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Tear function and ocular surface changes following corneal collagen cross-linking treatment in keratoconus patients: 18-month results.
Uysal, BS, Akcay, E, Kilicarslan, A, Mutlu, M, Hondur, G, Kosekahya, P, Cagil, N
International ophthalmology. 2020;(1):169-177
Abstract
PURPOSE To investigate the long-term effects that CXL has on the tear function and ocular surface in keratoconus. METHODS Twenty-one consecutive patients (24 eyes) with progressive keratoconus scheduled for CXL were included. All patients underwent the following procedures: conjunctival impression cytology analysis, ocular surface disease index (OSDI) score, tear osmolarity test, Schirmer test, tear film breakup time (TBUT), ophthalmic surface fluorescein (Fl) staining, and topographical corneal evaluation before as well as 3 and 18 months after accelerated CXL. RESULTS There was no change in the median OSDI score, tear osmolarity test, Schirmer test, and the Fl staining score after CXL. The median TBUT increased from 9.00 s at baseline to 12.00 s at 18 months postoperative (P < 0.001). The cytological features of the temporal and superior bulbar conjunctiva deteriorated at 3 months post-CXL (P < 0.001). An improvement in impression cytology analysis of the temporal conjunctiva was noted at 18-month follow-up (P < 0.001). Significant improvements in the median maximum keratometry and mean keratometry (K-mean) readings were also noted 18 months after CXL (P < 0.001). The changes in the K-mean correlated significantly with the changes in TBUT levels at 18-month follow-up as compared to baseline (r = - 0.688, P < 0.001). CONCLUSIONS The improvement in TBUT, conjunctival squamous metaplasia, and the goblet cell density indicates a favorable effect of CXL on the ocular surface and tear film in keratoconus, presumably due to the reduced corneal irregularity after CXL.
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Comparison of accelerated and conventional corneal collagen cross-linking for progressive keratoconus.
Cınar, Y, Cingü, AK, Türkcü, FM, Çınar, T, Yüksel, H, Özkurt, ZG, Çaça, I
Cutaneous and ocular toxicology. 2014;(3):218-22
Abstract
PURPOSE To compare outcomes of accelerated and conventional corneal cross-linking (CXL) for progressive keratoconus (KC). MATERIALS AND METHODS Patients were divided into two groups as the accelerated CXL group and the conventional CXL group. The uncorrected distant visual acuity (UDVA), corrected distant visual acuity (CDVA), refraction and keratometric values were measured preoperatively and postoperatively. The data of the two groups were compared statistically. RESULTS The mean UDVA and CDVA were better at the six month postoperative when compared with preoperative values in two groups. While change in UDVA and CDVA was statistically significant in the accelerated CXL group (p = 0.035 and p = 0.047, respectively), it did not reach statistical significance in the conventional CXL group (p = 0.184 and p = 0.113, respectively). The decrease in the mean corneal power (Km) and maximum keratometric value (Kmax) were statistically significant in both groups (p = 0.012 and 0.046, respectively in the accelerated CXL group, p = 0.012 and 0.041, respectively, in the conventional CXL group). There was no statistically significant difference in visual and refractive results between the two groups (p > 0.05). CONCLUSIONS Refractive and visual results of the accelerated CXL method and the conventional CXL method for the treatment of KC in short time period were similar. The accelerated CXL method faster and provide high throughput of the patients.
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Corneal collagen cross-linking with hypoosmolar riboflavin solution in keratoconic corneas.
Gu, S, Fan, Z, Wang, L, Tao, X, Zhang, Y, Mu, G
BioMed research international. 2014;:754182
Abstract
PURPOSE To report the 12-month outcomes of corneal collagen cross-linking (CXL) with a hypoosmolar riboflavin and ultraviolet-A (UVA) irradiation in thin corneas. METHODS Eight eyes underwent CXL using a hypoosmolar riboflavin solution after epithelial removal. The corrected distance visual acuity (CDVA), manifest refraction, the mean thinnest corneal thickness (MTCT), and the endothelial cell density (ECD) were evaluated before and 6 and 12 months after CXL. RESULTS The MTCT was 413.9 ± 12.4 μm before treatment and reduced to 381.1 ± 7.3 μm after the removal of the epithelium. After CXL, the thickness decreased to 410.3 ± 14.5 μm at the last follow-up. Before treatment, the mean K-value of the apex of the keratoconus corneas was 58.7 ± 3.5 diopters and slightly decreased (57.7 ± 4.9 diopters) at 12 months. The mean CDVA was 0.54 ± 0.23 logarithm of the minimal angle of resolution before treatment and increased to 0.51 ± 0.21 logarithm at the last follow-up. The ECD was 2731.4 ± 191.8 cells/mm(2) before treatment and was 2733.4 ± 222.6 cells/mm(2) at 12 months after treatment. CONCLUSIONS CXL with a hypoosmolar riboflavin in thin corneas seems to be a promising method for keratoconic eyes with the mean thinnest corneal thickness less than 400 μm without epithelium.
