Corneal collagen cross-linking (CXL) combined with refractive procedures for the treatment of corneal ectatic disorders: CXL plus.

PURPOSE: To discuss current combined corneal collagen cross-linking (CXL) and refractive surgical techniques (herein termed "CXL plus") for the treatment of corneal ectatic disorders to improve functional visual acuity in addition to corneal stability from CXL alone. METHODS: Literature review. RESULTS: Efficacious combined treatments with CXL include: photorefractive keratectomy, transepithelial phototherapeutic keratectomy, intrastromal corneal ring segments implantation, phakic intraocular lens implantation, and multiple combined procedures. Some uncertainty remains as to the optimal strategies for each patient. A decision tree is proposed to facilitate optimal patient management. CONCLUSIONS: With multiple adjuvant techniques, CXL plus is likely to benefit many patients with corneal ectatic disorders. The appropriate combined procedure will depend on multiple factors, such as refraction, corneal thickness, and degree of irregular astigmatism.

Simultaneous conventional photorefractive keratectomy and corneal collagen cross-linking for pellucid marginal corneal degeneration.

PURPOSE: To present the results after simultaneous conventional photorefractive keratectomy combined with corneal collagen cross-linking for pellucid marginal corneal degeneration. METHODS: In this prospective, interventional case series, 6 patients (8 eyes) with pellucid marginal corneal degeneration were enrolled. All patients underwent simultaneous conventional photorefractive keratectomy combined with corneal collagen cross-linking; corneal epithelium was removed by transepithelial phototherapeutic keratectomy during treatment (Cretan protocol plus conventional photorefractive keratectomy). Visual and refractive outcomes were evaluated along with endothelial cell density preoperatively and at 1, 3, 6, and 12 months postoperatively. RESULTS: No intraoperative or postoperative complications were observed in any of the patients. LogMAR mean uncorrected distance visual acuity improved significantly from 1.05 ± 0.33 preoperatively to 0.41 ± 0.27 (P = .018) at 12 months postoperatively. Mean corrected distance visual acuity did not change significantly (P > .05) postoperatively. Mean spherical equivalent improved significantly from -3.52 ± 2.29 diopters preoperatively to -1.57 ± 1.76 diopters (P = .028) at last follow-up. Mean corneal astigmatism was significantly reduced from -6.83 ± 2.33 diopters preoperatively to -4.71 ± 1.89 diopters (P = .018) at the last follow-up. No endothelial cell density alterations were observed throughout the follow-up period (P > .05). CONCLUSIONS: Simultaneous conventional photorefractive keratectomy combined with corneal collagen cross-linking seems to be an effective, safe, and promising treatment for the management of pellucid marginal corneal degeneration.

Topography-guided transepithelial PRK after intracorneal ring segments implantation and corneal collagen CXL in a three-step procedure for keratoconus.

PURPOSE: To present the results of topography-guided transepithelial photorefractive keratectomy (PRK) after intracorneal ring segments implantation followed by corneal collagen cross-linking (CXL) for keratoconus. METHODS: In this prospective case series, 10 patients (16 eyes) with progressive keratoconus were included. All patients underwent topography-guided transepithelial PRK after Keraring intracorneal ring segments (Mediphacos Ltda) implantation, followed by CXL treatment. The follow-up period was 6 months after the last procedure for all patients. Time interval between both intracorneal ring segments implantation and CXL and between CXL and topography-guided transepithelial PRK was 6 months. RESULTS: LogMAR mean uncorrected distance visual acuity and mean corrected distance visual acuity were significantly improved (P<.05) from 1.14±0.36 and 0.75±0.24 preoperatively to 0.25±0.13 and 0.13±0.06 after the completion of the three-step procedure, respectively. Mean spherical equivalent refraction was significantly reduced (P<.05) from -5.66±5.63 diopters (D) preoperatively to -0.98±2.21 D after the three-step procedure. Mean steep and flat keratometry values were significantly reduced (P<.05) from 54.65±5.80 D and 47.80±3.97 D preoperatively to 45.99±3.12 D and 44.69±3.19 D after the three-step procedure, respectively. CONCLUSIONS: Combined topography-guided transepithelial PRK with intracorneal ring segments implantation and CXL in a three-step procedure seems to be an effective, promising treatment sequence offering patients a functional visual acuity and ceasing progression of the ectatic disorder. A longer follow-up and larger case series are necessary to thoroughly evaluate safety, stability, and efficacy of this innovative procedure.

