References: LASIK Clinical Research
There is an enormous body of clinical data supporting LASIK laser eye surgery as safe and effective for those who are good candidates. In fact, LASIK is among the most studied procedures available today. To date, more than 7,000 studies have been conducted to evaluate the LASIK procedure and the technologies used to perform it. Research into LASIK continues and spans topics including:
- Patient selection and candidacy
- Advancements that expand the treatment indication to address the vision issues of more patients
- Techniques and technologies to help reduce the potential for side effects and complications
- Treatment modalities for addressing pre and post operative symptoms
- Case studies of rare patients, conditions and complications
Understanding LASIK Studies: No one study has a final, definitive answer about any medical treatment, device, procedure, or drug. A study is defined by a specific scope of work – the question it is trying to answer. The results of any given study may be compelling, interesting, and encouraging. Scientific research also provides clinicians / surgeons with a greater understanding of the procedure. However, those findings represent a single piece of a large and expanding body of understanding. This context is important to preventing misinformation based upon misleading or even harmful claims rooted in clinical data.
Below you will find a library of references and/or links to LASIK eye surgery clinical work used to substantiate the information curated by the Refractive Surgery Council. In some cases, specific methodology, conclusions or data is highlighted. Other times, we are providing a link to a recent study under a specific category for greater understanding. This page is frequently updated with new research added as available. New material will be added and, in some cases, studies may be removed and replaced with newer, more relevant papers. For media, we are happy to provide a clinician or refractive surgeon to answer any questions or clarify data. You can find more background in our press room. Any questions about the research provided below, or to provide research for consideration of inclusion, please contact Lisa Spicer at lisa@engagedcommunication.net.
FDA: Patient Reported Outcomes with LASIK (PROWL)
The FDA’s Patient Reported Outcomes with LASIK (PROWL), published in 2017, is a definitive study examining the patient experience with LASIK laser eye surgery. Originally designed to validate a scientific survey instrument, the study authors reported clinical data from the patient participants. Key LASIK safety findings among the participant population (PROWL 1 = 262; PROWL 2 = 312) include:
- One (1) patient reported a loss of two or more lines (Snellen chart) of vision following the procedure (a PROWL 1 participant with < 3 months of follow-up); a complication rate of .44%
- The number of patients reporting bothersome visual symptoms (very and extremely) was much higher before having the LASIK procedure. Importantly, only one patient reported having visual symptoms severe enough to interfere with activities.
- More than half of patients (59.2%) who had symptoms of dryness before LASIK reported their symptoms went away within three months after LASIK.
- Of those with no symptoms prior to LASIK, approximately 30 percent experienced new dry eye symptoms during the first 3 months of the postoperative period.
The FDA’s PROWL study specifically asked participants about their level of satisfaction as part of the patient questionnaire. Key LASIK satisfaction finding from PROWL:
- 98% satisfaction in PROWL-1; Up from 25% preoperatively (best-corrected vision)
- 96% satisfaction in PROWL-2; Up from 44% preoperatively (best-corrected vision)
Symptoms and Satisfaction of Patients in the Patient-Reported Outcomes With Laser In Situ Keratomileusis (PROWL) Studies (JAMA Ophthalmology, 2017)
Listening to the Patients: The Laser-Assisted In Situ Keratomileusis Quality of Life Collaboration Project (JAMA Ophthalmology, 2017)
LASIK Side Effects and Complications
While glare, halos, star bursting, ghosting, etc. (higher-order aberrations) are potential side effects from LASIK, data also shows LASIK can be an effective treatment for patients experiencing these visual distortions before LASIK:
Symptoms and Satisfaction of Patients in the Patient-Reported Outcomes With Laser In Situ Keratomileusis (PROWL) Studies (JAMA Ophthalmology, 2017)
- The PROWL study conducted by the FDA, Department of Defense, and the National Eye Institute showed symptoms such as ghosting, glare, halos, and starburst did not increase after LASIK. In fact, patients with ghosting actually decreased from 33% before surgery to only 6% after surgery.
Dry eye symptoms are the number one reason people see an eye doctor. In addition, dry eye symptoms are reported during the recovery and healing process after LASIK and other laser vision correction procedures. Not all patients experience these symptoms and, typically, those who do report they resolve with time and perhaps some additional treatment.
Dry Eye Post-Laser-Assisted In Situ Keratomileusis: Major Review and Latest Updates (J Ophthalmology 2018)
The data from the FDA’s PROWL study show most patients with dry eye symptoms before LASIK reported their symptoms were improved or resolved after the procedure.