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Intraoperative corneal thickness measurements during corneal collagen cross-linking with isotonic riboflavin solution without dextran in corneal ectasia.
Cınar, Y, Cingü, AK, Sahin, A, Türkcü, FM, Yüksel, H, Caca, I
Cutaneous and ocular toxicology. 2014;(1):28-31
Abstract
UNLABELLED Abstract Objective: To monitor the changes in corneal thickness during the corneal collagen cross-linking procedure by using isotonic riboflavin solution without dextran in ectatic corneal diseases. MATERIALS AND METHODS The corneal thickness measurements were obtained before epithelial removal, after epithelial removal, following the instillation of isotonic riboflavin solution without dextran for 30 min, and after 10 min of ultraviolet A irradiation. RESULTS Eleven eyes of eleven patients with progressive keratoconus (n = 10) and iatrogenic corneal ectasia (n = 1) were included in this study. The mean thinnest pachymetric measurements were 391.82 ± 30.34 µm (320-434 µm) after de-epithelialization of the cornea, 435 ± 21.17 µm (402-472 µm) following 30 min instillation of isotonic riboflavin solution without dextran and 431.73 ± 20.64 µm (387-461 µm) following 10 min of ultraviolet A irradiation to the cornea. CONCLUSION Performing corneal cross-linking procedure with isotonic riboflavin solution without dextran might not induce corneal thinning but a little swelling throughout the procedure.
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Corneal changes following collagen cross linking and simultaneous topography guided photoablation with collagen cross linking for keratoconus.
Padmanabhan, P, Radhakrishnan, A, Venkataraman, AP, Gupta, N, Srinivasan, B
Indian journal of ophthalmology. 2014;(2):229-35
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PURPOSE To compare the outcome of Collagen cross-linking (CXL) with that following topography-guided customized ablation treatment (T-CAT) with simultaneous CXL in eyes with progressive keratoconus. MATERIALS AND METHODS This was a prospective, non-randomized single centre study of 66 eyes with progressive keratoconus. Of these, 40 eyes underwent CXL and 26 eyes underwent T-CAT + CXL. The refractive, topographic, tomographic and aberrometric changes measured at baseline, 1, 3 and 6 months post-operatively were compared between both groups. RESULTS After a mean follow-up of 7.7 ± 1.3 months, the mean retinoscopic cylinder decreased by 1.02 ± 3.16 D in the CXL group ( P = 0.1) and 2.87 ± 3.22 D in the T-CAT + CXL group ( P = 0.04). The Best corrected visual acuity increased by 2 lines or more in 10% of eyes in the CXL group and in 23.3% of eyes in the T-CAT + CXL group. The mean steepest-K reduced by 0.40 ± 3.71 D ( P = 0.77) in the CXL group and by 2.91 ± 2.01D ( P = 0.03) in the T-CAT + CXL group. The sag factor and surface asymmetry index showed no significant change in the CXL group but reduced by 3.59 ± 5.94 D ( P = 0.01) and 0.72 ± 1.18 ( P = 0.02) respectively in the T-CAT + CXL group. There was a significant increase in the highest posterior corneal elevation in both groups (9.57 ± 14.93 μ in the CXL group and 7.85 ± 9.25 μ in the T-CAT + CXL group, P ≤ 0.001 for both). There was significantly greater reduction of mean coma ( P < 0.001) and mean higher-order aberrations ( P = 0.01) following T-CAT + CXL compared to CXL. CONCLUSIONS CAT + CXL is an effective approach to confer biomechanical stability and to improve the corneal contour in eyes with keratoconus and results in better refractive, topographic and aberrometric outcomes than CXL alone.
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Impact of collagen crosslinking on corneal sensitivity in keratoconus patients.
