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3. Settas G, Settas C, Minos E, Yeung IYL. Photorefractive keratectomy (PRK) versus laser assisted in situ keratomileusis (LASIK) for hyperopia correction. Cochrane Database Syst Rev(2):CD007112 4. Shammas HJ, Shammas MC, Hill WE. Intraocular lens power calculation in eyes with previous hyperopic laser in situ keratomileusis. J Cataract Refract Surg 2013; 39:739–744 5. Reinstein DZ, Archer TJ, Gobbe M. Refractive and topographic errors in topography-guided ablation produced by epithelial compensation predicted by 3D Artemis VHF digital ultrasound stromal and epithelial thickness mapping. J Refract Surg 2012; 28:657–663

contact lenses to give the patient better optical quality. A surgical treatment would be topography guided. A topography-guided treatment would probably be the best way to reestablish the corneal curvature and restore visual quality if it is possible to proceed with this treatment while respecting safety limits. Newton Kara-Junior, MD, PhD S~ao Paulo, Brazil

- I would have first approached this case with flap relifting. Laser in situ keratomileusis flaps created with a mechanical microkeratome are usually easy to lift, even years after the original surgery. For this patient, this would have been the best option with the best outcomes. I would not consider a new side cut with a femtosecond laser. First, it is difficult to determine an adequate diameter for the new side cut in a hyperopic retreatment. Second, this approach is not free of complications because slivers of tissue can be created and the same complication might occur. If it were a myopic case in which a smaller diameter side cut were possible, this would have been my first option. If flap lift were not possible, I would have treated with surface ablation and MMC 0.02% for 40 seconds. Refractive lens exchange would have been another reasonable option in terms of visual acuity results. In this case I would have chosen a standard spherical monofocal IOL or spherical aberration–neutral IOL to counterbalance the spherical aberration of the cornea after the hyperopic treatment. After the unsuccessful enhancement, I would recommend patience because the epithelium will heal and help make the corneal surface more regular. Before considering surgery, I would prescribe RGP

- This shows the need for case-by-case decisions regarding the type of refractive procedure to use. Because the patient was a 47 year old with presbyopic hyperopia at presentation, our option would have been RLE. We would implant a monofocal IOL to avoid further issues with contrast sensitivity, glare, and haloes in this already complicated eye. A spherical aberration– neutral or spherical IOL would be preferred. We would try to convince the patient to have RLE; if she adamantly declined, the next safer option would be advanced surface ablation, despite the higher incidence of regression. A larger treatment zone with a transition zone extending up to 9.5 mm often prevents regression that may otherwise occur secondary to sudden transitions between ablated and unablated corneas. Newer machines and algorithms with topography- and wavefront-guided treatments offer good outcomes for low to moderate hyperopia (!+5.00 D). With hyperopic LASIK and advanced surface ablation, care must be taken to avoid small optical zones and decentration, which cause loss of CDVA. With enhancements, it is necessary to avoid issues that make the situation worse. A decentered primary ablation can further worsen the situation. Larger flaps, even up to 10.0 mm, are recommended for hyperopic LASIK, although these may be difficult to create in small eyes. The smaller 8.5 mm flap used in this case

Figure 4. A: Similar case in which a thinner femtosecond laser–created flap was cut in a 7-year-old microkeratome flap. This shows the femtosecond flap being dissected. B: The posterior part of the old flap was accidentally dissected while trying to lift the flap from the opposite side. C: The posterior portion of the old flap was carefully and gently laid back and excimer laser ablation performed. The final UDVA was 20/20 3. J CATARACT REFRACT SURG - VOL 40, JUNE 2014

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could have contributed to the suboptimum results because of the smaller optic and transition zones. Creating a second flap above the first flaps often results in the 2 flaps intersecting or accidental lifting of the original flap during attempts to dissect the second flap (Figure 4). In this scenario, one must be extremely careful to avoid tearing the tissue that joins the 2 interfaces. If required, the procedure can be abandoned and a surface ablation performed later. Theoretical calculations of the safe gap between the original flap and new flap are often not practical because the old flap can be damaged during flap lifting. Microkeratome flaps are usually not planar, and depending on the type of microkeratome used during primary LASIK, the flap could be uneven in depth along its extent. This lack of uniformity in the depth of the old interface further increases the risks associated with creating a shallower, new flap and allows errors in theoretical calculations of the safe depth. If the location of the old hinge is known or can be seen, reverse-direction sub-Bowman keratomileusis could be performed with a microkeratome (ie, plan the hinge 180 degrees from the previous hinge). This would provide a sharp, smooth cut away from the direction of the hinge and therefore would likely not lift the old flap. This is unlike a femtosecond laser–created flap, which has to be manually dissected, leading to a higher chance of disturbing the old flap. If the original regression were myopic, our first option would still have been RLE. However, if the patient declined, it would have definitely made the choice of advanced surface ablation as the next choice easier. The present management in this case depends on the final refraction and CDVA. We would allow more time to pass before deciding on any other form of treatment. Brimonidine tartrate 0.2% eyedrops could be used in the meantime to decrease scotopic pupil dilation and scotopic symptoms. If the CDVA improves to 20/20, we would prefer RLE at this stage. If not, an RGP contact lens would probably solve many of the patient's symptoms.

EDITOR’S COMMENTS Residual refractive errors are relatively common after LASIK, especially after hyperopic treatments. Optimum refractive surgery outcomes often necessitate that eyes treated with LASIK have a reoperation (enhancement) to yield the best possible vision and maximum independence from glasses or contact lenses. Relifting the flap is the most common retreatment procedure, and studies suggest it has advantages, including increased safety, over recutting the flap–lamellar interface for LASIK retreatment. In this case, most respondents would have attempted a flap lift as the first approach. If the flap lift were really not possible, surface ablation with MMC was regarded as an adequate option despite the risks for regression. Some respondents considered the option of a femtosecond laser side cut only as an alternative, and the bulk of the respondents considered RLE to be an excellent approach. Although not free of complications, these would have been interesting approaches considering safety, the patient's age, and the predictability of the treatment. Another interesting point in this case is that for RLE, a standard nonaspheric or neutral monofocal IOL would have been the model of choice in an attempt to counterbalance the negative spherical aberration induced by the hyperopic treatment. As far as how to approach the case after the unsuccessful enhancement, a topography-guided surface ablation would make the cornea more even and improve the irregular astigmatism. There also seems to be an agreement that a conservative approach, such as RGP contact lens, would allow time for epithelial remodeling to fill in the areas of stromal tissue loss, which would probably have a significant impact on visual acuity.

Amar Agarwal, MS, FRCS, FRCO Soosan Jacob, MS, FRCS, DNB Chennai, India

Marcony R. Santhiago, MD, PhD Rio de Janeiro, Brazil

J CATARACT REFRACT SURG - VOL 40, JUNE 2014

June consultation #8.

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