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1.
Int J Ophthalmol ; 17(7): 1307-1312, 2024.
Article in English | MEDLINE | ID: mdl-39026900

ABSTRACT

AIM: To observe the effects of femtosecond laser-assisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking (FS-LASIK Xtra) on corneal densitometry after correcting for high myopia. METHODS: In this prospectively study, 130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia. Their right eyes were selected for inclusion in the study, of which 65 cases of 65 eyes in the FS-LASIK group, 65 patients with 65 eyes in the FS-LASIK Xtra group. Patients were evaluated for corneal densitometry at 1, 3, and 6mo postoperatively using Pentacam Scheimpflug imaging. RESULTS: Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant (P>0.05). Layer-by-layer analysis revealed statistically significant differences in the anterior (120 µm), central, and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively (all P<0.05), the FS-LASIK Xtra group is higher than that of the FS-LASIK group. Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0-2, 2-6, and 6-10 mm (both P<0.05); At 3mo postoperatively, the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0-2 and 2-6 mm (P<0.05). At 6mo postoperatively, there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges (all P>0.05). CONCLUSION: There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia. However, the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery, with the most significant changes observed in the superficial central zone.

2.
Int Ophthalmol ; 44(1): 145, 2024 Mar 18.
Article in English | MEDLINE | ID: mdl-38498219

ABSTRACT

PURPOSE: To compare the visual, refractive, and topographic outcomes of a high irradiance accelerated corneal crosslinking (ACXL) protocol after a 12-month follow-up between pediatric and adult patients with progressive keratoconus (KC). METHODS: Retrospective, comparative, cohort study. Patients with KC were divided into two groups: pediatric (≤ 18 years) and adult (> 18 years). All of them were managed with epi-OFF ACXL (30 mW/cm2, 8 min, pulsed 1:1 on and off = 7.2 J/cm2). Visual, refractive, and topographic values were measured preoperatively and at 1, 3, 6, and 12 months postoperative. KC progression, defined as a Kmax increase of ≥ 1D during follow-up, was recorded. RESULTS: Eighty-nine eyes (53 patients) were included for analysis; 45 (50.6%) eyes were from pediatric patients and 44 (49.4%) from adults. At one-year follow-up, pediatric patients experienced significantly higher rates of progression (22.2% vs. 4.5%, p = .014). Contrariwise, female gender (Beta = - 3.62, p = .018), a baseline uncorrected visual acuity of Snellen ≥ 20/60 (Beta = - 5.96, p = .007), and being ≥ 15 years at ACXL treatment (Beta = - 0.31, p = .021) were associated with non-progressive disease. A significant improvement in best-corrected visual acuity, Kmin, Km, and Kmax was recorded in both groups. Overall, 86.5% of eyes from both groups showed Kmax stabilization or improvement. CONCLUSIONS: Despite the similarity in visual, refractive, and topographic outcomes in both groups, younger age was associated with KC progression after ACXL at one year of follow-up.


Subject(s)
Keratoconus , Photochemotherapy , Adult , Humans , Female , Child , Keratoconus/diagnosis , Keratoconus/drug therapy , Photosensitizing Agents/therapeutic use , Photochemotherapy/methods , Corneal Cross-Linking , Retrospective Studies , Cohort Studies , Riboflavin/therapeutic use , Ultraviolet Rays , Corneal Topography/methods , Follow-Up Studies , Cross-Linking Reagents/therapeutic use , Collagen/therapeutic use
3.
Int Ophthalmol ; 43(11): 4333-4342, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37495937

