Seven Pearls for Ensuring Excellent Visual Outcome after Corneal Refractive Surgery
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The popularity of laser refractive surgery is staggering, with more than 17 million procedures performed to date and an estimated 1.3 million procedures performed worldwide each year.1 While LASIK and PRK have grown in acceptance, relatively few ophthalmology programs have offered their residents significant training and experience in performing these procedures. For those of you who are new to corneal refractive surgery, I offer these few tips and pearls aimed at improving your personal experience with the procedures and, ultimately, ensuring the excellent visual outcome for your patients.
1. Know your patient. To ensure that your patient is satisfied with the results of their expensive and often long-anticipated refractive surgery, it is important for you to understand the patient’s expectations and his or her goals for the procedure. If the patient is a 40-year old seeking complete independence from corrective lenses, you will need to have a long discussion about the impending onset of presbyopia, its implications and potential treatment options. Be sure that any patient who desires monovision LASIK or PRK has had a successful contact lens trial or previous experience with the arrangement.
A firm understanding of your patient’s profession, recreational activities and hobbies may also be of extreme importance and will help you to best advise your patient regarding treatment options. Certain professions (e.g. military pilots, FBI and police agencies) have restrictions regarding refractive surgeries that might have serious implications for your patient and his or her career.
Consider recommending LASIK to eligible patients whose hobbies or profession involve significant outdoor activity, as increased ultraviolet exposure may increase the risk of delayed haze and regression in PRK patients.2 If your triathlete patient is best suited to or prefers PRK, then consider a prolonged steroid taper and educate the patient as to the importance of ultraviolet blocking sunglasses. Remember, the time you spend discussing these issues with your patient before surgery may save you hours of discussion and heartache after the surgery.
2. Know your equipment. Familiarize yourself with your laser(s), your micro-keratome and your instruments. Time spent fumbling for buttons, knobs or instruments can lead to tissue desiccation, excess tissue ablation and ultimately overcorrection. Take the time to learn the operating parameters of your equipment and to understand the environmental conditions in your procedure room. Variations in temperature and humidity may have an effect on laser function and tissue ablation. With time and surgical experience, you can develop nomograms, which account for the idiosyncrasies of your laser, environment and your technique.
3. Embrace technology. Wavefront guided or “custom” treatments, femtosecond flap creation, pupil tracking and iris registration are next-generation technologies that can help you to achieve superior surgical results. Wavefront guided treatment increases the likelihood of a visual outcome equal to or better than 20/20.3 The use of Femtosecond laser technology leads to fast and safe LASIK flap creation, which may improve visual outcomes over bladed LASIK.4, 5
4. Centration, Centration, Centration. While you should embrace technology, you should not rely on it. Iris registration and pupil tracking technologies are helpful and reliable, but you should maintain a vigilant eye on laser centration during the procedure. Don’t just go along for the ride. You should actively center the reticle before and during surgery to ensure that your treatment encompasses the visual axis. You should also be prepared for unexpected problems such as failure to capture iris registration. For redundancy, consider marking every patient with a surgical marking pen so you can align the head and correct for cyclotorsion. Your efforts and attention to detail will result in improved patient outcomes.
5. Know your patient (Part 2). Take the time to talk to your patient about dry eyes. Dry eye is a common cause of patient dissatisfaction and visual disturbance after refractive surgery, and you need to educate your patients about the potential for dry eye prior to surgery. More importantly, you need to inquire about dry eye history prior to surgery so that you can best advise and treat your patient. While PRK may cause fewer dry eye symptoms, both LASIK and PRK patients may need postoperative artificial tears and even Restasis.
6. Prevent haze and regression. Low-dose Mitomycin (0.02%) has been shown to be safe and effective in reducing haze and regression in patients undergoing PRK for moderate to high myopia. Use of low-dose Mitomycin may result in improved results and refractive stability in patients with moderate or high astigmatism. Consider using Mitomycin in patients with lower levels of myopia, whose professional and recreational activities require significant ultraviolet exposure. Whenever you use Mitomycin, ensure that standard protocols are followed in mixing, handling and disposing of the medication.
7. Know your patient (Part 3). Consider adjusting your treatment parameters in accordance with the age and needs of your patient. As patients tend to trend towards increased myopia over time, aiming for slight hyperopia after LASIK and PRK may result in increased satisfaction and prolonged visual benefits for younger patients. Emmetropia is a better target for patients who are nearer to onset of presbyopia or who perform extensive near work.
Corneal refractive surgeries offer incredible benefits to our patients and can be equally rewarding to the surgeon. While today’s advanced technologies are integral to the success of any refractive surgery, it is incumbent upon the surgeon to be involved in all phases of treatment, from pre-op patient education to post-operative follow-up. With proper planning and attention to detail, the patient and surgeon will experience complete satisfaction.
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About the author: CDR Frank Bishop, MD, a native of Visalia, Calif., is a board-certified ophthalmologist. He is the staff comprehensive ophthalmologist at the Naval Medical Center San Diego, where he teaches and specializes in cataract and refractive surgeries. The views expressed in this article are those of the author and do not reflect the official policy or position of the Department of the Navy, Department of Defense or the U.S. government.
2 Nagy ZZ, Tóth J, Nagymihály A, Süveges I. The role of ultraviolet-B in corneal healing following excimer laser in situ keratomileusis. Pathology Oncology Research. 2002;8(1):41-6.
3 Zhang J, Zhou YH, Wang NL, Li R. Comparison of visual performance between conventional LASIK and wavefront-guided LASIK with iris-registration. Chinese Medical Journal. 2008 Jan 20;121(2): 137-42.
4 Montés-Micó R, Rondríguez-Galietero A, Alió JL, Cerviño A. Contrast sensitivity after LASIK flap creation with a femtosecond laser and a mechanical microkeratome. Journal of Refractive Surgery. 2007 Feb;23(2): 188-92.
5 Montés-Micó R. Rodíguez-Galietero A. Alió JL. Femtosecond laser versus mechanical keratome LASIK for myopia. Ophthalmology. 2007 Jan;114(1):62-8. Epub 2006 Oct 27.