PROWL-1 provides new insights on LASIK outcomes

Take-home message: The Patient Reported Outcomes with LASIK-1 study shows LASIK surgery had excellent efficacy and safety, resulted in very high patient satisfaction, and was more often followed by improvements in dry eye and visual symptoms than worsening or new onset of these problems.

By Cheryl Guttman Krader; Reviewed by Capt. Elizabeth M. Hofmeister, MD

Chicago-Results from the Patient Reported Outcomes with LASIK-1 (PROWL-1) provide further evidence that LASIK surgery is associated with excellent objective clinical and patient-reported outcomes, but also serve as a reminder that no surgical procedure is without risk.

PROWL-1, conducted at the Navy Refractive Surgery Center, San Diego, CA, represents phase II of the LASIK Quality of Life Collaboration Project that was undertaken as a government partnership involving the FDA, National Eye Institute, and Department of Defense.

Capt. Elizabeth M. Hofmeister, MD, refractive surgery advisor for Navy Ophthalmology, and assistant professor of surgery, Uniformed Services University, presented the PROWL-1 data at the annual meeting of the American Academy of Ophthalmology on Oct. 19, 2014.

PROWL-1 findings

In PROWL-1, 242 active duty military personnel were operated on by four surgeons using highly standardized techniques, a femtosecond laser for flap creation, and either a wavefront-guided or a wavefront-optimized excimer laser platform. Clinic visits and online questionnaires collecting patient-reported outcomes were conducted at 1, 3, and 6 months postoperatively; the 6-month assessments were completed by 90% of operated patients.

At 6 months 99.5% of subjects achieved 20/20 or better uncorrected visual acuity, the majority of patients had gained ≥1 line of best-corrected visual acuity (BCVA) compared with preoperatively, no patient had lost >1 line of BCVA, 98% of patients were satisfied with the result of their surgery, and 97% were satisfied with their vision.

The results also showed that visual symptoms and dry eye-related findings developed de novo in some patients after surgery, but these issues affected many patients preoperatively who tended to see improvement postoperatively.

“The goal of the Navy Warfighter Refractive Surgery Program is to improve the safety and operational readiness of our service members,” Dr. Hofmeister said. “Feedback received from our patients show again and again that refractive surgery makes them safer and more effective as they work in dangerous and austere environments around the world.

“However, while we have looked extensively at postoperative symptoms, especially as they affect visual performance and night vision, we have never conducted an anonymous computer-based survey,” she said.

PROWL-1 is the first prospective study to evaluate multiple aspects of patients’ experience with LASIK, including expectations, satisfaction, visual symptoms, and their impact on function. The results provide important data to further enhance our discussion with patients about the risks and benefits of surgery, Dr. Hofmeister said.

The PROWL-1 population included mostly men (79%) and eyes with myopia/myopic astigmatism (>90%). About half of the participants were using contact lenses as their primary means of correction prior to LASIK.

Visual symptoms

The online questionnaire asked patients about ghost images, glare, halos, and starburst. Preoperatively, these symptoms were present in between 29% and 49% of patients. Only halos was reported at a higher rate postoperatively than preoperatively, and only at 1 month as the incidence of halos and all other visual symptoms steadily declined from 1 to 6 months.

“Very few patients, <1%, noted that their visual symptoms had affected their ability to perform daily activities,” Dr. Hofmeister said.

Dry eye-related findings

Dry eye was assessed using the 6-point Oxford score to rate lissamine green corneal and conjunctival staining, and symptoms were rated as normal, mild, moderate, or severe based on Ocular Surface Disease Index (OSDI) scores.

Summarizing the results, Dr. Hofmesiter said that the Oxford score data for the cohort showed an increase in staining at 1 month after surgery with improvement toward baseline at 3 and 6 months. The OSDI data showed only 55% of patients had a normal score preoperatively.

Overall scores for the cohort were better at 1 month than preoperatively and improved over time. Whereas up to 21% of patients with a normal preoperative OSDI score had a score indicating mild, moderate or severe dry eye at 6 months, 70% of those cases were mild, and 65% of the subgroup of patients who had dry eye preoperatively based on their OSDI score had a normal score at 6 months.

“It was interesting to see that our patients had a significant amount of dry eye complaints preoperatively and that these symptoms improved for the cohort after surgery,” Dr. Hofmeister said. “Although the conventional wisdom is that LASIK causes dry eye, there are several factors that can account for our results.”

Listing the explanations, Dr. Hofmeister noted that LASIK gets patients out of their contact lenses. In addition, all patients who have LASIK are prescribed topical lubricant drops and those identified to have meibomian gland dysfunction are encouraged to treat their disorder with warm compresses and omega-3 supplements.

Only 4 patients were dissatisfied with their LASIK surgery at 6 months and 6 patients were dissatisfied with their vision. The small number of dissatisfied patients precluded valid statistical analyses to identify associated factors.

Qualitative comparisons were untaken and showed the satisfied and dissatisfied groups were similar in terms of residual refractive error, and the dissatisfied patients had slightly lower higher-order aberrations.

However, the dissatisfied patients seemed more likely to report visual symptoms and 2 of the 6 dissatisfied patients had severe OSDI scores.

Capt. Elizabeth M. Hofmeister, MD

E: elizabeth.hofmeister@med.navy.mil

This article was based on a presentation by Dr. Hofmeister at the 2014 meeting of the American Academy of Ophthalmology. Dr. Hofmeister has no relevant financial interests to disclose. The views expressed are her own and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the U.S. government.