The issue of blurred (foggy, hazy) vision can be due to a wide range of underlying causes. This problem can originate from the eyes themselves or from another part of the body.
Blurred vision should always be investigated, the source identified, and the appropriate treatment applied once the cause is understood. Blurred vision can be a constant issue, or it might appear occasionally or suddenly.
When approaching treatment, it is important to assess other symptoms that may accompany blurred vision, make an accurate diagnosis, and determine any underlying eye disease.
What is Blurred Vision?
Blurred vision is defined as a loss of visual acuity, where fine details cannot be seen clearly compared to normal vision. It can be associated with eye diseases or caused by other conditions such as migraines, carbon monoxide poisoning, shingles, meningitis, and encephalitis.
Causes of Blurred Vision
1. Myopia
Myopia, or nearsightedness, is a refractive error where close objects are seen clearly, but distant objects appear blurry or hard to distinguish. It occurs when the eye length is longer than its refractive power. Main symptoms include blurred vision, squinting to see clearly, difficulty reading signs or road signs, and headaches. Myopia often develops during childhood.
2. Hyperopia
Hyperopia, the opposite of myopia, is a refractive error where the eye length is shorter than its refractive power. Individuals with hyperopia may experience blurry vision at both near and far distances. It typically begins at birth. Symptoms include blurred vision and headaches. Treatment for hyperopia depends on the degree of the condition.
3. Astigmatism
Astigmatism is an eye condition caused by an irregularly shaped cornea, leading to visual problems. In astigmatism, blurred vision affects both near and distant objects. Other symptoms include a sense of tension in the eyes, headaches, difficulty distinguishing objects at night, and eye discomfort.
Astigmatism can be present from birth or develop due to other eye conditions. Types include myopic astigmatism (combined with myopia) and hyperopic astigmatism (combined with hyperopia).
4. Macular Degeneration
Macular degeneration occurs when the macula, an important part of the retina responsible for vision, does not function properly. Symptoms include difficulty recognizing faces, a black spot or haze in the central visual field, and seeing straight lines as wavy or distorted. The prevalence of this condition increases with age.
5. Cataracts
Cataracts develop when the lens inside the eye loses its transparency, leading to problems with light transmission. Symptoms include blurred vision, the need for brighter light to read, seeing halos around lights, reduced night vision, and double vision.
6. Glaucoma
Glaucoma occurs when increased pressure within the eye damages the optic nerve. Also known as ocular hypertension, it progresses slowly and may not present symptoms early on, making it difficult to detect. If left untreated, glaucoma can cause irreversible vision loss. High pressure may also cause blurred vision, nausea, vomiting, and headaches. Normal eye pressure should be below 21 mmHg.
7. Diabetic Retinopathy
Diabetic retinopathy is a complication of diabetes and is the leading cause of preventable blindness in people aged 20–65 worldwide. Individuals with diabetes are 25 times more likely to experience blindness than the general population. The risk of diabetic retinopathy increases with the duration of diabetes, highlighting the importance of blood sugar control.
8. Dry Eyes
Dry eyes, another cause of blurred vision, result from decreased lubrication and moisture on the eye’s surface. It is a chronic eye condition. Mild discomfort may be present, but untreated dry eyes can lead to severe inflammation.
Symptoms include burning, itching, blurred vision, eye redness, light sensitivity, and a sensation of dryness. Excessive tearing due to overactive tear glands as a response can also occur. Early treatment is crucial to prevent damage to the eye’s surface.
9. Eye Allergy (Allergic Conjunctivitis)
An eye allergy occurs when an allergen contacts the eye, causing it to release histamines. Symptoms include redness, watering, swelling, burning, and itching. Common allergens include pet dander, pollen, dust, grass, and smoke. Blurred vision may also be a symptom, along with light sensitivity.
10. Eye Bleeding
There are three types of eye bleeding. Subconjunctival bleeding occurs on the surface of the eye’s conjunctiva and is easily visible due to its proximity to the surface. It does not cause pain or vision problems and resolves on its own.
Hyphema is bleeding within the eye, often caused by trauma, eye inflammation, or diabetes, and it typically affects vision. Lastly, bleeding can occur in the back of the eye, which is not visible externally. This type is often due to uncontrolled blood pressure or blood sugar, affecting visual acuity. Treatment for eye bleeding depends on the cause.
How is Blurred Vision Diagnosed?
Several tests are used to diagnose blurred vision. These tests include:
- Computerized Visual Field Test: Measures the visual field in each eye separately and is used to diagnose conditions like glaucoma.
- Ocular Ultrasound: Commonly used to visualize eye structures and is necessary for some eye surgeries.
- Tonometer: A device used to measure intraocular pressure for glaucoma assessment.
- Visual Acuity Test: Evaluates vision by asking the patient to read letters or numbers from a specific distance.
- Vision Loss Test: Methods like retinal and optic nerve examinations are also used in diagnosing blurred vision.
What Are the Treatment Methods for Blurred Vision?
Treatment for blurred vision depends on the underlying cause. If the cause is a refractive error like myopia, hyperopia, or astigmatism, solutions include glasses with thick lenses, contact lenses, or laser surgery. Dry eye treatment involves artificial tear drops and lifestyle changes, such as reducing screen time and limiting smoking.
Taking breaks to rest the eyes when tired can also help. For blurry vision due to eye allergies, identifying the allergen through allergy tests is key, followed by the use of artificial tears or antihistamine medications to manage symptoms. Although there is no definitive cure for macular degeneration, tablets or injections can slow its progression.
Cataract treatment requires surgery, ideally before the cataract progresses. In this procedure, a new artificial lens is inserted to replace the cloudy one. Glaucoma treatment can involve medications, laser therapy, or surgery.
Blurred Vision Due to Diabetes
Treatment of diabetic retinopathy involves managing diabetes first. It is crucial to maintain good blood sugar control, personalize medication doses, and adopt lifestyle changes, particularly in diet. A dietitian should supervise and adjust the diet plan to suit the patient’s needs.
The eye is one of our most important sensory organs, and any symptom affecting vision should be taken seriously. Blurred vision is one such symptom that, as seen, can develop due to many underlying causes and may be accompanied by a variety of other symptoms.
Associated symptoms include stinging or burning, redness, watery eyes, vomiting, nausea, headaches, eye pain, and discharge. Blurred vision should be evaluated alongside other accompanying symptoms. Don’t forget to see an eye specialist for diagnosis and treatment.