ABSTRACT

BACKGROUND: Femtosecond laser-assisted in situ keratomileusis (FS-LASIK) with accelerated corneal crosslinking (FS-LASIK Xtra) is a recent procedure to achieve safer corneal ablation in myopic patients with borderline corneal thickness. Despite its well-accepted effectiveness, the development of remarkable interface haze is a potential concern but has rarely been reported and discussed. METHODS: We report for the first time a case series of 11 eyes of 7 patients who developed typical interface haze 1-3 months after FS-LASIK Xtra for the correction of myopia with astigmatism, with intensity grades ranging from 0.5 + to 3 + at the time of onset. RESULTS: The preclinical spherical diopters of the 7 patients ranged from - 2.25 D to - 9.25 D and cylindrical diopters ranged from - 0.25 D to - 2.50 D. The haze tended to be self-limiting, and topical anti-inflammatory therapy was given to moderate and severe cases, who responded well to treatment. CONCLUSIONS: The development of clinically significant interface haze is a relatively rare complication after FS-LASIK Xtra but tends to have a higher incidence and intensity compared to conventional stromal surgery such as FS-LASIK. Timely treatment and close follow-up are essential to patients undertaking FS-LASIK Xtra.


Subject(s)
Astigmatism , Keratomileusis, Laser In Situ , Myopia , Humans , Keratomileusis, Laser In Situ/adverse effects , Keratomileusis, Laser In Situ/methods , Visual Acuity , Lasers, Excimer/adverse effects , Cornea/surgery , Myopia/surgery , Astigmatism/etiology , Astigmatism/surgery , Corneal Stroma/surgery
4.
Int Ophthalmol ; 43(5): 1721-1735, 2023 May.
Article in English | MEDLINE | ID: mdl-36418804

ABSTRACT

PURPOSE: To evaluate the 12 months' changes in tomographic, densitometric, and aberrometric parameters in keratoconic eyes after accelerated corneal cross-linking (CCL) and classify a densitometric course in different stages of the keratoconus separately (mild, moderate, and severe). METHODS: In a prospective observational study, 67 keratoconic eyes of 67 patients that underwent accelerated epithelium-off corneal cross-linking (9 mW/cm2 and 10 min) for treatment of progressive keratoconus were included. Corneal tomographic, densitometric, and aberrometric values obtained using the Pentacam HR were recorded at the baseline and 3, 6, and 12 months post-operatively. RESULTS: One year after treatment, corrected distance visual acuity (CDVA) was improved, and maximum keratometry, thinnest pachymetry, higher order, and total root mean square (RMS) were significantly decreased (p < 0.001). Corneal densitometry values showed a significant elevation 3 months post-surgery compared to baseline and then decreased to baseline values at 1 year. Only the Anterior 0-2 mm zone densitometry at the 3rd month was different between the three groups. RMS at 1 year correlated with Anterior 0-2 mm, Anterior 2-6 mm, total corneal 0-2 mm, and total corneal 2-6 mm densitometry values in the 3rd month. Final CDVA at 12th month follow-up correlated with the Anterior 0-2 mm corneal densitometry in the 3rd month. CONCLUSION: Anterior 0-2 mm zone densitometry at the 3rd-month post-accelerated CCL is different in various stages of keratoconus. Due to the correlation between final aberrometric and peak densitometric values in keratoconic eyes, peak densitometric values can be used as a prognostic factor for the final visual outcomes after accelerated CCL.


Subject(s)
Keratoconus , Photochemotherapy , Humans , Keratoconus/diagnosis , Keratoconus/drug therapy , Corneal Cross-Linking , Photochemotherapy/methods , Photosensitizing Agents/therapeutic use , Ultraviolet Rays , Riboflavin/therapeutic use , Corneal Topography , Retrospective Studies , Collagen/therapeutic use , Cross-Linking Reagents/therapeutic use
5.
Cesk Slov Oftalmol ; 78(3): 122-127, 2022.
Article in English | MEDLINE | ID: mdl-35760583

