Refractive errors are one of the most common vision problems among children and adults. They occur when the shape of the eye affects the way light is focused, resulting in blurred vision. Refractive errors can range from mild to severe.
Types of Refractive Errors
Common types of refractive errors include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia.
Myopia, also known as nearsightedness, is an extremely common refractive error that occurs when the eyeball is too long or the lens is too curved. As a result, light entering the eye is not focused properly, resulting in blurry vision when looking at far away objects. Fortunately, myopia is easily corrected with glasses, contacts, or Lasik eye surgery.
Hyperopia, also known as farsightedness, is the opposite of myopia. In this condition, the eyeball is too short or the lens is too flat, causing light to focus behind the retina. People with hyperopia have difficulty focusing on near objects, and their vision often clears up when looking at far away objects. Just like myopia, hyperopia can be corrected with glasses, contacts, or Lasik surgery.
Astigmatism is a refractive error that occurs when the cornea is curved or stretched unevenly. The result is distorted vision, as light is scattered in different directions. Astigmatism can cause blurry or distorted vision at all distances. Fortunately, astigmatism is easily corrected with glasses, contacts, or Lasik eye surgery.
Presbyopia is a common refractive error that is caused by the natural aging process. As your eyes age, they become less flexible and cannot focus on near objects as easily. People with presbyopia often have difficulty reading and seeing close objects clearly. Presbyopia is typically treated with reading glasses or bifocals.
Causes of Refractive Errors
While the cause of refractive errors is typically related to an imbalance between the length of the eyeball and the power of the cornea and lens to bend light correctly, some other factors can contribute to the development of the condition. These include genetic predisposition, genetic mutations, and environmental factors such as diet, lifestyle, and medications.
Genetic predisposition is believed to be the strongest factor in the development of refractive errors. Studies have shown that there is a strong genetic component to the condition, and people with a family history of refractive errors are at an increased risk of developing the condition.
Genetic mutations can also contribute to the development of refractive errors. Mutations in certain genes can cause a disruption in the development of the eyeball or the cornea, resulting in a refractive error.
Environmental factors such as diet, lifestyle, and medications can also contribute to the development of refractive errors. Diet can affect the size and shape of the eyeball, and certain medications can alter the refractive power of the cornea or lens.
Diagnosis of Refractive Errors
The first step in diagnosing a refractive error is a thorough eye exam. This typically begins with a complete eye history, including any past eye problems or surgeries, medications, allergies, and family history of eye disease. The doctor or other eye care specialist will then examine the patient’s eyes using a variety of tests. These tests may include visual acuity, refraction, retinoscopy, and a slit-lamp examination.
Visual acuity is used to measure how well a person sees with glasses or contact lenses. The patient is asked to read a chart of letters from a set distance away, and the distance at which the patient can read the letters is used to measure visual acuity. This helps the doctor determine if the patient needs glasses or contact lenses.
Refraction is a common eye test used to measure how well the eye can focus light. During a refraction test, the patient looks through a device called a phoropter and is asked to view a series of lenses to determine which lens provides the clearest vision. This helps the doctor determine the correct power of the glasses or contact lenses.
Retinoscopy is another common test used to measure refractive errors. In this test, an instrument is used to shine a light into the patient’s eyes. As the light changes in intensity, the doctor is able to observe how the light reflects off the retina, which helps him or her determine the correct power of the glasses or contact lenses.
The slit-lamp examination is used to evaluate the front surface of the eye. During this test, a bright light is shone through a slit in the instrument and is used to magnify and examine the eyelids, cornea, sclera, iris, and lens. This helps the doctor check for any abnormalities or irregularities in the eye structure.
Prevention and Treatment of Refractive Errors
Prevention of refractive errors can be done in several ways. For children, proper nutrition and regular eye exams can help prevent the development of refractive errors. Eating a balanced diet that is high in vitamins, minerals, and antioxidants may help reduce the risk of developing myopia in children. Getting regular eye exams is also important, as refractive errors can be detected early on and treated to prevent further vision loss.
In adults, regular eye exams are still the best way to prevent refractive errors. Wearing sunglasses that provide 100% UV protection can also help to protect the eyes from sun damage and reduce the risk of refractive errors. Additionally, limiting the amount of time spent looking at screens can help to reduce eyestrain and potential vision damage.
When it comes to treating refractive errors, the most common method is with corrective lenses. Eyeglasses and contact lenses can be used to correct vision and can help improve sight while wearing them. Eyeglasses are available in many different styles and designs and can help correct myopia, hyperopia, and astigmatism. Contact lenses offer the same benefit as eyeglasses but with the added benefit of not needing to wear any frames.
Refractive surgery is another option for correcting refractive errors. This type of surgery reshapes the cornea to correct vision. The most common forms of refractive surgery are LASIK, photorefractive keratectomy (PRK), and implantable contact lenses (ICL). Each procedure has its own risks and benefits, and it is important to discuss the options with an eye care professional before deciding which procedure is best for you.