Mini-monovision approach offers good reading, uncorrected distance vision

Using a one-piece aspheric lens in certain patients achieved good spectacle independence and patient satisfaction in a prospective, observational study.

John R. Wittpenn

A mini-monovision approach is an alternative to multifocality and full monovision correction in cataract patients who want to minimize spectacle dependence following cataract surgery and IOL implantation, a clinician said.

“Multifocal lenses, accommodative lenses — we all know what their advantages are, what their problems may be. We certainly remember the monovision approach of setting one eye for distance and one eye for reading [at] –1.5 D and –2 D and getting successful results in those situations, but each have their problems,” John R. Wittpenn, MD, said at Hawaiian Eye 2010. “I use a slightly different approach. I call it a mini-monovision approach using a one-piece aspheric lens. I find that these patients can achieve very good reading [and] excellent uncorrected distance vision.”

Dr. Wittpenn conducted the prospective, observational study examining results of 26 subjects. Patients in the study had low astigmatism and no other ocular pathology. They ranged in age from 58 to 90 years. Each subject underwent cataract surgery, followed by implantation of the Tecnis ZCB00 (Abbott Medical Optics) one-piece acrylic lens in each eye.

For each patient, one eye was targeted for distance and the other eye was targeted for near reading. The target refraction was plano to –0.25 D for distance vision and –0.5 D to –1 D for reading vision. Dr. Wittpenn noted that the best visual performance occurs at 19 years of age, when contrast sensitivity and vision quality are sharpest, with zero spherical aberration. As the eye ages, it increases in positive spherical aberration, decreasing quality of vision.

“To get back to those youthful days, it does make sense to target zero spherical aberration, and this is what the Tecnis design has given us,” he said.

Patient expectations

Patients in the study were good candidates for multifocal vision but did not express a desire to purchase multifocal or accommodative lenses, Dr. Wittpenn said. However, they still wanted a certain degree of spectacle independence.

Following his presentation at the meeting, Dr. Wittpenn said that he is clear with patients when discussing expected results of spectacle independence. IOL calculation issues that might alter final results should be taken into consideration preoperatively.

“I never promise these people, ‘You won’t wear glasses,’” he said. “I take the approach that I’m going to address your cataract and minimize your dependence on glasses the best I can. If you want to go beyond that regarding your astigmatism or residual refractive error, we can then discuss that regarding refractive surgery and its appropriate charges.”

Study results

Most patients in the study had excellent binocular uncorrected distance visual acuity following the surgery, Dr. Wittpenn said. Twenty-three patients saw 20/25 or better, two patients saw 20/15 or better, and one patient saw 20/30 or better.

For the near reading eye, distance vision was also good, Dr. Wittpenn said, with the majority of eyes achieving 20/40 or better. The worst distance vision in a near eye was 20/70 in one patient, which refracted to 20/20 with a –1.25 sphere.

Mini-monovision allows for good near reading vision and satisfied patients, according to Dr. Wittpenn. However, patients were not reading at a J1+ level following surgery, which is the trade-off of the approach, he said. For binocular reading acuity in the study, 93% of patients read at J3 or better.

“To put it in perspective, J3 is the print of The New York Times. This is not measured in bright light; this is just measured in my exam room. I hand [patients] something to read and I do all the testing myself,” he said. “So I have … 93% basically reading The New York Times in my exam room without a pair of glasses, and [they are] quite happy.”

Case results

Dr. Wittpenn discussed the best and worst results of individual cases from the study. The first individual case that he presented was of a 75-year-old woman. She was one of the two subjects who did not achieve good distance correction.

The patient’s postoperative visual acuity was 20/30 in the right eye and 20/40 in the left eye. She achieved spectacle independence, reading at J3.

“Nevertheless, she was thrilled with her results and stated, ‘I do not need glasses at all.’ She actually has a very small refractive error to reach 20/20 in each eye,” Dr. Wittpenn said.

The second case he presented was an 84-year-old man whose postop visual acuity was 20/20 and 20/25, reading at J5.

“Despite J5 reading vision, he never used glasses, insisted he could read everything and was very happy with the results,” Dr. Wittpenn said.

The last case he presented, a 74-year-old retired physician, used +1.5 D correction for reading small print following Tecnis implantation.

“He admits that it’s mostly out of habit,” Dr. Wittpenn said. “But he could read easily 20/15 in the distance. He’s J2 without correction and his spherical correction was only –0.5.” – by Erin L. Boyle

• John R. Wittpenn, MD, can be reached at Ophthalmic Consultants of Long Island, 2500 Route 347, Stony Brook, NY 11790; 631-941-1400; fax: 631-941-1476; e-mail: jrwittpenn@aol.com.