Refractive Error


Nearsightedness or myopia is a visual condition in which people may see close objects clearly, but objects which are farther away will appear blurred. It is a condition of the eye in which the light that passes into the eye from a distant object doesn’t directly focus on the retina but in front of it, causing the image that one sees when looking at the distant object to be out of focus.

How does this happen?
Myopia may occur if the eyeball was too long or the cornea was too curved. Individuals who will spend considerably more time in reading, working at the computer, or doing other intense close visual work will be more likely to have myopia. Children who spend more time particularly in doing physical activity and outdoor activity have lower rates of myopia. Heredity is one more important factor which is related with the juvenile myopia. Long hours of exposure to the daylight appears to be a protective factor Myopia Treatment

How will you be affected?
If you are nearsighted you will typically have difficulty in reading the road signs and seeing distant or far objects clearly, but will be able to see well for close-up tasks like reading and computer use. Other signs and symptoms of myopia may include squinting, eye strain and headaches. Feeling fatigued when driving or playing sports may also be a symptom of uncorrected nearsightedness.

How does your doctor diagnose and treat myopia?
Diagnosis of myopia is generally confirmed by an eye examination which is done by an optometrist, or an ophthalmologist or orthoptist. An autorefractor or retinoscope Is used to give an preliminary objective assessment of the refractive status of the each eye, then trial lenses subjectively refine the patients eyeglass prescription. Optical correction is done by spectacles or contact lenses.
Astigmatism treatment
Astigmatism is a condition which occurs when the cornea is irregularly shaped or occasionally, due to the curvature of the lens in the eye. The cornea is the transparent layer of a tissue which is at the front of the eye. The normal cornea is regularly curved like the surface of football, but in astigmatism it is irregularly curved. So, light rays entering the eye wont focus properly on the retina, and thereby creating a blurred image. This may lead to discomfort in the eyes, and headaches. Slight astigmatism generally does not affect the vision and may not require any treatment.Astigmatism Treatment

Astigmatism may also occur because of a relatively rare condition known as keratoconus in which the cornea bulges forwards more than normal. It may gradually become thinner and cone shaped. This may results in a large amount of astigmatism, which will cause poor vision which may not be clearly corrected with the help of eyeglasses. People with keratoconus generally require contact lenses for the clear vision. Some of these patients may need a corneal transplant.

What symptoms will you have?
People with undetected astigmatism often have blurred vision which can be associated with fatigue and eyestrain and headaches. While these symptoms may not necessarily be the result of astigmatism, you should schedule an eye exam if you are experiencing one or more of these symptoms

Most of the people who are suffering from astigmatism are born with this condition, so its essential that your children should have regular eye tests. If vision is not regularly tested, conditions like astigmatism may remain undiagnosed for many years, which may cause a lazy eye.

What tests will the doctor perform?
A simple eye testcan evaluate your or your childs ability to focus on the objects which are at different distances. It generally includes reading letters on the chart known as Snellen chart. The letters will become gradually smaller on each line of the chart. The doctor may then use eye drops to dilate your eyes to get more accurate results of vision testing. In this case a final test is done a few days later to get accurate eye power. A device which is called as keratometer will be used to measure the degree of corneal astigmatism.

Almost all degrees of the astigmatism will be corrected with accurately prescribed spectacles or contact lenses.
hyperopia treatment
Farsightedness, or hyperopia, is a vision condition in which the distant objects will be visualized clearly, but close ones wont come into a proper focus. Farsightedness happens when eyeball is too short or the cornea is having too little curvature. As a result, the eye cannot properly focus the light which enters it. For the near objects, the eye needs to accommodate even more.

What are the symptoms you may have? Most common symptoms of hyperopia involves difficulty concentrating and maintaining a clear focus on the near objects, fatigue and/or headaches after doing a close work, eye strain, aching or burning eyes, and nervousness or irritability after sustained concentration. The most common symptom was "tiring" of the eyes . Difficulty of seeing with the two eyes can occur, as well as, difficulty with the depth perception.

How does this happen?
Hyperopia is mainly caused by:

♦ Low converging power of the eye lens due to the weak action of ciliary muscles (a ring of muscles around your lens) ♦ Abnormal shape of the cornea
Farsightedness usually occurs from the birth, but children have a very flexible eye lens, which helps make up for this problem.

How does your doctor diagnose hyperopia?
A simple vision test will reveal a problem with your vision. An autorefractor or retinoscopy will reveal farsightedness. In some cases especially in children, your doctor will have to dilate your pupils with eye drops to detect the exact degree of the problem and find the spectacle power. In this case a second test, a few days after the dilatation, will be needed before the spectacle power is fixed.

The treatment is by corrective spectacles or contact lenses.
Presbyopia treatment
Presbyopia is a condition where there is a gradual loss of the eyes ability to focus on nearby objects. It is a natural part of aging. Presbyopia usually becomes noticeable in the early to mid of 40s & continues to the worsen till around age 65. Presbyopia is usually confused with farsightedness, but these two are different. Presbyopia occurs when the natural lens in the eye loses its flexibility. Farsightedness or hypermetropia occurs because of a smaller than normal eyeball. You will be aware of presbyopia when you start holding the books & newspapers at arms length to be able to read them. A basic eye exam can confirm presbyopia. You can rectify this condition by using eyeglasses or contact lenses.

Presbyopia develops progressively. You will notice these signs and symptoms after the age 40:
  • A tendency to hold the reading material farther away to make the letters visible and clear.
  • Vision is blurred at normal reading distance
  • Eyestrain or headaches after reading or doing close work

You will notice these symptoms are worse when you are tired or if you are working in an area with a dim light.
How it happens:
When you are young, the lens in the eye is flexible & relatively elastic. It can change its shape depending on whether you are viewing a distant or a near object, so that you are able to see both distant and near objects clearly. With increasing the age, your lens gradually loses its flexibility & stiffens. So, your lens becomes unable to change its shape. Due to this hardening of your lens, your eye gradually loses its ability to focus clearly on near objects.

How is it diagnosed?
Presbyopia is diagnosed by a basic eye exam . Your eye doctor may put some drops into your eyes to dilate your pupils. This will makes your eyes more light sensitive for some hours after the eye exam. Dilatation enables doctor to more easily examine the inside of your eyes.

Your doctor may also use different instruments, aim bright lights at your eyes & will ask you to look into many lenses to test your distance & near vision. Each test will allow your doctor to examine a different aspect of your vision. The goal of treatment is to compensate for the inability of the eyes to focus on near objects.

What can be done for this ?
Treatment options include wearing the corrective glasses, undergoing refractive surgery (monovision) or getting multifocal intraocular lens implants after removing your original lens.


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