Wasilewski, D, Mello, GH, Moreira, H
Cornea. 2013;(7):899-902
Abstract
PURPOSE To evaluate changes in corneal sensitivity after corneal collagen crosslinking in patients having progressive keratoconus. METHODS Thirty-six consecutive patients having progressive keratoconus were included in the study. The crosslinking surgery was performed in one eye of each patient (study group) and the opposite eye was used as control (control group). The following steps were done in the procedure: central cornea epithelial debridement, riboflavin solution dropping (1 drop every 5 minutes) for 30 minutes, and subsequently, corneal surface irradiation with Ultraviolet A for 30 minutes, keeping the riboflavin instillation while irradiating. The analysis of corneal tactile sensitivity in each patient was performed using the Cochet-Bonnet aesthesiometer at 5 time points: preoperative and 7, 30, 90, and 180 days after surgery. RESULTS The study enrolled 72 eyes of 36 patients. Considering the eyes submitted to crosslinking, there was a significant statistical difference concerning the tactile corneal sensitivity at all 5 evaluated moments. The median sensitivity at each time point studied was: preoperative, 52.5 mm (range, 25-60 mm); 7 days, 20.0 mm (range, 5-60 mm); 30 days, 32.5 mm (range, 5-60 mm); 90 days, 40.0 mm (range, 10-60 mm) and 180 days, 45.0 mm (range, 25-60 mm) (P < 0.001). The control group showed no statistical difference among all 5 time points (P = 0.160). CONCLUSIONS Corneal crosslinking performed in keratoconus patients induced a considerable decrease in corneal sensitivity. This decrease was more intense at the first week after the procedure, with a progressive recovery up to 6 months.
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Intraoperative pachymetry using spectral-domain optical coherence tomography during accelerated corneal collagen crosslinking.
Chow, VW, Biswas, S, Yu, M, Wong, VW, Jhanji, V
BioMed research international. 2013;:848363
Abstract
PURPOSE To evaluate the role of spectral-domain optical coherence tomography (SDOCT) to measure corneal thickness during accelerated corneal crosslinking (CXL). METHODS Intraoperative pachymetry was performed using SDOCT and ultrasound pachymetry (USP) in 6 eyes of 6 patients with keratoconus. Pachymetry readings were obtained at baseline, after epithelium removal and after 30 minutes of riboflavin instillation. SDOCT measurements of eyes with and without lid speculum during riboflavin instillation were compared. RESULTS There was no statistically significant difference in central corneal thickness (CCT) measurements between SDOCT and USP (P > 0.05 for all). A significant decrease in both CCT (P = 0.031) and the thinnest corneal thickness (TCT) (P = 0.031) was observed during CXL. There was a greater reduction in CCT (38 ± 6%) with the use of lid speculum as compared to the no-speculum eyes (18 ± 9%) (P = 0.100). TCT was also reduced by a greater extent with the use of lid speculum (40 ± 5% versus 26 ± 7%; P = 0.100). CONCLUSION SDOCT can be successfully used to measure intraoperative corneal pachymetry during corneal CXL. SDOCT measurements demonstrated corneal thinning intraoperatively during CXL, which was further accentuated by the use of a lid speculum during the procedure.
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Transepithelial corneal collagen crosslinking for progressive keratoconus: 24-month clinical results.
Caporossi, A, Mazzotta, C, Paradiso, AL, Baiocchi, S, Marigliani, D, Caporossi, T
Journal of cataract and refractive surgery. 2013;(8):1157-63
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PURPOSE To assess the clinical results of transepithelial collagen crosslinking (CXL) in patients 26 years and younger with progressive keratoconus suitable for epithelium-off (epi-off) CXL. SETTING Department of Ophthalmology, Siena University Hospital, Siena, Italy. DESIGN Prospective case series. METHODS The study included 26 eyes (26 patients) treated by transepithelial (epithelium-on) CXL. The mean age was 22 years (range 11 to 26 years) (10 younger than 18 years; 16 between 19 years and 26 years). Preoperative and postoperative examinations included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, simulated maximum keratometry (K), coma and spherical aberration, and corneal optical coherence tomography optical pachymetry. The solution for transepithelial CXL (Ricrolin TE) comprised riboflavin 0.1%, dextran 15.0%, trometamol (Tris), and ethylenediaminetetraacetic acid. Ultraviolet-A treatment was performed with the Caporossi Baiocchi Mazzotta X Linker Vega at 3 mW/cm(2). RESULTS After relative improvement in the first 3 to 6 months, the UDVA and CDVA gradually returned to baseline preoperative values. After 12 months of stability, the simulated maximum K value worsened at 24 months. Coma aberration showed no statistically significant change. Spherical aberration increased at 24 months. Pachymetry showed a progressive, statistically significant decrease at 24 months. Fifty percent of pediatric patients were retreated with epi-off CXL due to significant deterioration of all parameters after 12 months of follow-up. CONCLUSIONS Functional results after transepithelial CXL showed keratoconus instability, in particular in pediatric patients 18 years old and younger; there was also functional regression in patients between 19 years and 26 years old after 24 months of follow-up. mentioned.
