Depending on patient, LASIK is most common choice among doctors for low myopia
Paul M. Karpecki, OD: Unfortunately there is no one answer that is best for this question. There are three possible procedures that would all work well: photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK) and Intacs or intrastromal corneal ring segment (KeraVision, Fremont, Calif.) implantation.
Each of these possibilities has its own benefits. Because the patient is a low myope, PRK is less likely to produce haze and would be considered an option in certain situations. Two things about PRK were discovered in early laser technology: accuracy and ability to make the new epithelium adhere tighter. If a patient has anterior membrane dystrophy or is prone to recurrent erosion, PRK would have the benefit of correcting the myopia and treating the pathology. Also, if the patient undergoes LASIK, an epithelial defect is more likely, along with loose or sloughing epithelium during the procedure, which would eventually lead to epithelial ingrowth. So, PRK is an option, but to a very limited group of patients.
The remaining two options are likely the primary procedures to be considered. LASIK offers rapid recovery and minimal postoperative discomfort. Additionally, close to 1 million procedures will be performed in 1999 alone, so doctors are more familiar with LASIK.
Some argue that there is a greater risk of complications with LASIK, but, in reviewing our data, we have found that in more than 7,000 procedures not a single complication occurred. The procedure is accurate in that re-treatment or enhancement rates are low and recovery is fast for the low myope. A patient who will never drive a new model car usually has a personality better suited for LASIK as opposed to Intacs.
Intacs offers a slightly less rapid recovery than that of LASIK and slightly greater postoperative discomfort. It is newer technology, meaning fewer procedures have been performed. Advantages are that it offers slightly greater visual acuity results and it is removable. In data collected during clinical trials, when comparing LASIK to Intacs in myopes less than 4 D with no enhancements, an equal number of patients were within 0.50 D of intended correction. However, visual acuity measurements on the EDTRS chart were significantly different. For example, the number of patients 20/16 or better at 3 months was 27% for LASIK and 65% for Intacs. This is probably explained by the fact that Intacs maintains a positive corneal asphericity (prolate cornea) postoperatively and no surgery takes place in the visual axis.
The second advantage to Intacs is removability, which could offer a patient the option to regain myopia after the onset of presbyopia. Finally, Intacs is a great choice for patients with an innovative or early-adapter type of personality. The type of patient who has had a cell phone for some time, is on the Internet, has the latest versions of computer software and is accustomed to new technology would meet this personality type.
Both LASIK and Intacs are great options for the low myope. The wow factor, which has propelled refractive surgery to where it is now, still applies. Candidates for these procedures are generally successful refractive surgery patients who benefit from fast visual recovery and better accuracy of results, and, unlike high myopes or hyperopes, they have multiple refractive surgery choices.
- Paul M. Karpecki, OD, is the clinical director of cornea and refractive surgery for Hunkeler Eye Centers. He may be reached at 5520 College Blvd., Suite 201, Overland Park, KS 66211; (913) 642-8010; fax: (913) 469-6686; e-mail: email@example.com. Dr. Karpecki has no financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
Depends on cornea, age, goals
Marlane Brown, OD: Determining which refractive procedure would best suit the 2.50-D myope depends on that patients corneal condition, age and goals. The options would be LASIK, Intacs, PRK and cataract extraction.
The young patient (between 19 and 35) who has pristine corneas, wears contacts or glasses full time and whose goal is excellent distance vision may do best with LASIK in both eyes. This patient may be involved in sports or performing arts and can see equally well at distance and at near with best-corrected vision. Visual recovery is usually quick and with little discomfort. It will be a number of years before you must have the presbyopia conversation with this patient.
The patient nearing presbyopia (age 38 to 42) who can read well now with and without glasses or contact lenses and whose goal is excellent distance vision may do better with Intacs in both eyes. The option of removing the Intacs exists for this patient. The results with Intacs have shown excellent visual acuity and quick visual recovery.
When this patient becomes dependent on reading glasses for near tasks, you can counsel him or her about several options, including reading glasses, wearing contact lenses (one for monovision) or bifocal lenses or removing one or both Intacs. Removing both will return the patient to his or her myopic state, and he or she will return to excellent vision for reading without dependence on glasses or contact lenses. Removing them from one eye should allow him or her to function at distance and near, as in a monovision contact lens fit. Of course, this patient may be so enamored with the excellent distance vision provided by Intacs that he or she may choose to leave them in and be content slipping on a pair of readers when needed.
If the patient is already presbyopic, has clear, normal corneas and has no signs of cataract, the option of LASIK or Intacs on one eye only could be considered. This patient already knows the advantage of his or her myopia and can perform most near tasks without glasses or contact lenses. If he or she can adapt to monovision, this may be the best surgical option for this patient.
