Safety & Training
Corrective Eye Surgery
October 17, 2007 By Tarek M. Sardana MD
What every pilot should know
Tired of wearing glasses while flying? How about contact lenses, not the most convenient option at times! Corrective or refractive eye surgery has come a long way over the past 20 years and is becoming increasingly more common in the civilian aviation community. Most major communities have several facilities that provide corrective eye surgery. Nowadays, much more highly sophisticated technical equipment is utilized, such as lasers, resulting in procedures that are more precise and safer, with faster recovery times. However, corrective eye surgery isn’t necessarily for everyone.
Refractive Surgery Techniques
The basic concept of refractive surgery involves changing the shape of your cornea, which changes where a visual object is focused on your retina (the back of your eye). In people who have ‘perfect’ or normal vision, the point of focus occurs on a small spot on the retina, and you can make small changes to your lens at the front of your eye to fine-tune this focus using the muscles in your eye to change the shape of your lens.
Many pilots do not have perfectly shaped corneas. Some corneas are too flat, resulting in far-sightedness (hyperopia), while others are too pointy or long, causing near-sightedness (myopia). Myopia is by far the more common condition for most people who wear glasses. Other corneas are curved irregularly, causing a condition called astigmatism. For most pilots who do not have perfect vision, your glasses are doing the task of changing your focal point on your retina and this is what refractive corrective surgery will change.
It is important to note that the age-related problem of close-up vision difficulties (called presbyopia) have really nothing to do with the shape of your cornea, as it is the lens of the eye that has become less pliable over time and you are no longer able to shape your lens to focus while reading, hence the requirement for reading glasses.
There are some newer techniques available on the market which involve actually exchanging the refractive lens with an artificial lens in your eye and this can correct both near- and far-sightedness. This procedure is referred to as a “Refractive Lens Exchange.” Another related procedure, the “Implantable Contact Lens” (ICL), is also available at some centres to correct conditions that may be too extreme for laser vision correction. However, it is very important to appreciate that these procedures are not approved by Transport Canada for use on pilots at this time. At present, refractive corrective surgery does not fix the condition of presbyopia, so if you are now wearing bifocals you will still require reading glasses post-surgery.
The two most common techniques performed in Canada to correct vision are Photo Refractive Keratectomy (PRK) and Laser Assisted in-Situ Keratomileusis (LASIK), with LASIK being the more common procedure. PRK involves literally burning or vapourizing the outer layer of your cornea to change the focal power of your eye, while LASIK involves slicing a thin three-sided flap off your central cornea and then reshaping the cornea underneath with a laser. Once the desired shape is obtained the flap is placed back on the cornea and allowed to heal.
It must be appreciated that, as with any surgical procedure, complications do occur, even if they may be rare. Refractive corrective eye surgery has an extremely low significant complication rate, much lower than one percent. However, occasionally potentially vision-threatening complications do occur, including: infection, significant haze development, scarring, night glare, perforation of the eye and prolonged post-operative steroid drop use, which can result in cataracts or glaucoma.
Less serious but more common complications of LASIK include detachment or movement of the flap, resulting in double vision; growth of corneal tissue into the flap; bleeding into the white part of the eye; and technical problems associated with surgical instruments themselves. Very common, but usually temporary side effects include mild irritation, dryness, sensitivity to bright lights and tearing. Despite these possible complications, hundreds of pilots in Canada have had the procedure done. Its cost varies significantly but is usually in the $2,000 range for both eyes. These procedures are generally not covered by provincial health-care plans and in fact are not covered generally by additionally purchased health care/drug plans, so the individual is usually on the hook for the entire fee.
Transport Canada has strict guidelines about flying after refractive surgery which can be found on its Web site at: www.tc.gc.ca/CivilAviation/Cam/eyesurgery.htm
There are significant grounding periods between the withdrawal of eye drops after refractive surgery and medical certification ranging from three to six months depending on the correction required and type of procedure. Generally PRK has a longer grounding period than LASIK, potentially as much as three months longer. The following requirements must also be met in order to return to flying duties:
1. Visual Acuity must meet the required standards.
2. No “haloing,” haze or night vision problems.
3. Refraction and visual acuity remaining stable, as demonstrated by refraction and visual acuity measurements at 3 and 6 months post-surgery.
4. No significant reduction in contrast sensitivity measurements
5. No ongoing medical treatment of the eyes.
6. Completion of specific questionnaire by your vision care specialist (available on the TC Web site).
7. Follow-up report by a vision care specialist 12 months after medical certification.
The FAA also has similar requirements and as such, if you hold a US certificate, please review its specific requirements on its Web site and/or talk to your designated FAA examiner.
NOTE: If you are thinking about joining the Canadian Forces, at present, pilots who have had corrective eye surgery are not being accepted for enrollment.
Before considering refractive corrective eye surgery I would recommend that you do some significant background research so that you can make an informed decision before proceeding with your correction. This would include finding out about your potential eye surgeon, including such information as number of procedures performed, technique utilized, complication rate, cost, etc. Advertisements in local papers often indicate a very low cost for “laser eye surgery.” I would encourage you to find out details as to what is included with the advertised price and what other additional costs you may incur. You may want to speak to former patients and perhaps even get a second opinion. Also, it would be worthwhile discussing your plans with your CAME for guidance from an aeromedical perspective. You only have two eyes and you don’t want to have poorer vision or an annoying side effect after your procedure. A poor outcome may have significant career and financial implications if you are a professional pilot. So do your background work and proceed once you are satisfied that you are making an informed decision. One final note: See if your ophthalmologist wears glasses and if he does, ask him why he hasn’t had the procedure done!
Dr. Sardana is a pilot, a Civil Aviation Medicine Examiner (CAME), Coroner and president of Aviation Medicine International (AMI) Inc. (www.aviationmedintl.com.)
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