Vision loss may occur suddenly or develop gradually over time.
Decreased vision may be:
- Bilateral (right and left sides)
- Unilateral (affecting only one eye)
- Just some parts of the visual field.
It can also refer to a loss of vision that can not be corrected with glasses or contact lenses.
- The partial blindness means that vision is very limited.
- The complete blindness means you can not see nothing, not even light.
(Most people use the term “blindness” to indicate complete blindness.)
Cataract – the patient refers to see:
- Intense brightness in the dark (therefore difficulty driving at night),
- The view is blurred,
- Colors appear more opaque and dull compared to the past.
In advanced cases, the cataractmay be visible to the naked eye (this is increasingly rare because it is currently involved early).
Age-related macular degeneration (AMD) – macular degeneration should be suspected if the patient is older than 50 years old and exhibits one of the following symptoms that usually affect one eye at a time:
- Distortion of vision in which straight lines appear wavy or distorted.
- Loss of vision or blurred vision in the central area or around the center.
- The person may describe a local black or gray spot that affects the central field of vision (scotoma).
- There may be other visual symptoms or the AMD can be detected by an optometrist by chance.
- Visual acuity with the Snellen chart may be normal or reduced.
While viewing an Amsler chart (or graph paper), patients may see broken, curled lines or some parts of the image are not visible.
Chronic open-angle (primary) glaucoma – usually found during a control.
If it is so advanced that the patient is the first to notice loss of vision, very little can be done.
The glaucoma is characterized by:
- Progressive loss of peripheral (or lateral) vision
- Altering the optical discs: The central area of the optical disc becomes larger and the peripheral plate decreases.
Diabetic retinopathy – the problem may be due to:
- Microvascular diabetic problems (ie, exudates and bleeding ),
- Associated diseases (eg, diabetic cataract ),
- Independent pathologies (eg, glaucoma ).
See your optician immediately (within one week) because early treatment for diabetic retinopathy may prevent further loss of vision.
Compression of the optic nerve or the optic pathway – rare disorder, but should be considered if there is a history of headaches and if there are possible neurological or endocrine abnormalities (eg acromegaly).
During the consultation the ophthalmologist seeks:
- A relative pupillary defect (usually not present),
- A pale or swollen optic disc (the margins are not well defined),
- Visual field defects.
Medications, toxins or nutritional deficiencies – for example:
- Amiodarone – causes various effects on the eye,
- Tuberculosis drugs – ethambutol and isoniazid (for optic neuritis ),
- Hydroxychloroquine (for maculopathy),
- Cortisone systemically (for cataracts and glaucoma),
- Phosphodiesterase inhibitors (for example, sildenafil or viagra citrate),
- Other drugs – tetracyclines (cause benign intracranial hypertension), isotretinoin, tamoxifen (various possible effects on vision),
- Contraceptive pill ,
- Alcohol , tobacco, and nutritional deficiencies (eg, toxic amblyopia caused by the tobacco-alcohol association),
- Poisoning by methanol,
- Vitamin A deficiency (usually causes night blindness).
Hereditary retinal dystrophies – these cases are rare and depending on the problem may be present since childhood.
Among the features there is a decrease in night vision and intolerance to light .
Movement in the peripheral visual field can not be clearly seen.
Children should have genetic control.
Cerebrovascular disease ( stroke and transient ischemic attack or TIA) – in which damage to brain cells occurs due to disruption of blood supply.
AIT (transient ischemic attack) causes loss of vision called transient amaurosis.
Papilledema – swelling of the optic disc (the point where the optic nerve enters the eye ) caused by intracranial hypertension. In the initial phase it can be asymptomatic (the patient has no symptoms).
At eye level, the consequences can be:
- Double vision (in the case of abducent nerve palsy that controls the muscles of the eye that perform the movement to the outside),
- Blurred vision,
- Reduction of the visual field with the appearance of shadows or colored spots.
Causes of sudden loss of vision without pain
1. Retinal detachment
2. Vitreous body haemorrhage
3. Retinal vein occlusion
4. Retinal artery occlusion
5. Wet macular degeneration
6. Anterior ischemic optic neuropathy
7. Optic neuritis
8. Cerebrovascular attack
Loss of gradual and slow vision
Among the causes of slow and progressive vision reduction are:
2. Refractive disorders,
4. Retinal edema.
Loss of vision accompanied by pain
This disorder is much more rare and it is necessary to consider a more serious condition such as:
- Acute Closed – angle Glaucoma Attack – Glaucoma is an eye disease linked to increased pressure inside the eye. The main symptoms are:
- Multiple Sclerosis – Vision loss is one of the most frequent and early symptoms of multiple sclerosis.
This disease causes damage to the optic nerve that serves to carry visual signals from the retina to the brain.
