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At Issue: post-LASIK dry eye
At Issue posed the following question to an international panel of ophthalmologists: “How have you modified your practice to avoid the occurrence of post-LASIK dry eye?”
Inform patients of postop risk
Hiroko Bissen-Miyajima, MD: Unfortunately, we do not have an efficient solution to avoid the incidence of post-LASIK dry eye. Dry eyes are common in patients who want to have the LASIK procedure performed on their eyes, so we inform these patients that the dry eye symptoms may worsen after LASIK. In our practice, we explain the possibility of dry eye symptoms to every patient in hopes that they will be prepared for this problem after the procedure.
It is important to mention that we do not insert punctal plugs before LASIK, because the complaint of dry eye symptoms following LASIK does not depend on the preoperative conditions. We routinely prescribe eye drops containing hyaluronic acid immediately after the surgery. For us, this seems to be the most effective drop for post-LASIK dry eye. Some patients may continue using these drops for more than 3 months. If the symptoms have not subsided, we then insert punctal plugs.
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Protect the epithelium
Joseph Colin, MD: Dry eye following LASIK is a growing problem in our practice, especially because LASIK has a tendency to induce more dry eye symptoms than PRK. In some cases, dry eye symptoms may eliminate the advantages of the positive visual results of the procedure.
Due to the increased number of LASIK procedures each year, the incidence of dry eye symptoms in our practice is increasing. In addition, there is an increase in the age of the patients asking for refractive surgery, especially of hyperopic patients. For these reasons, we have modified our practice to decrease post-LASIK dry eye.
Beginning in the preoperative evaluation, we test all LASIK candidates for dry eye. Great care must be taken to diagnose dry eyes preoperatively, and to treat to them, choose the proper surgical modality or to discourage the patient from having surgery.
Information is also obtained about dry eye symptoms and complaints and previous contact lens tolerance and intolerance. Other vital inquiries deal with previous cosmetic lid surgery and whether or not there is a risk of inferior corneal exposure. Systemic conditions include oral medications, beta-blockers, roaccutane and psychotropic drugs.
Emphasis is also placed on examinations in which patients are checked for red eyes, Schirmer’s syndrome, lid margin problems, chronic blepharitis and rosacea. If detected, we treat blepharitis with anti-inflammatory agents and give recommendations for lid hygiene; if rosacea is suspected, the patient is given oral cyclines for several weeks before the surgery. Punctal plugs are inserted in cases with moderate dry eye symptoms.
For surgery, the preoperative lacrimal conditions will determine the choice of the laser treatment. For example, mild or moderate dry eyes could undergo LASIK, while moderate to severe dry eyes would be candidates for PRK. We might choose PRK because the techniques used may induce less neurotrophic problems and are less aggressive for the goblet cells of the conjunctiva.
It should be noted that the epithelium is fragile in LASIK cases, so during the flap cut the epithelium is protected while the ocular surface is kept wet. We also prefer using a nasal hinge over a superior one; we also avoid povidone iodine contact with the cornea and excessive use of preservative-free anesthetic drops.
During postoperative management, great care must be taken to protect the epithelium, therefore we limit the use of topical NSAIDs, particularly diclofenac, to only a few days and prescribe lubricant drops and gel. A punctal plug may also be inserted if this was not performed preoperatively.
Additionally, we are cautious in cases of hyperopic LASIK because some patients have several predisposing factors for post-LASIK dry eye. For instance, older patients require more systemic treatments. Depending on the case, the patient’s corneal shape may need central steepening.
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Emphasize thorough, routine procedures
Hideharu Fukasaku, MD: I have not modified my practice in any significant way to avoid post-LASIK dry eye. I do, however, emphasize routine procedures that have always been part of my practice.
First and foremost is careful preoperative screening. As with any surgical procedure, I stress careful and complete evaluation of the patient. No procedure, however low the complication rate, should be approached cavalierly. I personally examine all of my patients before surgery, including a thorough review of systems including rheumatological diseases.
I am particularly careful with women over 30 years old and patients with a personal or family history of rheumatological or autoimmune diseases. My examination includes careful slit-lamp evaluation of the cornea, conjunctiva and tear system to include Schirmer’s test, tear meniscus volume and tear breakup time. In cases that warrant it, I perform a lactoferrin assay and corneal anesthesiometry.
Perhaps the most important thing one can do preoperatively is educate the patient. Prospective patients must be aware of possible dry eye problems following LASIK, especially those patients with the risk factors mentioned above. In the rush to promote LASIK, many surgeons either do not mention or gloss over this potential problem.
