September 2013

 

COVER FEATURE

 

Refractive challenges and innovations

LASIK complications and creation of a free cap


by Ellen Stodola EyeWorld Staff Writer

   
LASIK procedure

Dr. Desai experienced a complication during a LASIK procedure when a free cap was created that was about 128136 microns in depth, with a diameter of 5 mm centered on the cornea. Source: Neel Desai, MD

When complications occur, knowing how to deal with the issue and a patient's visual goals are key

When performing LASIK and other procedures, there is always the possibility of a complication, and complications must be handled accordingly to try to ensure the best possible outcome and satisfaction of the patient. Neel Desai, MD, director of cornea and refractive surgery, Eye Institute of West Florida, Largo, Fla., described a complication that occurred during a LASIK procedure on a presbyopic personal injury attorney when a free cap was created. Louis Probst, MD, national medical director, TLC Laser Eye Centers, Westchester, Ill., and James Salz, MD, clinical professor of ophthalmology, University of Southern California, Los Angeles, commented on the specifics of the case and how they might have reacted in this situation.

Case background

Dr. Desai's 44-year-old female myopic patient came to him for a LASIK evaluation, wanting to be spectacle and contact lens independent for both distance and near vision. The patient's manifest refraction was 4.00 sphere OD and 3.75 sphere OS, and both crystalline lenses were clear. Dr. Desai had a discussion with the patient about the options, including clear lensectomy with presbyopia-correcting IOLs versus the LASIK options, but since she had previously used monovision contact lenses, she was determined to have LASIK for monovision. Both femtosecond-assisted LASIK and conventional LASIK options were offered, but the patient elected to have flaps created with a traditional microkeratome, as her friends and family had previously.

When LASIK was performed, in this case with an Amadeus II microkeratome (Ziemer Ophthalmic Systems, Port, Switzerland) with a 140-micron head, the dominant right eye saw no complications. However, during flap creation in the non-dominant left eye, a 5 mm shallow free cap was created due to loss of suction. "The treatment was aborted and the free cap replaced, irrigated, and realigned," Dr. Desai said. "Weck-Cel spears were used to wick away interface fluid at the edge of the cap to aid in adherence. A bandage contact lens was placed for seven days." Postoperatively, the patient's right eye was plano and 20/20+, while the left eye MRx was 3.25 to 20/20. The free cap had healed well without striae or epithelial ingrowth.

Free cap details

Dr. Desai said an anterior segment OCT showed that the free cap was about 128136 microns in central depth, with a diameter of 5 mm centered on the cornea, rendering a second, deeper femto flap a risky option in his estimation. "Even though the LASIK treatment was aborted, the change in refraction suggests that the keratometry was significantly impacted by the free cap alone." Secondary PRK was considered but found less attractive due to the free cap depth, diameter, and risk of further complications with a treatment zone wider than the thin-edged free cap and the inherent risk of epi-ingrowth. "Due to flap depth, the patient was encouraged to reconsider lenticular-based options, so as to avoid potential further complications with attempted corneal refractive surgery," he said.

Reaction to surgery choice and the free cap

Dr. Salz said that he believes the choice to do a LASIK procedure in this case was the correct option. He said he would have chosen LASIK surgery over other lens-based surgeries or refractive lens exchanges. He said other options that involve taking out the lens could increase the risk of a detached retina postoperatively, and there is not that same increased risk with LASIK.

Dr. Salz said he believes the use of the mechanical microkeratome is the major factor contributing to the free cap complication in this procedure. He said in thousands of cases that he has done over the past eight years with the femtosecond, he has never had a free cap. It is possible for a free cap to occur with a femtosecond laser, though Dr. Salz said this is rare. Dr. Salz also emphasized the importance of presenting all possible options to the patient prior to surgery, ensuring a choice is being made based on informed consent. It is important to make sure the patient knows about both the microkeratome and femtosecond laser options, as well as the other procedures.

"Free caps are a recognized complication with the microkeratome," Dr. Probst said. "They are generally associated with extremely flat corneal curvature (<40) or poor suction." However, he said that this type of complication is basically eliminated when using a femtosecond laser. "In this case, the outcome has been excellent as many cases of free flaps can result in induced astigmatism and epithelial ingrowth," Dr. Probst said.