ABSTRACT

OBJECTIVES: Evaluation of the visibility and depth of the demarcation line in the corneal stroma in eyes with keratoconus 1 month and 3 months after epi-off accelerated corneal cross-linking (ACXL) using anterior segment optical coherence tomography (AS OCT). MATERIAL AND METHODS: This study analyses a group of 34 eyes with keratoconus 1 month and 3 months after ACXL (9 mW/cm2 for 10 min). The group was classified based on the ABCD clinical classification of keratoconus according to Belin and Duncan. AS OCT (ZeissCirrus 500, Anterior Segment Premier module) was used to assess the visibility and exact depth of the demarcation line in the corneal stroma. RESULTS: The demarcation line was visible 1 month after ACXL in 76.5% of eyes with a mean depth of 238.13 ±20.36 μm and 3 months after ACXL in 100% of eyes with a mean depth of 263.43 ±12.59 μm. Statistical analysis of the group did not show a significant relationship between the disease stage and the demarcation line visibility; however, there was a trend towards higher age (>30 years) in the group in those eyes where the demarcation line was visible vs. partially visible 3 months after ACXL. We found no difference in the mean and maximum line depth when comparing 1 month and 3 months after the procedure. There were no cases of disease progression 3 months after ACXL in the group. CONCLUSION: Our study suggests that the assessment of the demarcation line in the corneal stroma is more reliable 3 months compared to 1 month after ACXL. We also observed a trend towards higher patient age in eyes where the demarcation line was clearly visible 3 months after ACXL. We did not confirm a relationship between the stage of keratoconus and the depth of the line, nor a difference in its mean and maximum depth 1 month and 3 months after the procedure.


Subject(s)
Keratoconus , Adult , Collagen , Corneal Stroma , Cross-Linking Reagents , Humans , Infant , Keratoconus/diagnosis , Photosensitizing Agents , Riboflavin , Tomography, Optical Coherence/methods , Ultraviolet Rays
6.
Int Ophthalmol ; 42(12): 3725-3738, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35622219

ABSTRACT

PURPOSE: To evaluate the 36 months changes in posterior corneal surface parameters in keratoconic eyes after accelerated corneal cross-linking and to compare the data with uncross-linked progressive and non-progressive keratoconic eyes. METHODS: Thirty five cross-linked, 30 uncross-linked progressive, and 30 uncross-linked non-progressive keratoconic eyes were included. Maximum keratometry (Kmax), thinnest pachymetry, minimum radius of curvature back (Rminback), asphericity back, posterior elevation and corneal densitometry, back corneal higher order aberrations (HOAs), back surface deviation (Db), final D, posterior radius of curvature (PRC) and 'B' unit values were recorded at baseline and at the 12, 24, 36 months follow-up. Data were analyzed with repeated measures ANOVA and paired t-tests. RESULTS: Kmax and thinnest pachymetry were significantly changed in the cross-linked and progressive uncross-linked groups. Rminback, asphericity back, and HOAs did not change in either group. Total posterior corneal densitometry improved; posterior elevation, Db and B unit worsened in the cross-linked group and did not change in the uncross-linked groups. PRC and final D worsened in the cross-linked and progressive uncross-linked groups, and did not change in the non-progressive group. CONCLUSION: Despite a decreased Kmax, the posterior corneal surface parameters, posterior elevation values were determined to have significantly worsened in the cross-linked group and this increase was higher than in progressive uncross-linked eyes.


Subject(s)
Keratoconus , Photochemotherapy , Humans , Keratoconus/diagnosis , Keratoconus/drug therapy , Corneal Topography , Cross-Linking Reagents/therapeutic use , Riboflavin/therapeutic use , Photosensitizing Agents/therapeutic use , Collagen/therapeutic use , Visual Acuity , Corneal Pachymetry , Ultraviolet Rays
7.
Eur J Ophthalmol ; 32(5): 2565-2576, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35535408

