A 58-year-old male with an initial myopia of -8.00 D, underwent bilateral radial keratotomy in 1993 and again in 2000. These surgeries left him with 16 radial incisions and some central scarring (Figure 1). In August 2006, the patient presented with a severe overcorrection in his left eye and a bilateral loss of BCVA. His right eye measured 0.50- (BCVA) with 1.00 D sphere and -1.00 D cylinder at 20º. His left eye measured 0.50- (BCVA) with 5.00 D sphere and -1.00 D cylinder at 180º (UCVA 0.20). Topography showed small optical zones (OZs) decentered inferiorly (Figure 2), and a central pachymetry of 649 µm.
Topography-guided LASIK was performed in the left eye, shifting centration of the OZ superiorly and improving BCVA to 0.40- with a -2.00 D sphere (UCVA 0.30-). The patient was unsatisfied with this outcome, and the left eye was retreated 3 months later, which resulted in a central island and a BCVA of 0.10- with a -1.00 D sphere. How would you retreat the left eye?

JAVIER GAYTÁN-MELICOFF, MD, AND JOSÉ L. GÜELL, MD, PhD
This postradial keratotomy patient is a particularly challenging case because of his age and the 16 radial incisions. In our opinion, when planning a laser-assisted enhancement (eg, topography or wavefront-guided) to treat irregular astigmatism, corneal refractive stability should first be confirmed so that postoperative results will be closer to patient and surgeon expectations. As we are all aware, a cornea may develop instability after excessive incisional surgery. In this case, central scarring (Figure 1) and possible diffuse stromal edema (pachymetry 640 µm) also occurred; all of these factors may result in unpredictable postoperative biomechanical response.

Before any further treatment, we would examine the patient's visual capacity by fitting him with a rigid gas-permeable contact lens. If the visual capacity increases by no more than two lines—compared to BSCVA—we suggest performing a transepthelial topography-guided treatment (CRS-Master; Carl Zeiss Meditec AG, Jena, Germany). With this method of treatment, it is important to warn patients that previous surgeries could cause possible midterm refractive instability. This instability may require further corneal transplantation. When visual capacity increases more than two lines with a rigid gas-permeable contact lens, we recommend performing deep anterior lamellar keratoplasty.

If the patient has a high irregular astigmatism after multiple refractive laser procedures (either laser or incisional), with high potential visual capacity, we think that performing deep lamellar or penetrating corneal transplantation may achieve better refractive stability. Sometimes, as is the case here, a two-step topography-guided treatment may be performed. This, however, should only be done after explaining the possible risk of corneal instability and receiving patient consent.

Smoothing high irregularities, recentering, or enlarging OZs should be the first goal. This was partially achieved here (Figure 2). We would then evaluate subjective and objective optical quality of vision (OQAS; Visiometrics, Terrassa, Spain). If optical quality improves, the second step should be performed to correct only the residual refractive error. You should wait at least 3 months after the first step to relift the flap. Currently, we are working on the possibility of performing both steps during the same surgery.

If there is no objective or even subjective improvement, we propose performing deep anterior lamellar keratoplasty. At this point, we would not suggest the patient undergo any further laser retreatments. We believe that first restoring the corneal structure, will achieve better visual capacity.

The patient should be warned about risks of future crystalline lens opacity and phacoemulsification surgery, due to age, surgery, and corticosteriods treatment.

LEE T. NORDAN, MD
At the conclusion of the radial keratotomy (RK) procedure, the left eye is described as having significant scarring. This scarring is actually subepithelial fibrosis (as well as actual scars from the RK incisions). Additionally, the 5.00-D refraction and reduction in BCVA presented after these two surgeries is caused by an irregular corneal astigmatism, due to corneal ectasia secondary to the extensive RK procedure.

Treating the ectatic cornea with LASIK further increased the irregularity and worsened the patient's vision: Notice that the BCVA decreased to 0.40- and 0.10-, with each successive LASIK procedure.