Three-Year Results of Simultaneous Transepithelial Phototherapeutic Keratectomy and Conventional Photorefractive Keratectomy (Cretan Protocol Plus) Followed by Corneal Crosslinking for Keratoconus.

PURPOSE: The aim of this study was to present the 3-year outcomes after simultaneous transepithelial phototherapeutic keratectomy (t-PTK) and conventional photorefractive keratectomy (PRK) followed by corneal crosslinking (CXL) for keratoconus. METHODS: In this prospective, interventional case series, patients with progressive keratoconus underwent simultaneous t-PTK and conventional PRK followed by CXL (Cretan protocol plus). Visual, refractive, and topographic outcomes were evaluated along with endothelial cell density (ECD) preoperatively and at 1, 2, and 3 years postoperatively. RESULTS: Twenty-two patients (31 eyes) were enrolled. No intraoperative or postoperative complications were observed in any of the patients. Logarithm of the minimum angle of resolution (logMAR) mean uncorrected and mean corrected distance visual acuity improved from 0.81 ± 0.40 and 0.18 ± 0.21 preoperatively to 0.38 ± 0.33 ( P < 0.001) and 0.06 ± 0.12 ( P < 0.001) at 3-year follow-up. Mean spherical equivalent improved from -5.39 ± 3.89 diopters (D) preoperatively to -2.29 ± 2.65 D ( P < 0.001) at 3 years postoperatively. Mean corneal astigmatism reduced from -4.70 ± 2.86 D preoperatively to -3.55 ± 2.45 D ( P = 0.001) at 3 years postoperatively. No ECD alterations were observed throughout the 3-year follow-up ( P > 0.05). CONCLUSIONS: Simultaneous t-PTK and conventional PRK followed by CXL seems to be an effective and safe treatment for progressive keratoconus over 3-year follow-up.

Combined transepithelial phototherapeutic keratectomy and corneal collagen cross-linking for progressive keratoconus.

PURPOSE: To compare the outcomes of corneal collagen cross-linking (CXL) for the treatment of progressive keratoconus using 2 different techniques for epithelial removal: transepithelial phototherapeutic keratectomy (t-PTK) versus mechanical epithelial debridement. DESIGN: Prospective, comparative, interventional case series. PARTICIPANTS: Thirty-four patients (38 eyes) with progressive keratoconus were enrolled. METHODS: All patients underwent uneventful CXL treatment. Sixteen patients (19 eyes) underwent epithelial removal using t-PTK (group 1) and 18 patients (19 eyes) underwent mechanical epithelial debridement using a rotating brush (group 2) during CXL treatment. Visual and refractive outcomes were evaluated along with corneal confocal microscopy findings preoperatively and at 1, 3, 6, and 12 months postoperatively. MAIN OUTCOME MEASURES: Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and keratometry readings. RESULTS: No intraoperative or postoperative complications were observed in any of the patients. In group 1, logarithm of the minimum angle of resolution mean UDVA and mean CDVA improved from 0.99 ± 0.71 and 0.30 ± 0.26 preoperatively to 0.63 ± 0.42 (P = 0.02) and 0.19 ± 0.18 (P = 0.008) at 12 months postoperatively, respectively. In group 2, neither mean UDVA nor mean CDVA demonstrated a significant improvement at 12 months postoperatively (P>0.05). In group 1, mean corneal astigmatism improved from -5.84 ± 3.80 diopters (D) preoperatively to -4.31 ± 2.90 D (P = 0.015) at the last follow-up, whereas in group 2 there was no significant difference at the same postoperative interval (P>0.05). No endothelial cell density alterations were observed throughout the follow-up period for both groups (P>0.05). CONCLUSIONS: Epithelial removal using t-PTK during CXL results in better visual and refractive outcomes in comparison with mechanical epithelial debridement.

Femtosecond LASIK retreatment using side cutting only.

PURPOSE: To present visual and refractive outcomes in 11 eyes that underwent femtosecond LASIK and subsequent retreatment with flap lifting using only side cutting. METHODS: Seven patients (11 eyes) with a mean age of 30.55±5.42 years (range: 24 to 39 years) underwent retreatment 18.18±5.41 months (range: 12 to 26 months) after primary LASIK treatment with side cutting only using a femtosecond laser for the correction of residual refractive error. RESULTS: Mean follow-up after retreatment was 7.72±1.48 months (range: 6 to 10 months). No intra- or postoperative complications were found after LASIK retreatment. Uncorrected distance visual acuity (UDVA) improved in all patients. Mean UDVA improved from 0.54±0.12 (decimal scale) (range: 0.4 to 0.7) preoperatively to 0.99±0.03 (range: 0.9 to 1.0) after retreatment. No patient lost lines of corrected distance visual acuity. CONCLUSIONS: Retreatment using a femtosecond laser to create only a side cut is an effective modality to treat residual refractive errors in postoperative LASIK patients.

