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1.
Comparison of Femto-LASIK With Combined Accelerated Cross-linking to Femto-LASIK in High Myopic Eyes: A Prospective Randomized Trial.
Kohnen, T, Lwowski, C, Hemkeppler, E, de'Lorenzo, N, Petermann, K, Forster, R, Herzog, M, Böhm, M
American journal of ophthalmology. 2020;:42-55
Abstract
PURPOSE To evaluate the safety and efficacy of femtosecond (fs) laser-assisted in situ keratomileusis (LASIK) combined with accelerated corneal cross-linking (LASIK Xtra) compared to conventional fs-LASIK (convLASIK) in high myopic patients. DESIGN Prospective, randomized, fellow-eye controlled clinical trial. METHODS Setting: Department of Ophthalmology, Goethe University, Frankfurt/Germany. StudyPopulation: Twenty-six patients with high myopia and/or myopic astigmatism received randomized treatment with LASIK Xtra (30 mW/cm2, 90 seconds with continuous ultraviolet-A) in 1 eye and convLASIK in the other eye. MainOutcomeMeasures: Uncorrected distance visual acuity (UDVA), best spectacle-corrected VA (BSCVA), manifest refractive spherical equivalent (MRSE), endothelial cell count (ECC), and corneal thickness. RESULTS The UDVA improved from 1.26 ± 0.13 logMAR preoperative to -0.02 ± 0.15logMAR in LASIK Xtra eyes and from 1.27 ± 0.12 logMAR to 0.01 ± 0.15 logMAR in the convLASIK eyes (P > .05). The MRSE changed from -7.35 ± 1.15 diopters (D) and -7.5 ± 1.12 D to -0.17 ± 0.43 D and -0.25 ± 0.46 D, respectively. There was no significant difference in outcomes between both groups during the 12 months follow-up except for the convLASIK eyes' showing slightly better BSCVA after 1 week (P < .05). ConvLASIK eyes revealed a nonsignificant trend toward myopic regression from 3 to 12 months postoperative with a change in MRSE of -0.15 D compared to -0.1 D in LASIK Xtra eyes. Topography showed stability of corneal curvature with no signs of keratectasia in both groups at 12 months. CONCLUSION While apparently safe, LASIK Xtra showed no advantages over conventional LASIK. At 12 months, both groups showed no difference regarding UDVA and refractive stability, and no signs of keratectasia.
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2.
Noninvasive real-time assessment of riboflavin consumption in standard and accelerated corneal crosslinking.
Lombardo, M, Lombardo, G
Journal of cataract and refractive surgery. 2019;(1):80-86
Abstract
PURPOSE To estimate the noninvasive riboflavin concentration in the corneal stroma using a new ultraviolet-A (UVA) theranostic device for corneal crosslinking (CXL). SETTING Vision Engineering Italy srl, Rome, Italy. DESIGN Experimental study. METHODS Fourteen human donor corneas were treated according to conventional (UVA irradiance of 3 mW/cm2 for 30 minutes) and rapid (10 mW/cm2 for 9 minutes) riboflavin-UVA CXL protocols using a theranostic UVA device. Five additional samples were treated by 0.5 mW/cm2 for 9 minutes and used as positive controls to determine riboflavin photodegradation under near ambient lighting conditions. A 20% dextran-enriched 0.1% riboflavin solution was used in all cases. The device consisted of a UVA light source; a red-green-blue camera, which acquires the fluorescence images of the cornea during treatment; and a single-board computer for managing the overall operations and the raw data processing. RESULTS Preirradiation stromal soaking for 30 minutes achieved highly consistent intrastromal riboflavin concentration in all tissues (mean 0.015% ± 0.003% [SD]). There were no differences in the kinetics curves of riboflavin consumption between the 2 UVA irradiation protocols; the intrastromal riboflavin concentration decreased exponentially, with a mean constant energy rate of 2.8 ± 0.2 J/cm2. In the control group, the intrastromal riboflavin concentration decreased quasilinearly. CONCLUSIONS The theranostic device provided estimates of the intrastromal concentration of riboflavin noninvasively during treatment. In the 3 to 10 mW/cm2 range of power densities, the consumption of riboflavin in the stroma by UVA irradiation was only energy dependent in accordance with the Bunsen-Roscoe law.
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3.
Corneal crosslinking and intracorneal ring segments for keratoconus: A randomized study of concurrent versus sequential surgery.
