Contoura Vision Vs Lasik Vs Smile- What US FDA Clinical Trials Tell Us
Clinical trials are mandatory before any technology or treatment modality can be offered to the doctors and patients alike. The US FDA mandates these, and makes sure they are monitored and analyzed in great detail before granting approval to any technology.
All three techniques of refractive surgery, Contoura vision, LASIK and SMILE have US FDA approval, so you can be rest assured that all three have been proven to be safe and effective for refractive correction, clinically, and over time.
In addition, clinician scientists and doctors continue to analyze and publish their clinical results in peer reviewed journals for an interactive exchange of results and complications.
Femtosecond LASIK versus SMILE:
A systematic review and meta-analysis published in the highly acclaimed Journal of Refractive Surgery in 2016 by Zhang et al analyzed a total of 1,101 eyes, of which 532 eyes underwent SMILE and 569 eyes underwent femtosecond LASIK. The authors reported no significant difference between the two procedures in terms of final visual acuity achieved, or complications. In fact, the only difference that they could point out was that the tear break-up time was longer in the SMILE group than the femtosecond LASIK group at 1 and 6 months after surgery, implying that SMILE may result in lesser dry eye symptoms. They also reported that corneal sensitivity was higher in the SMILE group.
A more recent review in International Journal of Ophthalmology in 2017, published by Yan et al, reviewed as many as 4223 eyes undergoing the two procedures in terms of differences in visual acuity, aberration and biomechanical effects within six months after the surgery. They concluded that SMILE and femtosecond LASIK are comparable in efficacy, safety and predictability for correcting myopia. However, the aberration in the SMILE group is superior to that in the femtosecond LASIK group, and the loss of biomechanical effects may occur less frequently after SMILE than after femtosecond LASIK.
The real life implications of this are simple.
Both SMILE and Femtosecond LASIK are effective, safe and predictable.
The SMILE and femtosecond LASIK procedures, over time, give similar visual results, with patients reporting visual results that are similar.
SMILE may cause less dryness post surgery, and therefore, may be preferred in patients with preexisting dry eyes.
Postoperative aberration may occur less frequently after SMILE than after femtosecond LASIK. Contrast sensitivity was better in the SMILE group than in the femtosecond LASIK group at three to six months after surgery.
Contoura Vision:
Since there is a head to head comparison for Contoura Vision refractive correction versus SMILE, it is easier to compare the two.
Direct comparison of SMILE and Contoura Vision LASIK: Which is better?
Kanellopoulos et al published their results in the critically acclaimed journal, the Journal of Refractive Surgery in 2017.
They reported that in their study group of 44 eyes of 22 patients with bilateral myopia or myopic astigmatism, 22 eyes were treated with Contoura Vision LASIK and the other eye of each patient was treated with SMILE.
They found that the results of Contoura Vision LASIK at 3 months were far superior to that of SMILE, putting the Contoura Versus SMILE argument to rest.
As many as 86.4% of the LASIK group and 68.2% of the SMILE group had a vision of 20/20 and 59.1% and 31.8%, respectively, had vision of 20/16 (super vision). That is, vision better than 100% was achieved in more than half the patients getting Contoura Vision.
Especially in case of astigmatism, or correction of cylinder, Contoura Vision was much better than SMILE. The residual refraction cylinder (≤ 0.25 D), that is accuracy of correction of cylindrical power was 81.8% for the Contoura Vision group and 50% for the SMILE group.
In fact, the authors concluded that Topography-guided or Contoura Vision LASIK was superior in all visual performance parameters studied, both subjective and objective, including visual aberrations.
This difference could be because of the superior technology of Contoura Vision: the eye tracking, cyclorotation compensation, and active centration control.
FDA trial results:
Even if we compare the results of the multicentric clinical trials conducted under the aegis of the US FDA to analyze the visual results of the procedure, Contoura emerges the clear winner.
The real life implications of the Contoura Vision trials are also simple to understand:
More than 92% of patients treated with Contoura achieved 20/20 or 6/6 vision.
More than 64% achieved 20/16 vision or better. It is important to understand that 20/20 or 6/6 vision is considered normal for human beings. 20/16 vision implies that after the surgery, the patient could see from 20 feet away, what he or she should have been able to see from 16 feet, that is, vision far superior to what is considered normal for men and women.
In addition, the trials also found that patients having the surgery had better vision than that achieved with glasses or contact lenses. In fact almost one third of the patients had better unaided vision following surgery, than they had ever had with their glasses/contact lenses.
The patients also reported a lesser incidence of visual disturbances like glare and haloes and difficulty in night time driving and reading, as compared to their glasses. Thus, there was a significant improvement in their “quality of vision” also.
Most patients said they would choose the procedure again, and would be happy to recommend it to their friends and family, implying better patient acceptability.
Three Most Important Considerations
Super vision:
Vision better than 20/12.5 was noted in several Contoura patients, that is almost twice that of normal, for Contoura vision while super vision was not recordable to this level by SMILE.
100% of Contoura Vision patients were less than 1 diptre of target, but not true for SMILE.
Astigmatism
FDA has approved SMILE for correction of only 0.5 Diopter of astigmatism. Contoura has been approved for six times as much, that is, up to 3 Diopters of astigmatism, implying that Contoura is far more effective than SMILE.
WOW Factor and Patient Delight:
Vision recovery after SMILE takes a minimum of three days, while that after Contoura Vision, like LASIK, is instantaneous. The joy of walking out of the hospital with perfect vision is unparalleled.
Upto 30% patients at 1 week, and 15% patients at 1 month had loss of one line of best corrected visual acuity with SMILE. This never happened in the FDA results of Contoura.
Laser Refractive Surgeries
Moshirfar et al analyzed the impact of the three latest U.S. Food and Drug Administration (FDA)-approved lasers on patient-reported outcomes after LASIK, and their results were also published in the highly esteemed Journal of Refractive Surgery in 2017.
In this meta-analysis of patient-reported FDA data, an aggregated total of 718 eyes undergoing LASIK using VISX iDesign (Abbott Medical Optics Manufacturing, Milpitas, CA), Alcon Contoura (Alcon Research, Ltd., Fort Worth, TX), and Nidek CATz (Nidek Co. Ltd., Gamagori, Japan) lasers were evaluated for overall changes in visual symptoms postoperatively. The authors reported that at the end of one year of follow up, there was a decrease in the postoperative difficulty driving at night in almost one third of the patients (29%). There was a significant postoperative reduction in prior moderate to severe symptoms for light sensitivity, reading difficulty, double vision, glare and halos at the end of one year follow up following laser vision correction.
The real time interpretation of this is also simple:
Patients obviously experience a better vision after laser vision correction, regardless of the laser platform used.
Laser vision correction is safe and effective
Patients report a better quality of vision after surgery as well.