Transepithelial phototherapeutic keratectomy for recurrent corneal erosions in a patient with previous corneal collagen cross-linking.

PURPOSE: To report the significant visual and topographic improvement of a patient who had corneal collagen cross-linking (CXL) performed and was subsequently treated with transepithelial phototherapeutic keratectomy (t-PTK) for recurrent corneal erosions. METHODS: A 36-year-old woman presented with recurrent corneal erosions in the right eye due to foreign body corneal trauma 1 month prior to presentation. The patient had undergone CXL treatment for keratoconus on the same eye 1 year prior to presentation. After failed conservative treatment consisting of epithelial debridement and lubrication with artificial tears, the patient underwent t-PTK. RESULTS: Four months after t-PTK, corneal erosions did not recur and the patient remained asymptomatic. Slit-lamp examination revealed a clear cornea. The patient showed significant visual and topographic improvement after t-PTK. CONCLUSIONS: Transepithelial PTK for recurrent corneal erosions in a postoperative CXL patient successfully treated the corneal pathology, and visual and topographic improvement were observed.

Outcomes of refractive surgery in patients with topographic superior corneal steepening.

PURPOSE: To evaluate the outcomes of refractive surgery in patients with topographic superior corneal steepening. METHODS: This retrospective, noncomparative, interventional, clinical study included 16 patients (29 eyes) with persistent superior corneal steepening as a variation of corneal curvature (inferior to superior topographic corneal difference of at least 1.00 diopter [D] at a 3-mm zone) not related to any underlying disease or condition who underwent corneal refractive surgery. Refractive, keratometric, and visual outcomes were evaluated preoperatively and at 1, 3, 6, 12, and 24 months postoperatively. RESULTS: Twenty-two eyes underwent photorefractive keratectomy and 7 eyes underwent LASIK. Mean follow-up was 27.38±2.37 months (range: 25 to 32 months). Mean preoperative inferior to superior keratometric difference was 1.61±0.36 D (range: 1.20 to 2.63 D). Mean preoperative spherical equivalent refraction was -4.45±1.66 D (range: -2.25 to -8.00 D), which decreased to -0.09±0.61 D (range: +0.75 to -1.38 D) (P<.05) at last follow-up. Mean preoperative topographic corneal astigmatism was 1.44±0.79 D (range: 0.52 to 3.83 D), which decreased to 0.66±0.39 D (P<.05) 3 months postoperatively and remained stable during follow-up (P<.54). Mean preoperative uncorrected distance visual acuity and corrected distance visual acuity in logMAR units were 1.57±0.62 and 0.02±0.06, respectively, which improved at last follow-up to 0.00±0.05 and -0.02±0.04, respectively. No intra- or postoperative complications were noted; specifically, no patients developed postoperative ectasia. CONCLUSIONS: Corneal refractive surgery in patients with isolated topographic superior corneal steepening provided acceptable refractive and visual outcomes without any intra- or postoperative complications. Diligence is required to screen for the potential of ectatic corneal disorders in this population. Photorefractive keratectomy may be a safer option for these patients than LASIK.

Evolution of corneal flattening after repeated corneal cross-linking during a 6-year follow-up.

PURPOSE: To report the evolution of corneal flattening after repeated corneal cross-linking (CXL) in a patient with progressive keratoconus during a 6-year follow-up. METHODS: Case report. RESULTS: A 27-year-old female underwent CXL for progressive keratoconus. Postoperatively, corneal topography revealed keratoconus progression with an increase of 1.20 diopters (D) in maximum keratometry (Kmax) and CXL was repeated. After the second treatment, a continuing significant corneal flattening (up to 16.00 D in Kmax) was observed during the first 5 years followed by stabilization during the last sixth year of follow-up. Both uncorrected and corrected distance visual acuity were improved while corneal thickness was decreased. There were no complications such as corneal opacification or endothelial cells decrease during the follow-up period. CONCLUSION: Repeated CXL can induce an excessive corneal flattening more pronounced during the first years of follow-up followed by stabilization thereafter.

