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A new lubricating eye drop (blink Tears, Advanced Medical Optics) with the active ingredient polyethylene glycol is designed to provide a balance between viscosity and retention without sacrificing a patient's visual quality. It can help optimize the ocular surface before and after refractive surgery, aiding postoperative visual outcomes and patient satisfaction.
Refractive surgery no longer just means LASIK. Today, any procedure in which a patient has a high expectation for the visual outcome should be thought of as a refractive surgery procedure. Whether the patient is a 30-year-old seeking LASIK or a 65-year-old with cataracts considering implantation of a premium IOL, it is important to maximize every detail of pre-and postoperative care to achieve the outcomes he or she expects.
Across all these "refractive" groups, dry eye is a common problem and a real impediment to refractive success if not appropriately recognized and treated. In my experience, about 70% of people aged more than 60 years have some dry-eye signs or symptoms. Terry O'Brien, MD, has reported that 25% of patients visiting ophthalmic clinics report dry-eye symptoms, and that percentage reflects my experience with the younger refractive surgery population.
A healthy tear film and optimized ocular surface are prerequisites for accurate baseline refraction and wavefront measurements, and even for determination of candidacy for refractive surgery. During an initial consultation for laser vision correction, for example, it can be very difficult to assess whether topographic irregularities are due to forme fruste keratoconus, contact lens warpage, or tear film-related surface irregularities.
The lids are very important and often-overlooked and should be treated aggressively if signs of meibomian gland disease are present. I also use temporary collagen plugs as an adjunct to tears and other therapies. If necessary, I will delay surgery for several months until I'm satisfied with the health of the ocular surface and my preoperative measurements.
Postop dry eye
Optimization of the ocular surface is just as important postoperatively as it is preoperatively. Postoperatively, it's important to continue taking a proactive and aggressive approach to dry eye.
Surgery, especially LASIK, almost always will worsen a pre-existing dry-eye condition. I recommend that all patients use a lubricating drop four times daily for at least 3 months after surgery. About 80% of these patients also will be taking cyclosporine therapy. The deeper the ablation and the more significant the preoperative dry eye, the more likely I am to recommend additional measures such as ointments at night, oral doxycycline, oral vitamin C and flaxseed or fish oil, steroids, and/or punctual plugs.
If not managed effectively, dry eye will result in poor vision even if the surgery otherwise was perfect. When the eyes are dry, we see reduced Snellen acuity, poor contrast sensitivity, and an increase in higher-order aberrations (HOAs), which causes a reduction in the quality of vision and an increase in night-vision symptoms such as glare and halo.
Not surprisingly, these sequelae of dry eye significantly reduce the "wow" factor in refractive corneal and cataract surgery and put a damper on patient satisfaction and referrals. Patients likely will attribute their discomfort or visual symptoms to the laser surgery or the IOL implanted when, in fact, dryness is the culprit. As surgeons, we also are quick to blame poor visual outcomes and night vision disturbances on pupil size or IOLs and often overlook the more easily treated ocular surface issues.
Patients may seek an enhancement to improve the quality of their vision. In many cases, treating the dryness is the only enhancement needed, so it is absolutely critical to ensure that the ocular surface is maximized before performing any laser enhancement or IOL exchange.
Dry eye also may affect regression rates after LASIK. Albietz and colleagues found that patients with dry eye had significantly worse refractive outcomes after LASIK and that more than one-fourth of them experienced regression.1 As a clinician, it sometimes is difficult to differentiate between true refractive regression and simple ocular surface abnormalities. For patients, the answer to that question is irrelevant; they still cannot see as well as they expected.
First line of defense
Non-prescription artificial tears and lubricants always are the first line of defense in dry eye. Perhaps for this reason, ophthalmologists often overlook them as a critical part of dry-eye care. In many mild cases of dry eye, tears alone four times daily can ameliorate patients' symptoms, get them ready for surgery, or help them maintain an optimal outcome postoperatively.
The ideal lubricant offers good retention without blurring the patient's vision or causing discomfort or redness. It's also important to consider the effect of topical preservatives, especially in eyes with a compromised ocular surface or known allergies.
Retention is important because the longer the drop stays on the eye, the greater the relief from symptoms for the patient. That fact means that they can use the drops fewer times throughout the day, boosting quality of life and reducing that perception that "something is wrong."
As with any medication, we know that fewer doses throughout the day is likely to lead to better compliance, especially with young, healthy patients who have returned to their busy lives after refractive surgery. A tear that stays on the eye and allows the dosing frequency to be kept low is a real advantage in terms of clinical benefit, patient satisfaction, and compliance.