Symptoms and Satisfaction of Patients in the Patient-Reported Outcomes With Laser In Situ Keratomileusis (PROWL) Studies (JAMA Ophthalmology, 2017)
Nerve regeneration after LASIK laser eye surgery appears normal:
Corneal Reinnervation after LASIK: Prospective 3-year Longitudinal Study (Investigative Ophthalmology & Visual Science, 2004).
The risk of LASIK-induced ectasia is estimated at 1/2000 patients, which is far lower than the risk of ectasia in the general population (1/375). With today’s advanced diagnostics, improved patient screening protocols and thinner flaps created by femtosecond lasers, LASIK-induced ectasia is much less common.
Age-specific Incidence and Prevalence of Keratoconus: A Nationwide Registration Study. (Am. J. of Ophthalmology, 2017)
Very Rare Complications
Rhegmatogenous retinal detachment after LASIK for myopia of up to -10 diopters: 10 years of follow-up (Graef’s Archive for Clinical & Experimental Ophthalmology, 2012)
Neuropathic Corneal Pain Following LASIK Surgery: A Retrospective Case Series (Ophthalmol. Ther. 2021 )
- This article discusses 18 LASIK patients with neuropathic pain, however there is no denominator to describe the incidence of risk.
- There has never been a case of neuropathic corneal pain described in any of the FDA studies which includes thousands of LASIK cases.
Long-Term Safety and Efficacy Data
The 25th Anniversary of Laser Vision Correction in the United States (Clinical Ophthalmology, 2021)
Long-Term Follow-Up Safety and Effectiveness of Myopia Refractive Surgery (Int J Environ Res Public Health, 2020)
In addition, the following study is often misreported as it pertains to data related to frequency of patients noticing visual disturbances:
Patient-reported Outcomes Five Years After LASIK (J. Cataract & Refractive Surgery, 2016)
The correct reference, per the study author:
- Of the 2,530 study participants is less than 2 percent of participants reported visual disturbances such as glare, halos, starbursts, and double vision, even with wearing glasses or contact lenses
- That subset of study participants were then asked to to report specific symptoms. Of that very small subset:
- 18.5% of subjects reported seeing glare
- 14.3% of subjects reported seeing halos and/or starbursts
- 5.5% of subjects reported seeing double images or ghost images
Refractive error in general (or residual refractive error after LASIK – such as a small amount of myopia or hyperopia) is well established to be the reason why humans have visual symptoms (blurred vision, glare, halos, etc).
Satisfaction Rates
Researchers have looked into LASIK patient satisfaction including how happy patients are with their vision to how has it impacted quality of life. Patient satisfaction is a distinctly separate evaluation of LASIK outcomes, which are primarily determined by visual acuity measurements.
The data from PROWL mirrors previous patient satisfaction findings from two meta-analysis studies reviewing the available LASIK research published globally between 1988-2015. The first, LASIK World Literature Review, was published in 2009 and the second, Modern LASIK Outcomes, was published in 2016.
- The LASIK World Literature Review reviewed 3,000 papers published between 1988-2008. That body of evidence was filtered for quality and bias down to 309 high-quality studies. Of those studies reporting patient satisfaction data (N=19/2,198 subjects), the overall patient satisfaction rate was determined to be 95.4%
- The second meta-analysis, Modern LASIK Outcomes, picked up where the previous had left off, gathering studies from 2008-2015. Approximately 4,400 papers were evaluated and filtered down to 97 relevant studies representing 67,893 eyes. The overall laser eye surgery patient satisfaction rate from those reporting data was up to 98%.
Modern LASIK Outcomes (J. Cataract & Refractive Surgery, 2016)
LASIK World Literature Review (J. of Ophthalmology, 2009)
A recent study conducted over 3 years showed higher satisfaction with LASIK over contacts:
Three-Year Longitudinal Survey Comparing Visual Satisfaction with LASIK and Contact Lenses (J. of Ophthalmology, 2016)
LASIK in the Military
Branches of the U.S. military have relied on laser vision correction for service members to have the vision required for operational success and safety. In order for the Department of Defense to approve the use of LASIK and other laser vision correction procedures, extensive independent investigation into their safety and effectiveness was conducted.
