PROSTHETIC LENSES

Changing Lives With Prosthetic Soft Lenses

Prosthetic soft lenses can provide cosmetic, therapeutic, and psychological benefits to patients who need them.

By Mitchell Cassel, OD

Dr. Cassel has a group practice in New York City, specializing in primary eye care and colored contact lenses. He is the owner of Custom Color Contacts, providing soft lens designs for prosthetic, cosmetic, and special eye effects to eyecare professionals and to the motion picture and television industries. Dr. Cassel is a member of the American Optometric Association and the New York Optometric Society. He is also a consultant, lecturer, and investigator for several contact lens companies including Vistakon, CooperVision, and Ciba Vision.

One of the most gratifying moments in any practice is when you can change a patient's life. More than 20 years ago I realized that there was a need to help patients who have scarred and disfigured eyes resulting from congenital abnormalities or traumatic injuries. I wanted to get involved, realizing the emotional trauma and self-esteem issues that such individuals can experience.

Early in my career I became aware of many colored contact lens options that are used for special eye effects on actors in the movie industry, often to create an array of visual effects including eyes that appear bloody, scarred, misdirected, diseased, aged, supernatural, mirrored, etc. I realized that the same colored lens techniques that help to make actors' eyes appear scarred and/or disfigured could also be used to help patients who have scarred and/or disfigured eyes look “normal” (a 180-degree turn).

Who Can Benefit?

During your eyecare career, it is not uncommon to be confronted with patients who present with a cloudy, scarred, or disfigured eye. Patients who experience ocular trauma from an accident or injury can have complications to the cornea that result in corneal clouding and often a deformed, shrunken, or disfigured globe (Figures 1a and 1b). In addition, certain congenital, metabolic, and infectious diseases as well as nutritional deficiencies and environmental situations may cause the cornea to be less transparent and cloudy.

Figure 1a. Leukocoria secondary to trauma and surgical complications.

Figure 1b. Prosthetic lens fit to improve cosmetic appearance.

Causes of disfigured corneas may include:

• Congenital defects
• Surgical complications (glaucoma, retinal, corneal)
• Infectious diseases (river blindness, trachoma, herpetic keratoconjunctivitis)
• Sjögren's syndrome
• Retinal detachments, glaucoma
• Poor nutrition (Vitamin A deficiencies)
• Accident or injury (chemical burns, trauma, etc.)

In addition, there are many reasons why a child may lose vision and require an artificial eye or a scleral shell. Some of these conditions include:

• Anophthalmia
• Microphthalmia (Figures 2a and 2b)
• Retinoblastoma
• Retinopathy of Prematurity (ROP)
• Coloboma (Figures 3a and 3b)
• Persistent Hyperplastic Primary Vitreous (PHPV)
• Trauma (BB guns, paint guns, rocks, darts, bungee cords, pencils, sports injuries, chemical burns, etc.) (Figures 4a and 4b)
• Coat's Disease

Figure 2a. Microphthalmia—note different iris size.

Figure 2b. Prosthetic lens that matches iris diameter, color, and detail of healthy eye.

Figure 3a. Iris coloboma with strabismus.

Figure 3b. Prosthetic scleral lens with iris detail readjusting alignment to straighten eye appearance.

Figure 4a. Traumatic injury in a 5-year-old resulting in a severed iris and photophobia.

Figure 4b. Prosthetic soft lens that recreated the iris, maximizing cosmetic appearance and eliminating the photophobia symptoms.

Taking an interest in recommending cosmetic and, if applicable, therapeutic lens options will make a tremendous difference in these patients' lives. There are many patients who are unaware of the resources and options that an eyecare professional can use to cosmetically improve their disfigurement or, in sighted eyes, to eliminate uncomfortable visual disturbances including photophobia and diplopia.

What is a Soft Prosthetic Contact Lens?

A soft prosthetic lens consists of a contact lens material that will overlap an eye that is intact (not enucleated) to conceal a disfigurement and/or to provide therapeutic aid to sighted eyes for better quality of life. Table 1 lists manufacturers that offer soft prosthetic lenses as well as stock opaque and tinted colored contact lenses. When an eye is enucleated, a mold or impression of the eye is needed to create a scleral shell, commonly worked on by an ocularist.

In your practice, there are several reasons to suggest prosthetic lenses as an option to help patients cosmetically, therapeutically, and psychologically.

