Sclerochoroidal calcification (SCC) is a rare, often benign finding involving the deposition of calcium salts within the back layers of the eye. It is typically discovered incidentally during a routine eye examination. SCC is not a tumor or a cancer, but rather a form of calcium buildup in the soft tissues of the eye. Its presence sometimes prompts a broader look at a person’s overall health. This article covers SCC’s appearance, its link to systemic conditions, diagnosis, and long-term outlook.
What Sclerochoroidal Calcification Is
Sclerochoroidal calcification involves the two outer coats of the posterior eye: the sclera and the choroid. The sclera is the tough, white, protective outer layer of the eyeball, while the choroid is the vascular layer beneath it, providing nourishment to the outer retina. SCC is characterized by the accumulation of calcium pyrophosphate crystals within these layers.
When viewed by an eye care professional, these deposits appear as yellowish-white, slightly elevated lesions. They are most often found in the mid-peripheral region of the retina, away from the central vision area, commonly in the superotemporal quadrant. They frequently occur as multiple deposits in one or both eyes, with about half of reported cases being bilateral. These calcified plaques average approximately 2.6 millimeters in diameter and 1.1 to 1.8 millimeters in thickness.
Systemic Conditions Associated with SCC
While many cases of sclerochoroidal calcification are idiopathic (cause unknown), a significant portion is associated with systemic disorders that alter the body’s calcium and phosphate balance. This deposition is known as metastatic calcification, where calcium settles in normal soft tissues due to elevated levels in the bloodstream. The presence of SCC should always prompt a systemic evaluation, as it may be the first sign of an underlying, treatable health issue.
The most frequently identified systemic association is primary hyperparathyroidism, where one or more parathyroid glands become overactive. These small glands produce parathyroid hormone (PTH), which controls calcium levels in the blood. Overproduction of PTH causes excessive calcium to be drawn from the bones, leading to hypercalcemia (high calcium levels). This excess calcium can then deposit in various soft tissues, including the eye.
Other systemic conditions linked to SCC involve problems with kidney function and electrolyte balance. Chronic kidney disease can lead to secondary hyperparathyroidism and hyperphosphatemia, both driving metastatic calcification. Additionally, rare genetic disorders affecting the kidneys, such as Gitelman syndrome and Bartter syndrome, are associated with SCC. These syndromes involve defects in the kidney’s ability to manage electrolytes, creating an environment conducive to calcium deposition.
How Sclerochoroidal Calcification is Diagnosed
Diagnosis typically begins during a routine comprehensive eye examination when characteristic lesions are observed. An ophthalmologist can visually identify the yellowish-white, elevated plaques in the periphery of the retina. Because these lesions can sometimes resemble serious intraocular tumors, such as choroidal melanoma, further diagnostic testing is necessary for definitive identification.
The gold standard for confirming SCC is a B-scan ultrasound, a non-invasive imaging technique. Calcium deposits are highly dense, causing sound waves to reflect strongly, appearing on the B-scan as intense brightness or high internal reflectivity. A hallmark finding is the immediate blockage of sound waves, which creates a distinct “acoustic shadowing” behind the lesion. This combination of high reflectivity and posterior shadowing differentiates SCC from almost all other masses in the choroid and sclera.
Following the ophthalmic diagnosis, a systemic workup is performed to investigate potential underlying causes. This assessment involves blood tests to measure serum levels of calcium, phosphate, and parathyroid hormone. Identifying an abnormal calcium-phosphate metabolism helps determine if the SCC is a manifestation of a broader systemic condition, such as hyperparathyroidism or kidney dysfunction.
Treatment and Long-Term Outlook
Direct treatment of the calcification itself is rarely necessary, as the lesions are generally benign and stable over time. The primary management strategy centers on identifying and treating any underlying systemic condition driving the calcium deposition. If hyperparathyroidism is diagnosed, addressing the overactive parathyroid gland is the appropriate course of action, potentially involving surgery or medication.
Once a systemic cause is managed, the eye lesions typically remain stable and do not progress, though the existing calcification rarely resolves. For patients whose SCC is idiopathic, the long-term outlook remains favorable. The lesions are usually asymptomatic because they are located away from the macula, the area responsible for sharp central vision, meaning they do not typically impair sight.
Vision-threatening complications are exceedingly rare, but can include the development of a choroidal neovascular membrane in the affected area. Regular, dilated eye examinations are recommended to monitor the size and configuration of the lesions and check for any associated changes. This careful monitoring, combined with ongoing management of any systemic disease, ensures the best possible long-term outcome.