SOFT BIFOCAL LENS

Fitting a Soft Disposable Bifocal Contact Lens

By Corinne Odineal, OD
April 2001

Two practitioners conduct their own study to determine if a soft bifocal lens would be a success in their practice.

Since the time of Benjamin Franklin, patients and their eyecare practitioners have been searching for an effective tool to combat presbyopia. The knowledge that none of these products has proven to be a panacea may have tempered the enthusiasm with which practitioners greet new entries into the presbyopic care practice. For my partner and I, news of the Acuvue Bifocal contact lens was welcome.

With no prior knowledge or experience using the Acuvue Bifocal, we set out to do a mass trial fitting and research study. We had three goals:

• Determine the success rate for this lens in our practice before we adopted it
• Compress the learning curve to become proficient fitters in the shortest possible time
• Give as many patients as possible a chance to try the lens before they committed to a fitting.

Study Design

We wanted to mimic as much as possible the experience of fitting this specialty lens in a busy practice. We elected to do no patient pre-selection. We tried to fit every presbyopic patient who presented. We selected two afternoons for the study and set aside the hours from 3:00 pm to 7:00 pm, creating five-minute time slots for each candidate. We sent letters announcing the evaluation to all of our patients in the presbyopic age range who had less than 0.75D of astigmatism. We also placed a notice in the local newspaper asking anyone who was interested in trying a new bifocal contact lens to call our office. The notice explained that patients could try a new soft bifocal contact lens and wear the lenses for one week.

When patients arrived, they received a clinical trial waiver, a question and answer sheet about bifocal contact lenses and a fee chart.

Initial testing included autokeratometry, autorefraction, eye dominance, visual acuity with habitual correction and with autorefraction and slit lamp examination. We fitted lenses based on either the autorefraction or habitual correction, making no attempt to refine the refraction. We fitted different additions on both eyes. The non-dominant eye received the full near correction, the dominant eye received 0.50D less to reduce distance blur. Application, removal and lens care were taught to groups of five to six patients. After this training and 20 minutes of lens wear, visual acuity through the lens and slit lamp examination of the lens fit were performed. If we deemed fit and vision to be acceptable, the patient was released with a wearing schedule and instructed to return in one week.

At the one-week follow-up examination, patients completed a questionnaire. Visual acuity through the lenses was again measured and a slit lamp examination completed. We then questioned patients about their desire to become Acuvue Bifocal wearers.

Figure 1: Success rate with the Acuvue Bifocal

Results

A total of 78 patients completed the study (Figure 1). Forty-two (54 percent) stated that they wanted to continue with Acuvue Bifocal wear, four (five percent) were unsure what they preferred, and 32 (41 percent) stated that they did not want to continue as wearers. Their reasons not to continue as wearers are summarized in Figure 2. The most common reason was poor visual acuity, reported by nine patients (28 percent of those discontinuing).

Three Thumbs Up

The first objective for our evaluation was to determine the success rate for the Acuvue Bifocal in our practice. As novice fitters, we achieved a 54 percent success rate with our evaluation. We considered this very good, considering the patients were self-selected, and we made no attempt to optimize correction.

 

Our second objective was to shorten the learning curve of proficiency for my partner and myself. The evaluation setting was an excellent chance for us to learn all the nuances of fitting the Acuvue Bifocal in a very short period of time. When adopting a new contact lens, most practitioners simply add the lens to their armamentarium and wait for suitable candidates to appear. Their experience in learning to fit the lens is thus random and inefficient.

On the other hand, this evaluation compressed our experiences and reinforced each bit of knowledge about the intricacies of the lens. By the end of one week we had performed trial fittings on more patients than we would have randomly acquired in several months. We conclude that this is a highly effective method of learning a new lens type.

Our third objective was to give as many patients as possible a chance to try the lens before they committed to it. The manner in which most practitioners approach contact lenses, particularly specialty lenses such as the Acuvue Bifocal, deters many patients. Before patients can experience wearing a contact lens, they must commit to an examination, a contact lens fitting and the purchase of contact lenses. Our evaluation showed us that many patients want to experience bifocal contact lenses. Evidently the time and expense were impediments which prevented them from achieving this experience.

We encourage presbyopic patients in our practice who are interested in contact lenses to try the Acuvue Bifocal lens before trying another modality like monovision. As a result we do more bifocal contact lens fittings, but only for patients who are motivated and have a high probability of success. These fittings are more efficient because we know in advance either that the Acuvue Bifocal will work for this patient or we need to try another modality.

Not every new product is worth adopting into your practice. This study convinced us that the Acuvue Bifocal is a valuable addition to ours. The initial success rate of 54 percent (which we feel is higher in our normal practice) is exceptional for a specialty lens. The ability to wear the lens before the final fitting is very motivating for patients and an excellent clinical screening tool.

Dr. Odineal is a behavioral optometrist with a private practice in Auburn, CA. She has authored other contact lens-related articles and previously worked as a researcher for a contact lens company.

Dr. Odineal acknowledges Jeffrey Allgeier, OD, for his help with this study.