ABSTRACT

PURPOSE: To evaluate the effectiveness of epithelium-off (epi-off) accelerated corneal crosslinking (A-CXL, 9 mW/cm2, 10 min) in adult keratoconus (KC) patients. METHODS: The study included 151 KC corneas (124 patients) after A-CXL. The parameters best corrected visual acuity (BCVA) and the tomographic readings (Pentacam HR, Oculus, Germany) were analysed at 24, 12 and 6 months preoperatively, prior to surgery; and 6 weeks, 6 months, 1, 2 and >2 years postoperatively. The demarcation line was assessed by anterior segment optical coherence tomography (Tomey SS-1000, CASIA 2 (Tomey, Nagoya, Japan)). RESULTS: Comparing pre- to postoperative findings 6 weeks after A-CXL with paired t-test, the anterior steep (46.8 ± 4.0|47.1 ± 4.1), flat (50.2 ± 4.3|50.6 ± 4.6) and maximal keratometry (57.6 ± 6.8|58.3 ± 6.8) increased (p < 0.05), while the thinnest pachymetry decreased significantly (459 ± 39|444 ± 42, p < 0.05). Lateron, however, there was a decreasing anterior flat (1, 2 and >2 years; p < 0.0001), mean (1 year; p = 0.01 and 2 years; p = 0.03) and maximal keratometry (1, 2 and >2 years; p < 0.0001). The posterior corneal keratometry readings did not change significantly until >2 years after A-CXL (MANOVA; steep, p = 0.008; flat, p = 0.027; mean, p = 0.007). The mean depth of the demarcation line was 242 ± 62 µm (53.6%). The preoperative logMAR BCVA (0.35 ± 0.02) decreased 6 weeks after A-CXL (0.39 ± 0.03) followed by a continuous improvement until the latest follow-up (0.18 ± 0.04). CONCLUSION: A-CXL constitutes a successful method for KC stabilization. Signs of KC progression occur within the first 6 weeks postoperatively ("pseudoprogression"), but this is not indicative of the long-term effect.


Subject(s)
Keratoconus , Photochemotherapy , Adult , Collagen/therapeutic use , Cornea , Corneal Topography , Cross-Linking Reagents/therapeutic use , Humans , Keratoconus/diagnosis , Keratoconus/drug therapy , Photochemotherapy/methods , Photosensitizing Agents/therapeutic use , Riboflavin/therapeutic use , Ultraviolet Rays
8.
Eur J Ophthalmol ; 32(5): 2547-2553, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35450449

ABSTRACT

PURPOSE: To assess any changes in macular function and morphology in patients with progressive keratoconus undergoing accelerated corneal cross-linking (CXL). METHODS: This prospective case series included 9 eyes of 8 patients with progressive keratoconus undergoing CXL using a high intensity accelerated protocol (9 mW/cm2 for 14 min) with a total surface dose of 7.5 J/cm2. Visual acuity assessment, slit lamp biomicroscopy, dilated fundoscopy, corneal tomography, multifocal electroretinography (mfERG) and spectral domain optical coherence tomography scan were performed at baseline, 2 weeks and 6 weeks postoperatively. RESULTS: Uncorrected and corrected distance visual acuity did not change significantly at 2 weeks and 6 weeks following accelerated CXL compared to baseline. Retinal response density (RRD) of mfERG significantly decreased at 2 weeks postoperatively compared to baseline (p = 0.008) but did not differ from the baseline value at 6 weeks postoperatively in the fovea (ring 1) (p = 0.95). Similarly, P1 latency significantly decreased at 2 weeks (p = 0.04) but did not change at 6 weeks (p = 1.00) postoperatively compared to baseline in the fovea. No changes in RRD or P1 latency were observed in the retinal rings surrounding the fovea (rings 2 to 5). Central foveal thickness did not change at 2 weeks and 6 weeks postoperatively compared to baseline (p = 0.53 and p = 0.93, respectively). CONCLUSIONS: A short-term reversible decrease in macular electrical activity without any structural changes seems to occur after accelerated CXL in patients with progressive keratoconus. The return of macular response to the preoperative values shows the safety of the CXL protocol.