Cosmetic Benefits and Lens Types

Trauma or congenital defects can cause extreme disfigurements to an eye. Various colored lens designs can help mask the underlying problem and match eye coloring. Options can range from a basic, standard set of prosthetic colored lenses to custom hand-painted contact lenses.

There are several colored lens options to consider for cosmetic purposes based on cost and availability in addition to therapeutic and cosmetic expectations.

Transparent Tinting Enhanced tinting of lenses provides transparent coloring that overlaps the natural iris tones to slightly change iris coloring. You can accomplish this yourself using an in-office tinting system; several companies offer this tinting service as well, and some manufacturers offer stock tinted lenses.

Standard Opaque Designs Standard lenses are available in various base curves, pupil sizes with clear or black backing, iris diameters, and prescriptions. Dot matrix designs are available in three to five print patterns in various company-specific colors. These lenses are less expensive and more reproducible.

Custom Hand-Painted There are two different custom hand-painted lens techniques that help provide a more natural-looking lens. One-dimensional hand-painted designs have the color painted on the front surface. Three-dimensional hand-painted designs feature the color embedded in the lens matrix (these are also company-specific).

With hand-painted lens options you can customize base curves, lens diameters, iris diameters, iris color detailing with flecks and limbal rings (Figures 5a and 5b), pupils, and iris alignment for strabismus (Figures 6a, 6b, 7a, and 7b). Photographing an iris accurately is an important step to help provide custom contact lens companies with precise information for designing the most natural lens. Digital photographs with more exact coloring may help ensure more natural contact lens results.

Figure 5a. Traumatic injury causing a dense, white, disfigured cornea.

Figure 5b. Prosthetic lens with subtle iris flecks, natural coloring, and black pupil to match the sighted eye.

Figure 6a. Strabismus secondary to retinal/cataract surgical complications following traumatic injury.

Figure 6b. Prosthetic strabismus scleral lens design with iris imprint aligned to maximize cosmetic appearance.

Figure 7a. Traumatic injury caused cataract and scarred cornea with misaligned iris.

Figure 7b. Prosthetic scleral lens design with iris imprint positioned to maximize cosmetic appearance.

Therapeutic Benefits and Lens Types

Eliminating Diplopia/Occluder Lenses Occluder lenses are often preferable to an eye patch for eliminating diplopia. It is important to design the lens so that the black pupil is large enough to totally block out light (typically 2mm to 3mm larger than the maximum pupil size). Several companies provide solid black pupil lenses (clear outer edge) with various pupil sizes.

Eliminating Photophobia Many companies offer prosthetic iris lens designs with a clear pupil opening to recreate a normal pupil size, eliminating uncomfortable light sensitivity. Trauma can commonly cause complications to the iris and an irregular pupil opening (Figures 8a and 8b).

Figure 8a. Iris severed from traumatic injury, causing photophobia.

Figure 8b. Prosthetic lens eliminating photophobia symptoms and maximizing cosmetic appearance.

Enhancing Contrast/Vision Tinted lenses can be used as a sunglass effect to reduce light sensitivity, and some maximize contrast through various color tints (often for sports using gray, green, or amber).

Color Vision Benefits Several companies can provide red lenses (approximately 5mm to 8mm pupil size) for certain color deficiencies.

Psychological Benefits

There is usually tremendous emotional gratification for both you and your patients when you introduce prosthetic lenses to patients who can benefit from them. Whether you provide the lens in your office or refer a patient to a prosthetic lens specialist, it will result in a significant change in the patient's life. Most patients who would benefit from prosthetic or therapeutic lenses have not engaged in any prior conversations with an eyecare professional about the difficulties that the disfigurement or vision problem has caused in their daily life.

Patient Selection and Expectations

Potential patients must be able to wear a soft prosthetic contact lens comfortably. The decision to apply a contact lens to a newly disfigured eye is dependent on many factors, including corneal and conjunctival health and possible complications arising from sutures and blebs.

A patient's emotional state must be carefully noted, especially when discussing prosthetic lenses with a patient whose eye has been recently disfigured. There are many common concerns expressed by patients who are seeking a prosthetic lens for a disfigured eye. Their disfigurement makes them feel self-conscious and uncomfortable about looking different, and they experience emotional insecurity, low self-esteem, etc. There is obvious emotional and psychological distress that a newly inflicted traumatic injury can cause a patient. You must advise patients from the beginning that they will not be able to have a perfectly matching eye appearance to replace the disfigured eye. It is important to mention that the iris is translucent, which results in changes in iris coloring especially with lighter iris coloring.

