risk of practically all human ailments, as a result of particular physiology or lifestyle. The unique strength of the Sightrisk mathematical model is that it combines all applicable risks, according to their relative significance, and generates a lifetime risk prediction.
The following risk factors included in the Children's Cataract Calculator are the ones which have been considered sufficiently validated at the present time. As and when other risk factors have been confirmed, these too will be included in the mathematical model.
- Skin colour
- Diet: intake of fruit and vegetables
- Body mass index (BMI)
- Light exposure
- Steroid intake
- Spectacle prescription
Cataract and Latitude
Studies show an increase in prevalence of cataract with proximity to equatorial latitudes. One study in the US (Georgetown University, Washington) suggests a 3 per cent increase in cataract surgery per degree of latitude (southerly) in the US; the reasons for this being higher levels of UVA and UVB passing through the atmosphere where the incident light is less oblique (i.e. closer to the equator). However, other reasons have been cited: warmer climates leading to longer hours outdoors, also the angle (on the face) of sunlight appears to be a factor also. To balance this, another point increasingly mentioned is the depletion of the ozone layer across the poles, which would increase levels of UV radiation at higher latitudes.
With respect to the Children's Cataract Calculator, as this version has been created for use in the UK, the variation in risk with latitude has not been included.
Interestingly, if you applied the results of the Washington study to the UK, with a latitude spread of from around 50 degrees in Cornwall to 60 degrees North in Shetland, you would expect a 30 per cent variation in cataract surgery across the UK. As far as the statistics are available, this doesn't appear to be true; in fact the number of people with cataract in Scotland may be greater. This could be attributed to diet and lifestyle factors, there being a very high rate of coronary heart disease in Scotland, which has many similar risk factors (e.g. smoking, poor diet, diabetes etc).