KnowLASIK

Presbyopia is the term for the diminishing ability to focus on up-close objects with age. While the ability to focus on near objects grows progressively worse beginning at birth, it is often first noticed at age 40 when the near focus is approximately 40 cm. Since this is a standard reading distance, it is this age that people most often feel that they are losing there near vision. In fact, the ability to focus has grown progressively worse since childhood.

Consider this. A ten year old can focus clearly on a book located 7 cm from his face while a twenty-five year old must now hold the book 10 cm from his face. The loss of 3 cm of focus may be hardly noticeable but is equivalent to a loss of four diopters of focusing ability. As the person ages another fifteen years and loses another four diopters of accommodation, they can now focus at a distance of 16 cm for short periods of time and comfortably for long periods of time at about 33 cm. The forty year old will begin to notice that near vision is not as easy as it once was.

What options are there in correcting near vision? (continue reading…)