DRY EYE AND LASIK

Managing Pre- and Post-op Dry Eye

With aggressive treatment before surgery and a solid perioperative regimen, you can improve patient outcomes and resolve dry eye by 6 months post-op.

By Marguerite McDonald, M.D., F.A.C.S.

► The relationship between laser surgery and dry eye is a long one, and it has changed through the years. The femtosecond laser gives us exquisite control and enables us to create thinner, smaller flaps than mechanical microkeratomes, so we sever fewer nerves and induce less dry eye.¹ Nonetheless, postoperative dry eye remains an important consideration (Figure 1), even though it's generally a temporary condition that improves over time and resolves by 6 months post-op in most cases.²

Figure 1. The prevalence of dry eye increases after refractive surgery as shown in this slide that provides data from several notable studies.

Our ever-broadening perspective on the causes and treatment of dry eye enables us to reduce the postoperative complication rate even further. Due to the nature of the condition, we consider dry eye a major factor during candidate selection for laser surgery. Dry eye also is a driving factor in how we design pre- and postoperative medication regimens. In my practice, I'm obsessive about choosing successful laser candidates, treating dry eye and ensuring that patients get the best results from surgery. This cautionary approach results in a low enhancement rate and satisfied patients.

In this article, I'll discuss the importance of diagnosing and treating dry eye before laser surgery, my perioperative and postoperative medication regimens and how to handle post-op dry eye in patients who develop it despite presurgical preventive measures.

Diagnosing Dry Eye

If patients have dry eye before laser surgery, they're significantly more likely to develop severe dry eye after surgery.³ Of course, most patients seek LASIK because they have contact lens intolerance, so dry eye is a common complaint. It's essential to identify the problem and treat it aggressively before surgery.

In my experience, diagnosis starts with asking patients the following questions:

■ Did you have trouble wearing contact lenses?

■ Do your eyes burn, sting, feel dry or have a gritty sensation by the afternoon?

■ Does your vision fluctuate throughout the day, especially in the afternoon and evening?

■ Do your eyes become especially irritated in the presence of cigarette smoke or in windy conditions, when other people aren't affected to the same degree?

I also look at risk factors, such as age and medications. The slit lamp exam tells me the rest. I look for conjunctival erythema, especially in the interpalpebral areas, and superficial punctate keratitis. I check the tear film layer and tear breakup time with liquid fluorescein. Lissamine green may reveal conjunctival interpalpebral staining, a sign that's often present before one can see superficial punctate keratitis (SPK) on the cornea with fluorescein.

If my technicians or I suspect moderate to severe dry eye because of the patient's history or slit lamp findings, I may end the exam early. Some of the important data may change, such as the manifest refraction, wavefront map, topography map, after I treat the patient for dry eye. We don't continue the 2-hour presurgery workup until the patient's dry eye has been treated for at least 1 month.

Treating Existing Dry Eye

Many suboptimal patients become excellent laser candidates after aggressive treatment, so I begin treating dry eye the minute I detect it.

I prescribe cyclosporine ophthalmic emulsion 0.05% (Restasis, Allergan) twice a day for both eyes, so that the patient will produce more tears that are higher in quality. I ask them to open a fresh vial every night, and then use the other half in the morning. The cyclosporine vials are labeled for single-use only, but I feel comfortable allowing patients to get two doses out of one vial, as long as the vial is thrown away after it's been open for 9 hours. This reduces the cost of the medicine in half, which enhances compliance.

At the same time, patients begin treatment with loteprednol etabonate ophthalmic suspension 0.5% (Lotemax, Bausch & Lomb) 4 times a day for 2 weeks, followed by 2 times a day for 2 weeks, to ameliorate the burning sensation they may feel from the cyclosporine and to obtain immediate relief from their dry eye symptoms.

I ask my patients to use unpreserved, transiently or gently preserved tears, such as polyethylene glycol 400 0.25% (Blink Tears, Advanced Medical Optics) at least every 2 hours while awake. I also instruct them to use a nighttime ointment of mineral oil and white petrolatum ointment (Refresh P.M., Allergan). Finally, I tell patients to take oral dry eye dietary supplements, such as Thera Tears Nutrition soft gel caps (Advanced Vision Research) or FLEX Omega Benefits (LifeGuard Health), which are rich in Omega-3 fatty acids.

When patients return in 1 month, most of their eyes look dramatically better. We perform a complete presurgical exam. If all is well, we schedule surgery. If the patient has responded slightly or not at all to aggressive treatment, I don't consider him or her a candidate for laser surgery. If the patient has improved after 1 month of aggressive treatment, but still shows mild signs and symptoms of dry eye, I usually insert four Form Fit punctal plugs (OASIS Medical) at the end of the exam and schedule surgery. These one-size-fits-all dehydrated hydrogel plugs swell to several times their original size after they come in contact with tears. They sit just below the punctum, so they're not cosmetically objectionable, and they can't abrade the cornea. And they're easily removed with a gentle flush of balanced salt solution (BSS), in the rare case of post-plug epiphora.