The only possibility for obtaining a satisfactory result in this case is to perform a -3.00 D myopic PRK in an attempt to smooth the central corneal surface. You could also use a specific central island PRK procedure and then retreat it with a second PRK procedure to address the refractive error. The corneal irregularity in this patient, however, makes the current spherical equivalent unknown.

This two-step PRK treatment may have worked well following the RK procedure, because of the smaller degree of irregularity at that time. Currently, the corneal surface is probably too irregular for a PRK to smooth it sufficiently as seen by the BCVA of 0.10-.

A deep lamellar keratoplasty could possibly correct this in the short-term, but in my experience, corneal irregularities resulting from ectasia return after approximately 1 year. For this reason, I believe a penetrating keratoplasty procedure with subsequent PRK to address the refractive error, would be the best option of treatment for this patient.

This case brings up several important points: (1) irregular astigmatism should always be considered as the cause of reduced BCVA, (2) the patient's clinical history is more important than an exaggerated reliance on automated topography (the 5.00-D refraction and the reduced BCVA were overt evidence that corneal ectasia was present), and (3) performing LASIK—a known corneal weakening procedure—on an ectatic cornea only worsens the corneal irregularity. Performing LASIK twice on a weakened irregular cornea is counterproductive.

A myopic PRK will smooth the central cornea. A hyperopic PRK, on the other hand, will not, because it does not ablate a significant amount of stromal tissue in the center of the cornea.

In the future, this kind of problem should be solved in two steps: One step smooths the cornea, and the other corrects the residual refractive error. If the cornea were mildly irregular and the refractive error were -3.00 D, a one-step PRK may be adequate.

Surgeons involved in repairing corneas following keratorefractive surgery should always treat the existing corneal problems in the following steps: (1) ensure or verify corneal stability, (2) treat corneal irregular astigmatism, and (3) treat the refractive error. Because it is a weakening procedure, LASIK may be used for step three, but neither step one or two. PRK may be used for steps two and three, but not for step one.

If the corneal irregularity is superficial and the BCVA is around 0.5, then a PRK may be sufficient to smoothen the cornea enough to achieve 1.0 in visual acuity. If not, a lamellar keratoplasty may be performed.

When corneal irregularity is caused by ectasia (eg, full thickness stromal weakness), a penetrating keratoplasty procedure will be necessary. Keratorefractive surgery following penetrating keratoplasty would properly address the residual refractive error.

JORGE L. ALI”, MD, PhD
This 55-year-old patient had bilateral radial keratotomy surgery twice, with 16 incisions the first time and up to 24 incisions the second time. Later, he underwent LASIK and PRK retreatments in both eyes for the residual refractive error. No data on the original refraction of the patient or surgical details of the procedures were provided.

The patient came to me because he had poor vision in both eyes. His right eye maintained moderately acceptable vision with the use of a contact lens. The vision in this eye had partial corneal opacity, which was limited to the paracentral area where the proximal end of the incisions were created. The central axis of the right eye was eventually freed from the corneal opacity.

The left eye of this patient, however, was not correctable with spectacles due to central corneal scarring that affected the visual axis. Confocal microscopy showed a central corneal scar, (approximately 130 µm, including the epithelium). Total corneal thickness was 595 µm. Because of his vision, the patient was unable to perform daytime activities and certain work-related tasks.

Upon examination, we found Fuch's endothelial dystrophy in both eyes. This was bad news, because generally our first approach for this type of patient is to perform deep anterior lamellar graft. Unlike penetrating keratoplasty, we usually see good results with deep anterior lamellar grafts. The high amount of corneal cuts would cause penetrating keratoplasty to be unstable in topography, and large irregular astigmatism would create a poor outcome. Since this patient had 24 radial cuts, we would need to make a large graft near the limits of the cornea, which is also prone to induce corneal graft rejection.

