Scleral Lenses

Scleral lenses are very large diameter GP lenses that do not contact the cornea. Instead, their weight is distributed over a broad area on the relatively insensitive sclera, or white part of the eye. For this reason, they tend to be a very safe, effective, and comfortable means of vision correction for those with keratoconus. Scleral lenses have pros and cons associated with their wear:

A scleral lens is so large that it does not contact the sensitive cornea.  Instead, its weight is distributed on the insensitive sclera, or white part of the eye.  For this reason, scleral lenses are often the most comfortable lenses available.

Pros:

• Comfort- because they do not contact the cornea at all (the most highly innervated area of the human body) and rest on the insensitive sclera.
• The power of the tear reservoir- because of how they are fit, a scleral lens creates a tear reservoir behind the lens and in front of the cornea.  This tear reservoir provides a number key benefits.  The vision correction with scleral lenses is second to none.  Every minute irregularity of the corneal shape is neutralized by the fluid.  The tear reservoir also acts as a fluid bath for the cornea.  Patients often describe that dryness is much better with scleral lenses.  In fact, for those with extremely dry eyes due to other conditions, scleral lenses are often the treatment of choice.
• A high degree of precision- The fitter of true scleral lenses has control over every curvature value in the lens.  Even highly irregular eyes can be fit with scleral lenses because the sky is the limit on options available.
• The ultimate in customization- nearly any parameter can be manufactured, including toric front surfaces for the correction of internal astigmatism, notching for avoidance of elevated areas on the eye (such as from glaucoma filtering surgeries, or anatomical abnormalities), and coming soon are multifocal optics.

Cons:

• Doctor experience- scleral lenses are perhaps the most complicated contact lenses to fit.  Because of this, there are very few doctors who have a true understanding of the technology.  A very large contact lens company has tried to simplify the process for doctors with less experience.  They have released a semi-scleral lens that they promote as a scleral lens.  The problem with this technology is that it contacts the part of the eye that is most critical for maintaining corneal health, the limbus (and limbal stem cells).  Numerous near term and later term complications have been observed with patients fit with these lenses.
• Number of visits required for proper fit- there are a number of papers in the literature that discuss how many visits are typically required for a proper result with scleral lenses.  The average ranges from 3-8 visits depending on the paper, but individual results may vary widely.
• Expense- Because of the high degree of expertise required, the number of visits, and the cost of materials, scleral lenses are typically more expensive than other forms of vision correction.  However, many vision plans and medical insurances can help defray the cost of visits and materials.  An office that is highly experienced in dealing with insurances for complex corneas can help you navigate this on an individual basis.