It’s a question that our doctors hear nearly every day: “Has my vision got worse?” In fact, patients expect their vision to change every year. When we refract a patient during their eye exam (give them the “one or two” testing that quantifies their refractive error, or glasses prescription), we nearly always find some change in the amount of nearsightedness, farsightedness, or astigmatism. This change is usually normal.
“I like to think of the eyes as constantly fluctuating,” says Dr. Abert, of his yearly refractions on his patients. “At some point in a person’s life, the eyes generally stop dramatically increasing, and usually level out.” For most patients, this takes place in their early 20’s. While some patients experience progressive myopia, leading to extreme nearsightedness, most stop changing in their early 20’s. Parents often want to know if there is anything they can do to prevent their children’s nearsightedness from increasing. Let’s first look at what nearsightedness is, and then we can examine what efforts have been attempted to prevent its progression.
Myopia, or nearsightedness, is caused when the eye is too long from front to back (or, has a long ‘axial length’). The eye grows throughout childhood, and if the eye continues to elongate, the amount of nearsightedness will increase.
There have been a number of studies demonstrating that wearing hard contact lenses can prevent some axial elongation, though usually these amounts are too small to make any real difference. For example, if a 10 year-old patient has a near-sighted prescription of -3.00 D (a mild amount of nearsightedness), wearing hard contacts may slow their myopic progression slightly. If they had never worn contact lenses, their final amount of nearsightedness at age 25 might by -6.50 D (a moderate amount of nearsightedness). If they had worn hard lenses throughout childhood, perhaps their prescription at age 25 might by -6.25 D (also a moderate amount of nearsightedness). The difference between the two has been shown to be statistically significant, but is not necessarily clinically significant. The two scenarios both have an end point of a nearsighted eye that sees poorly without correction. Having 0.25 D less nearsightedness probably wouldn’t enhance the functionality of the patient.
Keeping all that in mind, wearing contact lenses remains an excellent way to maintain clear, comfortable vision. It is important to recognize that contact lenses (hard or soft) should not be thought of as therapy, but rather simply a pathway to clear vision while the contact lenses are worn.
“The eyeball is going to do whatever it’s going to do,” Dr. Abert says. “If a patient’s genetic programming calls for nearsighted eyes, then the patient will end up with nearsighted eyes.”
Because the eyes don’t generally level off in myopic progression until the third decade of life, the optometrists at Vista Eye Care doesn’t typically recommend refractive surgery (LASIK or PRK) until the patient is in their mid 20’s. At that age, patients can often enjoy 10-15 years with minimal corrective lens use until the onset of presbyopia (need for reading glasses in the late 30’s or early 40’s). Having refractive surgery too soon can result in the need for distance corrective lenses not long after surgery.
Nearsightedness is completely correctable with contact lenses, glasses, or (if the prescription falls within acceptable limits) refractive surgery. Please talk to your eye doctor about you options for vision correction at Vista Eye Care.