Corneal Transplant, Dislocated Pupil and Glaucoma Shunt

Some of the most challenging contact lens fittings involve patients who have undergone multiple eye surgeries. A patient with a corneal transplant, a dislocated pupil, and a glaucoma drainage shunt presents a unique set of obstacles for achieving clear, comfortable vision. At Insight Vision Optometry, Las Vegas, our specialty contact lens team has the advanced technology and experience to help patients with complex surgical histories see more clearly.

Why Is Vision So Difficult After Multiple Eye Surgeries?

Each eye surgery changes the anatomy and optics of the eye. A corneal transplant replaces damaged corneal tissue, but the donor tissue rarely matches the original curvature perfectly. This often results in significant irregular astigmatism, which means the cornea has an uneven surface that bends light unevenly. Standard glasses and soft contact lenses cannot correct this type of distortion effectively.

A dislocated or displaced pupil adds another layer of difficulty. The pupil controls how much light enters the eye and where it is focused. When the pupil is not centered, light enters the eye at unexpected angles, creating symptoms like ghosting, glare, and double images. Glasses cannot compensate for a displaced pupil because they sit too far from the eye to control light entry precisely.

A glaucoma drainage shunt, or tube shunt, is a device implanted to lower eye pressure in patients with glaucoma. While it serves a critical purpose in protecting the optic nerve, the shunt alters the shape of the sclera where it is placed. This can make fitting any contact lens more complicated, because the lens must avoid putting pressure on the shunt or disrupting its function.

How Do Scleral Lenses Help in These Cases?

Scleral lenses are often the best option for patients with this combination of conditions. Unlike standard contact lenses, scleral lenses are large-diameter gas permeable lenses that vault entirely over the cornea and rest on the sclera. This design offers several advantages:

• The lens creates a smooth, uniform optical surface over the irregular corneal transplant, correcting the distorted vision that glasses cannot fix.
• A larger optic zone can be designed to account for a displaced pupil, ensuring that light passes through the corrective portion of the lens regardless of where the pupil sits.
• The landing zone of the lens can be customized to avoid the area of the glaucoma shunt, allowing the lens to fit comfortably without interfering with the device.

What Technology Is Used to Fit These Lenses?

Fitting a scleral lens for a patient with multiple surgical modifications requires detailed mapping of the eye’s surface. Our practice uses sMap 3D corneo-scleral topography, which captures a precise three-dimensional image of both the cornea and the sclera. This allows our doctors to see exactly where the scleral surface is elevated from the glaucoma shunt and where the corneal transplant creates irregular curvature. With this data, the scleral lens can be designed with a customized shape that matches the unique contours of the patient’s eye.

Diagnostic trial lenses are used during the fitting process to evaluate vision and comfort before the final lens is ordered. In cases with a displaced pupil, the optic zone may be enlarged or decentered to ensure the best possible visual outcome.

What Kind of Vision Improvement Can Patients Expect?

Patients with a combination of corneal transplant, displaced pupil, and glaucoma shunt often have uncorrected vision in the range of 20/200 or worse. With a well-fitted scleral lens, many of these patients achieve significant improvement, commonly reaching 20/40 or better. Symptoms like ghosting, glare, and distortion are also typically reduced, making daily activities like reading and driving much more manageable.

Results vary depending on the health of the corneal transplant, the degree of pupil displacement, and other individual factors. A thorough evaluation is the first step in determining what level of improvement is realistic for each patient.

Schedule a Specialty Contact Lens Evaluation

If you have undergone a corneal transplant, glaucoma surgery, or other eye procedures and are struggling with blurred or distorted vision, a scleral lens evaluation may help. Dr. Stephanie Woo, OD, FAAO, FSLS, and Dr. Nathan Schramm, OD, FSLS, FBCLA, at Insight Vision Optometry in Las Vegas specialize in fitting scleral lenses for complex surgical eyes. Call 702-747-4070 or visit www.insightvisionlv.com to schedule your consultation.