Risk Management

When Lawyers Come Beckoning with the Color-Coded Maps

By Dean C. Brick, MD, Argus, October, 1994

As use of corneal topography increases, a risk management question arises: will ophthalmologists have to invest huge sums of money to protect themselves from the lawyer carrying the beautiful color-coded maps, who will try to persuade a jury that the results of treatment or surgery would have been different if this new technology had been used?

Background

For years ophthalmologists used standard keratometry to measure corneal curvature. Ophthalmologists who performed corneal transplantation realized the deficiencies of standard keratometry in evaluating patients after penetrating keratoplasty and became adept at interpreting Placido disc images or photokeratoscopic images. Recently, however, qualitative measurements of the cornea obtained by these instruments have been surpassed by quantitative corneal measurements with computer videokeratoscopes (CVK).

Most of the CVK systems currently available are based on Placido disc imaging recorded by a video camera and analyzed by computer software. Newer systems that measure the surface elevation of the cornea rather than analyze the Placido image are being developed, but the advantages of these newer systems have yet to be determined.

Quantitative corneal mapping has increased ophthalmologists’ knowledge of corneal shape and how to change it, primarily when performing refractive procedures. It has opened up new ways to diagnose corneal diseases, treat corneal problems, and fit contact lenses. In the future, corneal mapping may prove useful for predicting visual acuity before and after refractive surgery and for determining the refractive procedure most beneficial for a particular patient.

The Corneal Specialist

Corneal specialists appreciate topography for diagnosing pellucid marginal degeneration, keratoglobus, keratoconus, irregular astigmatism and other corneal diseases. Many of these conditions can be diagnosed by more conventional means; however, the CVK enables the physician to accurately follow the progression of the disease, assists in fitting contact lenses when these conditions are present, and aids in surgical planning and postop evaluation and management. The CVK also helps the corneal surgeon evaluate postoperative penetrating keratoplasty patients, including diagnosing the astigmatism axis and type, suture removal and adjustment, and secondary procedures to decrease astigmatism.

In many instances, CVK has not yet been proven to be superior to other clinical methods, but its increasingly widespread availability and published effectiveness is boosting its popularity. From a risk management standpoint, it seems prudent for ophthalmologists to use CVK in the diagnosis and management of corneal disease in which it has been shown to be effective, especially when it is available in the community.

The Refractive Surgeon

CVK is frequently used by refractive surgeons. Although corneal topography has not yet proven itself to be superior in planning primary radial keratotomy procedures, it is indispensable in other ways. It is effective in preoperative screening for diagnosing keratoconus and for recognizing asymmetric astigmatism. It also has been helpful in diagnosing “forme fruste” keratoconus. Although it is not known whether these patients respond differently to refractive surgery, the ophthalmologist should present this information during the informed consent discussion so patients with “forme fruste” keratoconus are not unpleasantly surprised if a complication arises.

CVK also has been shown to be effective when following patients in whom rigid or gas permeable contact lenses have been discontinued prior to refractive surgery. CVK has shown that the time required for the cornea to stabilize after contact lens removal is quite possibly much longer than commonly thought. Following the refractive surgery patient out of contacts until the topography stabilizes helps prevent postoperative surprises. It also allows for preoperative recognition of nonorthogonal astigmatism and helps with surgical planning.

Postoperatively, CVK assists in evaluating RK, AK and PRK patients. After RK and/or AK surgery, shallow or short incisions may show up as areas of less flattening. Using topography to find this condition allows for more accurate planning of secondary procedures. After PRK, topography has been useful in detecting central islands, recognizing and following regression, identifying eccentric ablations, and diagnosing irregular postop astigmatism.

From a review of the literature, it does not appear that topography has become “standard” when performing refractive procedures. However, this standard may change as more comprehensive studies are completed and the price of instrumentation drops, making it more available.

The General Ophthalmologist and the Cataract Surgeon

The general ophthalmologist and the cataract surgeon use CVK less frequently. It may be used to assist in contact lens fitting, but it has not proven superior to other methods. Similarly, it may help evaluate the corneal astigmatism of preoperative cataract patients, allowing the surgeon to plan wound construction and location. However, traditional methods of evaluating astigmatism in cataract patients also have proven effective over time. In the future, topography may help improve IOL power calculations; however, for risk management purposes, use of the CVK does not appear to have an impact on the general ophthalmologist or cataract surgeon at this time.

Conclusion

The role of computerized videokeratography in the practice of ophthalmology is evolving with almost every published article. Corneal specialists who perform refractive surgery should stay abreast of the published studies regarding the use of corneal topography and its effectiveness in diagnosing and treating diseases. Keeping current is important primarily to help ophthalmologists determine what is in the best interest of their patients, but it also may afford protection if confronted by the lawyer with the color-coded maps.