Subject(s)
Keratoconus , Collagen/radiation effects , Corneal Topography , Cross-Linking Reagents/therapeutic use , Humans , Keratoconus/diagnosis , Keratoconus/drug therapy , Refraction, Ocular , Ultraviolet Rays
9.
Front Med (Lausanne) ; 8: 657993, 2021.
Article in English | MEDLINE | ID: mdl-34722556

ABSTRACT

Purpose: To investigate the demographic and corneal factors associated with the occurrence of delayed reepithelialization (DRE) after epithelium-off crosslinking (epi-off CXL). Design:Retrospective case series. Methods:A chart review was performed to identify patients treated with epi-off CXL. DRE was defined as a corneal epithelial defect detected by fluorescein staining that persisted for more than 10 days. Slit-lamp examination, anterior segment optical coherence tomography, corneal topography, and corneal in vivo confocal microscopy (IVCM) were always performed preoperatively and at each follow-up visit (1, 3, 6, 12 months). A generalized estimating equation was used to assess the baseline factors associated with DRE. Results:Data from 153 eyes were analyzed. The mean age of patients was 24.9 ± 8.5 years, and 47 (30.7%) were women. The average reepithelization time was 4.7 ± 1.8 days. Six eyes (3.9%) experienced DRE. In the multivariate model, both the age of the patient (OR = 1.30; p = 0.02) and the corneal steepest meridian (OR = 0.44, p = 0.047) were associated with DRE. Baseline nerve count was also associated with DRE (0.87, p = 0.03). Male gender was associated with a slower early nerve regrowth (1-6 months) (p = 0.048), but not with the occurrence of DRE (p = 0.27). Preoperative central corneal thickness was not related to DRE (p = 0.16). DRE was not associated with keratoconus progression after epi-off CXL (p = 0.520). Conclusions:The association between DRE and age may reflect the age-related decrease in the corneal healing response. Also, low baseline corneal nerve count is associated with DRE. Gender seems to affect reinnervation measured by IVCM but not the reepithelization time. DRE does not seem to affect the efficacy of epi-off CXL.

10.
Int Ophthalmol ; 40(10): 2651-2658, 2020 Oct.
Article in English | MEDLINE | ID: mdl-32488590

ABSTRACT

PURPOSE: To report a comparison analysis of accelerated corneal cross-linking (A-CXL) treatment for progressive keratoconus patients in different pediatric age groups. STUDY DESIGN: Retrospective, cross-sectional. METHODS: Patients with progressive keratoconus aged ≤ 18 were retrospectively reviewed. Forty-one eyes of 41 patients were included in the study. Patients were divided into two groups according to their age (≤ 14 years and 15-18 years). All patients underwent epithelium-off A-CXL protocol. Acquired data were compared between the two groups. RESULTS: The mean age was 14.3 ± 1.8 (10-18) years. Twenty-five (61%) of the participants were male, and 16 (39%) were female. Twenty (49%) patients were separated into group 1 (≤ 14 years of age), and 21 (51%) were in group 2 (15-18 years). Age at presentation was found to be the only factor in anticipating the progression of keratoconus at the second postoperative year visit (p < 0.001). Progression in keratometric values was detected in seven (35%) of the 20 eyes in group 1, and one (4%) of the 21 patients in group 2 (Z = - 2.44, p = 0.014). CONCLUSION: Even if proper treatment is applied, the progression of keratoconus is likely in patients younger than 14 years of age. Instead of evaluating pediatric patients as a whole, closer follow-up and early treatment may be useful in younger age groups (≤ 14 years).


