Contact Lens Practice Pearls

Managing GP Lenses in Private Practice

Contact Lens Practice Pearls

Managing GP Lenses in Private Practice



As good as the contact lens curricula have become within the schools and colleges of optometry, there are aspects of GP lens management that you can only get from being in practice. While many of these management pearls seem rather elementary, failing to follow them can have a negative impact on patient outcomes and on your bottom line. This is often learned the hard way after having to deal with unhappy patients and to cover the cost of lens remakes. Following are some tips on managing your GP patients to minimize quality control issues and to maximize your practice profitability.

Measure Power

A golden rule of contact lenses is to never do an over-refraction on a lens of unknown power. While an invoice or order form may contain the power of the contact lenses that were ordered for a patient, after months of wear it is not uncommon for a GP lens to warp enough to induce a change in lens power.

If you reorder a new lens based on an over-refraction and the presumed power of the lens has changed but not been verified, then your resultant lens power will be incorrect. So, for GP contact lens exams I make a point of verifying and documenting the power of patients’ lenses. An easy method to measure power is to rinse the lens in non-preserved sterile saline, dry the lens with a Kimwipe, and place the lens on a lensometer in an upright position.

Differentiating Lenses

Another prudent reason to verify lens powers is to ensure that a patient has not switched lenses between the eyes. This happens more often than you would think. While lens manufacturers dot lenses (usually the right lens by convention) to avoid lens confusion, the ink wears off over time. These dots can be re-applied by rinsing and drying the lens as above and dotting it with an extra fine point Sharpie. It is best to let this ink dry for a few minutes prior to rinsing and reapplying the lens to maximize the longevity of the ink mark on the lens surface.

Another unique way to combat lens confusion is to order the right and left lenses in different colored material. Most GP lens materials have visibility tints, so using different colored lenses won’t alter eye color appearance when worn.

Time Your Refraction Right

A perplexing challenge of dealing with GPs is the issue of spectacle blur. A GP lens can induce changes in corneal curvature after hours of lens wear. This can make it difficult to get an accurate spectacle prescription as the cornea rebounds to its original shape after lens removal.

I find value in determining when patients are most reliant on wearing their glasses. Then, I’ll refract them at that time to provide them the best spectacle prescription for when they wear their glasses. For those patients who wear their GPs all day and only wear their glasses for an hour or two in the evening, I will perform their spectacle refraction shortly after removing their GPs. On the other hand, for patients who wear their glasses all day on the weekends or wear their glasses as an alternative to their GPs during the week, I will have patients return to the office on a different day having not worn their GPs on the day of that appointment.

It’s the Little Things

GP patients are some of the most loyal of any in your practice. Be consistent in managing these details of their exam to keep them seeing well and coming back to you for continued care. CLS

Dr. Nixon is a professor of clinical optometry and director of extern programs at The Ohio State University College of Optometry. He is also in a group private practice in Westerville, Ohio. He is on the Allergan Academic Advisory Board, the B+L Advisory Board, the Alcon Glaucoma Advisory Board, and the Alcon Speakers Bureau. You can reach him at