Take time to make sure that the patient fully understands the risk of postoperative dry eye and that for almost all patients this is resolved with conservative therapy within 6 months. Avoid doing LASIK on those patients who do not indicate an understanding of this potential problem and document meticulously.
Immediately following surgery, I place several drops of an antibiotic/steroid combination in the eye. Patients are instructed to use the combo drop four times a day for 4 days. I use several drops of an NSAID the day of surgery. The role of lubrication cannot be overemphasized when dry eye problems arise. I use Genteal (Novartis Ophthalmics) because its sodium perborate preservative is inactivated by enzymatic breakdown in the tears.
I will also place punctal plugs as necessary to lessen punctal tear loss. Postoperatively, I have found some value in putting the eyes at rest immediately after surgery, as suggested by Richard L. Lindstrom, MD.
Again, I cannot stress enough the value of a thorough preoperative procedure specifically aimed at identifying dry eye or potential dry eye patients and the value of making sure that potential patients understand the possibility of post-LASIK dry eye syndrome.
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Meticulous preop evaluation
Ioannis G. Pallikaris, MD: The symptoms of dry eye have increasingly bothered patients who undergo LASIK, especially during the first few months after the procedure. It is not uncommon to have patients complain of foreign body sensation and a sense of dryness.
In addition, punctate keratitis and low tear breakup time (BUT) have also become prevalent during slit-lamp examinations. This phenomenon has led refractive surgeons to be more alert regarding this potential postoperative problem.
In my practice, I have become more meticulous in preoperative evaluation of LASIK patients. A thorough patient history can identify systemic diseases that may be associated with xerophthalmia. The Schirmer test and tear BUT are standard examinations for all LASIK candidates. These are performed as a screening process for patients who face potential problems and aggravation after the procedure.
Of course, in cases of severe dry eye, any corneal procedure, including laser epithelial keratomileusis (LASEK), would not be recommended. In borderline cases, temporary collagen plugs can be used to provide a safe environment for corneal healing after LASIK.
It has also become a standard approach to recommend that patients use preservative-free artificial tears for at least 3 months postoperatively. In my practice, I follow up LASIK patients on day 1 and months 1, 3, 6 and 12. Patients are also instructed to report any problems or discomfort after the procedure.
After 3 months, most patients are in excellent shape, but in extreme cases in which problems persist, punctal occlusion with silicone plugs might be required.
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Informed consent, artificial tear regimen
Marc Y. Weiser, MD: The incidence of postoperative dry eye has always been a critical issue in my personal practice, after LASIK as well as after any type of anterior segment surgery.
The informed consent form that the patients fill out and sign before surgery expressly mentions this incidence and the need for artificial tears for a 6-month postoperative period. This regimen is started immediately after surgery, as well as that of anti-inflammatory drops. In case of postoperative keratitis, the anti-inflammatory drops are immediately stopped, and careful lubrication of the eyes is instituted.
Since this regimen has been applied to all my LASIK patients, the incidence of postoperative dry eyes has been dramatically reduced and is no longer a problem.
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Consider effects of corneal denervation
Maurizio Zanini, MD: There is still much to learn about post-LASIK dry eye and its treatment. First, we still have to understand the causes of the so-called LASIK-induced neurotrophic epitheliopathy (LNE).
This condition is likely caused by corneal denervation. Because LASIK severs the corneal nerves, it may interrupt the neuroanatomic integration that protects the ocular surface. From a hypothetical point of view, possible consequences may be a reduction of blinking, tear secretion and tear clearance.
I have studied the effects of LASIK on the ocular surface of patients without preoperative dry eye and, surprisingly, did not find any reduction of blinking. The explanation is probably related to the residual sensitivity of the corneal periphery and the conjunctiva, which continue stimulating blinking.
Reduction of tear secretion has been demonstrated by many studies. Unfortunately, in my opinion, Schirmer’s test, which is still the best way to detect it, is unreliable. I did not find any decrease in tear clearance either. In most of these cases, LNE will never occur.
Things change radically in patients suffering from preoperative dry eye. They are more likely to develop LNE. Even in this group of patients, I did not find significant differences in blinking, tear secretion and clearance between the pre- and postoperative periods.
Two points need to be studied in order to better understand the etiology of LNE: a more reliable yet still easy- to-use way to measure tear secretion, and the role played by lowered neurotrophic factors released from the nerves, as suggested by Steven E. Wilson, MD.
In the meantime I will go on prescribing the hourly application of preservative-free artificial tears for each patient and inserting collagen plugs in cases in which preoperative dry eye is detected.
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