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INTRODUCTION
Laser in situ keratomileusis (LASIK) is now the most widely used surgery to correct myopia, hyperopia, and astigmatism. It can lead to rapid recovery of vision with less pain and without occurrence of corneal opacity. However, the creation of the corneal flap can weaken the stroma beneath and there may be an increased risk for keratectasia postoperatively [111]. The options for management of iatrogenic keratectasia include contact lens, intracorneal ring segments, intralamellar keratoplasty, penetrating keratoplasty and collagen with riboflavin/UVA light crosslinking [1221]. We describe a patient with iatrogenic keratoconus after uneventful myopic LASIK, who was treated with rigid contact lenses, and visual outcome was good after three years followup.
Case Report
A 27yearold woman had primary LASIK in both eyes in September 2001. Preoperative examination revealed a manifest and cycloplegic refraction of 5.50/0.50×50° in the right eye and 4.50/1.00×15° in the left eye, yielding a best corrected visual acuity (BCVA) of 20/20 in both eyes. Preoperative ultrosonic pachymetry was 526μm in the right eye and 541μm in the left eye. Central keratometry measured 44.30×87°/42.63×176° and 44.12×93°/42.19×7°, respectively. Corneal topography showed a regular bowtie pattern and no signs of keratoconus or forme fruste keratoconus (Figure 1).
Intraoperatively, a Moria CB microkeratome (intended flap thickness 160μm) and Wavelight excimer laser (6.5mm optical zone, intended ablation depth 102μm OD and 86μm OS) were used. It was estimated to leave residual stromal beds of 264μm OD and 295μm OS. The same blade was used for both eyes, and right eye was treated first. The surgery was uneventful. Unfortunately, the corneal flap of the right eye was dislocated by her daughters inadvertent hit on the operative night and the flap was repositioned within one hour in our department. Topical ofloxacin, prednisolone acetate, and preservativefree artificial tears were used 4 times a day for 1030 days. Two days after surgery, the uncorrected visual acuity (UCVA) was 20/40 in the right eye and 20/25 in the left eye. Then the patient went home and there was no further information about her until 29 months later.Figure 1Corneal topography before LASIK. Central keratometry is 44.30×87°/42.63×176° OD and 44.12×93°/42.19×7° OS (3.0 mm zone). Corneal topography show a regular bowtie pattern and no signs of keratoconus or forme fruste keratoconus
Figure 2Corneal topography 29 months after LASIK procedure. The steepest hemimeridian is 61.91D and 53.21D, and there is a keratoconuslike pattern with inferior steepening and opposing paracentral asymmetric flattening
Figure 3Slitlamp pictures 29months after LASIK procedure. The central cornea of both eyes is steepening and thin. The cornea epithelium in the left eye has some slightly edema and cornea in right eye is clear
In February 2004, the patient came back to our department and complained of dramatically decreased visual acuity and foreign body sensation, especially in the right eye. The UCVA was 20/200 OD and 20/80 OS, improving to 20/33 with 12.50/ 4.00×160° in the right eye and 20/25 with 6.00/ 4.25×125° in the left eye. Corneal topography showed an area of steepening in the inferior region of both eyes (Figure 2). The maximal keratometry measured 61.91D OD and 53.21D OS, respectively. The thinnest pachymetry was 342μm in the right eye and 378μm in the left eye. The corneal epithelium in the left eye had slight edema, and cornea in right eye was clear (Figure 3), the flaps were well centered in both eyes. Based on all these findings, iatrogenic keratectasia was diagnosed and a rigid gaspermeable (RGP) contact lens was fitted to rehabilitate the BCVA. In order to establish 3point touch, a reversegeometry contact lens (RGL) was selected. The visual acuity after lens wearing in both eyes was 20/20.
In March 2006, the patient came to our department and complained of a slight foreign body sensation and unsteady visual acuity in the right eye. Physical examination revealed 3mm central opacity in the right eye, cornea of the left eye was clear (Figure 4). The UCVA was 20/200 OD and 20/100 OS, improving to 20/33 with 11.00/ 4.50×150° in the right eye and 20/25 with 6.25/ 4.00×120° in the left eye. Corneal topography showed roughly the same as that in February 2004. The maximal keratometry measured 61.84D OD and 53.45D OS respectively (Figure 5). The thinnest pachymetry was 350μm in the right eye and 375μm in the left eye. The RGP contact lens was changed with a slightly modify in order to achieve an acceptable fluorescein pattern. The BCVA was 20/25 OD and 20/20 OS.
In April 2007, the patient returned to our clinic for a routine examination and complained of a slightly decreased visual acuity in her left eye. The UCVA was 20/400 in both eyes, manifest Figure 4Slitlamp pictures 54 months after LASIK procedure. The central cornea epithelium in the right eye has some edema and opacity, the cornea in the left eye is clear
Figure 5Corneal topography 54 months after LASIK procedure. The maximal keratometry and the steepening area is almost the same as before, The steepest hemimeridian is 61.84D OD and 53.45D OS respectively
Figure 6Corneal topography 67 months after LASIK procedure. The steepening area in both eyes is larger than that in March 2006, while the maximal keratometry has no much change, it is 62.04D and 54.25D OS, respectively
Figure 7Slitlamp pictures 67 months after LASIK procedure. There has no edema and opacity in the right eye; the epithelium in the left eye has some defects in the center
refractive was 9.50/3.50×135° OD and 9.00/2.00×130° OS. Topography showed the steepening area in both eyes which were larger than before, while the maximal keratometry had no much change, 62.04D OD and 54.25D OS respectively(Figure 6). The corneal epithelium of the left eye had some defects in the center (Figure 7). The thinnest pachymetry was 363μm in the right eye and 385μm in the left eye. New RGP contact lens was changed according to the new clinical data, and sodium hyaluronate eye drop was given to left eye 3 times a day.
In these three years, the patient had a daily contact lens wearing time of 12 hours and the contact lens was tolerated well, the visual acuity with contact lens was 20/2520/20, which was almost the same as the preoperative value of 20/20.
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