The phenomenon of seeing the white part of the eye below the colored iris is medically termed inferior scleral show. This occurs when the lower eyelid sits lower than its typical position. Normally, the margin of the lower eyelid should rest precisely at or just slightly above the bottom edge of the iris, covering a tiny portion of the colored area.
Inferior scleral show happens when the balance between the lower eyelid and the globe of the eye is disrupted, causing the eyelid to retract downward. This retraction exposes the sclera that should be concealed, creating a visible gap between the iris and the eyelid margin. The sclera is the tough, white layer that maintains the eyeball’s shape.
Common and Non-Medical Causes
For many people, the visibility of the lower sclera is a natural anatomical variation present since birth, often called constitutional scleral show. This predisposition relates to the underlying bone structure of the face, such as a shallow eye socket or an under-projected maxilla (mid-face bone). These features can result in a “negative vector” eye, where the eyeball protrudes slightly and offers less support for the lower eyelid.
Age is another frequent contributor, as the supporting tissues naturally weaken over time. The skin loses elasticity, and the orbicularis oculi muscle, which holds the eyelid tight, loses tone. A reduction in soft tissue volume of the cheek and under-eye area, sometimes accelerated by weight loss, can also cause the lower eyelid to descend. These changes lead to mild lower eyelid laxity, allowing the eyelid margin to droop and expose more of the sclera.
Underlying Medical Conditions
When scleral show develops suddenly or worsens, it may signal an underlying medical condition affecting the eye or surrounding tissues. The most prominent medical cause is Thyroid Eye Disease (TED), also known as Graves’ orbitopathy, an autoimmune disorder often linked to an overactive thyroid. In TED, autoantibodies cause inflammation and expansion of fat and muscle tissue behind the eye.
This expansion increases the volume within the orbit, pushing the eyeball forward in a process called proptosis. The forward movement mechanically pushes the eyelids open and causes the lower eyelid to retract, leading to a pronounced scleral show. The severity of the scleral show is directly related to the degree of orbital tissue inflammation.
Another cause is the weakening of the lower eyelid muscles due to facial nerve paralysis, such as in cases of Bell’s palsy. This paralysis removes the muscular tension required to keep the eyelid snugly against the eye, causing it to sag downward. Scarring and contracture following previous eye or eyelid surgeries, particularly lower eyelid blepharoplasty, can also physically pull the eyelid tissue down.
When to Consult a Specialist and Treatment Options
A consultation with an ophthalmologist or an oculoplastic surgeon is recommended if the visible sclera is new, worsening, or accompanied by other symptoms. Signs that warrant immediate attention include persistent dryness, irritation, pain, excessive tearing, or changes in vision, as these indicate poor eyelid closure and corneal exposure. Systemic symptoms like sudden weight changes or rapid heart rate should also prompt a medical evaluation to rule out conditions like thyroid disease.
Management begins with conservative measures for mild cases, such as using artificial tears and lubricating ointments to protect the exposed ocular surface. For cases related to age or mild retraction, non-surgical options like hyaluronic acid fillers can be injected below the eyelid to add volume. This volume gently pushes the eyelid upward, providing cosmetic improvement and functional relief.
If the condition is severe or medically necessary, surgical options can restore the proper eyelid position. Procedures include a canthoplasty, which tightens the tendon supporting the outer corner of the lower eyelid, or the use of tissue grafts to lengthen the inner lining of the eyelid. For patients with severe Graves’ orbitopathy, orbital decompression surgery may be necessary to remove bone or fat tissue to reduce pressure and allow the eyeball to move back into the socket.