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Refractive surgical correction in amblyopia requires careful patient counseling
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Evaluate relative nature of amblyopia
 Steven B. Siepser |
Steven B. Siepser, MD, FACS: Amid the ever changing field of refractive surgery, my approach in dealing with “amblyopia” has evolved from time honored conventional methodology.
In the early days of refractive surgery, it was traditionally accepted that amblyopic patients were not considered candidates for surgery, and definitely not LASIK. My thinking began to change when patients with nystagmus and higher refractive error improved several lines after undergoing LASIK.
As positive results grew treating progressively greater levels of low vision nystagmus, my guidelines in caring for amblyopia became more liberal. Unequivocal clinical evidence led me to have a more progressive “operate and see” attitude. I am not an optics specialist, but it is easy to interpret positive clinical results.
In 2000 an opera star who could not tolerate her contacts nor wear glasses on stage came to our center. She was a 20/40 amblyope with high anisometropic myopia. I thought that she would be an excellent candidate, as she could still perform if catastrophe struck and she was left with only one amblyopic eye.
After surgery for her -8 D amblyopic eye, she improved two lines of vision to 20/25. From then on, my policy was if I could count on a patient having their worst eye seeing at least 20/40 or better after surgery, I would proceed.
With the use of Lotmar interferometry (manufactured by Haag-Streit), we found that some 20/200 amblyopes could perform at the 20/60 level, and those with 20/80 potential or better turned into 20/40 eyes after LASIK.
I came to use a graduated model incorporating the “relative” nature of amblyopia. The higher the myopia and greater the astigmatism or anisometropia, the higher I could go on my preoperative interferometry potential to get me to the important 20/40 level. Thus, if there was a 1/400,000 chance of a legal blindness outcome in one eye, the other eye could accommodate for most functions in our visual world, including driving.
Historically, patients had denser forms of untreated amblyopia. The present generation of amblyopic patients have usually been diagnosed and treated earlier than previous generations. Thus, patients with amblyopia have often had patching during their youth, which may have contributed toward some visual acuity gains at that time and a visual potential higher than previously found with never treated amblyopes. These individuals have been quite circumspect about moving forward with surgery because all of their lives they have heard that nothing could be done. This is no longer the case. Refractive procedures are now viable options.
It is gratifying and exciting for me to perform surgery improving limited vision whereas a short time ago such procedures were unavailable. The remaining problem, however, is encouraging patients to accept the relative risk. We are now quite positive with this technology and have even added ICL candidates to the list.
To best educate our patients, doctors must pool their anecdotal clinical findings to create objective documentation. Statistically significant analyses and results will help us counsel patients so they can make a well informed decision.
For more information:
- Steven B. Siepser, MD, FACS, can be reached at Siepser Laser Eyecare, 860 E. Swedesford Road, Wayne, PA 19087; (610) 265-2020; cell: (215) 990-1000; fax: (610) 265-4054; ssiepser@clear-sight.com. Dr. Siepser has no direct financial interest in the products he mentions, nor is he a paid consultant for any companies he mentions.
Consider the patient’s binocular status
 Sondra Black |
Sondra Black, OD: Amblyopia can present in many different forms, so the first issue is to establish the degree of amblyopia and the cause. Dealing with mild refractive amblyopia is different than dealing with the patient who has best corrected visual acuity of less than 20/40.
We will never treat a patient’s other eye if the BCVA on the amblyopic eye is 20/40 or worse. We consider that patient to be monocular and do not believe it is a risk worth taking. Sometimes that same patient will come in requesting only the amblyopic eye to be treated. This is usually to “balance” the glasses. The concern here is obviously the ramifications of taking a patient who has likely been suppressing for years and then trying to make their brain deal with multiple images. We will generally ask for a contact lens trial to simulate the result or a binocular vision consult.
The other amblyope that we will not treat is one with a constant strabismus. Regardless of the BCVA in each eye, that patient is also considered monocular and thereby a non-candidate.
How about the patient who is 20/20 BCVA in one eye but 20/30 in the other? Although that patient theoretically can still drive with his or her amblyopic eye according to the Department of Motor Vehicles, are they truly functional?
The best test is to have the patient cover the better eye. Ask him or her if they had to, would they be able to function with the vision they have out of the other eye? Nine times out of ten, they will tell you no. If not, again, we will not treat.
If the patient is mildly amblyopic and feels totally functional out of that eye, then we will treat the amblyopic eye first. We will go forward with treatment of the other eye only if the healing was normal and there was no loss of BCVA.
We generally like to separate the two eyes by several weeks. The patient is forewarned that if there is any type of healing abnormality with the amblyopic eye there will be no further treatment.
On any amblyopic patient, we will move forward only using wavefront-guided technology. This increases the chances of improving BCVA and decreases the risk of a healing problem.
In conclusion, there is no steadfast rule. Every patient gets treated and counseled differently depending on the case. It is also important to remember the binocular status of the patient and not merely look at the visual acuity. Taking a patient who has lived his or her whole life virtually monocularly and attempting to make them binocular could result in a patient who suffers from constant diplopia. Look at the whole picture before considering treatment on amblyopes. They are generally not ideal candidates.
For more information:
- Sondra Black, OD, is regional clinical director of TLC Mississauga. She can be reached at 50 Burnhamthorpe Road W., Suite 101, Mississauga, Ontario L5B 3C2; (905) 848-9562; fax: (905) 848-8750; e-mail: sondra.black@tlcvision.com.
Carefully manage patient expectations
 Thomas Chester |
Thomas Chester, OD, FAAO: When working with refractive surgery patients, setting the appropriate level of expectations is crucial. With amblyopic patients considering refractive surgery this is no less important because most of these patients are interested in undergoing refractive surgery to improve the vision in their amblyopic eye. Unfortunately, most patients are unaware of the etiology of their amblyopia and believe that LASIK will make them 20/20.