Long-term results of phakic refractive lens implantation in eyes with high myopia.

PURPOSE: To evaluate the long-term results of phakic refractive lens (PRL; Carl Zeiss Meditec) implantation in eyes with high myopia. METHODS: In this retrospective, noncomparative, interventional case series, 143 myopic eyes of 82 patients were treated for high myopia with the implantation of the silicone PRL in the posterior chamber. RESULTS: Mean follow-up was 3.8±1.7 years (range: 1 to 6 years). Six years postoperatively (n=34), a statistically significant reduction was noted in the cycloplegic spherical equivalent from -14.08±4.00 diopters (D) (range: -24.88 to -4.75 D) before PRL implantation to -0.45±0.62 D (range: -1.00 to 1.00 D) (P<.001). At 6 years, 67.6% (23 eyes) and 91.2% (31 eyes) were within ±0.50 and ±1.00 D of target refraction, respectively. Mean logMAR uncorrected and corrected distance visual acuity improved significantly (P<.001) (counting fingers preoperatively in all eyes to 0.17±0.15 [range: 0.54 to -0.06] and 0.19±0.19 [1.00 to -0.08] to 0.07±0.10 [range: 0.30 to -0.10], respectively). Complications included anterior capsule damage (3 eyes), temporary intraocular pressure increase (14 eyes), pigment dispersion (1 eye), and PRL decentration (1 eye). No eyes presented any signs of cataract up to 6 years postoperatively. CONCLUSIONS: Long-term results show that PRL implantation is an effective and safe method for treating high myopia.

Unintended epithelium-only flap creation using a femtosecond laser during LASIK.

PURPOSE: to present a patient in whom, during LASIK with the IntraLase femtosecond laser (Abbott Medical Optics), unintended epithelial (instead of anterior stromal) flaps were created in both eyes. METHODS: a 28-year-old man underwent bilateral LASIK using the IntraLase femtosecond laser programmed to create 100-microm flaps. Flap creation was performed uneventfully in both eyes but flap thickness was thinner than attempted. The flaps were easily torn during flap lift because they appeared to consist of epithelium only. Therefore, the procedure was immediately converted to photorefractive keratectomy with the use of mitomycin C. RESULTS: re-epithelialization occurred 3 days after the procedure in both eyes. Three months after treatment, uncorrected distance visual acuity was 20/25 in the right eye and 20/20 in the left eye with no signs of corneal haze on slit-lamp examination. CONCLUSIONS: despite the advantages of the IntraLase femtosecond laser in the creation of a LASIK flap, complications in terms of flap thickness may occur.

Intraocular Lens Refractive Index and Its Impact on External Surface Reflections.

PURPOSE: To determine and compare the origin of the external surface reflections produced by commonly used intraocular lenses (IOLs). METHODS: The specular reflection taking place at the anterior surface of eight types of IOLs (IOL power = 22.00 diopters [D]) with different refractive indices (RIs), optical design, and ultraviolet and blue light-filtering function were measured. The experimental set-up included a laser beam light source (3.5 mW, 532 nm) and a saline-filled model eye containing the IOL to be examined. External surface reflections were measured using a power meter, and the IOL surface reflectance (%) was compared among the eight IOLs investigated. RESULTS: External reflections from the anterior surface of the studied implants increased as the RI of the IOL material increased. The IOL models composed of high RI material (RI = 1.56 ± 0.02) were found to have a more than threefold higher external surface reflections compared to those with low RI (RI = 1.45 ± 0.02). Ultraviolet or blue light-filtering functions showed no significant correlation with the external reflectance. CONCLUSIONS: IOLs with a high RI are associated with external surface reflections that are more than threefold higher than those with lower RI. The "cat's eye" phenomenon seen in pseudophakic eyes by an outside observer strongly depends on the RI, but is independent of the filter incorporated in the IOL. [J Refract Surg. 2021;37(6):398-402.].

Small incision lenticule extraction retreatment in a patient with high residual refractive error after photorefractive keratectomy: A case report.

A 36-year-old male underwent uneventful small incision lenticule extraction (SMILE) for the correction of his high residual refractive error 12 years after photorefractive keratectomy (PRK). Preoperatively, uncorrected distance visual acuity (UDVA) was counting fingers in both eyes. Corrected distance visual acuity was 20/20 in the right and 20/30 in the left eye due to amblyopia. One month after SMILE, UDVA was 20/20 and 20/30 in the right and left eye, respectively; post-PRK corneal haze had reduced. During the 4-year follow-up, UDVA remained stable and there were no complications. SMILE could be a good alternative approach for retreatment in post-PRK patient.

