Refractive errors happen as a result of structural changes in the eyes. These changes typically cause light to enter the eyes in an uneven manner, resulting in impaired vision. There are four main types of refractive errors that can usually be diagnosed by carrying out a comprehensive eye exam. Understanding these different refractive errors can help patients take preventative measures that will protect their eyesight for years to come.
Hyperopia (Farsightedness)
This refractive error is usually caused by an excessively short eyeball, which causes light to be reflected to the back section of the retina instead of hitting the top of it. Patients with this condition typically have trouble seeing objects that are close up or carrying out activities that require near-range vision. However, their far-range vision may remain good until they develop presbyopia in their forties. This condition can be treated either by way of corrective eyewear or refractive surgeries.
Myopia or Nearsightedness
Myopia is a condition in which the eyeball is excessively long or has an overly-curved cornea. These factors cause light to hit the front of the retina instead of the top of it. Patients with myopia find that they see nearby objects, while distant ones look distorted or out of focus. Patients with this condition are often prescribed corrective eyewear such as eyeglasses or contacts. Sometimes LASIK is also prescribed to treat Myopia.
Astigmatism
Changes in the cornea or lens can result in the retina developing light-focusing issues. This ultimately leads to blurred or distorted vision (for both near and distant vision). Toric lenses are an effective means of treatment for patients who suffer from astigmatism. They are characterized by their distinct ‘sliced donut’ shape, which allows for different refractive levels. Astigmatism may be corrected with LASIK.
Presbyopia
Over time, our eyes’ natural lenses begin to lose their natural flexibility, resulting in presbyopia. Presbyopia is characterized by an impairment of focusing ability, specifically in regard to looking at nearby objects or performing tasks that require close-range vision. Eye doctors may recommend using bifocal or progressive lenses, which feature two prescriptions in one lens (the upper portion helps with seeing distant objects while the lower part is for close-range sight).
What is the takeaway?
Understanding the four main refractive errors and their characteristics enables patients to recognize their issues early on and take action. It is highly recommended that patients consult with a licensed, experienced doctor to gain a better understanding of their eye issues. Beyond that, taking action to protect one’s eyesight is always a great idea.