Multiple sclerosis causes loss of myelin (the insulation layer that surrounds the nerve) and the consequence is retrobulbar optic neuritis (NORB): inflammationof the optic nerve.
Generally loss of vision is temporary and can cause the appearance of blind spots (scotomas) and retrobulbar pain.
- Progressive ocular neoplasia (choroidal melanoma, for example) or an inflammatory process (eg chorioretinitis).
- Corneal Ulcer : is an open and painful wound on the cornea.
- A systemic problem (for example, sarcoidosis or vascular collagen diseases).
- Optic nerve injury (optic neuritis, neurinoma, or granuloma).
- Intracranial disease or tumor masses , a pituitary tumor can cause symptoms such as:
- Intracranial hypertension (can cause headaches ).
- Brain concussion . A head injury can cause vision loss or only blurred vision temporarily. According to the patient’s medical history, the following are performed:
- Neurological examination
- Blood tests (these can be done simultaneously).
All patients should be referred to a specialist within a few days.
Temporary loss of vision (amaurosis fugaz)
What is fleeting amaurosis?
A fleeting amaurosis is temporary loss of vision caused by lack of blood flow to the eye.
Vision loss usually occurs in one eye and lasts from a few seconds to a few minutes, up to about half an hour.
These disorders may be recurrent.
If the cause is resolved, temporary loss of vision may stop.
What causes fleeting amaurosis?
Among the most common causes of temporary loss of vision are:
- Narrowing of the carotid artery (called stenosis ) may reduce blood flow to the eye.
This is the most frequent cause of episodic blindness.
There are 2 carotid arteries, one on each side of the neck.
They take blood from the heart to the eyes and brain.
Some smaller arteries that branch from the carotid arteries carry blood to the eyes.
- Arterial thrombosis . Some atherosclerotic plaques may form along the inner walls of the arteries ( atherosclerosis ) causing a decrease in blood flow.
These plaques can break and block blood flow to the eyes.
- Diabetes , smoking, high blood pressure and high cholesterol can cause problems in the carotid arteries and lead to temporary blindness.
- A migraine can cause spasms and narrowing of the arteries that carry blood to the eye.
- Stress causes several symptoms, including insomnia and temporary loss of vision; in more severe cases, the patient may see everything black.
Loss of vision during pregnancy
During pregnancy the woman may have a temporary reduction in vision due to:
- Hormonal changes,
- Deficiency of iron ,
- High blood sugar that can cause gestational diabetes ,
- High blood pressure that can lead to pre-eclampsia or eclampsia .
The consequences are:
- Dry eye due to reduced production of tears,
- Tired eyes,
- Occurrence of lightning in the visual field.
Loss of vision from near and far
Hyperopia. Blurred vision through farsightedness allows you to see distant objects well, but the eyes can not focus properly on the foreground or notice unusual fatigue and fatigue in the eyes.
In cases of severe hyperopia, even distant objects appear blurred.
Myopia . This disorder causes loss of vision from afar.
Astigmatism . Loss of vision from near and far is often the symptom of astigmatism . In particular, the vision is hazy or hazy. This refractive error is usually caused by an irregular shape of the cornea or lens.
With astigmatism, the rays of light are unable to reach certain points on the retina to produce clear vision regardless of the distance between the object and the eyes.
Presbyopia. Those who are over 40 and begin to have blurred vision at close range, for example when reading a newspaper, is likely to be suffering from a disease called presbyopia .
It is a visual defect that affects adults over the age of 45 years or older.
The symptoms of presbyopia are identical to those caused by farsightedness(blurred vision and eye fatigue during reading).
The difference is that presbyopia is a decrease in the ability to see nearby objects due to tightening of the lens inside the eye, while farsightedness is a defect in vision caused by the shape of the eye.
A person who has lost vision may have trouble driving, reading, or doing simple tasks such as sewing or other professions.
You can make changes at home and in routines that help keep the patient independent and safe.
There are health services that provide the training and support needed to live independently.
Computer for Visually Impaired
Individuals Computers have operating systems (Windows, Mac, etc.) with easy access features that make it easier to use the computer for people who have vision problems or color blindness .
For the blind, Windows lets you receive information through sound technology or touch technology.
Listen to text read aloud by a storyteller
A storyteller is a reader who reads aloud the text that appears on the screen and describes the events, such as error messages.
A blind individual, who has lost vision partially or with vision problems, may be able to use a Windows operating system from the first time they turn on the computer.
Use Speech Recognition to Run Programs
Speech recognition software in “Windows Speech Recognition” is a technology that allows you to control your computer and dictate in virtually any application.
You can dictate documents, emails and surf the web.
An easy-to-install process and an interactive tutorial are available to allow the user to familiarize themselves with voice commands and train the computer to better understand the person who lost sight.