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BLURRED VISION: Blurred vision can be either of gradual or sudden onset and have many different causes. We will discuss a few of the common causes. GRADUAL ONSET: Blurred vision of gradual onset may be due to many factors. Fortunately, there is often nothing seriously wrong with the eye. Sometimes people tend to think that their vision is blurred because they
have compared their own vision to what someone else says he can see and think that theirs is not as good. Immediately they tend to think that there is
a defect with their own vision, where in fact the other person could have had better than normal vision and therefore see better. In this case the vision may actually be less clear, but not blurred.Often the cause for gradual onset of blurred vision is simply that spectacles are needed or that present spectacles need replacing because the eyes' refraction has changed. Often the spectacles are scratched or dirty.
There are however medical conditions which may also gradually decrease
the visual acuity.The Cornea of the eye can also become less clear due to inherited disease
or degeneration. If the shape becomes more conical, such as in a condition called keratoconus, the vision will become gradually blurred or less clear.Cataracts often begin by causing blurred vision. A cataract is an opacity in the lens of the eye. Cataracts can sometimes form very quickly, but more often they progress over a long period of time, sometimes many years. Depending on the type of cataract, symptoms may vary from seeing worse
in bright light to seeing worse in the dark. Often the decrease in vision is so gradual that patients are not aware of the deterioration. Surgery is generally performed in the more advanced cases and usually with excellent results. There is no non-surgical method to remove or reverse cataracts at this moment in time, though certain nutritional supplements high in antioxidants have shown promise.As we move towards the back of the eye, we come to the jelly or Vitreous. This usually clear substance can become hazy due to degeneration, inflammation or hemorrhage. This can blur the vision, and requires medical evaluation.
Many conditions affecting the Retina can cause blurred vision:
FSwelling of the retina due to injury, inflammation or infection occurs commonly.
FDiabetes may cause retinal swelling which blurs the vision.
FInherited retinal conditions such as retinitis pigmentosa can blur the vision.
FIn Retinitis Pigmentosa blurred vision is more pronounced in poorly illuminated or low-light environments.
FThe nerve of the eye may be subjected to an inflammatory process. This is typically associated with very blurred vision. Usually the onset is sudden rather than gradual in most cases and requires immediate medical attention.
SUDDEN ONSET: Blurred vision of sudden onset is usually an alarming experience. Depending on the cause, it could be serious.
Patients suffering from an infection causing "pink-eye" may experience sudden transient blurred vision as mucus is wiped over the cornea, and then experience relief again as it is wiped away a few seconds later by the blinking action of the eyelids. Infection of the cornea itself, which could occur with conditions such as Herpes, may also cause blurred vision.
The front part of the eye which is filled with a clear fluid called Aqueous can also cause blurred vision if the fluid becomes cloudy due to inflammation. The lens can also become totally opaque following injury to the eye within a very short period of time.
Another cause of sudden onset blurred vision is acute glaucoma. This condition is very painful and is due to an increase in the pressure inside the eye. It is a medical emergency, because if the pressure is not reduced promptly, permanent damage to the eye will result.
The Retina may also cause sudden blurred vision.
If the artery supplying blood to the retina were to suddenly occlude, for example due to a blood-clot, sudden deterioration in vision which is usually painless, will result.If the vein occludes, blurring of the vision also occurs, but normally not to the same extent as with an arterial occlusion.
A hemorrhage in the back of the eye from one of the retinal blood vessels will also blur the vision and if the hemorrhage is large, it may cause partial or total loss of vision.
Retinal detachment can also cause blurred vision.
The first sign of a detachment may be a dark area or curtain on the edge of the visual field which gradually approaches the central vision. Often lightning flashes accompany this condition. It is a medical emergency and your ophthalmologist should be notified immediately.A fitting final word could be the following: Vision is intended to be crisp and clear. If it is not, it should be investigated to ascertain the cause. It may be serious or it may not be serious, but one should not take a chance with sight.
This brief discussion of possible causes of blurred vision is by no means complete.
Blurred vision is not normal and makes daily tasks and living more difficult. It should be investigated and treated without delay. See your eye care practitioner as soon as possible if you are experiencing blurred vision.
If you have any further questions regarding blurred vision, please consult your eye specialist.