What to do when your perfect vision gets blurry at age 40

A brief anatomy and optics discussion is needed because this is not really easy to understand.  In contrast to nearsightedness where the eye is too long for the corneal shape, in farsightedness the opposite occurs.  Light rays want to focus behind the eye rather than on the retina where they belong, and this blurs the vision.  Unlike nearsightedness,  the youthful eye can overcome this with the lens inside the eye which can focus and overcome this defect in the shape.  However, as we age, the lens loses this ability, and things get out of focus.  For these eyes this is more true the closer something is that we are looking at, so this is why reading up close is the first thing to go.

With LASIK or any of the flavors of laser vision correction (such as PRK), we can change the shape of the eye and make it either a more powerful focusing cornea or a less powerful focusing cornea.  In the case of nearsightedness we basically flatten the cornea, reduce its focusing power and fix the eye.  In farsightedness we need to do the opposite, that is, make it a stronger or more curved shape.  How can we do this when the laser can only remove tissue and is not adding anything to the shape?  The answer is that we remove a donut shaped ring of tissue from the outer part of the cornea and this effectively steepens the middle of it.  Doing this we can also correct astigmatism by making the donut shape slightly oval, and fix just about any shape into any other shape within reason.  There you have it, hyperopic LASIK.

So for the 39 year old who is 2 diopters hyperopic, we can restore their distance AND their near vision with this one procedure.  Now what happens when they turn 47 or so?  They will still have good distance vision, but their near vision will again begin to fade away needing reading to supplement their near vision.  We bought them 5-10 years of vision like they had a decade earlier, and maybe even better, but at this point they are needing reading glasses again which might be ok but there is another option.

Monovision which works well for nearsighted people is making one eye for distance and the other eye for near.  This can be done with contact lenses or with LASIK and in the right individual delays or eliminates the need for reading glasses.  In our farsighted patient the same process can be done to buy them another decade free from glasses.  In this case the dominant eye is corrected fully for distance, and the non-dominant eye is corrected for reading.  Sometimes we do what is called partial monovision, where we make a compromise in the near eye so that it is still pretty good at distance (good enough to drive) but helps more with the near vision.  With this combination we can put off the reading glasses to closer to age 60 and retain good distance vision.  It is important to discuss this carefully with your eye doctor, and to try a simulation with glasses or contact lenses first.  For many, this is a great compromise.

The take home lesson is that for the millions of people who are in their late 30's to mid 40's who suddenly have lost their near vision, LASIK may provide a solution to allow them to enjoy improved vision at distance and near for an indeterminate period of time and has been a very succesful procedure for these people.  The newer lasers we have at our center are now able to successfully correct farsightedness and astigmatism to make this possible.  Many of these patients did not realize that LASIK could  help them and it is a good idea to investigate whether this could be a benefit to anyone in this situation.