This article is more than 5 years old. Information may no longer be current.
Standardization needed in refractive surgery
An article from the May 2002 issue of Ocular Surgery News Europe/Asia-Pacific Edition, “Standardization needed in refractive surgery,” is worth looking at. In this article, Philippe Sourdille, MD, states, “If there are no standard rules, we will never have reliable solutions and results.”
The parameters of testing, both objective and subjective, as well as treatment modalities, need to become more standardized, according to the article. It goes on to state that it is a difficult task to establish “standardization” when you take into consideration that even the testing techniques and instrumentation are not uniform.
For example, the criteria for accepting a patient as a good candidate for refractive surgery do not always take into consideration standardization of measurement of pupil size, corneal thickness, corneal topography, age and refractive error. In the past, there has been great latitude here. Some might even call it laxity.
Higher degrees of refractive error
Although outcomes for LASIK in the range of –1 to –6 D are generally good, higher degrees of refractive error may be better corrected with refractive surgery methods other than LASIK. LASIK, LASEK [laser epithelial keratomileusis] and PRK [photorefractive keratectomy], both standard and customized or wavefront-guided surgery have their known and lesser known pros and cons, which are still largely controversial.
In addition to excimer laser surgery, a whole new paradigm of treatment methodology is available now for refractive surgeons. Both clear lens extraction, or refractive lensectomy, and phakic IOLs (anterior or posterior chamber), which are now awaiting Food and Drug Administration approval, are being used to treat high degrees of myopia and hyperopia. In addition, these phakic IOLs (sometimes called implantable contact lenses [ICLs]) are being used in cases where age, corneal curvature or pupil size is an issue when considering LASIK or PRK.
Refractive lensectomy
Looking back 2 years in Ocular Surgery News, I found a round-table discussion by some of the leading refractive surgeons in the United States, “Current thinking about refractive lensectomy for hyperopes and myopes” (May 1, 2000). Included in the 8-page article were Drs. William Maloney, Kurt Buzard, Howard Fine, Paul Koch and Bruce Wallace III.
Here is a summary of some of the salient thoughts:
Lensectomy in myopes: risk vs. benefits. The verdict is not yet in for clear lens extraction as far as the risk of retinal detachment with high myopes is concerned. However, the trend appears to be in favor of clear lens extractions for some refractive surgeons. One refractive surgeon has even coined the term PHASER (phaco-assisted surgical extraction and replacement).
Where does LASIK cut off, and where does the possibility of refractive lensectomy begin? For clear lens extraction, the panel’s answers varied from 10 D to 15 D of myopia. The upper limit for LASIK is now considered by many refractive surgeons to be –11 D.
What is the range of acceptability for phakic IOL implants? For phakic IOL implants, –15 D is not considered a challenge in the hands of experienced surgeons, and many advocate IOL implants for myopes at –8 D (some even –6 D).
LASIK vs. lensectomy in the cataract age group. Dr. Buzard reported that, “We found that when we have any nuclear sclerosis and we do a LASIK procedure, we seem to get a fairly high loss of one and two lines of best-corrected visual acuity. Subjectively, the amount of nuclear sclerosis appears to get worse. When you talk about LASIK, patients even in their early 50s, if there is just a tinge of yellow, if you have any nuclear sclerosis, I think they do poorly with LASIK. For me, age 50 is the cutoff for LASIK. Once they get above 50, unless there is some compelling reason to do otherwise, such as a strong history of retinal problems or a history of retinal detachment, I tend to do lens exchange. Many people in their late 50s are going to have cataract surgery in 5 or 6 years anyway.”
Lensectomy for hyperopia. The panel advocates lens exchange for any hyperope over +3 D. PRELEX, or presbyopic lens exchange, is now being marketed in Europe and is in trials in the United States for both hyperopes and myopes.
Life-changing event
Refractive surgery is a wonderful procedure and has been variously described as a “life changing” and an “almost spiritual” event for those who have had good outcomes. Sometimes, however, the pure “quantity” of laser correction needed does not produce or meet the “quality of vision” expectations for doctor or patient. The reduced contrast sensitivity, increased glare and a whole host of optical aberrations are the result of not only the aberrations of the cornea, but also total eye aberrations resulting from the interaction of the cornea and lens of the eye.
These two articles demonstrate the need for standardization in patient selection, proper testing and appropriate treatment choice to provide optimum results for those seeking our professional advice on refractive surgery. I should point out that neither of these articles came from publications that require refereeing.
In conclusion, as Steven Wilson, MD, chair of the department of ophthalmology at the University of Washington puts it, “Don’t push the limits.” As optometrists, we play an important role in the decision making of our patients when it comes to their eye care and choosing the safest and most effective modality for correcting their refractive error.
Based on what my limited experience has been with comanaging refractive surgery patients and my recent review of the literature, I have developed a guideline for laser vision correction patient selection in my office (see chart below). These guidelines are not all-inclusive, and the standard review of medical and ocular history is not included here. In addition, all patients must have an Orbscan (Bausch & Lomb, Rochester, N.Y.) test conducted and actual pachymetry before surgery.
Finally, as one colleague reminded me, today’s guidelines may not be the same as next year’s. Guidelines are a moving target when it comes to laser vision correction.
Patient Selection Criteria for Laser Vision Correction |
|
For Your Information:
- Roger Christian Ede, OD, practices in Honolulu, Hawaii. He can be reached at 377 Keahole St., Honolulu, HI 96825; (808) 396-6311; fax: (808) 395-2448; e-mail: vision@pixi.com. Dr. Ede has no direct financial interest in any laser vision center.