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considered surface ablation even with its higher chances of regression? What would have been your approach if the original regression were myopic? How about refractive lens exchange (RLE)? After the unsuccessful enhancement in the left eye and considering that the curvature maps do not necessarily match the stromal curvature, how would you approach this case?

conservative approach and would give time for the cornea to remodel completely while improving visual function. Sonia H. Yoo, MD Miami, Florida, USA Dr. Yoo is a consultant to Alcon, Abbott Medical Optics, and Carl Zeiss Meditec. REFERENCES

- It has been reported that approximately 5% to 28% of patients who have LASIK require enhancements.1 Factors associated with retreatment include age greater than 40 years, high initial refractive errors, high astigmatism, and primary LASIK for hyperopia. So, it is not surprising that this patient ultimately required an enhancement. Strategies for retreatments include surface ablation, cutting a new flap, and flap relifting. Although surface ablation can be associated with postoperative haze and regression and flap relifting with epithelial ingrowth, these problems can be minimized by the application of intraoperative mitomycin-C (MMC) and use of a femtosecond laser to create a new side cut to the level of the old LASIK interface.2 Even in the case of epithelial ingrowth after LASIK retreatment, the visual acuity outcomes are generally good for patients who require flap lifting and scraping of the epithelial cells in the interface.3 My choice for retreatment of this patient would have been surface ablation with MMC or a new femtosecond laser–assisted side cut and flap lifting. I would prefer not to perform RLE in a 47 year old who still has some accommodative amplitude and who would not be an ideal multifocal intraocular lens (IOL) candidate given the previous hyperopic LASIK. This case highlights the difficulties that can arise from cutting a new flap for LASIK enhancement. Loss of slivers of tissue in the stroma can cause irregular astigmatism and loss of CDVA. At present, epithelial remodeling is helping fill in the areas of stromal tissue loss, and waiting another 6 to 12 months may lead to improved CDVA. Topography-guided surface ablation, not available in the United States, might be an option to improve the irregular astigmatism. If the stromal bed were thick enough, another therapeutic option might be to amputate the flap and then perform phototherapeutic keratectomy with MMC. It is likely, however, that the patient would require another refractive correction once the irregular astigmatism improved. Finally, use of a rigid gaspermeable (RGP) contact lens would be a more

1. Hersh PS, Fry KL, Bishop DS. Incidence and associations of retreatment after LASIK. Ophthalmology 2003; 110:748–754 2. Vaddavalli PK, Yoo SH, Diakonis VF, Canto AP, Shah NV, Haddock LJ, Feuer WJ, Culbertson WW. Femtosecond laser–assisted retreatment for residual refractive errors after laser in situ keratomileusis. J Cataract Refractive Surg 2013; 39:1241–1247 3. Henry CR, Canto AP, Galor A, Vaddavalli PK, Culbertson WW, Yoo SH. Epithelial ingrowth after LASIK: clinical characteristics, risk factors, and visual outcomes in patient requiring flap lift. J Refract Surg 2012; 28:488–492

- Surgical management of residual errors by excimer laser photoablation (enhancement) can be performed by lifting the flap, by cutting a new flap, or by surface ablation. I have successfully lifted flaps 10 years after primary LASIK. Potential problems associated with lifting flaps include the increased risks for epithelial ingrowth and diffuse lamellar keratitis. It is also possible that subepithelial fibrosis, flap tears, and striae occur at a higher rate with lifting than with recutting. The key issue is that most complications that can occur with flap lifting are generally reversible, self-limited, or treatable. Another reason lifting may be preferred over recutting is the possibility of future enhancements. I would not recommend cutting a new flap, and an 8.5 mm flap diameter is not large enough for hyperopic eyes. Although the method of relifting the old flap and treating the residual refractive errors appears to be safer than flap recutting and is the standard of care for retreatment, it has a much higher incidence of epithelial ingrowth than primary LASIK, with reported rates varying from 1.7% to 12.7%. Even with retreatments, the incidence seems to be lower in eyes with flaps created with a femtosecond laser (1.8%) than in eyes with flaps created with a microkeratome (12.7%).1 This is believed to be due to the vertical configuration of the side cut created by a femtosecond laser. Tran et al.2 propose a new method of LASIK retreatment in which a new side cut is created with a femtosecond laser, with the new cut reaching up to the old interface. Creating a new side cut in the old flap margin to facilitate flap lifting potentially reduces the incidence of epithelial ingrowth.3

