Fancy Names for Fuzzy Vision
Hello everyone! It’s been a bit but I am back again on the blog train. I know this is a great way for people to get answers they are looking for to questions I get from almost every patient! By the way, if you have any topics that you would like me to cover, send them over to email@example.com or just send us a message on our instagram or facebook pages.
Blurry Vision = Refractive Error
This time around I’m going to give an overview of REFRACTIVE ERROR. These words sound intimidating and concerning but they really are not at all. Refractive error just means that your eyes don’t focus light perfectly on the retina, and truthfully, most eyes don’t!
There are basically 3 different types of refractive error and they all have different names which they can be referred to. The most recognizable type of refractive error is called myopia. Myopia is also known as nearsightedness. Across the pond where they say a lot of things funny it is called “short-sighted.” Say it with me in a Sean Connery accent. I’ll take short-sighted for a 1000, Alex. Anyway, myopia is a condition where light rays from a distant object that enter the eye get focused IN FRONT OF the retina inside the eye. Lenses with minus powers shift the focal point backwards so it lands on the retina. How nearsighted someone is will determine how much shifting and therefore power is required. When someone is myopic there is no amount of work that can be done to see far away things. That is not how the physics of the eye works so it is impossible. Lenses have to be used to refocus the light.
In contrast to nearsightedness we have far-sightedness. This is also called hyperopia, hypermetropia, or Sean Connery says “long-sighted.” This is where light rays from a distant object that enter a relaxed eye get focused behind the retinal tissue inside the eye. I make note of a relaxed eye in this situation because there is work or effort that can be done by the muscles in the eye to move the focal point forward. This is so the light rays will land right on the retina and vision will be sharp. How much work is required by the eyes will determine how long the muscles can work before they get strained and maybe someone would get a headache or have tired eyes. If the work required is too much or the eyes are not able to do the work for a number of different reasons, plus powered lenses are used to do the work for the eyes.
Related to far-sightedness is a condition called presbyopia. Presbyopia is when the focusing system we just talked about becomes less flexible and less capable of the adjustments or accommodation work that is required. This is a completely normal change of the eye and typically happens to people in their 40s. When someone’s lenses that are meant to correct their distance vision are not usable or effective when looking at near objects, they can be said to be presbyopic. Near sighted people who are presbyopic can remove their distance glasses to see near things or they may need a different prescription near the bottom of their lenses called a bi-focal.
The last type of refractive error is everyone’s favorite. Why do I know it is everyone’s favorite? I know this because literally every time I have mentioned the word ASTIGMATISM in an exam, the response is “now tell me what that is again?!” Now, I am 100% ok with that because I’m an eye nerd and I love answering questions and making sense of things for people. SO! Astigmatism (one should note that this is one word, not “a stigmatism”) is a type of refractive error where the eye has two different focal points. One part of the eye will focus light behind another focal point from another part of the eye. I know, confusing, but bear with me. The way light gets focused has a lot to do with curves. Different curves on different glasses lenses (or contact lens) produce different focusing points. More curve equals more power. Ok, back to astigmatism. People with astigmatism require lenses of different curves in different areas of the lens to compensate for their dual focal points and provide them the sharpest vision possible. SO! Is astigmatism a life threatening condition as some would lead you to believe? No. It is very common and easily correctable and not a big deal.
So there you have it. The 4 different types of refractive error. Want to know more? Schedule an appointment with us and we can have more nerdy eye talk! See you soon!