Article

CUSTOM SOFT CORNER

CHALLENGES OF PROSTHETIC LENSES FOR IRIS ANOMALIES

During a recent continuing education webinar on surgical management of congenital and acquired aniridia, prosthetic soft contact lens options were briefly discussed. The challenges associated with their fitting were highlighted and are discussed below.

Five Fitting Challenges

  1. Time Consuming to Fit The prosthetic soft lens fitting process may involve the placement of multiple pigmented lenses on a patient’s eye to achieve the desired effect. Some labs offer a fitting set to aid in this process. Others may be able to manufacture a prosthetic lens based on a high-resolution photo. A non-seeing eye that has only subtle iris defects compared to the healthy fellow eye (Figure 1) will involve different customizations compared with a patient who still has visual function and is highly photophobic with a large iris defect (Figure 2). Each patient presents as a unique case.

    Figure 1. OD with no functional vision and mild structural changes due to iris atrophy.

    Figure 2. OD with functional vision and acquired partial aniridia.

  2. Reimbursement Sometimes Not Worth the Time Due to the customization involved with prosthetic lenses, a skilled artist may be required to hand-paint intricate iris details. Even simple computer-generated designs involve the layering of multiple pigments to create dimension and realism to each manufactured lens. They can be pricey to patients and often are only minimally reimbursed as medically necessary lenses when billing vision insurance.
  3. Managing Expectations Nearby observers can usually tell that a prosthetic lens is being worn, especially with loss of pupillary dynamics. Patients need to understand that a general aesthetic match from across a room or across a table is the goal. No matter how customized these lenses are, it is hard to match the fellow eye in some cases.
  4. Unwanted Aberrations Many patients who have suffered penetrating ocular injuries are aphakic and have an intraocular lens (IOL) to optimize vision, but they suffer from light sensitivity. When wearing a prosthetic lens in these cases, light can hit the optics and/or haptics of the IOL and create unwanted glare and halos. Incorporating iris occlusion and/or pupil tint can manage the photophobia often experienced while limiting the introduction of unwanted optical images.
  5. Poor Reproducibility, Instability, and Limited Availability The more customized a prosthetic contact lens, the harder it becomes to identically duplicate the final design, although a backup lens is recommended. Discuss optimal care and handling procedures with the lens manufacturer to minimize any pigment fading. Lastly, it can be difficult to find the right manufacturing lab to help you meet your fitting goals. Use online resources as a guide or call your current custom soft lens lab to help you get started.

Challenging but Rewarding

Surgery to normalize an iris defect is not always an option. Customized prosthetic soft contact lenses can be a rewarding addition to your practice and life-changing for a patient. While it helps to be aware of the challenges, don’t let them deter you. CLS