Refractive Errors of Eye - Definition, Types, Correction, Treatment

Refractive error is a disorder of the eyes that causes blurred vision due to the inability to focus. This is one of the most common disorders of the eye. The condition is caused due to the change in the shape of parts of the eyes responsible for bending (refracting) light rays to produce a clear image. The two parts of our eyes responsible for this refraction of light are the cornea and lens, and they bend the light rays to focus them on the retina of the eye.

Although refractive errors do not cause significant health issues in their initial stages, they can lead to severe eye disorders if left untreated for a long time. Nevertheless, one can treat them with medical treatments, like eyeglasses, contact lenses, and surgeries. Continue reading this article to learn about refractive errors of the eye, its types, symptoms, causes, risk factors, prevention, diagnosis, treatment and risk factors.

Refractive errors are eye disorders that cause difficulty in focusing. This happens when the refractive light rays to produce clear images on the retina due to changes in the parts of the eyes. This leads to blurry vision. If left untreated, refractive errors of the eye may lead to complete blindness. Therefore, one must not take the condition of refractive errors of the eye lightly. A proper eye checkup is mandatory to see clearer and live a normal life. 

Refractive errors of the eye can develop at any point in time. However, different types of refractive errors may affect different age groups. Myopia (Nearsightedness) occurs in children aged 6 to 14, while presbyopia onset is 40, for example. 

Depending on how distorted and blurry the vision is, there are four types of refractive errors: myopia, hyperopia, presbyopia, and astigmatism.

1. Nearsightedness (Myopia): Myopia is a refractive error in which the nearby objects are easier to see, but it becomes difficult to see the distant/faraway objects. Children aged 6 to 14 are more likely to develop myopia than any other age group. 
2. Farsightedness (Hyperopia): Hyperopia is the refractive error of the eye in which the patient cannot see nearby objects properly. However, they can comfortably see objects at a distance. Most times, hyperopia affects the age group of 8 to 15 years. 
3. Age-related Farsightedness (Presbyopia): Presbyopia is one of the most common refractive errors of the eye that affects middle-aged people and older citizens. To be more specific, it occurs in people older than 45. Presbyopia worsens over time, but it usually stops growing after 65 years of age. 
4. Astigmatism: It is a refractive error that makes the vision distorted or blurred. It can be caused as a result of eye surgery or an eye injury. Further, it can also be a congenital eye disorder. Frequently, astigmatism has been observed to develop in children and new adults. 

Patients with refractive errors of the eye may not show any symptoms, especially when the refractive error is in its initial stages. However, the following symptoms of refractive error may show up as the condition worsens. 

1. Unable to see nearby objects properly
2. Strain, tiredness, and soreness in the eyes
3. Unable to read 
4. Irritation in eyes
5. Crossed eyes
6. Squinting of eyes
7. Unstoppable blinking of eyes
8. Difficulty seeing at night
9. Unable to see far away objects 
10. Headache
11. Blurred and doubled vision 
12. Weakness in eyes

Refractive errors can occur in anyone and at any age. Generally, people develop refractive errors when the eye:

1. Change in shape of the cornea or length of the eyeballs (shorter or longer) in case of myopia, hyperopia, and astigmatism.
2. Ageing of the lens (shape deteriorates over time in case of presbyopia)
3. A flatter or steeper surface of the eye that is present naturally
4. A thicker or thinner lens than usual
5. The size of the eye in general, like it, might be too long or short than normal

When such abnormalities develop in the eyes, the light, instead of falling on the retina, forms in front or behind the retina, thus creating blurred images. Therefore, causing refractive errors of the eye. 

Nonetheless, the following are some common risk factors of refractive errors:

1. Watching television for long hours. 
2. Working in inadequate light.
3. Spending longer screentime, such as using mobile or laptop.
4. Family history of refractive errors.
5. Reading for longer hours.

