A healthy, stable tear film is essential for high quality visual function and stable interblink vision. If patients have dry eye disease, it must be successfully resolved before corneal refractive surgery takes place. Similarly, patients who do not have preoperative dry eye but are at high risk of developing the disease postoperatively also need special attention.
Both widely accepted, well-documented diagnostic and therapeutic options and newer or experimental approaches should be considered in the management of preoperative dry eye and strategy for preventing its postoperative development.
By Nancy Groves; Reviewed by Elizabeth Yeu, MD
Norfolk, VA-A healthy, stable tear film is essential for high-quality visual function and stable interblink vision. If patients have dry eye disease, it must be successfully resolved before corneal refractive surgery takes place. Similarly, patients who do not have preoperative dry eye, but are at high risk of developing the disease postoperatively, also need special attention.
While the basic steps of preoperative and postoperative management remain the same, recently introduced therapeutic and diagnostic options and others in the pipeline could convert more patients into good candidates for corneal refractive procedures, said Elizabeth Yeu, MD.
“Preoperatively, a careful evaluation is obviously very important, and I think that the dynamics of preoperative evaluation are changing as dry eye diagnostics and therapeutics are expanding,” said Dr. Yeu, an ophthalmologist in private practice in Norfolk, VA, and an assistant professor at Eastern Virginia Medical School.
Slit lamp examination and the patient’s history and subjective symptomatology are still the two most important considerations, she said, but advanced diagnostic tools for evaluating tear osmolarity, matrix metalloproteinase-9 (MMP-9), and lactoferrin levels are also gaining acceptance.
“We’ll probably be seeing more of that in our preoperative evaluations,” Dr. Yeu said. “These tests are potentially more sensitive and specific in helping identify and treat dry eye patients before surgery.”
MMP-9 levels in the tears have been shown to correlate well with the severity of dry eye, and this rapid, in-office test may be especially valuable in younger patients who may not have as much staining, but at the same time have more inflammation due to contact lens wear, extended computer use, or an erratic sleep schedule, Dr. Yeu said.
By determining the MMP-9 level preoperatively as part of the evaluation, the physician could recommend ocular surface optimization strategies that could reduce complications from refractive surgery.
“If you’re only relying on slit lamp examination, you may miss an opportunity to take care of a problem that could become much worse after surgery and cause a patient to fall into the category of chronic disease,” Dr. Yeu explained.
The type of refractive surgery procedure can also impact the risk of dry eye disease.
“We know that with regard to corneal refractive procedures, advanced surface ablation (ASA), femtosecond laser flaps, and thin-flap LASIK may have a lower incidence of dry eye, although as yet little has been published to compare thin-flap LASIK with ASA,” Dr. Yeu said.
As the flapless small-incision lenticule extraction (SMILE) procedure becomes more widely used, it may become the procedure of choice in corneal refractive surgery, she added. This procedure involves less NaFL staining and minimal transection of the corneal nerves in the anterior third of the corneal stroma than femtosecond LASIK and reduces inflammatory reaction and cell death.
In several clinical trials, SMILE had better dry eye outcomes than femtosecond LASIK.
Management of dry eye disease associated with corneal refractive surgery continues after the procedure, and taking an aggressive approach is very important, said Dr Yeu, noting that between 10% and 20% of LASIK patients and 3% to 7% of those who have had PRK, may suffer from dry eye disease at a more chronic level.
In addition to proven therapeutic options such as artificial tears and cyclosporine A, other therapies should be considered, although some are new and few studies on their safety and efficacy have been published.
Treatment modalities that may one day become standard include:
Self-retaining amniotic membrane therapy is also an option, particularly in patients planning to undergo ASA who are at higher risk of dry eye and healing defects of the corneal epithelium, Dr. Yeu said.
The use of serum plasma tears is a more advanced therapeutic approach, but in using such therapies, someone who is a high-risk candidate may do just as well as with the established options, she added.
A study in Japan showed that serum plasma tears could be safely used in patients with Sjögren’s syndrome who were undergoing ASA. However, this finding was contradicted in other literature.
Another of the newer therapies-the secretagogue diquafosol tetrasodium-has been shown to be effective in dry eye disease management outside of the United States, although a compound recently evaluated here did not receive FDA approval.
The thermal pulsation system (LipiFlow, TearScience) or similar treatment may be a good choice for patients whose dry eye symptoms are strongly associated with meibomian gland disease. The majority of dry eye cases have some meibomian gland involvement, Dr. Yeu said, and many patients could benefit from some form of in-office meibomian gland treatment.
While extensive evidence on the safety and efficacy of some newer treatment approaches to dry eye disease is not yet available, early positive findings confirm that good outcomes can be achieved when physicians combine aggressive treatment with appropriate management of patient expectations, Dr. Yeu said.
Elizabeth Yeu, MD
Dr. Yeu is on the advisory board for TearLab, the advisory board and speaker’s bureau for Allergan, and the speaker’s bureau for Alcon Laboratories.