He would counsel the patient and explain that this complication is uncommon, yet it is a recognized complication of LASIK. "I would emphasize that she had achieved an excellent resolution of the complication with preservation of her best corrected vision," he said. Dr. Probst would also explain the many options the patient has moving forward, including PRK, LASIK again, or clear lens extraction (CLE).

Dealing with the patient's refractive goals

With this kind of complication, it's extremely important to take another look at the patient's refractive goals and determine how to proceed.

"I don't think it's wise to take patients who are successful at monovision and try to talk them into more extensive and more risky lens-based surgery," Dr. Salz said. For a patient who has already done well with monovision, he does not think it is wise to do a high risk, expensive procedure.

"The refractive goals of this patient are challenging," Dr. Probst said. "She expressed an interest in monovision and has successfully used monovision in the past, however, we do not know the time period or duration of the monovision trial." He said the patient's age also comes into play because she would just be beginning to see the full effect of presbyopia, which means that a complete monovision experience could still be a few years away.

"Monovision for refractive surgery in general is challenging as it is permanent rather than adjustable as when done with contact lenses, results in a loss of depth perception and night glare, and does not give the same quality or quantity of vision of bilateral distance refraction correction with reading glasses for near vision," Dr. Probst said. Because of this, he said he would attempt to convince the patient to choose an option other than monovision. "If the patient has used monovision contacts for years, I would consider monovision correction but cautiously," he said.

Dr. Probst said that he does not see using a monovision contact in the left eye as an attractive option. "I do not believe that any patient that embarks on the refractive surgery course is ever truly interested in using contact lenses again," he said.

Dr. Desai's reaction and solution to the complication

Reacting to the free cap complication in his LASIK procedure, Dr. Desai chose to do a CLE. "Ultimately, we performed a CLE with bimanual microincisional techniques for monovision targeting assisted by ORA [WaveTec Vision, Aliso Viejo, Calif.], the intraoperative wavefront aberrometer," Dr. Desai said. On postoperative day one, the patient was 20/20 OD, and J1+ OS with a 2.25 refraction as targeted. "In retrospect, I think it would have been to this patient's advantage to consider CLE with presbyopia-correcting lenses from the start, as we originally suggested and as more and more patients are realizing the benefits of the high precision outcomes attainable with one surgery," he said. However, because the patient elected to have LASIK due to her familiarity with it, she elected to avoid an intraocular procedure. Dr. Desai said he has since stopped offering patients the option to have microkeratome-assisted LASIK and promotes the benefits in safety and precision with femtosecond-assisted procedures. "From a patient safety, patient counseling, and a practice management point of view, it doesn't make sense to maintain the microkeratome and even offer this as an option anymore," Dr. Desai said.

Comments on the solution

LASIK article summaryDr. Salz said he agrees with the way the complication was handled. "I agree that I would not do another LASIK procedure, especially with another microkeratome, perhaps creating a double flap and having a lot of trouble," he said. However, he would have approached the problem by doing PRK over that LASIK flap with mitomycin-C and avoided lens-based surgery. He thinks this would have turned out fine for the patient as well. "I've done several PRKs over aborted LASIK flaps," Dr. Salz said. "With mitomycin-C, they do quite well."

He said that it is very important to help the patient understand that there are a few choices in this case. The patient could do nothing and wear contact lenses, have PRK, or have a lens-based surgery, as was the case for this patient. The surgery turned out fine, Dr. Salz said, with the patient regaining her monovision.

Dr. Probst said with the free cap complication, he would not consider another lamellar surgery procedure. "A repeat cut with a microkeratome, even if done with a deeper cut, could result in intersecting wedges of tissue that would cause irregular astigmatism and a loss of best corrected vision," he said. "A femtosecond flap at a deeper level could result in vertical gas break through and another flap complication." Because these would all be bad outcomes, he said the possibilities would be either PRK or CLE.

"While both options are reasonable, I would have chosen custom PRK because of the age of the patient, the clear lenses, and the relative simplicity of the PRK procedure," he said.

Editors' note: The physicians have no financial interests related to this article.

Contact information

Desai: desaivision@hotmail.com
Probst: leprobst@gmail.com
Salz: drjjsalz@gmail.com

LASIK complications and creation of a free cap LASIK complications and creation of a free cap
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