Hersh, PS, Issa, R, Greenstein, SA
Journal of cataract and refractive surgery. 2019;(6):830-839
Abstract
PURPOSE To assess outcomes of corneal crosslinking (CXL) and intracorneal ring segments (ICRS) (Intacs) used adjunctively, and then compare the safety and efficacy of concurrent versus sequential surgery. SETTING Cornea and refractive surgery subspecialty practice. DESIGN Prospective randomized clinical trial. METHODS Patients were randomized to one of two groups: ICRS first, immediately followed by CXL during the same session (n = 104), or ICRS followed by CXL 3 months later (n = 94). Outcomes included changes in maximum keratometry (K) and topographic inferior-superior (I-S) difference, maximum flattening of topographic K, and changes in uncorrected (UDVA) and corrected (CDVA) distance visual acuities. These were analyzed in the entire cohort, in the two randomized groups, and in subgroups stratified to ICRS size and placement. Patients were followed for 6 months. RESULTS The study comprised 198 eyes of 198 patients. Overall, maximum K decreased by an average of 2.5 D, I-S difference improved by 3.9 D, and there was an average maximum flattening of -7.5 D. The UDVA improved by 2.0 logarithm of the minimum angle of resolution lines, on average, and the CDVA improved by 1.1 lines. There was no significant difference between the sequential and concurrent groups in any of the outcomes analyzed. There were 6 clinically significant adverse events. CONCLUSIONS CXL and ICRS can be used adjunctively with substantial improvement in corneal topography, and with no increase in safety concerns over each procedure alone. Sequential and concurrent treatment with ICRS and CXL show equivalent outcomes. Both thicker segment size and single segment placement seem to result in greater topographic improvement.
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4.
PACK-CXL in Reducing the Time to Heal in Suppurative Corneal Ulcers: Observations of a Pilot Study From South India.
Basaiawmoit, P, Selvin, SST, Korah, S
Cornea. 2018;(11):1376-1380
Abstract
PURPOSE To assess the usefulness of photoactivated chromophore for infectious keratitis-corneal collagen cross-linking in reducing the time to heal in suppurative corneal ulcers in a South Indian tertiary care center. METHODS This was an observational cohort study with 2 arms. In the prospective arm, 13 patients with suppurative corneal ulcers who presented to the outpatient department were recruited. Their ulcers were exposed to ultraviolet-A with riboflavin (B2) (photoactivated chromophore for infectious keratitis-corneal collagen cross-linking) up to a maximum of 4 sittings at 3-day intervals. Topical antimicrobial therapy was continued as per the standard department protocol. This cohort was compared with a retrospective cohort of 32 consecutive patients who had been admitted and treated at our department for a similar profile of ulcers in the previous 1 year. RESULTS The ulcers in the prospective arm had an average healing time of 21.6 days, whereas the retrospective arm had an average healing time of 48.8 days. This reduction in the time to heal trends not only toward being statistically significant (P = 0.06) but also highly clinically significant. CONCLUSIONS CXL reduced the time to heal in suppurative corneal ulcers less than 6 mm in diameter and can be used as an adjuvant to antimicrobial therapy.
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5.
Prospective Randomized Trial of Corneal Cross-linking Riboflavin Dosing Frequencies for Treatment of Keratoconus and Corneal Ectasia.
Price, MO, Fairchild, K, Feng, MT, Price, FW
Ophthalmology. 2018;(4):505-511
Abstract
PURPOSE To investigate whether the riboflavin dosing frequency affects corneal cross-linking efficacy or safety, given that isotonic riboflavin solution is viscous and each installation coats the corneal surface with a film that absorbs some of the incident ultraviolet A light. DESIGN Prospective, randomized, single-center equivalence trial. PARTICIPANTS Patients with progressive keratoconus or ectasia after refractive surgery (n = 510). METHODS One eye per patient was prospectively randomized to 2-minute or 5-minute riboflavin dosing intervals with standard corneal cross-linking (epithelial removal and 30-minute irradiation with 3 mW/cm2 ultraviolet A light). Block randomization resulted in comparable representation of keratoconus and ectasia after refractive surgery in the 2 treatment arms. Treatment equivalence was assessed using the 2 one-sided test. Fellow eyes (n = 207) were treated with 5-minute dosing and considered in the safety analysis. MAIN OUTCOME MEASURES The primary hypothesis was equivalent change in the topography-derived maximum keratometry value from baseline to 6 months with 2-minute vs. 5-minute dosing. A ±0.75-diopter margin of equivalence for the treatment difference between dosing regimens was considered clinically relevant. Adverse events and changes from baseline to 6 months in corrected distance visual acuity (CDVA), uncorrected distance visual acuity, and minimum corneal thickness were assessed. RESULTS The mean reduction in maximum keratometry from baseline was equivalent with 2-minute and 5-minute riboflavin dosing intervals at 6 months (0.97 and 0.76 diopters, respectively; 90% confidence interval for treatment difference, -0.23 to 0.66; per-protocol population). With both dosing intervals, the mean improvement in CDVA was 0.07 logarithm of the minimum angle of resolution or 3.5 letters at 6 months. Of the 635 study and fellow eyes examined at 6 months, 134 (21%) gained and 32 (5%) lost 2 or more lines of CDVA. Three eyes (0.4%) developed sterile infiltrates, 1 (0.1%) had delayed epithelial healing with dendrites, and 3 (0.4%) had recurrent epithelial defects. Three eyes (0.4%) were re-treated. CONCLUSIONS The 2 riboflavin dosing regimens produced equivalent reduction in the maximum keratometry value, with a favorable safety profile.