Subject(s)
Keratoconus , Photochemotherapy , Adolescent , Adult , Child , Collagen/therapeutic use , Corneal Topography , Cross-Linking Reagents/therapeutic use , Cross-Sectional Studies , Female , Humans , Keratoconus/diagnosis , Keratoconus/drug therapy , Male , Photosensitizing Agents/therapeutic use , Retrospective Studies , Riboflavin/therapeutic use , Ultraviolet Rays , Young Adult
11.
Eur J Ophthalmol ; 30(4): 650-657, 2020 Jul.
Article in English | MEDLINE | ID: mdl-30943777

ABSTRACT

PURPOSE: To compare long-term results between accelerated and standard corneal cross-linking protocols in the treatment of progressive keratoconus and compare their effectiveness between central (cone in the central 3 mm) and peripheral (cone beyond 3 mm) cases. METHODS: In this randomized clinical trial, we compared 31 eyes treated with accelerated corneal cross-linking (18 mW/cm2, 5 min) and 31 eyes treated with standard corneal cross-linking (3 mW/cm2, 30 min), 16 central and 11 peripheral keratoconus in each group. In this report, 4-year changes in vision, refraction, topography, corneal biomechanics, and corneal cell count were evaluated. RESULTS: Uncorrected distance visual acuity improvement was better with standard corneal cross-linking (0.19 ± 0.30 logMAR) than accelerated corneal cross-linking (0.08 ± 0.35 logMAR), but the intergroup difference was not statistically significant (p = 0.283). Cylinder and spherical equivalent significantly increased similarly in both groups. Among topographic indices, anterior Kmax-3 mm showed more reduction in standard corneal cross-linking than accelerated corneal cross-linking (1.35 ± 1.39 vs 0.36 ± 1.10 D, p = 0.011). Anterior Kmax-8 mm reduced by 1.50 ± 1.82 and 0.37 ± 1.58 D in the standard corneal cross-linking and accelerated corneal cross-linking groups, respectively (p = 0.029). Compared to 18-month results, none of the indices at 4 years showed any significant intergroup difference (all p > 0.05). In cases with peripheral keratoconus, changes in anterior Kmax-3 mm (+0.03 ± 0.66 vs -1.17 ± 1.15 D, p = 0.012) and anterior Kmax-8 mm (+0.43 ± 1.09 vs -1.57 ± 1.40 D, p = 0.003) were greater with standard corneal cross-linking. In central cases, no significant intergroup difference was observed. CONCLUSION: At 4 years after the procedure, standard corneal cross-linking offered better anterior corneal flattening in the center and periphery. These differences concerned cases of peripheral keratoconus, and the two protocols were similarly effective in central cases. Beyond the 18th month, the two protocols appeared to be similarly effective.


Subject(s)
Collagen/metabolism , Corneal Stroma/drug effects , Cross-Linking Reagents , Keratoconus/drug therapy , Photosensitizing Agents/therapeutic use , Riboflavin/therapeutic use , Adolescent , Adult , Biomechanical Phenomena/physiology , Cell Count , Corneal Stroma/metabolism , Corneal Topography , Double-Blind Method , Female , Humans , Keratoconus/metabolism , Male , Photochemotherapy/methods , Refraction, Ocular/physiology , Ultraviolet Rays , Visual Acuity/physiology , Young Adult
12.
Clin Ophthalmol ; 13: 1665-1673, 2019.
Article in English | MEDLINE | ID: mdl-31507315

