Introduction:
Ever wondered how we see things through our eyes? When we encounter a visual, a major nerve present behind the eyeball called the optic nerve sends the signals from the eye to the brain, making us see. Oxygen and nutrient supply to the nerve fibers happen through arteries; any injuries or problems in those arteries can highly influence the function of the optic nerve leading to vision changes. Certain damages to the optic nerve or the arteries supplying it fall under optic neuropathy.
What Is Optic Neuropathy?
It is damage to the optic nerve caused due to alteration in the blood flow. As a result of interrupted blood flow, the supply of oxygen to the optic nerve is disturbed, degrading its functions and leading to blindness if untreated. The resulting vision impairment could range from mild to severe. In addition, there might be sudden vision loss in one or both eyes.
What Are the Types of Ischemic Optic Neuropathy?
Ischemic optic neuropathy (ION) is classified as anterior (which shows swelling in the optic nerve) and posterior ischemic optic neuropathy (which does not show any swelling). It is further classified into three subtypes each such as; arteritic, non-arteritic and perioperative. Anterior ION is the most commonly occurring type of ischemic optic neuropathy.
Non-arteritic Ischemic Optic Neuropathy:
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It is the commonest of optic neuropathies.
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Non-arteritic ischemic optic neuropathy is more common in people who are 45 years or older but can affect other age groups as well.
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It occurs due to an alteration in the blood flow to the optic nerve. Interrupted blood flow compromises the oxygen supply leading to improper functioning of the optic nerve, resulting in vision problems or permanent vision loss.
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Risk factors of this condition include uncontrolled diabetes, high blood pressure, obstructive sleep apnea, atherosclerosis, habits like smoking, and certain drugs like Amiodarone, etc.
Arteritic Ischemic Optic Neuropathy:
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It affects people older than 55 years.
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Arteritic ischemic optic neuropathy occurs due to inflammation in the arteries, which blocks the blood supply to the optic nerve.
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This inflammation in the arteries supplying the optic nerve often results from temporal arteritis (inflammation involving the arteries on the side of the head). It is also called giant cell arteritis; it does not show any symptoms but could be the source of inflammation.
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It is more common in women.
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It is a serious condition and should be diagnosed and treated earlier to prevent vision loss; if not can result in permanent damage such as vision loss.
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When vision loss happens, it is impossible to bring it back to normal in this condition.
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The incidence of vision loss in arteritic neuropathy is more when compared to non-arteritic.
What Are the Symptoms of Optic Neuropathy?
Optic neuropathy shows various symptoms, such as;
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Pain in the eye, eye socket, other parts of the face, and the temporal region.
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Colors appear more faint than usual.
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Frequent fluctuated loss of vision partially or completely on one eye.
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Loss of peripheral vision.
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Frequent flashes of light when moving the eyeballs.
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Double vision.
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Fatigue, body pain, and weight loss.
What Are the Causes of Optic Neuropathy?
There are various causes of optic neuropathy, which include;
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Acute (sudden short-term) injuries to the optic nerve.
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Compression of the optic nerve due to tumors is named compression neuropathy.
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Certain neurological disorders might cause optic neuropathy.
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Hereditary factors can cause optic neuropathy as it runs in families.
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Infections such as herpes simplex, histoplasmosis, and other viral infections can cause optic neuropathy.
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Certain nutritional deficiencies.
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Intake of toxins can lead to optic neuropathy toxins such as alcohol and methanol could be the cause.
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Optic neuropathy can occur as a complication of medications such as Ethambutol, Methotrexate, cyclosporins, etc., which can directly or indirectly influence.
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There is no correlation between people having vision problems and the incidence of optic neuropathy.
Who Is at High Risk for Developing Optic Neuropathy?
The risk is more in people suffering from the following conditions;
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Uncontrolled diabetes.
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High blood pressure.
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Clogged arteries.
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Smokers.
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Migraine.
How Is Optic Neuropathy Diagnosed?
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The type of onset is essential to know the cause of neuropathy the patient is suffering. Slow onset vision loss happens in patients with toxic or nutritional optic neuropathy, while others usually show faster onset.
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Ophthalmologists will do an eye exam to look for signs of optic neuropathy.
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Dilated eye exam (a commonly performed eye examination involving applying eye drops to dilate the pupil and look for abnormal changes) detects optic nerve swelling and other damages.
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The fluid pressure of the eye (intraocular pressure) is analyzed.
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Vision changes, including peripheral vision, are checked.
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Dyes are injected into the arteries to check if there is any blockage using fluorescein angiography.
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CT (computed tomography) scan or MRI (magnetic resonance imaging) to confirm the damage to the optic nerve.
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Check the blood pressure, as that could be the cause.
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Blood tests rule out underlying diseases like diabetes, and certain vascular diseases, predisposing factors for optic neuropathy.
How Is Optic Neuropathy Treated?
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It is impossible to recover the vision loss to normal in optic neuropathy. The ophthalmologist might suggest some aids to see with low vision.
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Certain drugs can be harmful to the optic nerve; it is important to note such drugs; avoid taking them without a prescription, and mention them to the ophthalmologist during history taking.
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Steroids such as Prednisolone could be prescribed when initial symptoms show up to prevent the occurrence of optic neuropathy.
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If other health complications cause optic neuropathy, treatment for the underlying condition is a must before undergoing treatment for optic neuropathy.
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In case of cancers compressing the optic nerve, ophthalmologists suggest undergoing radiotherapy.
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In some cases, surgical treatment becomes necessary.
Conclusion:
Ophthalmologists say that optic neuropathy is a common cause of vision loss. Hence, getting an eye check-up when you have symptoms is very important. In addition, early identification can prevent severe complications such as vision loss due to optic neuropathy.
