Scleral Lenses can Benefit Severe Dry Eye Patients
BY ANN LAURENZI-JONES, OD, FAAO
The cornea is one of the most densely enervated tissues in the human body; even mild dry eye signs can cause patients to have constant irritation, pain, and photophobia. Severe dry eye conditions such as Sjögren’s syndrome, Grave’s Eye disease, and primary keratitis sicca may intensify patient symptoms. The unstable tear film associated with these conditions makes the cornea vulnerable to inflammation, punctate staining, potential erosions, and more intense complications such as filamentary keratitis and infection. These patients may benefit most from scleral lenses, which create an aqueous environment lubricating the ocular surface that other treatments cannot provide.
Figure 1. Fluorescein pattern of a steep scleral lens.
Figure 2. Fluorescein pattern of a flat scleral lens.
Scleral Lens Fitting
A properly fit scleral lens completely vaults the cornea and limbus. The fit maintains a constant aqueous interface by retaining the precorneal tear layer, which hydrates the cornea in these dry eye conditions.
You can evaluate the fit in different ways to ensure that the aqueous layer under the scleral lens is adequate to benefit the patient. Clinically, the most convenient way is to observe the fluorescein pattern under the lens. Fill the concave side of the lens with saline, add fluoroscein dye, then observe the fluoroscein pattern after the lens has been placed on the eye. The most acceptable fit is a complete vault of the cornea with slightly more fluoroscein pooling in the limbal area. There will be very little if any lens movement, and the weight of the lens will bear in the peripheral curves that land on the conjunctival sclera. A steep lens will exhibit too much pooling in the central optical zone and bearing in the peripheral cornea and limbal area (Figure 1). A lens that is too flat will bear on the central cornea and may have edge lift (Figure 2).
Another way to observe the vault is through optical coherence tomography (OCT). Anterior segment OCT can evaluate whether the lens properly vaults the cornea and whether it lands on the conjunctival sclera. Figure 3 shows an OCT image of a scleral lens fit too steep, while Figure 4 shows a scleral lens fit too flat.
Figure 3. Anterior segment OCT image of a steep scleral lens.
Figure 4. Anterior segment OCT image of a flat scleral lens.
When All Else Fails
There are many therapeutic options available for treating patients who have dry eye. Scleral contact lenses may bring relief to severe dry eye patients when other more conventional dry eye treatments cannot. CLS
Dr. Laurenzi-Jones currently has a staff position at NorthShore University Hospital in Glenbrook, Illinois. You can reach her at email@example.com.