Based on our observations and an absense of cataracts, I recommended the patient continue using a rigid contact lens in his right eye—which provided a vision of 0.6 (Snellen). The BSCVA in this eye was +4.0 (Snellen).

We decided to treat the left eye with a femtosecond assisted superficial corneal excision using IntraLase (IntraLase Corp., Irvine, California) following our previous clinical research in the field.¹ Before femtosecond technology was available, we used microkeratomes to create a controlled excision of the superficial cornea including the superficial leucoma. To eliminate superficial corneal scars we would calculate the depth of the corneal excision based on the depth of the cornea from the epithelium with confocal microscopy. Since femtosecond technology is more precise, we thought that the IntraLase-assisted corneal excision in this case could lead toward a better visual outcome (Figure 3). We performed a corneal excision of 125 µm and used .002% mitomycin C for 30 seconds, before leaving the cornea to heal under a contact lens bandage tamponade. Approximately 4 weeks of recovery time was needed to achieve a stable cornea. There was no interference with the central axis.

Six months after surgery, BSCVA was 0.4 with the use of myopic correction of -2.00 D and -1.00 D of astigmatism. With a contact lens, BSCVA reached 0.6 in the operated eye.

Although the patient can now tolerate contact lenses, we believe this is an acceptable, albeit temporary solution. In the next 4 years or 5 years, the patient will probably need corneal grafting because his cornea is now thicker than normal and his endothelial cell count is low.

For the present, however, we consider femtosecond-assisted controlled superficial lamellar keratectomy a good treatment option for these types of cases.

Jorge L. Alió, MD, PhD, is Professor and Chairman of Ophthalmology at the Miguel Hernández University, in Alicante, Spain, and Medical Director of VISSUM Corp., in Spain. He may be reached at +34 96 515 00 25; jlalio@vissum.com.

Javier Gaytán-Melicoff, MD, is staff of the Cornea and Refractive Surgery Unit at the Instituto de Microciruglia, in Barcelona, Spain. Dr. Melicoff states that he has no financial interest in the products or companies mentioned. He may be reached at imo@imo.es.

José L. Güell, MD, PhD, is the Director of the Cornea and Refractive Surgery Unit at the Instituto de Microciruglía, in Barcelona, Spain and Associate Professor of Ophthalmology at the Autonoma University of Barcelona. He states that he has no financial interest in the products or companies mentioned. Dr. Güell may be reached at +34 93 253 15 00; guell@imo.es.

A. John Kanellopoulos, MD, is Director of Laservision Eye Institute, in Athens, Greece. He is Attending Surgeon for the Department of Ophthalmology at the Manhattan Eye, Ear, & Throat Hospital, in New York and Clinical Associate Professor of Ophthalmology at New York University Medical School.
Dr. Kanellopoulos states that he has no financial interest in the products or companies mentioned. He is a member of the CRST Europe Editorial Board. Dr. Kanellopoulos may be reached at +30 21 07 27 27 77; laservision@internet.gr.

Lee T. Nordan, MD, is Assistant Clinical Professor at Jules Stein Eye Institute, Los Angeles, and a technology consultant for Vision Membrane Technologies, Inc., in Carlsbad, California. He states that he has no financial interest in the products or companies mentioned.
Dr. Nordan may be reached at +1 858 487 9600; laserltn@aol.com.

Jérôme C. Vryghem, MD, is from the Brussels Eye Doctors in Brussels, Belgium. Dr. Vryghem states that he has no financial interest in the products or companies mentioned. Dr. Vryghem is a member of the CRST Europe Editorial Board. He may be reached +32 2 741 69 99; j.c.vryghem@vryghem.be.

1. Alio JL, Javaloy J, Merayo J, Galal A. Automated superficial lamellar keratectomy augmented by excimer laser masked PTK in the management of severe superficial corneal opacities. Br J Ophthalmol. 2004;88:1289-1294.