Blurry or hazy vision is a condition in which the person see an object indistinctly. Hazy vision may affect the way one sees a sign board. It may also make one bump into things at home and outside.
Some people describe blurry vision as having a filter in the eye, which reduces the focus. Blurred vision may be restricted to one part of the vision, or be generalized and affect the entire line of vision and focus.
This includes peripheral vision or vision of one side, like right or left. Blurry vision may affect only one eye or both the eyes. People with blurred vision tend to blink or squint often to get a better view of things. It is often considered to be a part of aging or as an indication of the need to get reading glasses.
Blurry vision is sometimes accompanied by other symptoms like:
- Loss of peripheral vision
- Sensitivity to light
- Abnormal discharge from eyes
- Dryness in eyes
- Itching in eyes
- Increased production of tear
- Pain in the affected eye
- Reduced night vision
- Poor near vision
People who forget to wear the corrective lenses may experience hazy vision. But, blurry vision may also be a symptom of an underlying problem. If hazy vision has a sudden onset and is associated with symptoms like a severe headache, difficulty in speaking, facial drooping, or difficulty in seeing, it warrants immediate medical attention.
This is particularly true if the accompanying symptom is the loss of muscle control on one side of the body. Severe pain in the eye and loss of vision are also serious symptoms that need emergency medical attention.
Blurry vision is caused by multiple factors, like:
Certain medications also are known to cause blurry vision. This includes certain anticholinergics, antihypertensives, oral contraceptives, cortisone, some antidepressants, and some medications used for cardiac problems.
Physical examination and review of medical history are important steps in the diagnosis of the underlying causes of the condition. The doctor may ask for information on the onset of the symptom, other associated symptoms, and also the conditions that improve or worsen hazy vision.
Review of family history of eye problems is equally important. One or more of the following test is conducted to identify the causative factor.
- Slit lamp examination – in this procedure, the doctor looks at the different parts in the front and back of the eye. It helps to map the functioning and structure of different parts within the eye.
- Refraction test – it measures the need for prescription corrective lenses using a refractor.
- Tonometry – this method is used to measure eye pressure using a tonometer.
Other tests are recommended based on the suspected cause of blurred vision. Treatment methods are based on the underlying cause of hazy vision. Eye drops, laser surgeries, corrective lenses, and medications are suggested to control blurred vision.
Hazy vision can be prevented in most of the cases. Wearing sunglasses, eating healthy diet, quitting smoking, having regular eye exams, and wearing protective eyewear while operating heavy machinery will help in preventing damage to the eyes and hazy vision
There are multiple causes for blurred vision. The underlying cause of the symptom is often diagnosed based on the laterality, speed of onset, and associated pain.
Some of the causes that result in sudden blurry vision in one eye associated with pain include:
- Trauma – usually associated with injuries and inflammation
- Orbital cellulitis – characterized by reddish, swollen and tender region around the eye.
- Endophthalmitis – patient may have history of surgical trauma and is characterized by reddish eye with reduced visual acuity.
- Corneal problems – may be caused by trauma, infection, or dry eyes.
- Anterior uveitis – sensitivity to light, reddishness in eyes, and head ache are the accompanying symptoms.
- Glaucoma – it is associated with headache, nausea and vomiting.
- Optic neuropathy – headache, jaw claudication, weight loss, anorexia, and fever are common symptoms along with hazy vision.
- Optic neuritis – it is a symptom of multiple sclerosis and is characterized by pain while moving the eye.
- Migraine – it often starts with visual disturbances, including hazy vision, followed by headache.
The major causes of sudden onset of blurry vision in one of the eyes without pain are:
- Vitreous hemorrhage – it presents as sudden floaters or hazy vision. It is caused by multiple factors including diabetic retinopathy, and retinal detachment.
- Central retinal artery occlusion – it is characterized by a sudden reduction of vision in one of the eyes. In some severe cases, there may be a complete loss of vision.
- Age-related macular degeneration (AMD) – this is characterized by deterioration of macula of the eye. It causes a progressive decline in vision.
- Retinal detachment – it produces a filter or a block across the visual field, reducing vision.
