Figure 3. Corneal topography.

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- ThepatienthadbilateralLASIKformoderatemyopia,complicated by incomplete flaps. It resulted in decreasedvisual acuity and poor quality of vision in both eyes.On examination 3 years later, the BSCVA in both eyesis 20/25, with 1.00 D of against-the-rule astigmatism.

Theslitlampphotographsofbotheyes showacornealstromal scar consistent with a superior LASIK-flaphinge well within the pupillary area. The topographyshows asymmetric corneal optics and a small ablationzone. The Scheimpflug images confirm the small abla-tion zone, while the configuration of the posteriorsurface and the pachymetry map do not raise concernof compromised corneal biomechanical stability. Thethinnest point in both eyes is approximately 420 mm.

The patient’s poor quality of vision can be explainedby irregular astigmatism (caused by asymmetric op-tics), a small optical zone, and possibly a decrease intransparency and/or scattering (caused by the scarat the flap hinge). A very-high-frequency digital ultra-sound scan (Artemis, ArcScan Inc.) or high-definitioncorneal OCT would be crucial in this case for precisemapping of the thickness of the flap and the depth ofthe scar.

Wavefront aberrometrymay be useful in confirmingthe effect of the irregular astigmatism and the smalloptical zone. It may also give an estimate of the corre-lation between the amount of HOAs and the patient’ssymptoms of decreased quality of vision. If the symp-toms of poor quality of vision cannot be explained bythe amount of HOAs, theymight have originated fromthe decrease in transparency, the scattering, or both. In

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addition, a hard contact lens trial would help deter-mine the magnitude of influence of the transparencyand scattering on the subjective quality of vision bytemporarily reducing the HOAs originating from thecorneal surface.

Regarding treatment, the goal should be to improvethe quality of vision by regularizing the irregular cor-neal optics, removing the scar (if shown to be a sourceof transparency decrease/scattering), and correctingthe residual spherocylinder. A conservative approachwith gas-permeable hard contact lenses should be con-sidered. If this approach were not acceptable to the pa-tient, topography-guided surface custom ablation ontop of the flap seems to be themost attractive and safestoption. Customablationwith a relift is not an option be-cause of the ‘‘short’’ flap with superior hinge inside thepupillary area. Not only would a flap recut be risky be-cause of the relatively thin cornea, itwould bynomeansaddress the issue of scars within the optical area. If thedecreased transparency/scattering is indeed a part ofthe reason for thepoor quality of vision, a surface topog-raphy-guidedablation that includesablationof the scarsshould be considered if the scars are superficial enough.Ifwe also take into consideration that significant epithe-lial remodeling likely occurred in this case, any ap-proach in which the epithelium is simply removedwithout taking the remodeling effect into account (asin common surface ablation) could result in a significanterror and might induce new optical irregularities.

This leaves a transepithelial approach, in whichepithelial removal is an integral part of the custom

RG - VOL 35, MAY 2009

I would treat the second eye 6 months after the firsteye has stabilized.

David T.C. Lin, FRCSCVancouver, Canada

- This is a case of a 27-year-old woman who reportspoor quality of vision after LASIK with incompleteflaps. The Scheimpflug images show that in botheyes, there is a thin, flat cornea in the center and a thick,steeper cornea superiorly. These findings are compat-ible with the slitlamp examination, which shows a cor-neal stromal scar consistent with a flap hingeapproaching the visual axis in both eyes.

Considering this scenario, the best option would beto perform a corneal wavefront examination followedby corneal wavefront-guided PRK. We would recom-mend removal of the epithelium with an excimerlaser using the PTK mode (depth 45 mm in

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ablation, as our best option. I have successfully treatedsimilar cases with flap or interface irregularities usingcustom transepithelial no-touch ablation on the iVISSuite laser system (iVIS Technologies). The patient’s re-fraction; corneal anterior elevation (measured byScheimpflug topography); pachymetrymap;andpupil,iris, and scleral registration information would be im-ported into the ablation-planning software to designanablationwith the aimof transforming thedetected ir-regular corneal shape into a regularized aspheric shapeplaced at the specified depth under the pathology thatcauses visual disturbances. I would not hesitate to usesuch a technique in this case if the measurements ofthe depth of the scars confirm that there would beenough corneal tissue for a safe procedure.

Aleksandar Stojanovic, MDTromsoe and Oslo, Norway

- The patient has bilateral irregular astigmatism fromincomplete flaps with hinges within the pupil. The pa-tient is symptomatic, and I would first repeat the to-pographies with a Topolyzer corneal topographer(Alcon) to determine whether I can produce repeatabletopographies. If the topographies were reproducible, Iwould consider retreating the patient with topogra-phy-guided PRK. I would treat 1 eye at a time. I woulddetermine eye dominance and treat the nondominanteye first. Repeat procedures are less predictable thanprimary treatments, so treating 1 eye at a time ismore prudent.

The procedure of choice would be transepithelialPRK. This procedure is less disruptive to a previousflap. In addition, one would not risk dislocating a pre-vious flap during manual epithelial removal. Thiswould be followed by a topography-guided treat-ment linked to the corneal topography used for therepeat topographies. After PRK, I would use MMC0.02% for 20 seconds followed by copious irrigation.A tapering steroid regimen over 3 months wouldfollow.

a 9.0 mm area) or the use of dilute alcohol, in whichcase the epithelium would have to be extremely looseso that the flap will not accidentally be dislodgedduring epithelial removal. After epithelial debride-ment, the corneal wavefront-guided ablation wouldbe applied using the pupil center under mesopic con-ditions as a reference. After the laser treatment, wewould recommend the use of a sponge soaked withMMC 0.02% placed for 12 seconds on the exposedcorneal bed followed by abundant irrigation witha balanced salt solution. Finally, a soft contact lenswould be placed and maintained until reepithelializa-tion is complete (in 4 to 6 days).

In the postoperative period, we would prescribeaggressive use of topical steroidal drops until theepithelium has healed. This would be useful consideringthat epithelial defects in LASIK are a risk factor forthe development of diffuse lamellar keratitis.

Artur Schmitt, MDFernanda Piccoli, MD

Miami, Florida, USACuritiba, Parana, Brazil

J CATARACT REFRACT SURG - VOL 35, MAY 2009