PROSTHETIC LENSES

Current Prosthetic Lens Choices

With new technology and materials available, prosthetic lenses are easier to fit and more economical than ever.

By Mitch Cassel, OD, and Sandy Fenner
November 2000

Prosthetic soft contact lens designs help many patients achieve both therapeutic and cosmetic benefits. Practitioners are more willing to fit prosthetic lenses due to new lens designs, easier fitting methods and decreased cost.

It is not unusual to find several patients in your practice who can use specialty prosthetic lenses for cosmetic, psychological and, in some cases, therapeutic benefits. Helping patients regain their wholeness, self esteem and smile is the most rewarding part of fitting prosthetic lenses.

When to Fit Prosthetic Lenses

A patient might need to be fit with a soft prosthetic contact lens for congenital or traumatic complications . Figures 1 and 2 show two patients who benefitted from a prosthetic lens.

First decide on a soft prosthetic lens or a scleral shell design. If the cornea is intact and the globe of the eye can be fit with a contact lens, then various prosthetic lens companies can help you design a soft prosthetic lens. If the eye is shrunken and soft (phthsical) or enucluated, refer to an ocularist for a hard scleral shell.

New Materials

With the recent introduction of computer generated opaque prosthetic contact lens designs (CooperVision, Wesley Jessen), fitting has become easier and less expensive. Trial fitting sets with various colors and base curves can help you quickly determine fit and color. The lenses are less costly, and the color is reproducible for future lens orders. CooperVision plans to release Cooper Prosthetic (Figure 3) this month in 14 colors to start, including shades of blue, gray, green, brown and hazel. Clear back and black back variations are also available.

Hand Painted Opaque

Choose laminated hand painted lenses by Custom Color Contacts for patients who require the most accurate color matching and realness of an eye. The laminating process uniquely bonds color to create a 3-D effect with natural coloring and real eye detail, especially for lighter eye colors. The laminating process also prevents the color from fading and adds to better handling. It is commonly used in the motion picture, TV and videos industries.

In addition, Prosthetic Soft Lens Corporation, Crystal Reflections and Adventures in Color Technologies all manufacture opaque hand-painted non-laminated contact lenses. The eyecare professional supplies a lens, and the manufacturer matches the color from photos. Prosthetic Soft Lens Corporation also provides their own lenses for both custom painting and printing. For most hand-painted processing, white opaquing agents are typically used first, then reactive colorants are added.

Although hand-painted laminated lenses are all custom designed, Custom Color Contacts offers lens samples to trial for color and fit. Eyecare professionals can achieve an easy color match if there are no contraindications to fit both eyes with the same coloring. Some patients are sighted in only one eye, and practitioners may oppose the use of a contact lens in the sighted eye.

Transparent Tinting

The eye color you are trying to match will sometimes dictate which prosthetic lens company and lens type to choose. Dark brown eyes are the easiest and least expensive colors to match. Most manufacturers can easily provide transparent coloring, overlapping color to the eye when scarring is minimal. You can custom tint most soft lenses for your patients with Softchrome's in-office tinting system. Prosthetic custom tinting using this system works best when you over-tint an opaque lens such as a CIBA Vision Illusions (gray) or CooperVision Natural touch (sultry grey). This system provides standard colors or a combination of colors to create custom colors.

Alden offers many lens colors and a color chart to help match coloring and black occluders. Crystal Reflections, Kontur, Specialty Tint, Custom Color Contacts and Adventures in Color Technology can also help with color matching and for black occluded pupils. All manufacturers can match a requested color with a lens supplied by your office (such as CIBA Vision SoftColor matching).

Computer Generated Opaque Designs

The Cooper Prosthetic offers a comfortable, natural color lens design for darker and lighter eye coloring. Some manufacturers offer trial lenses for easier and more accurate fitting. Lighter blues, greens, browns and grays are more challenging and may require more exacting designs and detail using hand-painted laminated opaque or hand-painted opaque designs.

Wesley Jessen recently introduced a new light under-printing for its FreshLook ColorBlends lenses. These lenses are available in blue, gray, green, brown, turquoise or honey. They can be combined with the black or the light under-printing (available in black and clear pupils) to match patients' natural eye color. Including DuraSoft Colors, DuraSoft Complements and FreshLook Colors lenses, WJ offers 25 colors, most of which can be single printed, double printed or under-printed.

Both companies offer standard lens coloring to help fit patients quickly and inexpensively. In addition, fitting sets with standard pupil sizes, iris diameters and base curves are available. Disposable and frequently replaced prosthetic lenses have the advantages of decreased costs and minimal ordering time for future lens replacements.

Prosthetic Lens Design Guidelines

Fitting the patient successfully is very easy if you can provide the prosthetic lens company with the following accurate information:

• Iris diameter of the good eye
• Total diameter of contact lens depending on aperture
• Pupil size in normal room illumination. Use a Burton lamp to accurately measure pupils of patients with darker iris
• Base curve ­ if possible, use a standard lens from your inventory to determine movement (check fit with 8.4mm, 8.6mm, 8.9mm and 15mm lenses)
• Black back surface (recommended for photophobia)
• Photos of eye color

Color photos help an artist match a prosthetic hand-painted soft contact lens to the patient's natural eye color. I recommend professional photos, which can be color corrected by a film processing lab to achieve more exacting color. Do not use Polaroid pictures or slides. Canon is debuting a new digital camera (Model D30) with a soft white flash to color correct the most natural tones. Color chips or prosthetic iris shells also help with more accurate color matching.

Severely disfigured leukocoric (dense white opacity) eyes present irregular corneas. Use an opaque contact lens to conceal this disfigurement. In this and other conditions, the lens may not position exactly in the same plane as the sighted eye or non-disfigured eye. The lens may appear to be riding exo, eso or hyper. Some manufacturers can alter the eye alignment.

Discuss comfort, fading, exact color matching, ordering time and expense with your patients. Taking extra time to present new prosthetic contact lens designs will make a tremendous difference in their lives.