Will Wearing Glasses Make Your Vision Worse?9:06 PM
A question for the ages. As an optometrist, I answer a lot of questions about vision and ocular health every day, but this particular question pops up more frequently than I would have suspected. The simplest answer is this: if your glasses are the correct prescription, wearing them will in NO way hurt your vision. To be more thorough with this answer though, we actually need to break it down into several common scenarios:
1) My glasses prescription is correct, but it seems like my vision is worse than before when I take them off.
I hear this often from patients that are new glasses or contact lens wearers. If the glasses prescription truly hasn't changed, then vision without glasses looks worse than the patient remembered because they had never previously had crisp and clear 20/20 vision to compare to their own vision. If your world looks blurry all the time, that becomes your normal. Once you get used to 20/20 vision in your new glasses, that same amount of blur looks just terrible because now you know what you are missing!
2) I wear over the counter reading glasses, and I just keep having to get stronger and stronger powers. Have I made my vision worse with the wrong reader?
For those individuals over age 40 that suffer from presbyopia (see this post for more details), reading glasses become a way of life. Because over the counter readers are readily available, many patients will pick a pair in the store based on what feels most comfortable, without seeing a doctor first to verify the necessary Rx. The good news is that wearing readers will not hurt your vision even if you select the wrong power. They can give you headaches if the prescription is too strong or too weak, but this is really the only side effect. And rest assured, even though it feels like you are getting more and more dependent on your reading glasses, it is because your visual system is gradually declining at near due to normal aging changes (none of us are immune!) and not because of the readers. My patients are also often concerned that they selected too strong a power in reading glasses (the powers typically span from +1.00 to +3.00), but a stronger pair will only give you greater magnification and force you to hold things closer if it is stronger than you really need. No permanent harm done, but you will get used to a certain level of magnification if you use a particular power for a while.
3) Every year my child's glasses prescription is getting stronger. Is wearing glasses making his vision worse?
This question is the only one where we can get into a scientific debate. Myopia can progress quite rapidly in children, and a number of factors influence this progression. Being near-sighted is a function of the curvature and length of your eye, which in turn is influenced by both genetics and environment. Numerous studies have shown a correlational relationship between amount of time doing near work (like reading) and the presence of myopia. Whether myopic children tend to read more because it is easier for them than distance activities, or if they are myopic because of doing so much reading is under constant debate. There is a school of thought however that near strain, or the strain on the eyes' focusing system when performing a task at near, can induce myopia in an effort to relieve that strain. An overview of these theories can be found in Myopia and Nearwork by Rosenfield and Gilmartin. As optometrists, we try to counteract this progression of myopia from near strain by:
- Prescribing the lowest possible prescription to attain 20/20 vision, and thus limiting the amount of near strain when reading with glasses.
- Prescribing bifocals or progressives for children when needed to ensure that their distance prescription does not adversely affect their reading facility.
- Studies have shown that certain contact lenses such as rigid gas permeable lenses or orthokeratology (where the patient sleeps in rigid contact lenses that act like a retainer to change their prescription overnight) can help slow the myopic progression in some cases. For more information (though it is quite technical), try this article:
|This rigid gas permeable (or hard) contact lens has a special design that flattens the cornea overnight, leaving a myope with clear distance vision the next day. This technique is best for myopes -4.00 in prescription or less.|
One more important point to this question: if your glasses are the wrong prescription or incorrectly made, they can cause symptoms like eye strain, headaches, double vision, and of course blur. These symptoms will not have lasting damage when the problem with your glasses is fixed, so if you notice any of these issues, you should have your doctor check your prescription.