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Evaluation of corneal hysteresis and corneal resistance factor after corneal cross-linking for keratoconus.
Gkika, M, Labiris, G, Giarmoukakis, A, Koutsogianni, A, Kozobolis, V
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2012;(4):565-73
Abstract
BACKGROUND To evaluate corneal hysteresis (CH) and corneal resistance factor (CRF) in keratoconic (KC) eyes before and after corneal collagen cross-linking (CXL). Furthermore, to determine potential correlations with a series of corneal and demographic factors. METHODS The study consisted of 50 KC eyes that underwent CXL. CH and CRF were measured by the ocular response analyzer (ORA). Correlations were attempted with uncorrected visual acuity (UVA), best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), mean keratometry (Km), astigmatism (Astig.), residual astigmatism, age, and gender. Fifty non-KC eyes served as controls. RESULTS CH and CRF (mean ± SD) for non-KC eyes were 10.1 ± 1.9 mmHg and 9.7 ± 2.4 mmHg respectively, while for KC eyes preoperatively they were 8.2 ± 1.4 mmHg (p = 0.007) and 7.4 ± 2.3 mmHg (p = 0.01) respectively. Non-significant differences were detected between preoperative and postoperative CH and CRF measurements in KC eyes (p = 0.518 and p = 0.479 respectively). Significant correlations were found between ORA parameters and BSCVA, CCT, Km, Astig. and residual astigmatism. CONCLUSIONS ORA parameters demonstrate significant differences between KC and non-KC eyes. Both CH and CRF present significant correlations with visual acuity and corneal parameters. CXL exerts a non-significant impact on ORA measurements.
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Morphological and functional correlations in riboflavin UV A corneal collagen cross-linking for keratoconus.
Mazzotta, C, Caporossi, T, Denaro, R, Bovone, C, Sparano, C, Paradiso, A, Baiocchi, S, Caporossi, A
Acta ophthalmologica. 2012;(3):259-65
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PURPOSE To investigate the correlations between corneal structural modifications assessed by in vivo corneal confocal microscopy with visual function [uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA)] and morphological data (corneal topography, pachymetry, elevation analysis) after riboflavin UV A corneal collagen cross-linking (CXL) for the stabilization of progressive keratoconus. METHODS Forty-four eyes with progressive keratoconus were enrolled in the Siena Eye Cross Study (prospective nonrandomized phase II open trial). All eyes underwent Riboflavin UV A CXL. Preoperative and postoperative evaluation comprised: UCVA, BSCVA, optical pachymetry (Visante OCT, Zeiss, Germany), corneal topography (CSO, Florence, Italy) and tomography (Orbscan IIz; B&L, Rochester, NY, USA) and in vivo confocal microscopy (Heidelberg Retina Tomograph II; Rostock, Heidelberg Gmbh, Germany). Examinations were performed preoperatively 6 months and one day before treatment and at 1, 3, 6 and 12 months of follow-up. RESULTS In vivo corneal confocal microscopy showed time-dependent postoperative epithelial and stromal modifications after cross-linking. Epithelial thinning associated with stromal oedema and keratocytes apoptosis explained initial tendency towards slightly reduced VA and more glare one month postoperatively in 70% of eyes. Furthermore, a statistically not significant early worsening of topographic mean K values was observed. Orbscan II analysis significantly underestimated pachymetric values after treatment. Pachymetric underestimation was rectified by high-resolution optical pachymetry provided by the Visante OCT system. After the third post-CXL month, epithelial thickening, disappearance of oedema and new collagen compaction recorded by in vivo corneal confocal microscopy explained the improvements in visual performance during the follow-up. Changes in stromal reflectivity and collagen compaction observed by in vivo confocal microscopy were associated with corneal flattening and reduction in anterior elevation values recorded by differential topographic analysis. CONCLUSION Corneal structural changes assessed by in vivo corneal confocal microscopy demonstrated significant correlations with visual function (UCVA and BSCVA) and morphological (corneal topography, pachymetry, elevation analysis) findings recorded after riboflavin-UV A-induced CXL.