While refractive errors of the eye can be corrected with glasses, contact lenses, or surgery, it is always better to prevent them from developing in the first place. Here are some tips for preventing refractive errors of the eye:

1. Get regular eye exams: Regular eye exams are essential for maintaining good eye health and preventing refractive errors. Eye exams can detect early signs of vision problems and allow for prompt treatment before the condition worsens.
2. Practice good eye hygiene: Good eye hygiene, such as washing your hands before touching your eyes and avoiding rubbing your eyes, can help prevent eye infections and other conditions that can contribute to refractive errors.
3. Take breaks from screen time: Prolonged screen time can lead to eye strain and fatigue, which can contribute to refractive errors. Taking regular breaks from screen time and practising the 20-20-20 rule (looking away from the screen every 20 minutes for 20 seconds at something 20 feet away) can help reduce eye strain.
4. Wear protective eyewear: Wearing protective eyewear, such as safety glasses or goggles, can help prevent eye injuries that can lead to refractive errors.
5. Maintain a healthy lifestyle: A healthy lifestyle, including a balanced diet and regular exercise, can help prevent eye conditions and other health problems that can contribute to refractive errors.

An eye doctor could diagnose refractive errors by studying the patient's medical history and performing various clinical examinations. 

Patient's Medical History: The doctor will ask the patient about any previous or current cases of refractive error of the eye or other eye disorders. The doctor may also ask the patient the following questions:  

1. Tell me your family history of refractive errors.
2. What is your screen time per day?
3. Do you experience headaches?
4. Do you experience difficulty seeing at night?
5. Do you face problems in seeing nearby or faraway objects?
6. What is your sleeping pattern?
7. How frequently do you wash your eyes?
8. Do you feel pain in one or both eyes?
9. Do you have dry eyes or crossed eyes?
10. Do you need to squint (to close your eyes partially) to see objects clearer?

Apart from the medical history, the doctor may also recommend clinical investigations. Some diagnostic tests to diagnose refractive errors include

In Adults: 

1. Visual acuity test: It is performed to check how accurately the patient can see objects. In this test, the doctor asks the patient to read the alphabet located nearby and far away.
2. Visual field test: During the test, the doctor tests how the patient can see objects placed to the side of the eyes, and that too, without moving the eyes.  
3. Eye muscle function test: During the test, the doctor moves an object and asks the patient to keep seeing it. This is performed to check if the patient's eye muscles are working fine. 
4. Pupil response test: In this refractive error diagnostic test, the doctor flashes light in the eyes of the patient to detect how the pupil responds to the light. 
5. Tonometry test: The doctor blows air into the eyes of the patient to check the pressure in the patient's eye.
6. Dilation: This test is where the doctor examines the inner parts of the eyes by widening the pupil. The widening or dilation is achieved by using an eye drop that may temporarily make the eyes blurry and light-sensitive. 

In Children:

The refractive errors in children must be caught as soon as possible. Earlier the diagnosis, the slower the progression. The paediatric ophthalmologist will use the following steps to diagnose any refractive errors:

1. A regular eye examination using a dilated eye exam as described for adults.
2. In children whose standard charts cannot be used, the steps are
3. The pupils are dilated using eye drops.
4. Then, a retinoscopy is performed. This is an examination that observes the reflection of lights off the retina.

How to prepare for a doctor’s consultation?

1. Make an early appointment to visit the doctor's clinic.
2. Carry previous medical reports (if any).
3. The doctor will ask questions about the undergoing treatment (in case of any eye disorders). 
4. The doctor shall also advise further diagnostic tests to confirm the disease. 
5. The doctor may also dilate the patient's pupil. Hence, it's recommended not to self-drive after the test. 
6. The patient can also ask the following questions to the eye specialist.
7. Can the refractive errors of an eye be treated without surgery?
8. Will the refractive error go away with eyeglasses or lenses?
9. How much time will it take for the refractive error to resolve?
10. Do I need to undergo refractive error surgery? 
11. Do I have to undergo LASIK?
12. What is the optimal time of surgery in my case?
13. Will the refractive error disturb my vision permanently?
14. What is better for me – LASIK or PRK?
15. What is the recovery period after surgery?
16. What foods should I eat and avoid after the surgery?
17. How can I relieve my eye pain?
18.  Why do I need to undergo surgery?
19.  Is there any alternative to surgery?
20. Will the refractive error cause blindness?

