Blurred vision

Eyes problems are the most common reason for blurry vision. These include:

• Refractive errors of the eyes: This refers to the condition in which the eye cannot clearly focus the images. The blurring can occur in one or both eyes. It can be present in one of four forms:
  • Myopia or nearsightedness is the most common vision problem in which people can see objects near them clearly, but objects farther away can seem blurry. It occurs because the lens of their eye causes the light rays to bend (refract) incorrectly, focusing images in front of their retina instead of on their retina.
  • Hypermetropia or farsightedness is a vision condition in which people can clearly see distant objects, but are unable to focus on objects that are close. Hypermetropia occurs because the light rays that pass through the lens of the eye does not bend properly and form the image behind the retina instead of on the retina.
  • Presbyopia is a condition in which older people get a blurry view of the objects that are placed close to them. It is because of the age-related changes in the natural lens of the eye.
  • Astigmatism is blurring of vision due to the irregular shape of the cornea (front layer of the eye) or the lens of the eye is medically called astigmatism.
• Dry eyes: Dry eyes are a sign of a medical condition known as keratoconjunctivitis sicca. In keratoconjunctivitis, people suffer from dryness of the conjunctiva (the membrane that covers the white of the eye) and cornea (the clear layer in front of the iris and pupil). It occurs because the lacrimal glands (tear glands) don't produce enough tears to keep the layers of eyes moist.
• After LASIK: LASIK (laser-assisted in situ keratomileuses) is a common laser eye surgery to correct vision problems such as myopia (nearsightedness), hyperopia (farsightedness) and astigmatism. People who undergo LASIK may experience blurriness for a few days. The condition typically resolves with the prescribed medicines and eye drops.

• Cataract: When the protein of the eye lens starts to break down, it leads to blurring and clouding of the vision - this is medically known as a cataract. A cataract is usually seen in elderly people but can happen to anyone, especially to people living with diabetes. The blurring of vision may be noticed in one or both the eyes.

• Glaucoma: Glaucoma is a serious eye condition in which the optic nerve (the nerve that connects the eye to the brain) gets damaged. This can lead to complete loss of vision, which could be permanent if not treated early. Although the exact cause of glaucoma is unknown, it is believed that damage to the nerve occurs due to an increase in the pressure in the eye. The symptoms involve sudden narrowing of the field of vision, often called tunnel vision, accompanied by the blurred vision at the edges of the field of view.

• Macular degeneration: It is a medical condition which is associated with blurring and loss of vision due to damage to the macula, the central part of the retina. Age-related macular degeneration (AMD) is the most common reason for vision loss in people over 50 years of age. People with AMD tend to lose their central vision but their peripheral vision is normal. 

  For instance, if they are looking at a wall clock with hands, they will be able to see the numbers around the clock but won’t be able to see the hands as they look blurred.
  In dry AMD, the macula gets thin and protein clumps start growing on it, whereas in wet AMD, new abnormal blood vessels start growing under the retina.

If you have blurry vision in addition to symptoms like dizziness or increased sensitivity to lights, or if you have a chronic condition like high blood pressure, diabetes or migraine, don't be alarmed but do visit your doctor as soon as possible. Some of the conditions that may be linked to blurry vision are:

• Fatigue: When you're very tired, your eye muscles may also be tired and have trouble focusing. This can cause blurriness. The fix is simple: take adequate rest.
• Sleep deprivation: Adults need at least seven hours of sleep daily. Going without proper or adequate sleep for days or weeks may result in symptoms like confusion and blurred vision. Lack of sleep or low-quality sleep over a longer period of time can result in more serious health problems.
• Dehydration: Similar to fatigue, dehydration in the body can cause the eyes to become dry, too. This, in turn, can cause blurry vision.
• Computer vision syndrome: Also known as digital eye strain, computer vision syndrome occurs as a result of overusing computer/laptop/mobile screens. Its classic symptoms include eye strain, blurry vision, dry eyes, neck pain and shoulder pain.
• Hypertension: High blood pressure (BP) affects every part of the body. It increases wear and tear in the blood vessels, including the blood vessels in the eyes. This may lead to blurry vision or bleeding from the eye. Many people with high BP don't know they are living with this condition. If you have not been diagnosed with high BP, but notice symptoms like frequent headaches, breathlessness, unexplained bleeding from the nose and/or blurry vision, ask your doctor about appropriate methods to check your BP such as the ambulatory blood pressure monitoring machine which takes your BP for up to 24 hours.
• Migraines: Many people suffering from classical migraine experience temporary blurring of vision which may be accompanied by flickering light, halos or zigzag patterns before the headache starts.

• Medications: Blurry vision is a side-effect of some medications like anti-depressants (amitriptyline, used in migraines), anti-tuberculosis drugs (ethambutol, isoniazid) and even viagra (sildenafil). To be sure, not everyone experiences these side-effects on taking these medicines.

• Diabetic retinopathy: It is one of the serious complications of diabetes. People with uncontrolled diabetes might undergo progressive damage to the retina, either due to fluid leaking into macula or abnormal blood vessels leaking blood on the surface of the retina. This leads to blurred vision and dark spot in the centre of the vision.

• Stroke: Sudden blurry vision in both the eyes along with drooping of the face, muscle weakness and slurred speech could be a sign of stroke in a person. Immediate medical care is needed in this case.