The need for reading glasses can be delayed or completely averted by intentionally under correcting the non dominant eye leaving it -1.00 to -2.00. This situation where the one eye is at zero and the other at -1.00 or -2.00 is known as monovision.

Monovision is a good option for those who would like to reduce their dependence on near and distance glasses, and who are also prepared to live with the side effects of monovision, namely that the clarity of vision is not 100% and that there is increased glare and halos at night.

With monovision, many people still use glasses when driving at night to reduce the incidence of haloes in the untreated eye and also when reading for more than ½ hour.

It is important to note that not all people are candidates for monovision:

• People in jobs with variable needs for vision i.e. a mix of distance and near vision interspersed during the day tend to do well with monovision.
• Those who need to look at the same distance for prolonged periods (airline pilots, drivers, computer programmers, etc.) and those with visually demanding jobs tend not to like monovision at all and prefer both eyes corrected to zero with the knowledge that they will need reading glasses after 42 years of age.
• Golfers and tennis players tend to prefer both eyes at zero whereas other sports men and women tend to accept monovision quite well.

If you are younger than 40 years, it normally makes sense to aim for zero in both eyes. If you are older than 40, it may be sensible to try monovision. During your consultation the doctor can demonstrate monovision to you, and may ask you to try out monovision with the use of extended-wear contact lenses left in for a number of weeks to get a better idea of its suitability for you.

Remember that if you opt for monovision and find out later that you don’t like it, the reading eye can be changed back to zero at a later date by giving you further laser.