From the Institute of Vision and Optics (GDK, MAG, AEK, ZP, IGP), Faculty of Medicine, University of Crete, Heraklion, Crete, Greece; and Bascom Palmer Eye Institute (SHY), University of Miami, Miami, Florida.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to George D. Kymionis, MD, PhD, Institute of Vision and Optics, University of Crete, Faculty of Medicine, 71003 Heraklion, Crete, Greece. E-mail: email@example.com
Keratoconus is a progressive corneal disorder characterized by irregular astigmatism and corneal scarring, resulting in severe vision deterioration.1 Until recently, treatment options adopted to enhance visual acuity in patients with keratoconus included spectacles, contact lenses, intracorneal ring segment implantation,2 and, in advanced cases, lamellar or penetrating keratoplasty.3
The advancement of the disorder can be obstructed by corneal collagen cross-linking (CXL) with riboflavin and ultraviolet irradiation-A. CXL treatment strengthens the cornea by modifying corneal stromal structures through augmenting the cross-links between collagen fibrils.4,5
Several different techniques have been proposed to enhance residual refractive error combined with CXL treatment. Simultaneously customized topography-guided surface ablation with CXL has been reported in patients with keratoconus to ameliorate refractive outcomes.6 Combined treatment of Intacs and CXL in eyes with keratoconus has also been reported.7
In this case report, we present a patient with keratoconus who underwent combined CXL treatment for the stabilization of the ectatic disorder and posterior chamber toric phakic implantable Collamer lens (ICL) implantation for the correction of high myopia and astigmatism.
A 29-year-old woman with progressive keratoconus (Fig. 1) and contact lens intolerance presented to our institute for consultation. At the time of the examination, uncorrected distance visual acuity was counting fingers in both eyes and corrected distance visual acuity was 20/100 (manifest refraction −15.00 −4.00 × 180) in the right eye and 20/50 (manifest refraction −10.00 −5.00 × 155) in the left eye. Keratometric readings using corneal topography (Technomed C–Scan, Baesweiler, Germany) were 63.51/57.24 in the right eye and 57.77/50.63 in the left eye. Central corneal thickness using ultrasound pachymetry (Corneo-Gage plus; Sonogage, Cleveland, OH) was 454 μm in the right eye and 465 μm in the left eye. Intraocular pressure was 11 mm Hg in both eyes. Ophthalmic examination showed no other anterior or posterior segment abnormality. To stabilize the ectatic cornea, we decided to perform CXL in both eyes.
Figure 1. Corneal Topography (Technomed C–Scan, Baesweiler, Germany) 6 Months Before (left) and Immediately Before (right) Corneal Collagen Cross-Linking Treatment Showing the Progression of Keratoconus in a 6-Month Period.
CXL was conducted under sterile conditions. The patient’s eye was anesthetized with proxymetacaine hydrochloride 0.5% eye drops (Alcaine; Alcon Laboratories, Inc., Fort Worth, TX). An 8.0-mm diameter of the corneal epithelium was mechanically removed using a rotating brush. After epithelial removal, riboflavin 0.1% solution was instilled every 2 to 3 minutes for approximately 30 minutes. Penetration of the cornea and presence of riboflavin in the anterior chamber (riboflavin shielding) was monitored by slit-lamp examination.
Ultraviolet irradiation-A was performed using a commercially available ultraviolet irradiation-A optical system (UV-X illumination system version 1000; IROC AG, Zurich, Switzerland) with a light source consisting of an array of ultraviolet diode lasers (365 nm) with a potentiometer in series to allow regulation of voltage. Before treatment, intended irradiance of 3.0 mW/cm2 (5.4 J/cm2 surface dose after 30 minutes) was calibrated using the ultraviolet irradiation-A light meter YK-34UV (Lutron, Coopersburg, PA), which is supplied with the UV-X device. Irradiance was performed for 30 minutes, corresponding to a dose of 5.4 J/cm2. During treatment, riboflavin 0.1% solution was applied every 3 to 5 minutes to saturate the cornea with riboflavin. At the end of the procedure, a silicon-hydrogel bandage contact lens (Lotrafilcon B, Air Optix: 14.0-mm diameter, 8.6 base curvature, Dk = 140 barrers; Ciba Vision, Duluth, GA) was applied until full reepithelialization.
Postoperative medication included diclofenac sodium 0.1% for 2 days and antibiotic/corticosteroid (tobramycin/dexamethasone) drops four times daily until the removal of the bandage contact lens. The treated right eye was examined daily until the epithelium was completely healed. The contact lens was removed at the fifth postoperative day and no signs of edema or inflammation were cited by slit-lamp biomicroscopy. After the removal of the contact lens, the patient received corticosteroid drops (fluorometholone 0.1%) tapering for the next 20 days and was encouraged to use artificial tears at least six times per day for 3 months postoperatively.
Twelve months after the CXL procedure, uncorrected distance visual acuity was counting fingers in both eyes. Corrected distance visual acuity was 20/63 in the right eye (manifest refraction −12.00 −4.50 × 180) and 20/30 in the left eye (−11.00 −3.25 × 160). Slit-lamp biomicroscopy revealed a clear cornea with no signs of haze formation. Intraocular pressure was 12 mm Hg in both eyes. Keratometric readings were 61.72/57.17 in the right eye (Fig. 2) and 57.45/50.37 in the left eye. To achieve an improvement in the visual outcome of the right eye, we decided to proceed with posterior chamber toric phakic Visian ICL implantation.