Additional patient expectations to discuss prior to fitting a prosthetic contact lens include expectations for natural color tones (standard versus custom hand-painted), therapeutic benefits (black pupil eliminating light versus clear openings), prescription options if applicable, wearing schedules (extended versus daily wear), replacement schedule, contact lens care, and possible administration of ophthalmic medications (e.g. for glaucoma).

Fitting Techniques

Prosthetic fitting involves additional fitting considerations compared to standard soft lens fitting. It is recommended to record the following measurements to start the fitting process.

Eye Health Normal contraindications for contact lens wear should be considered, including dry eyes and ocular allergies.

Pupil Size Measure the pupil diameter in 0.5mm increments in normal illumination. For a dark brown iris, a Burton lamp can create more contrast between the pupil and the iris in determining the size of the pupil. Black occluder pupils for diplopia must be measured in dim illumination to determine the maximum size needed to prevent any light from entering. Pupil openings (e.g. for aniridia causing photophobia) should be measured at normal room illumination to maximize cosmetic appearance.

Iris Diameter The iris diameter should be measured in 0.5mm increments and needs to be large enough to ensure coverage of the natural disfigured eye. Matching the iris size of the healthy eye is important to ensure more natural results.

Base Curves Keratometry readings cannot always be obtained because of a disfigurement. Trial lenses from various companies can help evaluate movement. The lens must exhibit some movement to prevent excessive tightening. Excessive movement is not ideal as it detracts from a natural eye effect.

Lens Diameter Using the largest diameter will ensure better centration to maximize cosmetic and therapeutic effects.

Prescription Use the spherical equivalent to determine the exact contact lens power. Several companies can tint toric lenses with transparent colors.

Color Matching As mentioned previously, digital photography can help you achieve an accurate iris color, which you can further fine-tune using various software programs including Photoshop. Use natural lighting conditions when photographing the iris color. Scleral shells or iris color chips can also be helpful in attaining a more accurate final lens color.

Less expensive, stock, disposable colored lenses can be a good choice, especially for patients who have darker iris coloring. These lenses are reproducible and often readily available.

Darker iris colors (brown tones) are easier to match using fitting sets of some of the more generic prosthetic lens options provided by various companies. Lighter iris colors (lighter blues, greens) are more difficult to match because the iris reflects light and its coloring changes in various lighting conditions, reflects off of clothing, etc. Hand-painted options would be recommended to ensure the best possible matching of lighter iris colors. Using the same color lens on the healthy eye is another option to ensure exact color matching.

Patient Management After a Successful Fit

Advise all prosthetic lens patients to wear glasses over their prosthetic lenses for two primary reasons. First, wearing glasses that have polycarbonate, shatterproof lenses is important to help protect their eyes from injury. In addition, glasses can help maximize the patient's appearance, camouflaging the prosthetic lens. You can ensure this by selecting an interesting frame and perhaps a lens tint. If the prosthetic eye is smaller in appearance, consider magnification in the spectacle lens to enlarge the eye or lid aperture.

It is important to emphasize the need for routine eye care. Often your prosthetic lens patients are relying on one healthy eye, which must be examined on a regular basis.

How Long Do Prosthetic Lenses Last?

There are some standard and custom prosthetic color lenses that can fade; caution patients about this and properly instruct them about cleaning and disinfecting solutions to prevent this situation. Hand-painted soft lenses that have the coloring bonded within the matrix of the lens design do not fade when patients use proper care solutions.

Recommend that patients purchase a spare lens to ensure continuity of lens wear in the event that a replacement lens is needed.

Coding and Reimbursement

Prosthetic lenses that provide therapeutic benefits are often reimbursed by medical insurance. The prosthetic lens special procedure code (92499) is recommended with a diagnosis specific to your patient (e.g. photophobia, diplopia etc.).

Insurance companies will generally not reimburse use of a prosthetic contact lens design that is prescribed only for cosmetic benefit.

Making a Difference

Taking the time to discuss various prosthetic lens options with patients who can benefit from them will be very rewarding for both you and your patients. An International Prosthetic Lens Society is currently being formed and is represented by several leading prosthetic lens companies. For more information, please e-mail mitch.cassel@gmail.com. CLS