ABSTRACT

PURPOSE: To report the visual and topographic outcomes of two pulsed-light-accelerated CXL (A-CXL) protocols at a 12-month follow-up and their correlation with the corneal stromal demarcation line (DL) depth. PATIENTS AND METHODS: Retrospective comparative cohort of patients with documented progressive keratoconus were included. Two epi-off pulsed-light [1s on-1s off] A-CXL protocols were compared: irradiance 30*8 and 45*5:20 (fluence 7.2 J/cm2). UDVA, CDVA, spherical equivalent (SE), topographic astigmatism, Kmin, Kmax, Km, central corneal thickness (CCT), thinnest pachymetry (TCT) and endothelial cell density (ECD) were measured preoperatively and months 1, 3, 6 and 12 postoperative. Corneal DL was measured 1 month postoperatively using anterior segment optical coherence tomography. RESULTS: Fifty eyes (27 patients): 22 eyes in group A-CXL (30*8), 28 eyes in group A-CXL (45*5:20). Mean age (years) was 19.04±4.71 and 20.32±4.57. DL depth (µm) at month 1 was 200.63±10.01 µm and 184.53±19.68 µm for group A-CXL (30*8) and group A-CXL (45*5:20), respectively (p<0.001). Significant improvement in CDVA, topographic astigmatism, Kmin, Kmax and Km was observed in both groups (no significant difference between groups) and no significant changes were observed in CCT, TCT and ECD with regard to baseline. Over 85% of the eyes in both protocols achieved stabilization or improvement in maximum K at the end of the follow-up. No significant correlations between DL and any visual or topographic outcomes were observed at 12 months. CONCLUSION: No correlation between DL depth and visual or topographic outcomes was observed on either protocol. Although significant improvement on CDVA, topographic astigmatism, Kmin, Kmax and Km was observed in both groups at 12 months, further research is needed to assure safety and effectiveness at stabilizing keratoconus progression.

13.
J Biomech ; 93: 209-212, 2019 Aug 27.
Article in English | MEDLINE | ID: mdl-31300155

ABSTRACT

The objective of this non-randomized trial was comparison of two-year changes in dynamic corneal response (DCR) between 18 mW/cm2 (5- min) and 9 mW/cm2 (10-min) cross-linking (CXL) protocols, using novel stiffness parameters and correlating them to clinical indices. The two groups were evaluated before and 2 years after the procedure using Corvis ST (Oculus Optikgeräte GmbH, Germany) and DCR parameters such as deformation amplitude ratio at 1 mm and 2 mm (DA ratio-1 mm and DA ratio-2 mm) and integrated radius and stiffness parameters at A1 (SP-A1). Two-year follow-up was completed for 16 of the 30 eyes in the 5-min group and 21 of the 25 eyes in the 10-min group; data from those who were lost to follow-up was not included in the analyses. Mean age at baseline was 21.7 ±â€¯4.9 and 21.5 ±â€¯5.2 years in the 5- and 10-min groups, respectively (P = 0.895). At 2 years after CXL, in the 5-min group, the reduction in integrated radius (-1.12 ±â€¯1.27 mm, P = 0.003) was significant, and the increase in SP-A1 (7.11 ±â€¯14.86 mmHg/mm, P = 0.075) was borderline, while in the 10-min group, the decrease in DA ratio-2 mm (-0.43 ±â€¯0.58, P = 0.003) and integrated radius (-1.89 ±â€¯1.72 mm, P < 0.001), and increase in SP-A1 (7.67 ±â€¯10.92 mmHg/mm, P = 0.004) were significant. In both groups, the strongest and significant correlation was observed between DCR parameters and changes in radius of curvature. In conclusion, results indicated corneal strengthening with both protocols especially with the 9 mW/cm2. Corvis ST indices can provide "in vivo" biomechanical evidence on the efficacy of CXL that may occur prior to clinical indices.


Subject(s)
Cross-Linking Reagents/therapeutic use , Keratoconus/drug therapy , Adolescent , Adult , Biophysics , Cornea/drug effects , Cornea/pathology , Cornea/surgery , Corneal Topography , Cross-Linking Reagents/pharmacology , Elasticity/drug effects , Female , Humans , Keratoconus/surgery , Male , Time , Treatment Outcome , Young Adult
14.
Int Ophthalmol ; 39(6): 1329-1335, 2019 Jun.
Article in English | MEDLINE | ID: mdl-29948500

