Surgeons aim to optimize quick return to daily functions after LASIK

One portion of an ongoing study shows that the WaveLight platform may hasten visual recovery.

Issue: June 25, 2012

ByDaniel S. Durrie, MD

In our practice we have had the opportunity to work with five generations of IntraLase lasers from Abbott Medical Optics, two Ziemer femtosecond lasers and Alcon’s WaveLight FS200 femtosecond laser. With this experience and with the arrival of novel technologies to market, we have sought to field test nascent laser platforms in a way that allows for ongoing improvement of accuracy and results. We have used these outcomes to provide manufacturers with a set of baseline data against which technical refinements and future clinical results can be measured. We have also looked from the perspective of our patients to examine how we can optimize their experience with each laser and improve upon the speed of visual recovery.

For this particular iteration of the study we used the Alcon WaveLight Refractive Suite, which includes the WaveLight FS200 femtosecond laser for flap creation and the Allegretto Wave Eye-Q excimer laser for photoablation. We quantified the speed of visual recovery after LASIK using ETDRS visual acuity, contrast sensitivity and a subjective questionnaire. Patients were asked at multiple time points within the first few hours of surgery if their vision was good enough to send a text message or drive a car. We compared these answers with their visual acuity and contrast sensitivity measurements at each time point. Our aim was to reduce the amount of recovery time after surgery, with the goal of having patients return to their daily activities within 2 hours or less. Our hope is that this procedure can be refined to the point where patients can safely drive themselves to and from their procedure.

Study details

In this portion of the study, we evaluated 44 eyes of 22 patients (nine men and 13 women). Participants had manifest refraction spherical equivalent of –6 D or less with up to 3 D of astigmatism. Preoperative medications included proparacaine, gatifloxacin and dilute brimonidine. The WaveLight FS200 femtosecond laser was used to create a superior hinge flap with an angle of 60°. Flaps were 8.5 mm in diameter, round and 110 µm thick with a 120° inverted side cut. The Allegretto Wave Eye-Q excimer laser was used to perform a wavefront-optimized treatment. Patients were evaluated immediately upon sitting up from the laser and at 30 minutes, 1 hour, 2 hours, 4 hours and 1 day after treatment.

Daniel S. Durrie

While this cohort was treated with a wavefront-optimized algorithm, we employ wavefront-guided treatments as well. These are usually reserved for patients with significant higher-order aberrations. For consistency, only patients without significant higher-order aberrations were included in this cohort, whereas in previous cohorts we evaluated patients treated with wavefront-guided technology. The comparison of these two arms constitutes another aim of this ongoing study.

My philosophy on flap creation is guided by the assumption that patients may require additional photoablative treatment and that surgeons should plan accordingly. With lasers such as the WaveLight FS200, we are able to create reliably thin flaps, leaving even highly myopic patients with a 300-µm residual bed. This is not a hard and fast cutoff, although we are conservative. We still follow the old “250 rule,” but include in this a plan for possible enhancement. Preoperatively, the surgeon spends about 20 minutes of face time with each new patient and ensures all patient questions are addressed. We do not hesitate to turn away patients if the residual stromal bed, including possible enhancement, falls below 250 µm. We also avoid MD or OD co-management postoperatively, unless the patient is traveling a significant distance, such as by plane.

Study results

One of the more interesting findings was that contrast sensitivity improved at all spatial frequencies after LASIK. It returned to normal levels within the first few hours and was significantly better than preop levels by day 1. In patients who are good candidates for surgery, we are confident that we can achieve 20/20 or 20/16 vision with no loss of contrast sensitivity. The improvement in contrast sensitivity to supraphysiologic levels seems attributable to the WaveLight platform, although we are still generating data to confirm these initial observations.

The majority of eyes were 20/40 immediately after surgery, 85% were 20/40 by 2 hours, 100% were 20/40 by 4 hours, and 65% were 20/20 by 4 hours. At postop day 1, 98% of eyes were 20/20, 70% were 20/16, and 35% were 20/12.5. Binocular visual acuity recovered quickly as well. One hour after surgery 90% of patients were 20/40, and at postop day 1, 95% of patients were 20/16.

The questionnaire results are interesting because visual acuity improved more quickly than patient comfort with driving. Most could pass a driver’s license test within 30 minutes, but it was not until 4 hours after surgery that 100% of patients were comfortable driving. Surgeons cannot simply rely on the patient’s ability to read at 20/40 or better on an eye chart to determine safety behind the wheel. Patients have to feel confident in their ability to drive. Curiously, 27% of cohort patients felt they were able to drive the moment they sat up from the laser bed and 45% felt comfortable driving at 30 minutes.

‘White eye project’

Aesthetics represents the final frontier in the patient experience. Patients are ecstatic when they can see clearly immediately after surgery, but when friends, family and work colleagues comment on puffy eyelids or red, irritated-looking eyes, patients may internalize these comments and become anxious that their eyes are not healing appropriately.

About 10 years ago in our practice we began the “white eye project.” We would not discharge a patient until his or her eyes appeared white and healthy, as though they had never undergone surgery. At the time, subconjunctival hemorrhages were still common from microkeratomes and from the suction ring component of the femtosecond laser patient interface. We administered anesthetics, antibiotics and antiseptics to keep the patients’ eyes safe, but we learned that the downside to these medications is that they can irritate the eye, blur the vision and make the eye look red.

Today we use a minimal number of drops: We give one drop of antibiotic 30 minutes preoperatively and an additional drop of topical anesthetic before flap creation. When we compared preoperative naphazoline hydrochloride, a topical allergy drop, to quarter-strength brimonidine, an anti-glaucoma medication, we found that brimonidine left patients feeling more comfortable and with whiter eyes. We found that naphazoline can occasionally throw off the tracking system of the laser by dilating the pupil, while brimonidine does not do this. This combination of medications has resulted in people complaining far less often about significant discomfort with the procedure, which we believe has improved patient satisfaction and word-of-mouth referrals.

The results presented from this cohort represent one part in an ongoing series evaluating modern laser technology. We have conducted studies on the Visx/IntraLase and Ziemer femtosecond laser platforms as well. As we continue studying the various femtosecond and excimer lasers, we hope that by optimizing laser technology and the patient experience we can achieve more rapid visual recovery and get patients back to work with minimal time off. Our results from the other cohorts will be available later this year. We are hopeful that with continued improvement of our technologies and outcomes, the concept of “lunch break LASIK” can become a reality.

Reference:

Brinton JP, Durrie DS, Stahl ES. Comparison study of 4 femtosecond lasers for the creation of corneal flaps for sub-Bowman’s keratomileusis. Presented at: American Academy of Ophthalmology annual meeting; Oct. 24, 2011; Orlando, Fla.

For more information:

Daniel S. Durrie, MD, can be reached at Durrie Vision, 4420 College Blvd., Suite 201, Overland Park, KS 66211; 913-871-1166; fax: 913-491-9650; email: ddurrie@durrievision.com.
Disclosure: Dr. Durrie is a clinical investigator for Alcon and Abbott Medical Optics.