By Michael Hutton 

Monovision contact lenses  using the optical science of orthokeratology could be a key weapon for short-sighted over 40s women who are losing the battle of the sexes when it comes to eyesight problems for older adults according to new research by the University of California in Berkeley. This research published in the latest edition of "Investigative Ophthalmology & Visual Science" reviewed a number of clinical studies on presbyopia - the clinical term for when near objects like books and menus become more difficult to read as you get older - which highlighted the fact that women were more at risk from this condition. However, the interesting conclusion from the research is that this gender bias appears to be more the result of the kinds of tasks women perform, where the tasks are undertaken and the typical viewing distances involved.

Put simply, the authors of the research suggest that having shorter arms means that women tend to hold reading materials much closer than men as well as performing many other hand-held tasks with a similar effect, resulting in their vision being concentrated on shorter focusing distances. Given the further suggestion that women typically spend more time than men indoors where light levels are up to one-tenth of those outside, this is a further explanation for the apparent gender bias of presbyopia. With monovision contact lenses , a person is initially corrected with two orthokeratology lenses for distance vision so that they can see far objects clearly. Thereafter, only one lens is worn - usually in the dominant eye which for most people is the right eye - and this provides excellent distance vision whilst the uncorrected eye deals with all near vision requirements like reading.

Presbyopia is age-related and is caused by a loss of elasticity in the lens of the eye and in the muscles around the lens so that the eyes progressively become less able to switch from looking at distance objects to focus on objects close by. For many short-sighted people who are already wearing glasses or daytime contact lenses, the onset of presbyopia often means the inconvenience of additionally having to carry reading glasses around. However, with orthokeratology lenses - or ortho-k for short - a new treatment is now available which, uniquely, has the advantage of correcting eyesight while the lens wearer is asleep. They work by gently flattening the surface of the eye using the mild pressure of closed eyelids during sleep to achieve the correct focusing distance and the effect lasts for over 24 hours. So with monovision contact lenses , the wearer has perfect all-day natural vision, both for near and distant objects so being a woman with short arms is no longer an issue!

Check if you are suitable for overnight ortho-k corrective contact lenses  for monovision.