Treatment for refractive errors of the eye depends on the nature and stage of the refractive error. Therefore, the doctors can opt for one of the following treatments:  

Refractive Error treatment without surgery

1. Eyeglasses: Based on the type of refractive errors, the eye specialist can prescribe one of the following eyeglasses: 
2. Reading glasses: Most commonly prescribed for people suffering from presbyopia.
3. Single-vision prescription lenses: It lets the patient see nearby and faraway objects clearly. However, it cannot correct myopia and hyperopia at the same time. 
4. Multifocal prescription lenses: These eyeglasses are prescribed for both myopia and hyperopia. 
5. Contact Lenses: There are numerous options of contact lenses one can consider wearing. These are 
6. Soft Lenses and Hard Lenses: Soft Lenses are easier to wear and more common than hard lenses. Hard lenses make images more clear than soft lenses. However, it takes more time to get used to these lenses.
7. Extended Wear Contact Lenses: These are wearable for 30 days and nights, after which patients have to replace them. One can sleep wearing it; however, these can cause eye infections.
8. Single-Use Contact Lenses: These lenses can only be used for a day. They can only be used once.
9. Reusable Contact Lenses: Patients can use these lenses for 7 to 30 days. They should be taken out at night. Wash them daily before use. These contact lenses can cause eye infections. 
10. Daily Wear Contact Lenses: Patients can wear daily-wear contact lenses the whole day but must take them out before sleeping. It is advised to clean and disinfect these contact lenses daily. These contact lenses may lead to serious eye infections. 

Refractive Error treatment with surgery

Based on the type of refractive errors and if the above non-surgical methods do not help in providing proper vision, the eye specialist can prescribe one of the following surgeries:   

1. Laser-assisted in situ keratomileusis (LASIK): LASIK is an advanced laser eye surgery, which helps modify the shape of the cornea. Consequently, it helps in refractive error correction.
2. Conductive Keratoplasty (CK): It is a refractive surgery performed to help cure hyperopia in adults over 40 years of age. 
3. Photorefractive keratectomy (PRK): PRK changes the shape of the cornea using the help of a laser. Thereupon treating refractive error. It is best for people who have a hectic lifestyle.  Photorefractive keratectomy (PRK) helps treat refractive errors, such as myopia, hyperopia, and astigmatism. 

If left untreated, the refractive errors of eye can lead to severe risks and complications. Some of the risks and complications of refractive errors are as follows: 

1. A higher degree of near-sightedness or myopia may cause retinal detachment requiring surgical repair 
2. Lazy eye (amblyopia) in children
3. Eye strain and fatigue
4. Headache
5. Increased risk of accidents
6. Reduced quality of life

When to See a Doctor? 

One must visit a doctor if they have trouble seeing faraway or nearby objects. Moreover, one must seek urgent medical care if they face: 

1. Extreme headache or eye pain
2. Eye irritation of infection
3. Dry eyes
4. Immediate loss of vision 
5. Flashes in eyes

Diet plays a major role in the formation as well as in the treatment of refractive error. Therefore, people with refractive error must pay proper attention to the foods they consume. Given below is a list of food that people with refractive error should and should not eat. 

Patients with refractive errors should eat the following foods for the management of refractive errors: 

1. Carrot
2. Spinach
3. Almond
4. Indian gooseberry
5. Coconut

Patients with refractive error should 'not' eat the following foods for the management of refractive errors: 

1. Food high in sugar content
2. Processed meat
3. Junk food
4. Saturated fat

Refractive error are the disorders of the eye that develops when the images do not fall properly on the retina. Thus leading to blurred vision. There are four types of refractive disorders including myopia, hyperopia, presbyopia, and astigmatism. You must treat refractive errors at the earliest. Otherwise it could lead to blindness. Major treatment options for refractive error include eyeglasses, contact lenses, and surgeries. 

If you or your loved ones have refractive error of the eye, talking to an experienced team of doctors and getting the proper treatment is necessary. At HexaHealth, we have a qualified team of eye specialists who can help to treat refractive errors at the earliest time possible. Wait no more; get on a free consultation call with us TODAY.