Once in a while, it is worth ruminating on issues that seem to be of ever increasing importance. I believe that several topics continue to dominate discussions concerning anterior segment surgery and that they are therefore worth contemplating here.
An earlier column I wrote this year related to optometry generated a great deal of response.1 Although I cannot answer each e-mail individually, it is clear that optometrists will continue to play a growing role in eye care in the US. Both the public and other eye care professionals have the right to know whether or not a school of optometry teaches and/or endorses methods of improving visual acuity that are based on following LED light patterns, exercises, or similar programs. Because one system I have seen for sale to the public is based on such principles and is advertised as being designed by a school of optometry, optometry's view on the validity of such teaching and products is relevant. Are such programs valid, yes or no? That's it. Responders should not confuse or dodge the issue with statements about the ophthalmology/optometry relationship, personalities, hidden agendas, etc.
Bifocal IOLs, both pseudophakic and phakic, are certain to become more important for the correction of presbyopia. It is much more difficult for a cataract/IOL surgeon to adjust to a refractive surgery mentality than it is for a keratorefractive surgeon to perform IOL surgery. Those attending a course to learn about IOL/refractive surgery should remember that the adjustment will affect all aspects of their office routine and staff. Refractive surgery is an attitude as well as a surgical act.
Within 5 to 7 years, discussions of cataract/IOL surgery versus IOL/refractive surgery versus keratorefractive surgery will be nearly pointless. Ophthalmologists will instead talk about how to achieve the best appropriate UCVA for a given patient. We are now at the beginning of this revolution.
TESTING CONTRAST ACUITY
In order to gain truly meaningful information concerning keratorefractive surgery and bifocal IOLs, a Snellen contrast acuity test in some form must be used instead of the original Snellen test (this is another topic I discussed in an earlier column this year2). I am trying to orchestrate a campaign to use 12.5% contrast letters for such a test. In my experience, 25% contrast letters are not sensitive enough to determine slight changes in visual performance. The difference in contrast between the borders of objects is the essence of vision, and advances in refractive surgery demand that we move beyond the original Snellen chart (94% contrast for all letters) in evaluating refractive surgery. Also, perhaps we can all agree that contrast sensitivity curves are of little value clinically and that a new system (whatever that might be) that could represent visual performance with a single number on a known scale would be much more useful.
In refractive surgery, the contralateral testing of different products in the same patient is gaining significance. Taking into account the constancy of the subjective response is far superior than trying to design and implement a trial that can effectively account for the differences between patients' impressions of their visual experience. We must address whatever practical and ethical considerations exist and get on with this task.
Lee T. Nordan, MD, is a technology consultant for Vision Membrane Technologies, Inc., in Carlsbad, California.
Dr. Nordan may be reached at (760) 431-1846; firstname.lastname@example.org.
1. Nordan LT. Optometry, heal thyself. Cataract & Refractive Surgery Today. 2005 April;5:4:33-36.
2. Nordan LT. Measuring the results of refractive surgery. Cataract & Refractive Surgery Today. 2005 May;5:5:19-20.