Scleral show is an anatomical condition where the white part of the eye (the sclera) becomes noticeably visible below the iris (the colored part). Normally, the lower eyelid rests gently at or slightly above the bottom edge of the iris. When the lower eyelid retracts or droops downward, it exposes this additional portion of the sclera, a condition also referred to as lower eyelid retraction or “round eye.” This exposure shifts the eye’s appearance from a typical almond shape toward a more circular contour. The condition is defined by the measurable vertical gap between the lower eyelid margin and the limbus, which is the border between the iris and the sclera.
Defining Scleral Show and Its Appearance
Scleral show is identified by a band of white beneath the iris when the eye is in a neutral, forward gaze. This results from the lower eyelid margin sitting lower than its typical position, increasing the vertical opening of the eye. While the lower eyelid normally covers the eyeball up to the base of the iris, scleral show creates a visible crescent of white space below this line. This excess visibility can make the eyes appear rounded, wide-eyed, or perpetually startled. Although lower scleral show is most common, some conditions can cause upper eyelid retraction, resulting in a visible white band above the iris as well. A pronounced show usually indicates a loss of support or an underlying tissue change causing the eyelid to be pulled down.
Underlying Causes of Scleral Show
The development of scleral show is rooted in the abnormal positioning or structural change of the lower eyelid.
Thyroid Eye Disease (TED)
One major systemic cause is Thyroid Eye Disease (TED), often associated with Graves’ disease. This autoimmune inflammatory disorder leads to fibrotic remodeling of the eyelid muscles and tissues, pulling the upper eyelid upward and the lower eyelid downward.
Age-Related Changes
Age-related, or involutional, changes are also common. As a person ages, the ligaments and tendons supporting the lower eyelid weaken, and tissues lose elasticity. This laxity, combined with the downward descent of midface fat, causes the lower eyelid to descend from its normal position.
Iatrogenic Causes
Another frequent cause is iatrogenic, meaning it results from a medical or surgical procedure, particularly following lower blepharoplasty (eyelid surgery). Scleral show can occur if too much tissue is aggressively removed, or if scarring and contracture pull the delicate eyelid structures downward. Inadequate canthal fixation during surgery further contributes to this complication. Less common causes include trauma, facial nerve paralysis, or congenital factors that result in a structural deficiency of the eye socket or a pre-existing negative orbital vector.
Associated Functional and Aesthetic Concerns
The increase in exposed sclera creates significant functional problems for the eye, not just cosmetic issues. The abnormal position of the lower eyelid impairs the eye’s natural lubrication system, leading to tear film instability. Increased exposure to air and irritants causes symptoms like chronic dry eye, a gritty sensation, and excessive tearing.
In severe cases, the inability of the eyelid to properly cover the globe can lead to exposure keratopathy, which involves drying and damage to the cornea and can threaten vision. Patients may also experience photophobia (light sensitivity) and a persistent foreign body sensation. Aesthetically, scleral show often results in a tired, anxious, or perpetually surprised appearance due to the rounder, more open eye shape.
Treatment and Correction Options
The treatment approach is guided by the underlying cause and severity, often beginning with non-surgical management.
Non-Surgical Management
For functional symptoms like dryness and irritation, palliative care includes the frequent use of artificial tears, lubricating gels, and nighttime ointments to protect the exposed ocular surface. Temporary measures, such as taping the lower eyelid during sleep, can help ensure proper lid closure and corneal protection.
Surgical Correction
When non-surgical options are insufficient or the scleral show is pronounced, surgical correction is pursued. The goal of surgery is to physically elevate and tighten the lower eyelid to restore its normal position against the eyeball. A common technique is a lateral canthoplasty or canthopexy, which involves adjusting and tightening the lateral canthal tendon, the structure anchoring the eyelid to the outer eye socket.
For more significant retraction, a spacer graft is often required to physically lengthen the inner layer of the lower eyelid. These grafts provide structural support and vertically elevate the eyelid margin. Grafts can be made from materials such as:
- Hard palate mucosa
- Ear cartilage
- Donor tissue (such as Alloderm)
In cases due to thyroid eye disease, surgery may involve loosening the fibrotic lower eyelid retractors and combining the procedure with orbital decompression to maximize the effectiveness of the eyelid repair.