Figure 2. Corneal Topography (Technomed C–Scan, Baesweiler, Germany) Immediately Before (left) and 12 Months After (right) Corneal Collagen Cross-Linking Treatment.
ICL implantation was performed 12 months after CXL treatment. The zero horizontal axis was marked at a slit lamp while the patient was sitting upright to control for potential cyclotorsion on lying supine. The ICL was sized according to corneal white-to-white and anterior chamber depth measurements by IOL Master (Carl Zeiss, Meditec, Dublin, CA). The ICL was inserted through a horizontal temporal 3-mm corneal incision to the anterior chamber and allowed to unfold slowly. The four footplates were placed underneath the iris using the Vukich Visian ICL manipulator (Asico LLC, Westmont, IL). Adjustment of the implant was accomplished by a gentle movement touching the ICL at the junction of the haptic and optic. Correct positioning of the ICL in the center of the pupillary zone was verified before an intraocular miotic was used to decrease pupil size. Any remaining viscoelastic was irrigated with balanced salt solution. An iridectomy was performed at the 12-o’clock position as peripherally as possible using the probe of a vitreotome.
Three months postoperatively, uncorrected distance visual acuity of the right treated eye improved to 20/40 and corrected distance visual acuity improved to 20/30 with manifest refraction of −0.25 −0.50 × 40 (Fig. 3). Intraocular pressure was 13 mm Hg.
Figure 3. Anterior Segment Optical Coherence Tomography (RTVue, Model RT100; Optovue Inc., Fremont, CA) Showing the Corneal Thinning (left) and the Implanted Posterior Chamber Toric Implantable Collamer Lens (Visian ICL; STAAR Surgical, Monrovia, CA) (right).
Keratoconus is an ectatic disorder of the cornea that affects the patient’s life due to the poor quality of vision produced by the associated irregular astigmatism.1 The goal of keratoconus treatment should be corneal biomechanical stability and efficient visual acuity.
CXL treatment can achieve corneal stabilization due to the induction of cross-links between corneal collagen fibrils.4,5 Despite the arresting effect in terms of corneal instability, topographic images and visual performance of patients treated with CXL show minimal improvement. Especially for patients suffering from high myopia or contact lens intolerance, spectacles do not offer a functional visual rehabilitation.
A combination of CXL treatment with techniques that improve visual acuity may offer a comprehensive treatment for patients with corneal ectatic disorders. A simultaneous approach of photorefractive keratectomy followed by CXL seems to be a promising treatment capable of offering functional vision in patients with keratoconus.6 Chan et al. reported a study with combined treatment of Intacs and CXL in eyes with keratoconus showing that this combination could lead to better refractive results than Intacs insertion alone.7
In another study, Conskunseven et al. reported a case series of patients with keratoconus who underwent Intacs followed by implantation of a toric Visian ICL posterior chamber phakic refractive lens in a two-step procedure to correct residual myopia.8 No intraoperative or postoperative complications were observed.
In this case report, a combined technique of CXL and ICL was used to treat a patient with keratoconus who had high myopia and astigmatism in a two-step procedure. In the first step, the CXL procedure was performed to stiffen the cornea and arrest keratoconus progression. In the second step, after keratoconus stabilization confirmed by topographic findings, an ICL was implanted to treat residual myopia and astigmatism, which were verified by topographic images and objective refraction. No intraoperative or postoperative complications were observed. The application of CXL treatment alone stabilized the ectatic cornea, but was not enough to provide functional vision. The aim of the combined treatment was to correct the myopic astigmatism after arresting keratoconus progression to enhance the final visual and refractive outcome. After the combined treatment, a significant improvement in visual acuity (both uncorrected distance visual acuity and corrected distance visual acuity) was noticed.
The two-step procedure of CXL and ICL implantation for the treatment of keratoconus in a patient with high myopia and astigmatism seems to be a safe and reasonable technique, especially in patients with contact lens intolerance.
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- Kymionis GD, Siganos CS, Tsiklis NS, et al. Long-term follow-up of Intacs in keratoconus. Am J Ophthalmol. 2007;143:236–244. doi:10.1016/j.ajo.2006.10.041 [CrossRef]
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- Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol. 2003;135:620–627. doi:10.1016/S0002-9394(02)02220-1 [CrossRef]
- Wollensak G, Spoerl E, Seiler T. Stress–strain measurements of human and porcine corneas after riboflavin-ultraviolet-A-induced cross-linking. J Cataract Refract Surg. 2003;29:1780–1785. doi:10.1016/S0886-3350(03)00407-3 [CrossRef]
- Kymionis GD, Kontadakis GA, Kounis GA, et al. Simultaneous topography-guided PRK followed by corneal collagen cross-linking for keratoconus. J Refract Surg. 2009;25:S807–S811. doi:10.3928/1081597X-20090813-09 [CrossRef]
- Chan CC, Sharma M, Wachler BS. Effect of inferior-segment Intacs with and without C3-R on keratoconus. J Cataract Refract Surg. 2007;33:75–80. doi:10.1016/j.jcrs.2006.09.012 [CrossRef]
- Coskunseven E, Onder M, Kymionis GD, et al. Combined Intacs and posterior chamber toric implantable collamer lens implantation for keratoconic patients with extreme myopia. Am J Ophthalmol. 2007;144:387–389. doi:10.1016/j.ajo.2007.05.035 [CrossRef]