Occasionally, I ask the patient to continue his medication and to return to my office in another month. If needed, I recommend Tears Again Liposome Spray four times a day for both eyes and/or the use of Lacriserts once a day in both inferior cul de sacs.

Many of my post-LASIK patients with dry eye complaints are referrals who want enhancements. Once I treat their dry eye, many of them return to plano and avoid an enhancement.

Perioperative Instructions

Patients who are being successfully treated for dry eye and those who have no preexisting dry eye are put on the same perioperative regimen. We book the laser surgery once I'm satisfied with the preop workup, at which time I prescribe the following supplements and medications:

■ Vitamin C 500 mg: twice a day, starting immediately, because numerous published reports indicate that Vitamin C facilitates corneal stromal healingn

■ Cyclosporine ophthalmic emulsion 0.05%: 1 drop in each eye twice a day, starting immediately on the day they book the surgery (and continuing for those who were undergoing dry eye treatment previously)

■ Prednisone 10 mg: Oral steroids have been remarkably effective in preventing pain and photophobia after surface ablation. I give patients undergoing surface ablation 8 tablets to take all at once at the surgery center, 30 minutes before the procedure. The patient then takes 8 tablets 1 day after surgery, 4 tablets 2 days after surgery, 2 tablets 3 days after surgery, 1 tablet 4 days after surgery, and a ½ tablet 5 days after surgery. Dosage may be reduced for patients under 110 pounds, tapering from 60 mg on the first 2 days. Diabetes patients eligible for laser surgery receive a drug substitution, such as Vicodin, every 4 to 6 hours as needed for pain.

Postoperative Instructions

After surgery, patients begin their postoperative instructions, which include these medications:

■ Cyclosporine ophthalmic emulsion 0.05%: Patients continue to instill 1 drop in each eye twice a day, for at least 3 months post-op

■ Ranitidine 150 mg: twice a day for 6 days, beginning the day of surgery

■ Prednisolone acetate: 1 drop in each eye 4 times a day for 7 days, starting the day of surgery

■ Gatifloxacin (Zymar, Allergan): 1 drop in each eye 4 times a day for 7 days, starting the day of surgery

■ Ketorolac tromethamine 0.4% (Acular LS, Allergan): 1 drop in each eye 4 times a day for 3 days, starting the day of surgery

■ "Comfort drops" (1/10th of 1% tetracaine): 1 drop in each eye every hour as needed for pain for the first 3 days post-op

■ Preservative-free artificial tears. I recommend patients use Refresh Plus Lubricant Eye Drops (Allergan), Tears or Tears Plus (OASIS Medical) or another unpreserved tear for at least the first 3 months post-op. Afterward, the patient can return to a gently preserved tear, such as Blink Tears Lubricating Eye Drops (Advance Medical Optics).

■ Carboxylmethylcellulose sodium 1.0% (Refresh Celluvisc, Allergan): 1 drop in each eye at night until bandage contact lens is removed (6 days after surgery), and then replaced with nighttime ointment (see below for details)

■ Mineral oil and white petrolatum ointment: a 1-inch strip in each eye at night, starting immediately after removal of the bandage contact lens and ending 1 month after surgery. I recommend ointment at night to prevent recurrent erosions, typically Refresh PM Lubricant Eye Ointment (Allergan) because it's very soothing.

■ Acetaminophen 500mg: 1 tablet every 4 to 6 hours as needed for pain

■ Meperidine and promethazine: 1 tablet every 4 to 6 hours as the escape medicine for severe pain

■ Ice packs: Applied 10 minutes after surgery, on the way home in the car, and as needed.

Patients return to see me at day 4, day 6, 1 month and 3 months after surgery so I can evaluate their progress and alter their post-op regimen if necessary.

Figure 2. Severe superficial punctate keratitis is seen in this slit lamp photograph, which was taken after instillation of fluorescein and was viewed with cobalt blue light.

Watch for Post-op Dry Eye

At follow-up visits, I look for, among other things, signs and symptoms of dry eye. Because nerves are severed and ablated away during the surgery, patients may not feel a burning sensation and pain, even if the eyes are dry. They may experience fluctuating, hazy or distorted vision, or photophobia. Signs will be visible through the slit lamp as well.

All patients remain on key dry eye-fighting medications for at least 3 months post-op, even if they didn't have preoperative dry eye.

If they have preoperative dry eye, or suffer from it postoperatively, I'll extend the treatment period as needed. I do this because there are several peer-reviewed publications documenting that all patients (young or old, male or female, with or without dry eye) benefit from an aggressive perioperative dry eye regimen that includes cyclosporine ophthalmic emulsion 0.05%.

When they follow my recommended regimen, it's quite rare for LASIK or surface ablation patients to have significant postoperative dry eye signs and symptoms for more than 3 weeks. nMD