By The Right Contact Team http://www.therightcontact.com
Although optometrists do not perform laser vision correction here in the United States, they can still provide a valuable role in this procedure that is gaining unprecedented popularity. According to recent data, a record 16 million people have had LASIK vision correction in the US though 20111. This is an amazing opportunity for optometry. Whether it is screening good candidates, co- managing post-ops or managing complications, there is a lot the optometric profession has to offer.
There many issues that a practitioner should review when considering candidacy for laser vision correction. The following are a few concerns to be addressed prior to referring the patient for the procedure. ◦ Candidacy as defined by the FDA ◦ Anterior surface concerns ◦ Patient habits
Who is a good candidate for laser vision correction?Since its FDA approval in 19952, many factors have remainedunchanged INDICATIONS *Age 18 years of age or older with stable refraction for one year. *Myopia (nearsightedness) up to -14 diopters either without astigmatism or from -0.5 to -5 diopters of astigmatism *Hyperopia (farsightedness) from +1 to +4.5 diopters with less than 1 diopters of astigmatism *No history of eye disease, corneal scarring or retinal problems *Not pregnant or nursing for 3 months and not planning a pregnancy in the 3 months following surgery CONTRAINDICATIONS Laser refractive surgery is contraindicated: * in patients with collagen vascular, autoimmune or immunodeficiency diseases. * in pregnant or nursing women. * in patients with signs of keratoconus or abnormal corneal topography * in patients who are taking one or both of the following medications: isotretinoin (Accutane®) or amiodarone hydrochloride (Cordarone®).
Dry Eye Ideally you want to identify dry eye during the pre-op period Spend at least a few weeks to months treating it. Utilizing tools such as artificial tears, punctal plugs, cyclosporine eye drops and nutritional therapy (omega-3 fatty acids) 3 can prove very useful.Blepharitis Laser vision correction causes significant inflammation in normal eyes. Consider the consequences surgery can have when handling patients that already suffer from anterior surface disease. Treatment options include ◦ oral tetracycline ◦ topical macrolide antibiotics ◦ combination steroid/antibiotic drops ◦ nutritional options (such as flaxseed oil). 4
Does the patient work or live in environments of excessive heat? Does the patient suffer from allergies or habits that pre-dispose them to eye rubbing? Avoiding these issues can greatly affect the potential outcome of the procedure.
Most surgeons recommend a very specific follow-up schedule to ensure proper healing. An average schedule would include ◦ 1st day ◦ 1st week ◦ 1st month ◦ 3 – 6 months Each post-op appointment has very specific concerns that are to be addressed. Each visit should take the opportunity to re- educate the patient on their status and the overall healing process.
During this visit, the practitioner will access vision and make a corneal evaluation. The corneal evaluation will obviously vary depending on the procedure performed. ◦ If the patient has undergone LASIK, than flap evaluation will take place. ◦ If PRK or LASEK was performed, the corneal evaluation will be done under the bandage contact lens. Patient instruction is very specific at this visit. ◦ Remind the PRK and LASEK patients that discomfort within the first few days is common but will subside. After a discussion about all topical post-op medications, patient’s activities need to be discussed. Aggressive rubbing should be addressed. ◦ The patient should be discouraged from performing any tasks that could potentially hit the eye. Be specific, state avoiding things like water striking the eye during bathing, make-up (no mascara or eyeliner), sports, and exercise. The patient should wear a protective shield at night. Provided the vision is adequate, the patient is definitely able to resume deskwork or driving immediately.
At this visit a re-assessment of vision and corneal integrity is taken. As compared to their first post-op, patients that underwent PRK and LASEK should note a dramatic increase in comfort and vision. Many times topical medications are discontinued at this visit. The patient is often informed that they can begin a moderate level of activities including exercise, swimming, hot tubs and contact sports.
The 1 month post-op evaluation again evaluates the vision and corneal surface. At this stage the cornea should be completely attached and the patient is able to resume all activities. ◦ These activities would include those that were previously restricted such as gardening, scuba diving, etc.
These visits are routine health evaluations. At this time, many doctors will have to manage issues associated with dryness.
When discussing any type of surgery you always have to be aware of the risks associated with the procedure. Even though laser vision correction has a very good track record, sometimes there are unfortunate results that have to be addressed. The following is a listing of possible complications that can occur with laser vision correction.
Doctors are trained not to be over concerned about initial signs of overcorrection. ◦ This is because immediate post-ops can show correction issues secondary to expected corneal swelling. ◦ The patient should be educated that these symptoms will subside within a few days to two weeks. Despite extensive pre-testing, sometimes the eyes do not respond in a predictable fashion. Regardless of the reason, the patient still has options. ◦ If the patient is interested in additional surgery, an enhancement may be considered. ◦ Non-surgical treatment options include glasses and contacts.
Visual distortion can arise from several areas. Quite often this is related to the size of the treatment zone5. ◦ If the pupil is wider than the treatment zone the patients may report glare or haze. Retreatment is a possibility, but optic zone size can also be addressed with topical drops. ◦ The patient may be given a drop that has mitotic effects for things like night driving.
During surgery, if the flap is not made correctly, either to thin or to thick, it may not correctly adhere to the corneal surface. ◦ This can cause microscopic wrinkles, or striae which will interfere with the patient’s visual outcome. Wrinkles may also occur due to patient compliance issues. A patients rubbing or squeezing the eye too tightly within the first few hours of the procedure could also result in wrinkles. ◦ Patients should be discouraged from this behavior for the first 24-48 hours after the procedure.
