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LASIK PROWL Studies: Outcomes, Side Effects, Expectations & More

The U.S. Food and Drug Administration (FDA) has been studying patients’ experiences with LASIK. PROWL stands for Patient-Reported Outcomes with LASIK.

What Are the LASIK PROWL Studies?

The PROWL studies offer insight into how patients experience their vision before and after the corrective eye surgery. The project sought to use a scientifically validated questionnaire to help patients describe their experiences and report symptoms and overall satisfaction. 

The PROWL studies were done by government agencies that have no financial stake in LASIK. The organizations involved in the joint group included the FDA, the Department of Defense (DoD), and the National Eye Institute (NEI). They were launched as part of the LASIK Quality of Life Collaboration Project (LQOLCP).

PROWL studies are considered impartial because they were not conducted by a provider of LASIK or a company that makes LASIK technology.

The initial project was validated with two sample military populations. 

  • PROWL-1 was conducted at a U.S. Navy center, with 262 active personnel. Participants were between 21 and 52 years old. 
  • PROWL-2 was conducted with civilians in private clinics and practices around the United States. Participants were between 21 and 57 years old.

The purpose of the project was to evaluate if a thorough questionnaire helps patients accurately report their experiences.

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The PROWL Questionnaire

The FDA’s PROWL questionnaire is a survey instrument that is designed to help patients assess their experience. It helps individuals self-assess any visual symptoms that may occur after the surgery, such as halos, glares, starbursts, or double images.

Using 68 questions, the baseline questionnaire takes individuals an average of 20 minutes to fill out. The questionnaire includes written descriptions as well as visual images to help individuals identify issues and assess the intensity of their symptoms.

What Were the PROWL Results?

The results confirmed very high satisfaction rates regarding LASIK. 

It also confirmed that a small percentage of people experience new visual side effects that they did not have before the procedure. These include dry eye symptoms, with varying severity, as well as visual halos, glares, starbursts, and changes in nighttime vision. 

These are some of the top PROWL findings:

  • Between 96 and 99 percent  of people reported high satisfaction rates with LASIK.
  • A small portion of patients experienced new visual symptoms after LASIK, including halos, glare, and starbursts. Some patients reported severe dry eye symptoms, which lasted three months after the procedure.
  • The majority of people who experienced visual symptoms and dry eye noted that these decreased over time in the months following LASIK.
  • At three months, only 1 percent of patients reported that the symptoms interfered with normal activities and daily well-being .
  • Night driving improved by 18 percent among patients who had contacts or glasses before LASIK.
  • There was a 35 percent reduction in visual symptoms like glares and starbursts among LASIK patients.

Limitations of the LASIK PROWL Studies

The PROWL studies did not follow up beyond three months. 

According to Primary Care Optometry News, the three-month marker is significant as none of the participants were allowed to have further surgeries, called enhancements

At three months, about 4 percent of patients were dissatisfied with their vision. This percentage is approximately equal to the rate of the 3 to 4 percent of people who get an enhancement or touch-up surgery. 

Because the study did not go beyond three months, the statistics on dry eye are considered somewhat misleading by some experts. While dry eye can potentially develop after LASIK, it tends to get better in about three to six months. Without data beyond three months, it is not possible to determine if new dry eye symptoms resolved during this time.

What Was Learned From the Studies?

While many studies have focused on the success of LASIK, the PROWL studies focus on the patient experience. The striking results are the very high satisfaction ratings with this procedure. 

The learning for medical providers is that a validated questionnaire is an excellent way to understand the patient experience. Using a system like this one can help providers gather consistent, accurate, and relevant insights. 

Providers may want to incorporate a questionnaire such as PROWL into their patient care protocols. It may help health care professionals to determine the best approach, taking into account a patient’s condition, lifestyle, and expectations. Doctors can use the questionnaire format to gather insights to make the best diagnosis and create treatment plans to serve each individual. 

For people who are considering LASIK, the study confirms why LASIK has such a positive reputation. It is also a verification that some patients experience side effects. 

Has PROWL Changed Understanding of LASIK Side Effects?

The results of the survey have not significantly changed the understanding of LASIK side effects. The PROWL studies did emphasize the importance of pre-procedure counseling for patients.


  1. Symptoms and Satisfaction of Patients in the Patient-Reported Outcomes With Laser In Situ Keratomileusis (PROWL) Studies. (January 2017). Journal of American Medicine Ophthalmology.

  2. Research Access: Prowl. National Eye Institute.

  3. Starbursts Around Lights. (December 2020). American Academy of Ophthalmology.

  4. Dry Eyes After Laser in situ Keratomileusis (LASIK). (October 2021). American Academy of Ophthalmology.

  5. LASIK Patients Report High Satisfaction Rate in FDA Outcomes Study. (February 2015). Primary Care Optometry News.

  6. Modern Laser in Situ Keratomileusis Outcomes. (August 2016). Journal of Cataract and Refractive Surgery.

  7. The PROWL Questionnaire. U.S. Food and Drug Administration.

  8. Patient-Reported Outcomes with LASIK Symptoms and Satisfaction (PROWL-SS) and Scoring Guide. American Academy of Ophthalmology.

  9. Assessment of the Psychometric Properties of a Questionnaire Assessing Patient-Reported Outcomes With Laser In Situ Keratomileusis (PROWL). (January 2017). JAMA Ophthalmology.

  10. Patient-Reported Outcomes Following LASIK Quality of Life in the PROWL Studies. (January 2017). JAMA.

  11. Comparing Patient-Reported Outcomes of Laser In Situ Keratomileusis and Small-Incision Lenticule Extraction: A Review. (September–October 2019). Asia-Pacific Journal of Ophthalmology.

  12. LASIK Quality of Life Collaboration Project. U.S. Food and Drug Administration.

  13. PROWL-1 Provides New Insights on LASIK Outcomes. (March 2015). Ophthalmology Times.

  14. The 25th Anniversary of Laser Vision Correction in the United States. (March 2021). Clinical Ophthalmology.

Last Updated September 7, 2022

Note: This page should not serve as a substitute for professional medical advice from a doctor or specialist. Please review our about page for more information.

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