Arcus senilis is an age-related eye disorder characterized by deposition of lipids and cholesterol on the outer border of the cornea. It is often considered as a prognostic factor for cardiovascular diseases and may reflect hypercholesterolemia or hypertriglyceridemia. The diagnosis can be made during physical examination or with the use of a slit lamp. As the condition is benign and produces no symptoms, therapeutic strategies do not exist.
The disease is related to the following processes: degenerative and has an incidence of about 6 / 100.000.
Arcus senilis is one of the many changes in the eye that occur as a result of aging and comprises accumulation of lipids in the corneal stroma, usually forming a ring-like opacity on the very periphery of the cornea , at the sclerocorneal junction. Macroscopically, arcus senilis appears as a yellow-grayish-white arc that has a sharply demarcated outer and indistinct inner border . It usually starts in the superior or inferior corneal pole and eventually develops and encompasses the entire circumference, whereas the presence of the lucid interval of Vogt (a clear area between the arcus senilis and the sclera) is considered as one of the hallmarks of this condition . As a result of progressive degenerative changes in the eye due to aging, accumulation of lipids, mainly cholesterol esters, but also triglycerides in the extracellular matrix of the corneal stroma occurs.  Studies have further confirmed the age-related etiology by observing that tissue necrosis and atrophy do not occur and that pileup of fats is the only pathological event . Arcus senilis has often been mentioned as a prognostic and predictive marker of cardiovascular disease, hypertriglyceridemia and hypercholesterolemia, while its clear association with alcoholism, diabetes mellitus, smoking, obesity and hypertension needs further clarification . Advanced age is certainly the single most important risk factor and in terms of gender predisposition, a male predominance has been observed in various reports . Clinical presentation is asymptomatic, since arcus senilis does not produce any symptoms or signs, nor does it cause any visual disturbances. The diagnosis can be made during regular physical examination, as this formation can be seen with the naked eye during close inspection. A more direct view can be achieved by the use of a slit lamp, which can detect the corneal arcus with great precision . If the diagnosis is confirmed, it is recommended to obtain serum values of both high-density and low-density lipoproteins (HDL and LDL, respectively), total cholesterol and triglycerides, but it is not uncommon for patients to have normal values of circulating lipids . Since arcus senilis does not cause any symptoms and poses no risk for the patient, treatment principles currently do not exist.
Deposition of lipids and cholesterol esters and connective tissue degeneration as a result of age-related changes is the cause of arcus senilis. Current studies hypothesize that the origin of these changes stems from atherosclerosis of corneal vessels and subsequent accumulation of triglycerides and cholesterol in the extracellular matrix . Although hyperlipidemia and hypercholesterolemia have been considered as contributing factors to development of arcus senilis, these findings require additional confirmation, but arcus senilis has been often referred together with xanthelasmas (sharply demarcated, yellowish plaques that develop on either lower or upper eyelids), which arise as a result of high serum lipid levels .
Studies have shown that approximately 20-35% of the population develop this clinical entity in advanced age , but the incidence is reported to be as high as 80% and a strong gender predilection toward males has been commonly observed . In general, prevalence rates rise as age increases, with isolated reports showing a 26%-41% prevalence in the age group 30-49 years and 59%-86% in the age group 50-69 years for female and male gender, respectively . Other studies in randomized samples report an overall prevalence rate of around 50% .
The main and practically only pathophysiological mechanism in arcus senilis is accumulation of lipids in the corneal stroma. Normally, the extracellular matrix is composed of fibroblasts and a network of blood vessels composed of smooth muscle cells, but in advanced age, degeneration of connective tissue and atherosclerosis are considered as underlying mechanisms for deposition of cholesterol esters, triglycerides and phospholipids. As a result, a distinct yellowish-to-white appearance is characteristic for arcus senilis . Accumulation initially starts on the inferior poles and then progressively spread to the superior pole, eventually forming a ring-like structure that is located on the outer corneal rim .
Arcus senilis is a benign and self-limiting condition that does not pose a risk for the patient's vision or general health. Certain studies have attempted to asses whether arcus senilis is a prognostic factor for myocardial infarction, coronary heart disease, dyslipidemia and increased intraocular pressure, but conflicting results have been obtained. Nevertheless, many patients in whom arcus senilis was diagnosed had elevated serum levels of LDL and reduced HDL , which is why it is necessary to perform these laboratory tests.
All individuals who develop arcus senilis are asymptomatic and the diagnosis is often made incidentally. Visual disturbances are absent and bilateral development is observed in most cases.
The initial diagnosis can be made during physical examination, when white, yellow or grayish opacities on the outer corneal border (at the corneoscleral junction) can be observed. Depending on the severity of lipid accumulation, opacities can be located only at the poles or a ring-like formation can be noted in later stages. As mentioned previously, bilateral presentation is almost universal, but to confirm the diagnosis, the slit lamp examination is necessary. A clear visualization of the lipid ring and the lucid interval of Vogt, a very subtle clear area between the sclera and the arcus that further confirms the diagnosis. Additional findings during this examination may include increased intraocular pressure (IOP) and lower central corneal thickness . In all patients with arcus senilis, a full lipid panel consisting of LDL, HDL, total cholesterol and triglycerides should be obtained, as well as blood glucose levels, as it has shown to be associated with hyperlipidemia and diabetes mellitus, respectively .
At this moment, treatment strategies do not exist for this condition, as it does not cause any symptoms nor does it interfere with vision. The focus of treatment should be directed to hyperlipidemia and hypercholesterolemia (if present) and the use of lipid-lowering drugs such as statins should be advocated, as well as evaluation of dietary habits and potential corrections.
Since a more or less clear association between arcus senilis and disturbed levels of LDL, HDL and triglycerides, preventive strategies may include dietary corrections and lifestyle changes that will result in improvement of lipid profile. As this entity is an age-related process, however, little can be done in terms of preventing its appearance.
Arcus senilis is a benign ocular condition that is characterized by deposition of fats on the outer part of the cornea, which is responsible for light refraction. As the name implies, this disorder arises due to aging and degeneration of connective tissue situated in the cornea, which results in accumulation of cholesterol and triglycerides. As a result, a yellowish, grayish or white opacity on the border of the cornea and sclera (the white part of the eye) appears. Initially, these opacities develop on either upper or lower pole, but as accumulation and age progress, a ring-like formation can be observed, especially in older individuals. It is hypothesized that virtually all individuals will eventually develop arcus senilis at some point and isolated studies indicate that up to 80% of males and 50% of females aged between 50-69 years suffer from this age-related disorder. Gender predilection toward males is commonly observed. In many reports, this condition has been reported to be in association with increased levels of circulating cholesterol, indicating that atherosclerosis, hyperlipidemia and other illnesses that trigger such events may serve as predisposing factors. Diabetes mellitus, smoking and alcohol consumption have also been brought into connection with arcus senilis, but further studies are necessary to identify their exact link. The course of the disease is completely asymptomatic, as arcus senilis does not induce any symptoms, nor does it impair vision, which is why it is often discovered incidentally during regular check-ups. The initial diagnosis can be made just by close inspection of both eyes (in virtually all patients, both eyes are affected), but to confirm arcus senilis, a slit lamp examination that is usually performed by an ophtalmologist is performed. It is highly recommended to draw blood for evaluation of cholesterol and triglyceride levels in these individuals, due to the fact that is has been commonly associated with cardiovascular diseases. Treatment principles currently do not exist, as this condition does not cause any harm to the patient and it is interpreted as a manifestation of aging. Nevertheless, dietary changes and correction of possibly elevated lipid levels in blood should be performed to preserve the cardiovascular system.