The practice known as injected sclera, or scleral tattooing, is a non-medical, cosmetic body modification involving the deposition of concentrated pigment beneath the thin outer layer of the eye. The procedure aims to permanently change the color of the white part of the eye, but it is not endorsed by any recognized medical or ophthalmological body. This elective modification is considered extremely high-risk due to the delicate anatomy of the eye and the potential for severe, sight-threatening complications. The lack of medical training among practitioners and the use of unapproved materials contribute significantly to the procedure’s danger profile.
Structure and Function of the Sclera
The sclera is the tough, opaque outer layer that forms the protective shell of the eyeball, providing structural integrity and maintaining the eye’s spherical shape. This fibrous tissue extends from the transparent cornea at the front of the eye to the optic nerve sheath at the back. The layer’s thickness varies, being thinnest (approximately 0.3 millimeters) at the insertion points of the extraocular muscles.
The sclera is intimately connected to crucial internal structures, including the light-sensitive retina and the optic nerve, which transmits visual information to the brain. This proximity means any penetration or damage risks injury to the deeper, sight-governing tissues. Its primary function is protection, making it highly sensitive to foreign substances and punctures.
The Scleral Injection Procedure
The technique for scleral tattooing involves injecting liquid pigment into the subconjunctival space, the region just beneath the conjunctiva (the clear membrane covering the sclera). Practitioners, who are typically body modification artists rather than medical professionals, use fine-gauge needles, such as a 31-gauge insulin needle. The goal is to deposit the ink so it spreads across the white surface of the eye, creating a uniform color effect.
The procedure relies heavily on the practitioner’s manual skill to ensure the needle enters the correct tissue layer without penetrating the deeper globe. The injected substance is usually a concentrated tattoo ink, which is neither formulated nor approved for use inside the human eye. Achieving full coloration often involves multiple injections, increasing the chances of procedural error and trauma with each needle stick.
Acute Medical Complications
The most severe risk of a scleral injection is globe perforation, which occurs when the needle inadvertently punctures the eyeball itself. This can lead to the catastrophic injection of tattoo ink directly into the vitreous humor or anterior chamber, resulting in partial or total vision loss. Inadvertent globe penetration has been reported in documented cases, underscoring the difficulty and danger of the procedure.
A major complication is severe infection, specifically endophthalmitis, which is an inflammation of the internal contents of the eye. This infection can rapidly destroy the delicate inner tissues and often requires emergency surgical intervention and intensive antibiotic therapy. The use of non-sterile equipment and unapproved inks increases the risk of introducing bacteria or fungi into the eye.
The physical trauma and inflammatory response to the ink can cause a rapid increase in intraocular pressure, known as secondary glaucoma. This rise in pressure can quickly damage the optic nerve fibers, leading to irreversible vision loss. Trauma can also trigger a retinal detachment or cause lens luxation, where the lens shifts out of its normal position. In the most severe instances of uncontrolled infection, pain, or irreparable damage, the entire eye may need to be surgically removed (enucleation).
Chronic Effects and Regulatory Oversight
Beyond the immediate crisis, scleral injections can result in long-term ocular issues that manifest over months or years. Chronic inflammation is common, leading to persistent discomfort, redness, and photophobia (extreme sensitivity to light). The tattoo pigment can migrate over time, spreading from the sclera to other ocular tissues, including the iris or the inner lining of the eyelids.
The body’s immune system may react to the foreign pigment by forming small lumps or nodules called granulomas. These granulomatous reactions are a delayed inflammatory response that can cause swelling and mechanical irritation within the eye. Such chronic conditions often require ongoing medical management and, in some cases, surgical excision of the inflamed tissue.
Due to the well-documented dangers, there is a universal lack of medical regulation or official safety standards for scleral tattooing. Major ophthalmological organizations strongly advise against the procedure, emphasizing that no ink has been approved for injection into the eye. A growing number of jurisdictions, including several states in the United States and the Canadian province of Ontario, have moved to ban the practice entirely to protect public health from these severe complications.