The phrase “good to go” has worked its way into everyday speech, but its roots are actually in the military, where it denoted that an individual or group was mission-ready. Though the military initially took a skeptical view of refractive surgery for its soldiers and seamen, procedures such as PRK and LASIK are now good to go and mission-ready themselves, and can often allow soldiers to operate more effectively without the need for vision correction. Refractive surgery isn’t suitable in all cases though, and there are rules governing it that refractive surgeons need to be aware of, since some of their patients may want or need refractive surgery in order to enlist. Here’s what you need to know.
In general, the Department of Defense will disallow anyone who isn’t correctable with spectacles to one of the following: 20/40 in one eye and 20/70 in the other; 20/30 in one and 20/100 in the other or 20/20 in one eye and 20/400 in the other.1 However, refractive surgery starts to enter the discussion because particular occupations have more stringent requirements. For example, individuals with flight status or those in the elite special forces must be correctable to 20/20. “This gets to the premise for performing refractive surgery in the armed forces, specifically in aviators,” says David Tanzer, MD, an ophthalmologist in San Diego and a retired Navy flight surgeon who has either directed or participated in several landmark military refractive surgery studies. “It’s because the environmental stresses those warriors face make the wearing of contact lenses and/or glasses much more difficult. For an aviator, G-forces will pull spectacles down off the nose and contact lenses have been shown to occasionally become displaced in an aviation environment. Also, for a special operator, having his glasses broken or developing microbial keratitis from contact lens wear would make him a casualty, unable to do his job and a danger to his team.”
Dr. Tanzer says that for the best chance at a good result, surgeons should use the latest technology. “If at all possible, I’d strongly encourage any civilian surgeon who is performing refractive surgery on a candidate who wants to join the military to use wavefront-guided or wavefront-optimized ablation profiles,” he says. “Conventional profiles should be avoided because of the known issues regarding induced aberrations, specifically spherical aberration. And, if someone elects to perform LASIK, create the flap with a femtosecond laser, preferably with one that allows a reverse-bevel side cut, which has been shown to be stronger than an externally angulated side cut.”2,3
The military makes free refractive surgery available to all its members, but there is a wait list in which certain occupations get priority. In the Navy, for example, those on flight status or dive status (i.e., special forces) are at the top. Because of this and for logistical reasons, there are many warriors who aren’t able to receive refractive surgery in a timely fashion. “So individuals will seek us out, the civilian refractive surgeon,” says Dr. Tanzer. “They may have a deployment coming in three to six months, and they’ve been told their name might not reach the top of the surgery list for another nine to 12 months. However, they don’t want to make their deployment—often their second, third or fourth—wearing glasses or contact lenses.” Dr. Tanzer notes that designated personnel on flight status in the Navy must receive their refractive surgery at a Navy refractive surgery center but anyone else on active duty can have surgery by a civilian surgeon, provided they have received permission from their commanding officer.
Dr. Tanzer says he sees a number of people who want to join the military but need better vision to be able to get the occupation they want. It’s with these patients the civilian surgeon needs to be especially careful, since there are rules regarding what surgeries can be done. Specifically, any incisional refractive surgery, such as corneal transplants, RK, AK or corneal implants will disqualify the applicant, as will refractive lens exchange or pseudophakic status in general (though Dr. Tanzer believes pseudophakia might be handled on a case-by-case basis). Also, even though laser refractive surgery such as PRK and LASIK are allowed, the military retains the right to disqualify a post-refractive patient for a number of reasons, and all the information regarding the procedure has to be presented upon the candidate’s military physical exam.
“A college senior came into my office who wanted to be a naval aviator and he felt refractive surgery could help him achieve that,” recalls Dr. Tanzer. “His refractive error, however, was -9.5 D, and I had to be the bearer of bad news, telling him that not only is his error outside the accepted parameters for being a naval aviator regardless of surgery, but he can’t even join the service: No one can have a refractive error outside of ±8 D.” Additionally, pre-surgical astigmatism can’t exceed
3 D. Navy regulations require that there be at least 12 months between the last procedure and the candidate’s physical to allow the eyes to stabilize (a time interval that varies by branch of service), and there must not have been any complications or interventions as a result of the surgery.
It’s also crucial for the civilian eye surgeon to know that some procedures are allowed only if the candidate gets a waiver beforehand. “I saw another young man in my office three months ago,” says Dr. Tanzer, “He was a senior going to a local college on the Navy ROTC scholarship, and his dream was to become an [explosive ordnance disposal] officer. To achieve that, though, you can’t wear contact lenses. As a -7 D myope, he was surveying his options with regard to refractive surgery in order to be free of contact lenses for the EOD officer training. Unfortunately, his workup showed that his corneas were 460 µm thick.
“I explained to him, though, that he could have an ICL,” Dr. Tanzer continues. “The problem is that phakic IOLs aren’t allowed for someone who is not already on active duty, which he technically wasn’t. I told him if I were to implant ICLs, the Navy would have the option to essentially kick him out of the program. I recommended he discuss it with his recruiter and request a waiver so we could consider the ICLs. A month later, he completed the waiver process, received permission, and we performed bilateral, simultaneous ICL surgery on him. He had a great result. He was 20/15 uncorrected in each eye on day one postop and with a perfect vault between the ICL and the crystalline lens. He’s been accepted for entrance into the EOD officer training program upon graduation. Words can’t describe how good I felt.”
In the military, lens surgery is approached a bit differently. “The caveat is anyone on flight status,” he says. “If an aviator has a lens-based procedure, multifocal IOLs are not allowed because of the known decrease in contrast acuity and the potential for glare and halo.” He did, however, successfully implant an aspheric accommodating monofocal lens in a Navy SEAL who had developed a visually significant cataract. Dr. Tanzer says he recently ran into this patient and he reported his eyes were still doing great. “This is yet another example of our ability to take the outstanding technology available to us as ophthalmologists and use it appropriately in these motivated individuals to keep them doing what they are trained to do,” Dr. Tanzer says. “I derive a tremendous amount of satisfaction in being able to do that as a civilian surgeon.”
The work military researchers have done on LASIK is making its way to physicians in general, and a large-scale LASIK study Dr. Tanzer performed while in the service is being considered for publication. “The study shows what I consider to be the best results I’ve seen published demonstrating the safety and effectiveness of wavefront-guided LASIK with a femtosecond flap,” he says. “And it was based on those results that LASIK is now allowed as a routine procedure on someone in the Navy on flight status.” REVIEW
1. Department of Defense. Medical standards for appointment, enlistment or induction. Website: www.dtic.mil/whs/directives/corres/pdf/613003p.pdf Accessed: December 10, 2012.
2. Knox Cartwright NE, Tyrer JR, Jaycock PD, Marshall J. Effects of variation in depth and side cut angulations in LASIK and thin-flap LASIK using a femtosecond laser: A biomechanical study. J Refract Surg 2012;28:6:419-25.
3. Knorz MC, Vossmerbaeumer U. Comparison of flap adhesion strength using the Amadeus microkeratome and the IntraLase iFS femtosecond laser in rabbits. J Refract Surg 2008;24:9:875-8.