- Intermediate or posterior uveitis – it is characterized by floaters and blurring of vision
- Optic neuropathy – defect in the pupil, hemorrhages, and swelling in the optic disc are characteristic features of the condition.
- Hydrops – it is characterized by edema of the cornea.
Some of the systemic causes of the condition are:
- Giant cell arteritis – blurry vision in the initial stages may lead to progressive loss of vision in the eye.
- Papilloedema – edema of optic disc caused by increased pressure within the cranium may lead to vision problems, including hazy vision.
- Migraine prodrome – this occurs in some people, but may not lead to a headache after the vision defects.
- Toxic illness
The bilateral hazy vision that is sudden and painless is caused by papilloedema, cerebrovascular disease, and certain medications.
Gradual and painless blurry vision is caused by:
- Glaucoma – progressive loss of vision in the peripheral region
- Refractive errors – gradual vision loss is caused by many types of refractive errors
- Cataract – characterized by hazy vision and subdued colors
- Cystoid macular edema
- Diabetic maculopathy
- Genetic disease
- Drug toxicity
- Other toxic agents
- Inflammatory optic neuropathy
- Chronic eye strain
Visual loss and blurred vision may also occur when the cause cannot be ascertained. The visual loss may be psychosomatic or as in some cases the systemic disease that cause blurred vision is not diagnosed.
Review of medical history and eye examination are used in the confirmatory diagnosis of this symptom. When presented with blurry vision, the doctor may try to define blurriness in vision.
The presenting complaint can be defined in different ways. This includes whether the indistinct vision is for near or far objects. It also includes information on whether the image is distorted or appears smaller or bigger.
Information on floaters and other interference in the image also may be of help. While reviewing the presenting symptoms, they may see whether blurriness is unilateral or bilateral and whether the change in vision is sudden or gradual.
Other associated factors like pain, eye complaints, or systemic complaints are also noted. In the medical history, information on the history of other eye diseases, other systemic diseases, current medication, family history of eye diseases, and occupational history provide important clues on suspected cause of the condition.
During an eye examination, one of more of the following tests may be performed:
Slit-lamp examination – in this method, the patient is asked to keep the chin on a pad while doctor focuses on different internal structures in the eye. This helps to ascertain the functioning of different parts of the eye.
Light and magnification of the device are adjusted to observe different parts clearly. The surface of the eye is made numb by using anesthetic eye drops. Fluorescein eye drops forms a coat on the surface of the eye and will indicate the presence of any abnormal structures on the cornea. It is also used to measure the pressure within the eyes.
Refraction test – this test uses a refractor or phoropter to suggest the prescription for the corrective lens.
Tonometry – this method is used to measure the eye pressure using fluorescein eye drops. In this process, the tonometer is attached to the slit-lamp. The tonometer is kept at the same level as the eye with the help of the slit-lamp and pressure measured.
Treatment depends on the underlying cause of blurry vision. Eyeglasses, contact lenses, and refractive surgery help to treat conditions like myopia, hyperopia, and astigmatism. Special multifocal lenses or surgical treatment is suggested for correcting presbyopia.
Dry eyes are treated with artificial tears, prescription medication or punctual plugs that help to keep eyes lubricated. Prescription medications are suggested for reducing migraine. If certain medications are the cause of blurry vision, the doctor may suggest appropriate methods change or reduce the causative drug.
Overuse of contact lenses may lead to irritation and infection in eyes. The risk of infection and irritation can be reduced by avoiding over-use of the contact lenses. Specific treatment methods are recommended to control eye conditions that lead to hazy vision.
Artificial lenses and surgery are the treatment of choice for cataracts. Prescriptions and surgical repair help to reduce ocular pressure in glaucoma. Managing diabetes helps to keep eye problems under control. Cardiovascular and another systemic disease that cause hazy vision are treated by respective specialists and this alleviates blurry vision.
Most forms of blurry vision can be prevented to a large extent. Wearing sunglasses, eating a healthy diet, quitting smoking, undergoing a regular eye examination, and wearing protective eye gear, while being in risky occupations, are all important steps in preventing hazy vision.