There are a number of things that will change over time. One of the most annoying changes is the inability to focus on the things that are within your reach. This is called presbyopia.
Presbyopia is the condition where the lens inside your eye loses its natural ability to focus things up close. Fortunately, we have several ways to correct this. One form of treatment for this is reading glasses.
These usually come in powers ranging from +1.00 to +3.00. As a general rule, the higher the number, the more power and magnification it gives you. As a rule of thumb, you should generally use the lowest possible wattage that allows you to see what you need.
The downside to these glasses is that they will blur things out for you if you look at things from a distance. This is why these glasses are often worn lower on the bridge of your nose or you have to keep putting them on and taking them off your face.
Sometimes you can’t just use over-the-counter reading glasses because you also need a prescription to help you see from a distance. In these cases, your near vision can be corrected with a bifocal.
There are several types of bifocals. A traditional bifocal has a small boat-shaped lens at the bottom of the lens that lets you focus on things up close. The good thing about it is that you know exactly where to look through the glasses to help you see up close. The downside to this lens design is that there is a line in the lens that people often have a hard time adjusting to.
For more advanced levels of presbyopia, sometimes people will also need a trifocal. A trifocal lens is a lens that not only has the lens at the bottom of the glasses to help you see up close, but a second lens above the bifocal lens that is placed between your remote prescription and your near prescription. This central lens allows you to see things from an intermediate distance, which is usually when looking at things 2 to 3 feet away.
There are more advanced spectacle lens technologies called progressive addition lenses. A PAL allows you to see from afar through the top of the lens and gradually progresses down the lens where the power is up close. The advantage of this lens design is that there are no lines in the lens. There is a slow and gradual increase in power up close as your eyes descend through the lens.
While bifocal, trifocal, and PAL lenses work well to provide patients with far and near vision, the main downside is that they can be difficult to use on a computer screen. If you’ve ever worn any of these lens designs and tried working on a computer screen, you would have had to tilt your head back in order to access the powers at the bottom of the lens to see the screen from the computer. There is another solution to help optimize vision on a computer screen which is often referred to as a computer lens.
In a computer glass, the top of the eyeglass lens is focused for the computer screen while the bottom of the glass is focused for near vision (16 inches away). The advantage of this
is that when a person wears it, they don’t have to tilt their head back to see the computer screen clearly. The downside is that if someone tries to look far away with this lens design, it won’t give them good distance vision because the top of the lens is not configured to optimize far vision it is. configured to optimize the distance from the computer screen.
Special contact lenses are now designed to help you see better up close. Monovision is a way of wearing contact lenses so that one eye is set to focus far away and the other eye is set to focus near. This allows you to see far and near without the need for reading glasses. The advantage of monovision is that it allows you to skip glasses for most of the things you will need to see. The downside is that it can take a while to get used to having each eye focused on a different distance. About two-thirds of people who try monovision will succeed.
There is another type of contact lens called a multifocal contact lens. A multifocal contact lens is based on the principle of simultaneous vision. This means that far and near targets are focused on the retina at exactly the same time. The brain pays more attention to what it is trying to focus on and ignores what it is not trying to focus on. The advantage of this lens design is that you use both eyes to see things both from a distance and up close. The downside is that because you increase the depth of field, some people will not be able to get used to the vision provided by the lenses.
Soon there will be eye drops approved to help people with presbyopia see better up close. These drops decrease the size of the pupil. In doing so, they extend your depth of field so that your near vision improves. These drops will be intended to be used once a day.
There are currently several options for treating presbyopia and soon there will be drops that will help you see more clearly up close. Be sure to discuss these options with your optometrist to determine which one is best for you.
Mile Brujic, OD, FAAO graduated in 2002 from the New England College of Optometry. He is a partner of Premier Vision Group, an optometry practice with three locations in Northwest Ohio. He practices comprehensive optometry with an emphasis on the management of anterior segment eye disease and specialized contact lenses. Brujic is a member of the editorial board of several optometric publications. He has published over 350 articles and lectured over 1,600 nationally and internationally on contemporary eye care topics.