Many people wear glasses or contact lenses and might wonder what the various components of their prescriptions mean. These can be confusing topics to understand without learning a lot about them.
The three main types of refractive error are nearsightedness, farsightedness, and astigmatism, along with related presbyopia. This article will explain each of these.
Myopia and Nearsightedness
Also called myopia, this is when vision is blurry at distance without correction. A prescription with a minus sign is required as the eye is either too long or too powerful in its bending of light rays.
Myopia usually begins in late childhood or adolescence, but in recent years its onset has been becoming sooner and sooner in life, with the result that people are getting more and more nearsighted.
When an eye becomes very nearsighted, it also becomes very long, leading to an increased likelihood of retinal and eye health issues later in life.
Lately, methods have been proposed that can be instituted in children to slow the progression of myopia and therefore reduce the magnitude of the overall prescription that one ends up with. This is called myopia control and a growing number of eye doctors offer it to their patients.
Farsightedness and Hyperopia
Hyperopia is when the eye requires a plus glasses prescription to see clearly, mostly at near. The eye is either too small or too weak in its refracting power.
Hyperopia can be sometimes confusing to explain to patients because the eye’s natural focusing system for near work can partially neutralize a farsighted prescription.
This means that if you are a mild hyperope, you may not need glasses to see clearly at all until you are older and your focusing system begins to noticeably fail, a normal aging change.
Our eye doctors expect to see a mild degree of hyperopia in young children and having this is protective against developing nearsightedness.
Astigmatism Can be a Combination of Your Glasses Prescriptions
In contrast to the previous refractive errors, astigmatism refers to an inability for the eye to focus light evenly onto the nerve fiber layer at the back.
This means that in different directions, the prescription varies and thus a lens must be designed with differing prescriptions in various directions in order for the patient to see clearly.
This prescription is often accounted for in glasses already and it is common for most individuals to have a small degree of astigmatism.
Some of the most common symptoms of astigmatism are noticing a starburst of lights around headlights when driving at night or seeing letters or images as smeared in a certain direction.
Presbyopia and Bifocals for Your Glasses Prescription
This refers to a change that occurs later on in life, starting around the early 40s. Around this time, individuals will start to lose flexibility in the focusing system within the eye that is responsible for allowing nearby objects to appear clear.
This is a natural part of aging and is thus unavoidable. Luckily there is a solution to this issue and that is a near addition.
This refers to a specific prescription on top of the current prescription used to view distant objects that brings near objects into focus. As we age, this near add will increase in power, ultimately reaching an absolute level around our 60s.
Our eye doctors at EyeDocs Family Eye Care in Brookville, OH excel in prescription of glasses, contact lenses and the diagnosis of a variety of eye disese. Call our optometrists at 937-770-1265 or schedule an eye exam appointment online if you would like to be evaluated for a new glasses prescription. Our eye doctors, Dr. Kyle Maxam and Dr. Cara Wampler, provide the highest quality optometry services and eye exams in Brookville, Ohio.
You can schedule your next appointment with us online!
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