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Enhancement with surface ablation is not advantageous; because the cornea was previously deformed, subsequent excimer laser treatment would induce further spherical aberration. In addition, high hyperopic ablations are prone to regression and irregularity and have limited predictability. In cases of recurrent hyperopia after LASIK, RLE may be the best option. I would prefer a monofocal IOL for both eyes. Requirements for a multifocal IOL were not met in this case. There was no chance of excellent biometry, and a normal prolate cornea and good binocular function were not present. Standard monofocal IOLs have positive spherical aberration and can therefore partially compensate for the negative spherical aberration induced by the previous hyperopic ablation. Intraoperative autorefraction is useful after excimer laser surgery. I would consider lamellar graft surgery in this case of unsuccessful enhancement. Aylin Kılıc¸, MD Istanbul, Turkey

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approach is always successful. If creation of a new flap were required, I would have used a mechanical microkeratome to create a wider, deeper flap. It takes some force to lift a femtosecond laser–created flap, and the force might tear the corneal tissue. A microkeratome-created flap can be easily lifted without force. Because making a second cut, even with a microkeratome, does not completely prevent the formation of a thin sliver of tissue, I always try to lift the previous flap unless it is incomplete, too small, or dislocated. Photorefractive keratectomy (PRK) might be an option; however, hyperopic PRK in eyes with previous LASIK would have a high risk for subepithelial haze and regression. I would rather perform RLE if the patient does not want to risk flap complications. If this were a case of myopic regression, I would also try to lift the original flap. Alternatively, if I could determine the flap margin and approximate depth, I would create only a side cut inside the original flap margin using a femtosecond laser to prevent epithelial ingrowth. Ikuko Toda, MD, PhD Tokyo, Japan

REFERENCES lu G, Ertan A. Epithelial ingrowth after femtosecond 1. Kamburog laser-assisted in situ keratomileusis. Cornea 2008; 27:1122– 1125 2. Tran DB, Binder PS, Brame CL. LASIK flap revision using the IntraLase femtosecond laser. Int Ophthalmol Clin 2008; 48(1):51– 63 3. Vaddavalli PK, Yoo SH, Diakonis VF, Canto AP, Shah NV, Haddock LJ, Feuer WJ, Culbertson WW. Femtosecond laser-assisted retreatment for residual refractive errors after laser in situ keratomileusis. J Cataract Refractive Surg 2013; 39:1241–1247

- I would not have performed hyperopic LASIK in this patient who required more than +3.00 D of correction because of the possibility of regression and decreased quality of vision. Hyperopic correction by LASIK induces higher-order aberrations and sometimes results in loss of CDVA (with spectacles) and symptoms such as halo and glare. I would have suggested implantation of phakic IOLs (pIOLs) to this patient. However, patients with hyperopia often have a shallow anterior chamber and are thus not candidates for pIOLs. In that case, I would suggest multifocal contact lenses and wait to perform cataract surgery with implantation of multifocal IOLs. If this patient presented to me after initial hyperopic LASIK, I would try to lift the original flap. In my experience, flap lifting is always possible, even when the flap margin cannot be seen on slitlamp examination. I use fluorescein staining and/or light pressure at the peripheral cornea to find the flap margin. This

- I believe the risk related to creation of a new flap became too high from the moment the surgeon was not able to properly identify the edges of the flap. Often, preoperative high-resolution corneal optical coherence tomography (OCT) is helpful in this identification. Therefore, my primary approach for this patient would have been to perform personalized PRK with MMC 0.02% applied for 30 seconds, although the risk for regression and decentration might be relatively significant based on the excimer laser used. However, creating a new flap without properly identifying the limits of the old one can lead to more severe complications, such as deterioration in visual quality due to double interface syndrome. Furthermore, the new flap can be cut inside the old one, which is likely to create a buttonhole. Irregular astigmatism can also appear if the old flap slips or the new one is not positioned properly. Finally, attempting to relift an old flap created with a mechanical microkeratome creates a major risk for epithelial ingrowth. Refractive lens exchange might be a reasonable approach considering the high chance of regression and induced postoperative dryness. However, monovision with a monofocal IOL after a contact lens trial to test the patient's satisfaction and tolerance to monofocality is preferred over a multifocal IOL approach. The implantation of a multifocal IOL behind a

J CATARACT REFRACT SURG - VOL 40, JUNE 2014

June consultation #3.

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