ABSTRACT

PURPOSE: The aim of this study is to compare the effect of different riboflavin solutions (hypotonic and isotonic) used during accelerated corneal cross-linking (CXL) on the mean depth of the demarcation line (DDL) formed in corneal stroma. METHODS: This prospective, cross-sectional study included 38 eyes of 26 patients. All patients underwent accelerated CXL due to progressive keratoconus. When the corneal epithelium was removed, 17 eyes of 12 patients with corneal thickness < 400 µm were categorized as Group 1, and 21 eyes of 14 patients with corneal thickness > 400 µm as Group 2. Hypotonic riboflavin was applied to Group 1 patients, and isotonic riboflavin to Group 2 patients. Anterior segment optical coherence tomography was performed on all patients by two independent observers at the end of the first and third months. RESULT: Group 1 included 5 male and 7 female patients with an average age of 25.1 ± 8.0 years, whereas Group 2 included 7 male and 7 female patients with an average age of 31.8 ± 10.12 years. At the end of the first month, the mean DDL in Group 1 and Group 2 was 180.32 ± 10.26 and 287.21 ± 15.01 µm, respectively. This difference was statistically significant (p < 0.05). CONCLUSION: Application of different riboflavin solutions was observed to have an effect on measured corneal thickness after saturation and the depth of the demarcation line. The use of hypotonic riboflavin results in swelling of the cornea and more superficial localization of the stromal demarcation line after CXL.


Subject(s)
Collagen/metabolism , Corneal Stroma/pathology , Cross-Linking Reagents/therapeutic use , Keratoconus/drug therapy , Riboflavin/therapeutic use , Adult , Cross-Sectional Studies , Dose-Response Relationship, Drug , Female , Humans , Keratoconus/pathology , Male , Middle Aged , Prospective Studies , Young Adult
15.
Middle East Afr J Ophthalmol ; 24(3): 121-125, 2017.
Article in English | MEDLINE | ID: mdl-29279651

ABSTRACT

PURPOSE: The purpose of the study was to determine 2-year changes in mesopic higher-order aberrations (HOAs) and contrast sensitivity (CS) after accelerated corneal cross-linking (CXL) in keratoconus patients. MATERIALS AND METHODS: In this before-after interventional case series, patients with progressive keratoconus were subjected to accelerated CXL (18 mW/cm2, 5 min). Patients were examined with the OPD-Scan III and CVS-1000 grating charts under mesopic conditions at baseline and at 12 and 24 months after CXL. RESULTS: At 24 months after CXL, compared to baseline, mesopic CS in spatial frequencies of 3, 6, 12, and 18 cycle per degree reduced respectively to 0.09 ± 0.27, 0.09 ± 0.32, 0.11 ± 0.19, and 0.02 ± 0.10; these changes were not statistically significant (all P > 0.05). The reduction in ocular HOAs was 0.11 ± 0.43; ocular coma, trefoil, and spherical aberration (SA) decreased by 0.09 ± 0.36, 0.05 ± 0.35, and 0.00 ± 0.13 microns, respectively (all P > 0.05). Reductions in corneal HOAs (0.89 ± 7.08) including coma (0.99 ± 3.55), SA (1.14 ± 3.92), and trefoil (1.28 ± 5.53) were not statistically significant (all P > 0.05). Coma had the highest share of corneal HOAs before and 24 months after CXL and the largest 24-month decrease was seen in corneal SA. CONCLUSION: At 2 years after accelerated CXL, despite reduced keratometry and corneal flattening, mesopic CS as well as ocular and corneal HOA remained unchanged, and the procedure did not cause a reduction in patients' vision quality.


Subject(s)
Corneal Stroma/metabolism , Cross-Linking Reagents , Keratoconus/drug therapy , Mesopic Vision/physiology , Photosensitizing Agents/therapeutic use , Riboflavin/therapeutic use , Adult , Collagen/metabolism , Contrast Sensitivity/physiology , Controlled Before-After Studies , Corneal Topography , Female , Humans , Keratoconus/metabolism , Keratoconus/physiopathology , Male , Photochemotherapy/methods , Prospective Studies , Visual Acuity/physiology , Young Adult
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