During the preoperative examination, the source of amblyopia (deprivational, strabismic or ametropic) should be identified and explained to the patient. The preoperative discussion should then describe how the “wiring” has been set since childhood and, with the optimal result, refractive surgery will merely provide the same best corrected vision as spectacles, but without the dependence on them. If the patient is not willing to accept this level of expectation, elective refractive surgery of any kind should not be performed. Granted, there have been several studies indicating that refractive surgery has shown slight improvements in vision with anisometropic amblyopic eyes, but the importance of setting realistic expectations cannot be minimized.
During the same preoperative discussion, patients should also be made aware that if their amblyopic eye is significantly compromised (that is, not the legal limit to drive), they are encouraged to wear spectacles for protection of the good eye, despite refractive error. This is also the time to mention the increased level of risk for the nonamblyopic eye because the patient is having an elective procedure on their only “good” eye. In the extremely rare chance that a complication occurs, the patient has a higher risk of having nonfunctional vision.
Once the patient understands and agrees with the appropriate desired result, the procedure discussion can begin. With the amblyopic patient, an emphasis should be placed on the safety of the procedure options. It is important for the patient to understand the differences and inherent risks associated with microkeratomes, laser microkeratomes and laser ablation.
With that being said, I would recommend that the patient proceed with an “all laser LASIK,” using a laser microkeratome, or photorefractive keratectomy. This will help limit the possibility of intraoperative complications.
It is also important to evaluate patients relative to refractive error and keratometry readings to decrease refractive complications. Patients who are highly myopic or highly hyperopic as well as patients with flat K readings (myopes) and steep K readings (hyperopes) should be avoided due to the potential loss of best corrected vision.
The most conservative treatment plan would be to wait several weeks between procedures to determine healing. This may be more important with photorefractive keratectomy because it has a slightly longer healing time and requires reepithelialization. However, if the procedures are performed bilaterally, the ambyopic eye should be done first to determine if any intraoperative issues exist.
The postoperative course for amblyopic patients should be similar to nonamblyopic patients, with the continuing emphasis placed on expectation management. Patients should be given the after-hours emergency number and be advised to call if any changes occur during the postoperative period.
For more information:
- Thomas Chester, OD, FAAO, is clinical director of the Cleveland Eye Clinic. He can be reached at 2740 Carnegie Ave., Cleveland, OH 44115; (216) 621-6132; fax: (216) 621-2803; e-mail: drchester@clevelandeyeclinic.com.
Discuss expected outcomes
Arthur A. Medina Jr., OD: I would conduct my preoperative evaluation, with the normal attention to detail, with any patient that has less than 20/20 acuity. I would make a definitive diagnosis. If I could verify that the patient was amblyopic and could document the diagnosis with clinical findings, I would have no reservations with performing refractive surgery on an amblyopic eye. The patient would sign the informed consent documenting the best corrected acuity and the expected outcomes.
I would then counsel the patient indicating that the procedure works well enough on a 20/20 eye, so it should work for an amblyopic eye. I would spend extra time explaining that the preoperative best corrected vision would be the expected best corrected postoperative correction. In my clinical experience I have found that some postrefractive surgery patients with amblyopia have received better than their preoperative corrected vision.
For more information:
- Arthur A. Medina Jr., OD, is a member of the PCON Editorial Board. He can be reached at 1110 McCullough, San Antonio, TX 78212; (210) 225-4141; fax: (210) 229-9400; e-mail: medinaa@airmail.net.
Note severity of amblyopia, age
 Marc Bloomenstein |
Marc Bloomenstein, OD, FAAO: My primary goal in evaluating a patient for refractive surgery is to determine whether he or she has all of the attributes to lead to a healthy and predictable result. The secondary objective is to help the patient get a handle on his or her surgical expectations.
An amblyopic patient is treated no differently than anyone seeking contact lens or spectacle freedom. Because, by definition, the amblyope has no pathology, the rationale is that the patient is limited only by the “perceived” benefit from surgery. I view this no differently than anyone’s best corrected visual acuity. The amblyope is seeing his or her best corrected visual acuity in a slightly less clear manner than a person who is not amblyopic.
The severity of the amblyopia and the age of the patient will dictate my recommendations and consultation. Because an amblyopic patient is limited only by the end point of his or her vision, undergoing refractive surgery should not be a concern. I have the same discussion with myopes about loss of nearsightedness and the advancement of presbyopia.
However, if a presbyope wants to rid themselves of both distance and near prescriptions, this may be a challenge. Monovision discussion with amblyopic patients centers on the depth of the amblyopia in either eye and the compromise the patient is willing to make. Because the vision is split between the two eyes, I want to ensure the patient can function in both arenas before making that decision. Thus, a distance correction may be the only suitable option. Again, presenting this up front will help guide the patient.
For the hyperopic presbyope I believe a great option is a presbyopia correcting lens such as the ReZoom (AMO, Santa Ana, Calif.), ReStor (Alcon, Fort Worth, Texas) or Crystalens (Bausch & Lomb Surgical, Tampa, Fla.). Any of these lenses will provide the amblyope with correctable binocular vision. This option is beneficial because they can maintain the clarity they had with their best correction and will not be limited by the two eyes. The sum of the parts is always greater than the whole.
For more information:
- Marc R. Bloomenstein, OD, FAAO, is a member of the PCON Editorial Board and director of optometric services at Schwartz Laser Eye Center, 8416 E. Shea Blvd., Ste., C-101, Scottsdale, AZ 85260; (480) 483-3937; e-mail: drbloomenstein@schwartzlaser.com. He has no direct financial interest in the products he mentions, nor is he a paid consultant for any companies he mentions.