I would advise PRK if a superficial corneal scar exists or if the patient has signs of anterior basement membrane dystrophy (ABMD). In low amounts of myopia, PRK shows excellent results, may remove a visually significant scar and may solve a recurrent erosion problem for a patient with symptomatic ABMD.
Lastly, the patient with 2.50 D of myopia who has a visually significant cataract should be counseled about cataract extraction and IOL implantation. With improved surgical techniques, improved optics of IOL materials and good lens calculations, cataract surgery is a viable method of refractive surgery.
- Marlane J. Brown, OD, FAAO, is the director of optometric services for Minnesota Eye Consultants/Richard L. Lindstrom, MD. She is the current president of the Minnesota Optometric Assn. and can be contacted at Minneapolis Eye Consultants, 710 East 24th St., Ste. 106, Minneapolis, MN 55404; (612) 813-3600 ext. 121; fax: (612) 813-3601; e-mail: firstname.lastname@example.org. Dr. Brown has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.
LASIK is procedure of choice
David I. Geffen, OD, FAAO: I would recommend LASIK as the procedure of choice. In our office, we have found LASIK to be the most accurate refractive procedure. Intacs would be an alternative, but we have found LASIK to be more accurate. However, if the patient is between the ages of 18 and 22, we might consider Intacs as an alternative due to possible prescription fluctuation. PRK, while still an effective procedure, especially for this amount of myopia, is not our choice due to the longer recovery period and the need to perform monocular procedures at least a week apart. Patients are much more inclined to choose LASIK today, especially with the low complication rate our office has had. Patients with this low of a prescription generally are seeing 20/30 or better on day 1 and rarely need an enhancement. They are able to go back to full activities within 1 week.
- David I. Geffen, OD, FAAO, is optometric director of refractive surgery at Vision Surgery and Laser Center in San Diego. He can be contacted at Vision Surgery and Laser Center, 8910 University Center Lane, Ste. 800, San Diego, CA 92122: (619) 455-9950; fax: (619) 455-9954. Dr. Geffen has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
Depends on age, surgical comfort
Vance Thompson, MD: Currently, we educate the patient on LASIK, PRK or Intacs at this level of correction. The majority of the time, we end up performing LASIK. But this has been an evolution in our practice. In 1993, we would have offered this patient radial keratotomy (RK) or PRK, leaning towards RK. In 1995, we would have offered the same two options, leaning towards PRK. In 1997, we would have offered RK, PRK or LASIK, leaning towards PRK or LASIK.
In 1999, we, again, offer LASIK, PRK or Intacs. The ultimate answer is somewhat dependent on age and my surgical comfort. My tendency to offer LASIK at lower levels of correction increased as I became more comfortable with the procedure. My tendency to offer Intacs is increasing as I become more comfortable with that procedure. I enjoy the Intacs option in particular for the presbyopic low myope. It is reversible, and patients can still have LASIK if the Intacs do not do the job.
In summary, LASIK is the most common procedure I perform at this level of correction. Intacs is growing in my practice at this level of correction and lower, especially in the presbyopic age group. I still think PRK is a great procedure, and I still educate patients on it, but most want LASIK or Intacs.
- Vance Thompson, MD, can be contacted at 1200 South Euclid, Sioux Falls, SD 57105; (605) 336-6294; fax: (605) 336-6970; e-mail: email@example.com. Dr. Thompson has no direct financial interest in the products mentioned in this article. He is a paid consultant for Summit Technology.
Marguerite B. McDonald, MD, FACS: A 2.5-D myope would do well with any of three procedures. At the moment, I would offer the patient a LASIK procedure, especially if there were accompanying astigmatism and a need for rapid visual recovery.
If this patient did not have more than 0.75 D of astigmatism, he or she would also do well with an intrastromal corneal ring segment procedure (Intacs), though the visual recovery takes 1 day longer, on average. If the patient insisted upon a removable/repeatable procedure, however, Intacs are perfect. The patient must also have a medium to small resting pupil size to avoid debilitating glare at night.
A 2.5-D myope also does extremely well with PRK, at least as well as with LASIK. If rapid recovery is an issue, though, PRK is out of the question. Nevertheless, PRK is ideal for people who are afraid of microkeratomes, have recurrent erosion syndrome, previous scleral buckles (with very anterior scleral bands that would prevent adequate suction during LASIK) or very thin corneas, though this is unlikely to be a problem with a correction of only 2.5 D.
Therefore, in the absence of other information, I would offer LASIK to this 2.5-D myope, but would easily change my mind and offer one of the other two procedures if circumstances warranted it.
- Marguerite B. McDonald, MD, FACS, is a clinical professor of ophthalmology at Tulane University School of Medicine. She can be reached at 2626 Napoleon Ave., New Orleans, LA 70115; (504) 896-1250; fax: (504) 896-1251; e-mail: firstname.lastname@example.org. Dr. McDonald has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.
For Your Information:
- Intacs are available from KeraVision at (510) 353-3000.