What Is the Cornea of the Eye?
The cornea is the most exterior transparent part of the eye. It protects the innermost structures of the eye. The primary function of the cornea is to refract the light entering the eye. The cornea by itself is devoid of any blood vessels. Maximum perfusion of the blood in the cornea is present in the superior and inferior regions.
What Do You Mean by Arcus Senilis?
Arcus senilis (AS), also known as corneal arcus, is an ocular condition characterized by the deposition of lipids in the form of rings in the cornea's periphery.
What Is the Main Causative Factor in the Development of Arcus Senilis?
The specific causative factor linked to arcus senilis is not known. However, it occurs due to the deposition of lipids or fat molecules in the blood vessels supplying the cornea. The blood vessels supplying the cornea are in the limbus region (border between the cornea and sclera). Therefore, the nature of these blood vessels determines the severity of the condition.
What Is the Specific Mechanism Behind the Formation of Arcus Senilis?
Fats like lipids, cholesterols, phospholipids, and triglycerides get deposited preferentially in the capillaries supplying blood to the cornea. The superior and inferior areas of the cornea have a higher deposition of fat due to greater perfusion and permeability of the vessels. The amount of fat deposition depends on the nature of blood vessels perfusing the cornea.
Who Is at a Greater Risk of Getting Arcus Senilis?
Corneal arcus is more prevalent in the South Asian and African populations. Males significantly above fifty years are more vulnerable to contracting arcus senilis. The incidence of the disease increases with age. Arcus senilis presence is considered normal for people of eighty. The incidence of corneal arcus in younger men below forty years of age is predictive of underlying diseases like:
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Cardiovascular diseases like congestive heart failure.
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Disorder with defective lipid metabolism.
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Carotid artery pathology like blood flow stasis in the carotid artery.
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The deposition of lipids occurs mainly in the acellular, fibrous layer (Bowman's layer) present in the anterior stroma of the cornea and basement membrane of the endothelium of the cornea (Descemet's membrane). Deposition of fat is more in the Descemet's membrane.
What Are the Risk Factors Associated With Arcus Senilis?
The risk factors that contribute to aggravating the incidence of arcus senilis include:
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Alcoholism.
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Older age.
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Male sex.
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Race.
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People with a familial history of high cholesterol.
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Unilateral arcus senilis mainly is more common in people with a history of
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Reduced ocular pressure of less than 5 mm Hg.
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Patients have a narrow carotid artery of the neck.
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Asymmetrical blood supply to the brain.
What Are the Clinical Signs and Symptoms to Watch Out for in Inpatients With Arcus Senilis?
Patients with arcus senilis are primarily asymptomatic. However, evaluation of the eye by slit-lamp technique reveals a yellowish-white or white band in the superior and inferior aspect of the cornea around the limbus region.
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Arcus senilis may also show the presence of crystalloid edges that are specific for lipid keratopathy.
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Arcus senilis primarily affects both the eyes. Therefore, unilateral presentation of the state indicates a severe ocular or systemic pathology.
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There is the presence of classic white or blue ring-like opacity in the cornea's periphery.
How Is Arcus Senilis Diagnosed?
The diagnosis of arcus senilis primarily depends on the history and clinical appearance of the disease. Therefore, no other particular tests or imaging are required.
However, in case of suspicion of underlying disease, lab tests are prescribed to determine the lipid profile of the patients. Lipid tests are blood tests performed to assess the concentration of fat molecules like lipids and triglycerides present in the blood.
What Are the Conditions That Are Similar to Arcus Senilis?
Before forming a definitive diagnosis of arcus senilis, there is a need to rule out other similar diseases. The few disorders that share similarities with arcus senilis clinically include:
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Pseudogerontoxon is an allergic eye disease. The lesion of pseudogerotoxon is smaller than arcus senilis.
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Terrien marginal degeneration characterizes marginal thinning of the eye's cornea, causing deposition of lipid and opacification.
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Osteogenesis imperfecta is a heritable disorder disrupting corneal rigidity.
What Are the Different Approaches Used to Treat Patients With Arcus Senilis?
Arcus senilis or gerontoxon separately does not require any treatment. However, if it presents any other systemic condition, there is a need to control the underlying state.
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Lifestyle management and treatment of the basal cardiac and lipid disorders help control the disease's visual presentation.
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Patients should be kept in regular follow-up to prevent any further severe complications.
What Are the Complications Linked to Arcus Senilis?
Arcus senilis itself is a complication of acute systemic disease. However, it does not further lead to any complications.
Is It Possible to Prevent Arcus Senilis?
It is imperative to teach the patients about the non-serious nature of the disease. There is a need to emphasize that arcus senilis might present underlying cardiovascular problems.
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Patients should be comforted regarding the esthetic compromise and lack of regression of the lesion associated with the disease.
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Also, encouraging the patient to follow a few lifestyle changes and stop harmful habits will help eradicate the root cause. Also, interprofessional coordination among health professionals will help early diagnosis and prompt patient referral.
What Is the Prognosis of Arcus Senilis?
Arcus senilis overall enjoys a very favorable outcome. It does not affect the vision of the person. Only the esthetic value of the eye gets compromised.
Conclusion
Arcus senilis is a benign eye complication of an underlying disease. Most of the patients presenting with gerontoxon are asymptomatic. In addition, patients with gerotoxon usually do not require any treatment to correct the ocular state. Therefore, arcus senilis enjoys a very favorable outlook with no complications.
