On the road to optical precision

May 15, 2012
Lynda Charters

The corrections following phacoemulsification and IOL implantation that are achievable today are a far cry from those commanded in the 1970s when 20/40 corrected bilaterally was considered an accomplishment following implantation of the early IOLs.

Randall J. Olson, MD, took a look at where cataract surgery has been, the current problems, and where the field is going during presentation of the 2012 Binkhorst Lecture entitled, "Where Are We on the Road to Optical Perfection?" at the opening session of the American Society of Cataract and Refractive Surgery annual meeting.

From the time of intracapsular cataract extraction and aphakic spectacles, Dr. Olson realized what a godsend IOLs were going to be; however, looking back, the IOL technology was primitive. He recounted the first IOL that he implanted in 1976, a Medallion IOL (Dutch Medical Workshop), for which the biometry consisted of inputting the refractive error on a little dial that was then spun to determine the power of the IOL to be implanted. At that time, 20/40 uncorrected was an excellent result!

"20/20 uncorrected is the standard today. And even with that, many patients are still unsatisfied," he said. Patients, who he refers to as "20/20 unhappys," frequently complain of washed-out vision, shadowing or doubling of vision, or even, visual acuity not achieving 20/15.

The making of the 20/20 unhappys

"What makes people with 20/20 vision after cataract surgery unhappy with their vision and still believe that their visual quality is not very good?" Dr. Olson asked.

A few candidates come to mind, such as uncorrected visual acuity, severe glare, and dysphotopsia.

Dr. Olson and colleagues conducted a study of patients who underwent cataract surgery regarding their levels of satisfaction postoperatively (Can J Ophthalmol. 2010;45:140).

"We found that the number one factor responsible for patient dissatisfaction was pseudophakic dysphotopsia. The level of best-corrected vision was borderline significant, which indicated that there was a great deal of confounding morphology in the study. Interestingly, uncorrected visual acuity was not significant. Dysphotopsia was by far the biggest problem after cataract surgery, despite 20/20 or better visual acuity," he said.

The question arose about dysphotopsia being a frequent age-related issue in most individuals over the age of 65 years and not IOL related. In response to this, investigators gathered 40 individuals over age 65 and asked them to respond to the same survey questions as the study patients.

"We found that the glare [was 5.5 times more common in the pseudophakic group.] Generally, light sensitivity was dramatically greater. In addition, only pseudophakic patients reported peripheral flashes, not the phakic patients.