Epithelial ingrowth is another rare but potentially serious complication. ◦ Studies continue to show that early detection is vital. ◦ The use of optical coherence tomography has proven to be a useful tool in diagnosing this abnormal finding6. Not all cases of epithelial ingrowth need to be treated and therefore careful monitoring is required. Surgical removal of epithelial accumulation is indicated before the formation of a scar7.
Diffuse lamellar keratitis (Sands of Sahara) is accumulation of white blood cells between the flap and stroma. These cells develop at the stromal interface and create unwanted inflammation. ◦ This presentation is usually evident 1-5 days after LASIK but can occur many months after the procedure8. ◦ With slit-lamp evaluation this finding appears as waves of sand. ◦ Patients present with pain, photophobia, foreign body sensation, and /or decreased vision. The cause of diffuse lamellar keratitis is unknown. ◦ These infiltrates are sterile, but the cornea attacks them causing serious damage. Because these infiltrates are not alive, these cells are able to elude proper sterilization techniques. Quick diagnosis is a must, and topical or oral treatment is often adequate. Common treatment would include topical antibiotics and steroids. ◦ Accepted dosaging is every 2 hours on both, and possibly an ointment at night. ◦ If topical treatment is inadequate re-lifting the flap, and removal of the infiltrates may be required.
Subconjuntival hemorrhages ◦ These often occur with no long term side effects. ◦ No topical treatment is required. ◦ The most important issue would be educating the patient on its presentation.
Keratectasia is a very difficult complication to mange. This finding results in an increase in refractive error due to the progressive steepening of the cornea9. Corneal ectasia can occur as quickly as one week after the procedure but can also manifest several years post-operatively. Managing this condition may eventually begin with specialty contact lenses, but may mature to the need for additional surgery like a penetrating keratoplasty or intacs10.
Technology continues to advance. One of the more recent advances would involve wave front technology. These methods now allow for an extremely precise individualized vision correction. ◦ The procedure addresses higher order aberrations, something earlier designs couldn’t come close to affecting. Post-operative care is also being modified. Researchers are looking at developing contact lenses designed to release a continuous supply of medication during the post-op period. These designs use vitamin E to help release the drugs automatically overtime11. Although optometrists cannot perform the procedure, as you can see, we can play quite an active role in the patient pre- and post care.
1. 2011 Market Scope, LLC2. FDA. (2010). FDA-Approved Lasers for PRK and Other Refractive Surgeries. Retrieved from http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/SurgeryandLifeSupport/LASIK/ucm192110.htm3. Saadia Rashid, MD; Yiping Jin, MD, PhD; Tatiana Ecoiffier, MSc; Stefano Barabino, MD, PhD; Debra A. Schaumberg, ScD, MPH; M. Reza Dana, MD, MSc, MPH. Topical Omega-3 and Omega-6 Fatty Acids for Treatment of Dry Eye. Arch Ophthalmol. 2008;126(2):219-225.4. Goldman D. Treating blepharitis to maximize surgical success. Cataract Refractive Surgery Today. 2009 May:61-3.5. Gregory W. Schmidt, MD; Michael Yoon, MD; Gerald McGwin, PhD; Paul P. Lee, MD, JD; Stephen D. McLeod, MD. Evaluation of the Relationship Between Ablation Diameter, Pupil Size, and Visual Function With Vision-Specific Quality-of-Life Measures After Laser In Situ Keratomileusis. Arch Ophthalmol. 2007;125(8):1037-1042.6. Alissa Coyne, O.D., and Joseph Shovlin, O.D.AS-OCT Technology: Analyzing the Anterior Segment. Review of Optometry. Continuing Education. April 2012;7. Irene Naoumidi, PhD; Thekla Papadaki, MD; Ioannis Zacharopoulos, MD; Charalambos Siganos, MD, PhD; Ioannis Pallikaris, MD, PhD. Epithelial Ingrowth After Laser In Situ KeratomileusisA Histopathologic Study in Human Corneas. Arch Ophthalmol. 2003;121(7):950-955.8. Bennie H. Jeng, MD; Jay M. Stewart, MD; Stephen D. McLeod, MD; David G. Hwang, MD. Relapsing Diffuse Lamellar Keratitis After Laser In Situ KeratomileusisAssociated With Recurrent Erosion Syndrome. Arch Ophthalmol. 2004;122(3):396-398.9. Beeran Meghpara, BA; Hiroshi Nakamura, MD; Marian Macsai, MD; Joel Sugar, MD; Ahmed Hidayat, MD; Beatrice Y. J. T. Yue, PhD; Deepak P. Edward, MD. Keratectasia After Laser In Situ KeratomileusisA Histopathologic and Immunohistochemical Study. Arch Ophthalmol. 2008;126(12):1655-1663.10. George D. Kymionis, MD, PhD; Charalambos S. Siganos, MD, PhD; George Kounis, BSc; Nikolaos Astyrakakis, OD; Maria I. Kalyvianaki, MD; Ioannis G. Pallikaris, MD, PhD. Management of Post-LASIK Corneal Ectasia With Intacs InsertsOne-Year Results. Arch Ophthalmol. 2003;121(3):322-326.11. Peng CC, Burke MT, Chauhan A. Transport of topical anesthetics in vitamin e loaded silicone hydrogel contact lenses. Langmuir. 2012 Jan 17;28(2):1478-87. Epub 2011 Dec 22.