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Chronic dry eye develops in small percentage of patients after PRK, LASIK
Tear film and ocular surface health scores showed different changes after each laser refractive procedure.
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Chronic dry eye developed in a small percentage of eyes up to 12 months after PRK and LASIK, according to a study.
In addition, ocular surface staining scores and corneal sensitivity changed after both laser refractive procedures.
“Going in, we knew that dry eye is one of the more common complaints following these laser vision correction procedures, so we wanted to see if there were any predictive factors for folks who might be at higher risk for a profound or longer-lasting dry eye, and if there was a significant difference in the healing course between PRK and LASIK,” Kraig S. Bower, MD, the corresponding author, told Ocular Surgery News. “Most people say that LASIK causes worse dry eye than PRK. That has been previously reported, and we wanted to see if we could confirm that.”
Bower and colleagues set out to evaluate the incidence of surgically induced dry eye.
“Severe dry eye that requires heavy management preoperatively is often a warning sign for postoperative problems,” Bower said. “So, if somebody requires punctal plugs and Restasis [cyclosporine ophthalmic emulsion 0.05%, Allergan] or multiple drops and still has trouble with their surface, they might not be well served by either of these laser procedures. Our study looked specifically at patients who had no pre-existing problems with dry eye.”
Study design
The prospective nonrandomized study, published in the Journal of Cataract and Refractive Surgery, included 143 active-duty U.S. Army personnel with myopia or myopic astigmatism who underwent PRK or LASIK; 73 patients underwent bilateral PRK, 69 patients underwent bilateral LASIK, and one patient had unilateral LASIK.
Outcome measures were dry eye manifestations, incidence and predictive factors for chronic dry eye. Diagnostic tests for dry eye were conducted preoperatively and at 1, 3, 6 and 12 months postoperatively.
Soft contact lens wearers were asked to refrain from using their lenses for 2 weeks, and hard contact lens users were asked to discontinue use for at least 4 weeks.
Outcomes
Chronic dry eye, defined as dry eye lasting 6 months and beyond postoperatively, developed in 5% of eyes in the PRK group and 0.8% of eyes in the LASIK group. No patients had bilateral chronic dry eye.
“Normal postoperative healing involves some degree of ocular surface dry eye, but this typically recovers to preoperative levels over time,” Bower said. “We found a pretty low number of patients who had long-lasting severe dry eye still present at the 12-month visit. Interestingly, there were a few more cases in the PRK as opposed to the LASIK group.”
Schirmer scores changed significantly after PRK (P < .001) but not after LASIK. The scores were significantly lower at 1 month (P = .003) and 3 months (P = .004) after PRK.
Tear breakup time did not change significantly over time after PRK but did change significantly after LASIK (P < .001). Tear breakup time was significantly faster at 1 month, 3 months and 12 months after LASIK (all P < .001) compared with baseline values.
Corneal sensitivity decreased significantly at 1 month after PRK (P = .010) but increased significantly at 12 months (P = .007) compared with baseline. It decreased significantly at 1 month (P < .001), 3 months (P < .001) and 6 months (P = .009) after LASIK.
Corneal staining scores changed significantly after PRK (P = .044) and LASIK (P = .002). Postoperative staining scores were significantly higher only at 3 months after PRK (P = .004). Staining scores were significantly higher than preoperative values at 1 month (P = .005), 3 months (P < .001), 6 months (P = .006) and 12 months (P = .001) after LASIK.
The relationship between chronic dry eye and the use of intraoperative mitomycin C in PRK was not significant.
The study did not focus on heavy computer use as a contributing factor in dry eye, Bower said.
“Those folks who are spending prolonged periods of time on the computer may have more trouble with dry eye in general and specifically after the surgeries. We did not isolate workforce things like that. That would make an interesting study to look at,” he said. – by Matt Hasson
- Reference:
- Bower KS, et al. J Cataract Refract Surg. 2015;doi:10.1016/j.jcrs.2015.06.037.
- For more information:
- Kraig S. Bower, MD, can be reached at Wilmer Eye Institute, Green Spring Station, Pavilion II, Suite 455, Lutherville, MD 21093; email: kbower5@jhmi.edu.
Disclosure: Bower reports no relevant financial disclosures.
Perspective
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Eric D. Donnenfeld, MD
The authors have evaluated 143 patients who had LASIK or PRK and followed them for 1 year to evaluate the development of dry eye disease. The incidence of dry eye following PRK was 5% and following LASIK was 0.8%. There are two important findings in this study. One is that at 1 year following LASIK, the incidence of dry eye was very low. With the return of corneal sensation, dry eye resolves in most cases. More importantly, preoperative low Schirmer scores and corneal staining increased the risk of postoperative dry eye.
This study reinforces that the preoperative evaluation of refractive surgery candidates for dry eye disease is extremely important. We have found the incorporation of objective evidence-based testing such as tear osmolarity and MMP-9 levels to be additive to the physical examination in diagnosing dry eye before corneal refractive surgery.
Patients with preoperative low Schirmer scores, corneal staining as well as other signs of dry eye disease should be treated with improvement in their ocular surface or discouraged from undergoing corneal refractive surgery.
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