Passive smoking in children may influence their refractive error, according to a study in the latest issue of Ophthalmic and Physiological Optics.
The number of parental cigarettes smoked was matched with urinary levels of cotinine and creatinine in a sample of 300 children. Those with hyperopia had significantly higher urinary cotinine values than the myopes and emmetropes. The authors concluded that passive smoking was related to refractive error and that it should be considered as a risk factor for a hypermetropic shift.
The authors, based at Ain Shams University in Cairo, noted that a causal relationship might have been better evaluated by further follow-up in a smoke-free environment.
Optician clinical editor Bill Harvey commented: 'Further study needs to decide on any direct association when one bears in mind other factors such as the socio-economic status of smoking parents and the environmental conditions in which children are brought up.
There is, for example, already increasing evidence of a link between less myopic progression and increased outdoor activity. A more studious and indoor-based child in a non-smoking middle class environment might be more prone to myopia than one more used to less study in a lower socio-economic environment where both parents smoke.'