Wavefront-Guided Versus Wavefront-Optimized Photorefractive Keratectomy: Visual and Military Task Performance (Military Medicine, 2017)
Visual Performance with Night Vision Goggles after Photorefractive Keratectomy for Myopia (Ophthalmology, 2003)
Comparison of Night Driving Performance after Wavefront-Guided and Conventional LASIK for Moderate Myopia (Ophthalmology, 2009)
Visual and Flight Performance Recovery after PRK or LASIK in Helicopter Pilots (Aviat Space Environ Med, 2007)
Night Firing Range Performance following Photorefractive Keratectomy and Laser In Situ Keratomileusis (Military Medicine, 2006)
LASIK in United States Naval Aviators (J of Cataract & Refractive Surgery, 2013)
Wavefront-Guided PRK Treatment of Myopia Using a Refractive Aberrometer (J Cataract & Refractive Surgery, 2023)
LASIK Safety Compared to Contact Lens Use
There have been several studies that confirm LASIK laser eye surgery is safer than long-term wear of contact lenses, primarily from a significant reduction in the risk of infection
Risk for microbial keratitis: Comparative Metaanalysis of Contact Lens Wearers and Post LASIK Patients (J. Cataract & Refractive Surgery, 2017)
Risk of LASIK Surgery vs Contact Lenses (Archives of Ophthalmology, 2006)
Long-Term Visual and Subjective Outcomes: LASIK vs. Contact Lenses. (Healio, 2016)
Recent research suggests that contact lens wear may cause chronic dry eye problems and, with appropriate patient selection, many patients have fewer dry eye symptoms after LASIK than they had with their contact lenses.
Contact Lens Wear is Associated with Decrease of Meibomian Glands (Ophthalmology, 2009)
LASIK and Pupil Size
Data from published studies of modern LASIK techniques fail to demonstrate a relationship between pupil size and the quality of postoperative vision. People with large pupils or thin corneas can safely have LASIK.
Pupil Measurements Prior to Refractive Surgery (AAO)
The Role of the Mesopic Pupil on Patient-Reported Outcomes in Young Patients with Myopia 1 Month after Wavefront-Guided LASIK (J Refractive Surgery, 2014)
Visual Outcome after Correcting the Refractive Error of Large Pupil Patients with Wavefront-Guided Ablation (Clinical Ophthalmology, 2012)
Effect of Preoperative Pupil Size on Quality of Vision after Wavefront-Guided LASIK (Ophthalmology, 2011)
Comparison of Night Driving Performance after Wavefront-Guided and Conventional LASIK for Moderate Myopia (Ophthalmology, 2009)
Patient Satisfaction and Visual Symptoms after Wavefront-Guided and Wavefront-Optimized LASIK with the Wavelight Platform (J Refractive Surgery, 2008)
Night Vision Disturbances after Successful LASIK Surgery (Br J Ophthalmology, 2007)
Evaluation of the Relationship between Ablation Diameter, Pupil Size, and Visual Function with Vision-Specific Quality-Of-Life Measures after LASIK (Arch Ophthalmology, 2007)
Improved Contrast Sensitivity and Visual Acuity After Wavefront-Guided LASIK: In-Depth Statistical Analysis (J Cataract & Refractive Surgery, 2006)
Functional Outcomes and Patient Satisfaction after LASIK for Correction of Myopia (J Cataract & Refractive Surgery, 2005)
Risk Factors for Night Vision Complaints after LASIK for Myopia (Ophthalmology, 2004)
Patient Satisfaction and Visual Symptoms after LASIK (Ophthalmology, 2003)
Quality of Vision after LASIK: Influence of Dioptric Correction and Pupil Size on Visual Function (J Cataract & Refractive Surgery, 2003)
Pupil Size and Quality of Cision after LASIK (Ophthalmology, 2003)
Effect of Preoperative Pupil Measurements on Glare, Halos, and Visual Function after Photoastigmatic Refractive Keratectomy (J Cataract & Refractive Surgery, 2001)
Developing Cataracts After Laser Eye Surgery
Research shows patients with severe myopia – regardless of history with LASIK – have an increased risk for early onset of cataracts.
Myopia and Incident Cataract and Cataract Surgery: The Blue Mountains Eye Study (Investigative Ophthalmology & Visual Science, 2002)
Axial Length, Myopia, and the Severity of Lens Opacity at the Time of Cataract Surgery (Arch. Ophthalmology, 2006)
Clinical Characteristics and Outcomes of Cataract Surgery in Highly Myopic Koreans (Korean J. Ophthalmology, 2011)
Eye Doctors Choose LASIK for Themselves
Eye doctors who specialize in performing laser vision correction are five more times likely to have their own vision corrected with laser eye surgery than the general public. Doctors who had laser vision correction described better quality of life with 39% reporting their ability to perform medical procedures accurately had improved compared with their glasses or contact lenses.
Prevalence of Laser Vision Correction in Ophthalmologists Who Perform Refractive Surgery (J. Cataract & Refractive Surgery, 2015)
Advanced Technologies
Refractive surgeons can recommend specialized technologies to customize vision correction treatments to a patient’s specific anatomy, vision, and lifestyle demands.
Results of topography-guided laser in situ keratomileusis custom ablation treatment with a refractive excimer laser (J. Cataract & Refractive Surgery, 2016)
For more information, please visit the Refractive Surgery Council press room.