prescribing for astigmatism

Planned Replacement Boosts Low Cylinder Toric Fits

Following a plateau in the late 1980s and early 1990s, there has recently been about a nine percent growth in the contact lens market, according to data from Health Products Research

BY GLENDA SECOR, OD
DECEMBER 1998

(HPR), Inc. Most experts feel that this growth reflects the increase in the use of planned replacement and disposable contact lenses, which significantly enhance convenience and have helped reduce the drop-out rate.

Soft Toric Appeal

The real growth in the market, however, is in the specialty lens category. There are reports that 16 percent of all new contact lens patients are fitted with toric soft lenses. Ten years ago, this category accounted for only 10 percent of new fits. Unfortunately, this increase appears to be at the expense of RGP lenses. The good news is that today's practitioners are more willing to fit specialty lenses, and planned replacement has added to the appeal.

As the disposable toric market debuts with Wesley Jessen's FreshLook Toric lens and other soon-to-be released toric lenses from Vistakon and Bausch & Lomb, practitioners and patients can now experience the best of both worlds. According to Mary Loranger, product manager for FreshLook Toric lenses at Wesley Jessen, 42 percent of the company's sales have been in the 0.75D cylinder. This is a higher-than-normal distribution, since the lens is available in three cylinder powers (-0.75D, -1.25D and -1.75D). To me, this indicates that practitioners aren't afraid of tackling small cylinders.

20/Happy with a Soft Toric

I recently examined a keratoconus-suspect patient whose previous doctor had been suspicious of keratoconus because of an irregular fluorescein pattern. She was uncomfortable with her RGP lenses and never achieved an adequate wearing schedule.

The retinoscopy reflex did not appear distorted and the subjective refraction revealed: OD -1.00 sphere, 20/20+; OS -0.50 -1.25 x 097, 20/20-. Keratometry readings were: OD 45.00/45.50 @ 090; OS 46.12/46.37 @090. No mire distortion was noted in either eye. Slit lamp appearance was negative with no signs of scarring, Fleischer's ring, striae or anything remotely representing keratoconus. Videokeratography revealed slight irregular maps and simulated K values of OD 44.12/43.58 @ 020 and OS 50.02/45.11@ 150 (Fig. 1). Though the maps were inconclusive, the steepness (over 50.00D) raised a concern.

FIG. 1: Videokeratography of a keratoconus-suspect patient.

The patient declined RGPs because she wanted the comfort of a soft lens. I decided to fit her with the following quarterly replacement lenses, which I ordered empirically: OD 8.6mm, -0.75D, 14.0mm, Preference; and OS 8.7mm, -0.50 -0.75 X 095, 14.4mm, Preference Toric.

The lenses performed perfectly at dispensing and the patient has worn them successfully for four months. Her visual acuity has consistently been 20/20 OD, OS and OU, and she is thrilled with the comfort. Although the diagnosis of keratoconus remains elusive, a toric lens has made her 20/happy and we will continue to monitor her progress.

Dr. Secor, a contact lens specialist in Huntingdon Beach, Calif., is a diplomate in the AAO Cornea and Contact Lens Section and is a charter member of the AOA's Contact Lens Section.