Can You Be Farsighted And Nearsighted At The Same Time?

Iris photo taken by Dr. Jillian Wong, optometrist @ OPT clinic

Iris photo taken by Dr. Jillian Wong, optometrist @ OPT clinic

 
Anatomy of the eye

Anatomy of the eye

Eye problems can occur at any stage in life and OPT Clinic is committed to diagnosing and treating any eye problems before any permanent damage occurs. The most common eye problem that people experience is vision change. Some people have difficulty seeing up close while others have difficulty seeing far away. These are examples of "refractive error", which means there is an error in how the light is focussing in your eye (either the light is focussing in front or behind the retina, or sometimes both!) If someone has difficulty seeing up close but can see far away, that means they are farsighted. The opposite is nearsightedness, where someone can see up close better than far away. But is it possible that a person is unable to clearly see both the objects kept near to him and objects placed at a distance? Before we answer this question, we have to take a closer look at nearsightedness and farsightedness.

What is Nearsightedness?

Myopia or nearsightedness is the most common vision problem. If someone is nearsighted that means they can see better up close than far away. If you are nearsighted, that means that light entering the eye focusses in front of the retina (the back of the eye) instead of on the retina itself.

What is Farsightedness?

Hypermetropia, also known as hyperopia or farsightedness, is when someone sees better far away than up close. Farsightedness is the opposite of nearsightedness and it occurs when the light focusses behind the retina. People with low amounts of farsightedness typically do not require any glasses until they reach their 40s because they have the ability to focus through small prescriptions of farsightedness. Everyone in their 40s or older will slowly lose the ability to focus so that is why reading glasses are typically required when people reach a certain age!

What is Astigmatism?

Astigmatism is another type of refractive error. Astigmatism occurs when the light does not focus on the retina as a single point. Astigmatism is very common and occurs in approximately 70% of people. Astigmatism results from asymmetry in the cornea or the lens. The asymmetry causes the light to focus differently in different meridians - for example, the horizontal light focusses in a different place than vertical light. There are occasions in astigmatic eyes that part of the light will focus in front of the retina and the light in the opposite direction will focus behind the retina. This is a case where you can consider one meridian to be nearsighted and the other farsighted! Typically those who have uncorrected astigmatism will notice it most during the nighttime. If you look at a streetlight and see streaking lines, that is from uncorrected astigmatism!

What is Anisometropia?

Anisometropia is when someone has a different prescription in each eye. Usually there has to be a large difference before we label it as anisometropia. Another time you can be farsighted and nearsighted at the same time is if you have antimetropia. Antimetropia is a special type of anisometropia where one eye is nearsighted and the other is farsighted. Large differences in prescriptions between eyes can result in something called lazy eye or amblyopia. In cases of amblyopia, treatment should be initiated as soon as possible (before 6 years of age!), before permanent blindness occurs. This is one of the major reasons why kids need an eye exam as early as 6 months!

So, can you be farsighted and nearsighted at the same time? The answer is yes! It can occur within the same eye if you have astigmatism, or between two eyes if you have antimetropia. Any type of refractive errors can occur and the only way to find out is by having your eyes checked! OPT clinic provides thorough eye examinations that include checking your prescription AND checking the health of your eyes! Book online to schedule your eye exam at your convenience!