INTACS followed by KeraRing intrastromal corneal ring segment implantation for keratoconus.

PURPOSE: To describe the visual and refractive outcomes in three eyes (two keratoconic patients) with previous intrastromal corneal ring segments (INTACS, Addition Technology Inc) that underwent adjuvant single KeraRing (Mediphacos) intrastromal corneal ring segment implantation. METHODS: Two keratoconic patients (three eyes) with implanted INTACS segments underwent an additional (without explanting previous INTACS) single KeraRing segment implantation. RESULTS: No intraoperative complications occurred. Six months postoperatively, uncorrected distance visual acuity improved from 20/100 and 20/200 to 20/32 and 20/40 in the right and left eyes, respectively, of patient 1, and from 20/400 to 20/50 in the treated right eye of patient 2. Corrected distance visual acuity improved from 20/50 and 20/100 to 20/30 and 20/32 in the right and left eyes, respectively, of patient 1 and from 20/200 to 20/40 in patient 2. Keratometric measurements improved from 51.00/45.70 to 47.00/44.60 diopters (D) and from 50.80/48.80 to 42.70/40.30 D in the right and left eyes, respectively, of patient 1, and from 49.30/45.70 to 45.60/44.10 D in patient 2. CONCLUSIONS: In keratoconic patients with INTACS in place, adjuvant single intrastromal corneal ring segment (KeraRing) implantation could improve visual and refractive outcome.

Comparison of anterior capsule contraction between hydrophobic and hydrophilic intraocular lens models.

BACKGROUND: To compare the incidence of anterior capsule contraction syndrome (ACCS) after hydrophobic and hydrophilic intraocular lens (IOLs) implantation. METHODS: In this retrospective study, 639 eyes of 639 patients (one eye from each patient) were included, and were divided in two groups according to the type of IOL implanted [hydrophobic (group 1: 273 eyes) or hydrophilic (group 2: 366 eyes, two different IOL models: group 2a, 267 eyes and group 2b, 99 eyes)]. ACCS incidence between groups 1 and 2 as well as between hydrophilic group IOL models was compared. RESULTS: ACCS was significantly (p = 0.012) less frequent in group 1 (hydrophobic) than group 2 (hydrophilic) (four eyes versus 19 eyes respectively). In the hydrophilic group, no statistically significant difference was observed between the two IOL models (ACCS was observed in 13 eyes of the Quatrix and six eyes of the ACR6D IOL model: p = 0.65). CONCLUSIONS: ACCS was significantly greater after hydrophilic IOL implantation when compared with hydrophobic lenses, while there was no statistical significant difference between the two hydrophilic IOL models.

Burr-Assisted Anterior Lamellar Keratoplasty (DALK) in Patients with Corneal Stromal Scarring: A Case Series.

PURPOSE: To describe a modified technique of deep anterior lamellar keratoplasty (DALK) assisted by diamond ophthalmic burr (DOB) in two patients with corneal stromal scarring. METHODS: Two patients with corneal stromal scarring underwent a modified DALK technique with corneal stromal polishing assisted by a DOB until the level of the Descemet membrane. RESULTS: There were no intra- or postoperative complications. Six months postoperatively, the corneal graft was clear, while corrected distance visual acuity improved in both cases. CONCLUSIONS: Burr-assisted DALK seems to represent an alternative surgical technique in patients with corneal stromal scarring.

A New Surgical Approach for the Management of Acute Corneal Hydrops Complicated With Corneal Perforation.

PURPOSE: To report an unusual case of a patient with keratoconus and acute hydrops complicated with corneal perforation and describe its management using a new surgical approach. METHODS: A case report and new surgical approach description. RESULTS: A 47-year-old female patient with a history of keratoconus and implantable contact lens surgery presented at our institute with symptoms of acute corneal hydrops in her right eye. On examination, best corrected visual acuity was of counting fingers in the involved eye. Slit-lamp examination revealed a small inferotemporal corneal perforation, surrounded by marked corneal edema and a positive Seidel test. Initial attempts of conservative treatment with cyanoacrylate tissue adhesive application and bandage soft contact lens placement were ineffective. We decided to proceed with an inferior, lamellar wedge resection of the diseased corneal tissue. One month postoperatively, the cornea remained clear, whereas best corrected visual acuity was 0.1. CONCLUSIONS: Lamellar wedge resection could represent an alternative surgical approach for keratoconic patients, with eccentric acute hydrops and subsequent corneal perforation that provides rapid visual rehabilitation.

