Millions wear glasses or contact lenses to see clearly. These are the simple solution to refractive errors when the eye can’t focus light onto the retina and you get blurry vision. Glasses and contact lenses bend or refract light as it enters the eye so the retina gets a focused image.
Let’s take a closer look at common vision problems and how specific lenses are designed to fix each one.
Common Vision Problems
There are four types of refractive errors that glasses and contact lenses correct:
Myopia (Nearsightedness): You can see close-up objects clearly but distant objects are blurry. This is because the light entering the eye focuses in front of the retina instead of on it, often because the eye is too long.
Hyperopia (Farsightedness): You can see distant objects more clearly than close-up ones. This is because the eye is too short so light focuses behind the retina instead of on it.
Astigmatism: This is when the cornea or lens is irregularly shaped and light focuses unevenly on the retina. Astigmatism causes blurry or distorted vision at any distance.
Presbyopia: This occurs with age and affects the eye’s ability to focus on close-up objects. This is because the eye’s lens hardens and loses flexibility.
How Do Glasses Work?
Glasses work by using specially designed lenses to refocus light onto the retina. Depending on the type of vision problem, lenses are customized to the wearer’s specific needs.
Concave Lenses: Curved inward lenses are used for myopia. These lenses diverge the light rays before they enter the eye, moving the focal point back onto the retina so close-up objects become clear.
Convex Lenses: Curved outward lenses are used for hyperopia. These lenses converge light rays, moving the focal point forward and onto the retina so nearby objects become clear.
Cylindrical Lenses: For astigmatism, glasses use cylindrical lenses that are shaped to compensate for the irregular curvature of the cornea or lens so light rays focus evenly.
Bifocal or Multifocal Lenses: Used for presbyopia, these lenses have two or more zones for viewing objects at different distances so you can see clearly up close and far away.
How Do Contact Lenses Work?
Contact lenses work like glasses by refracting light to correct vision but instead of sitting in front of the eyes, they sit on the surface of the cornea. There are two main types of contact lenses:
Soft Contact Lenses: Made of flexible material these lenses allow oxygen to pass through to the cornea. Used for myopia, hyperopia, astigmatism, and presbyopia.
Rigid Gas Permeable (RGP) Lenses: Harder lenses that give sharper vision and are used for people with more severe astigmatism or other irregularities of the cornea.
Glasses vs Contact Lenses
Glasses are easy to maintain and don’t touch the eyes so there’s less risk of infection. Contact lenses give a more natural field of vision and are more convenient for active lifestyles. No matter what you choose, make sure to schedule regular eye exams to keep your prescription accurate.
At Vasan Healthcare Sri Lanka, we use the latest technology to offer a full range of eye care services. Our experienced ophthalmologists conduct advanced diagnostic exams to provide customized treatment for refractive errors and various eye conditions.
Book an appointment today.