Using corneal graft from keratoconic donor for lamellar and penetrating keratoplasties.

We report the use of two corneal grafts derived from a donor, with a history of early stage keratoconus, for lamellar and penetrating keratoplasty. The first graft was used to perform Descemet stripping automated endothelial keratoplasty (DSAEK) in a patient with endothelial dysfunction and advanced pseudoexfoliative glaucoma. The second graft was used for an emergency penetrating keratoplasty in a patient with corneal perforation secondary to uncontrolled herpes keratitis. In the first case, 1 year postoperatively, the graft was clear and attached with no signs of rejection or failure. In the second case, the perforation did not relapse after keratoplasty and the globe retained its structural integrity during the 1-year follow-up.

Corneal cross-linking (CXL) combined with refractive surgery for the comprehensive management of keratoconus: CXL plus.

The past two decades have witnessed an unprecedented evolution in the management of keratoconus that demands a holistic approach comprising of inhibiting the ectatic progression as well as visual rehabilitation. The advent of corneal cross-linking (CXL) in the late 1990s resulted in long-term stabilization of the ectatic cornea along with limited reduction in corneal steepening and regularization of corneal curvature. However, CXL as a standalone procedure does not suffice in rehabilitating the functional vision especially in patients who are unwilling or intolerant towards contact lenses. The concept of "CXL plus" was proposed which incorporates adjunctive use of refractive procedures with CXL in order to overcome the optical inefficiency due to corneal irregularity, decrease the irregular astigmatism, correct the residual refractive error and improve functional visual outcome in keratoconus. Several refractive procedures such as conductive keratoplasty (CK), photorefractive keratectomy (PRK), transepithelial phototherapeutic keratectomy (t-PTK), intrastromal corneal ring segments (ICRS) implantation, phakic intraocular lens (PIOL) implantation and multiple other techniques have been combined with CXL to optimize and enhance the CXL outcome. This review aimed to summarize the different protocols of CXL plus, provide guidelines for selection of the optimum CXL plus technique and aid in decision-making for the comprehensive management of cases with primary keratoconus in addition to discussing the future and scope for innovations in the existing treatment protocols.

Intraoperative pachymetric measurements during corneal collagen cross-linking with riboflavin and ultraviolet A irradiation.

OBJECTIVE: To study central corneal pachymetric variations during corneal collagen cross-linking (CXL) treatment with the use of riboflavin and ultraviolet A irradiation (UVA). DESIGN: Prospective, noncomparative, interventional clinical study. PARTICIPANTS: Fifteen keratoconic patients (19 eyes) were enrolled. METHODS: All patients underwent riboflavin-UVA-induced corneal CXL. Intraoperative central corneal thickness (CCT) measurements using ultrasound pachymetry were performed during the procedure. Measurements were obtained after epithelial removal, after riboflavin drop instillation, and every 5 minutes (6 interval times) during UVA irradiation (30 minutes). MAIN OUTCOME MEASURES: Central corneal thickness measurements. RESULTS: Mean patient age was 26.9+/-6.5 years (range, 17-40 years). Ten were male and 5 were female. Mean preoperative CCT was 458.5+/-21.5 microm (range, 427-494 microm; 95% confidence interval [CI], 448-467 microm) and 415.7+/-20.6 microm (range, 400-468 microm; 95% CI, 406-426 microm) before and after epithelial removal, respectively. There was a statistically significant decrease (mean, 75 microm) of CCT between the epithelial removal interval (415.7+/-20.6 microm; range, 400-468 microm) and at the end of riboflavin solution instillation (340.7+/-22.9 microm; range, 292-386 microm; P<0.001). There was no statistically significant change in CCT during irradiation (P>0.05). There was no statistically significant difference between preoperative and 1-month postoperative endothelial cell count (preoperative, 2780+/-197 to 1-month postoperative, 2713+/-116; P = 0.14). No intraoperative, early postoperative, or late postoperative complications were observed in this patient series. CONCLUSIONS: During corneal CXL with the use of riboflavin and UVA irradiation, a statistically significant decrease of CCT was demonstrated.