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6.
Outcomes of Simultaneous and Sequential Cross-linking With Excimer Laser Surface Ablation in Keratoconus.
Bardan, AS, Lee, H, Nanavaty, MA
Journal of refractive surgery (Thorofare, N.J. : 1995). 2018;(10):690-696
Abstract
PURPOSE To evaluate the outcomes of simultaneous and sequential corneal crosslinking (CXL) and excimer laser surface ablation protocols in keratoconus. METHODS A literature review was conducted using MEDLINE. The studies were divided into three groups: the sequential group included studies with CXL followed by excimer laser surface ablation later, the simultaneous group included simultaneous excimer laser surface ablation and CXL, and the no CXL group included excimer laser surface ablation only with no CXL. The data on change in logMAR uncorrected distance visual acuity (UDVA), spectacle corrected distance visual acuity (CDVA), change in spherical equivalent (SE) and refractive astigmatism, change in maximum keratometry (Kmax), complications, and safety and efficacy indices were presented for the latest follow-up visits in all groups. RESULTS Twenty-one studies (3 = sequential; 11 = simultaneous, 7 = no CXL) were included. UDVA improved in all groups. CDVA improved more in the sequential group. SE change was greatest in the no CXL group and the refractive astigmatism reduced comparably in the sequential and no CXL groups but less in the simultaneous group. Kmax reduced in all groups. Only the sequential group showed no progression. Corneal haze was reported in 100%, 54.5%, and 57.1% studies, respectively. Safety and efficacy indices were 1.96 and 1.58, 1.41 ± 0.32 and 0.91 ± 0.41, and 1 and 0.82, respectively. CONCLUSIONS The sequential group showed greater improvement in CDVA, SE, and refractive astigmatism. Corneal haze was frequently reported in all protocols. Safety and efficacy indices were highest when CXL was performed before excimer laser and least when excimer laser was performed alone without CXL. [J Refract Surg. 2018;34(10):690-696.].
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7.
Accelerated versus conventional corneal collagen cross-linking in patients with keratoconus: an intrapatient comparative study.
Sadoughi, MM, Einollahi, B, Baradaran-Rafii, A, Roshandel, D, Hasani, H, Nazeri, M
International ophthalmology. 2018;(1):67-74
Abstract
PURPOSE To compare the outcomes of the conventional and accelerated corneal collagen cross-linking (CXL) in patients with bilateral progressive keratoconus (KC). METHODS Fifteen consecutive patients with bilateral progressive KC were enrolled. In each patient, the fellow eyes were randomly assigned to the conventional CXL (3 mW/cm2 for 30 min) or accelerated CXL (ACXL) (9 mW/cm2 for 10 min) groups. Manifest refraction; uncorrected and corrected distant visual acuity; maximum and mean keratometry; corneal hysteresis and corneal resistance factor; endothelial cell density and morphology; central corneal thickness; and wavefront aberrations were measured before and 12 months after the CXL. RESULTS Manifest refraction spherical equivalent and refractive cylinder improved significantly only in conventional group. Uncorrected and corrected distant visual acuity did not change significantly in either group. Also there was no significant change in the maximum and mean keratometry after 12 months. There was significant decrease in central corneal thickness in both groups which was more prominent in conventional group. Endothelial cell density reduced only in the conventional group which was not statistically significant (P = 0.147). CH, CRF, and wavefront aberrations did not change significantly in either group. We did not observe any significant difference in the changes of the variables between the two groups. CONCLUSIONS Accelerated CXL with 9 mW/cm2 irradiation for 10 min had similar refractive, visual, keratometric, and aberrometric results and less adverse effects on the corneal thickness and endothelial cells as compared with the conventional method after 12 months follow-up. However, randomized clinical trials with longer follow-ups and larger sample sizes are needed.
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8.
Randomized Controlled Trial Comparing Transepithelial Corneal Cross-linking Using Iontophoresis with the Dresden Protocol in Progressive Keratoconus.
Lombardo, M, Giannini, D, Lombardo, G, Serrao, S
Ophthalmology. 2017;(6):804-812
Abstract
PURPOSE To compare clinical outcomes of transepithelial corneal cross-linking using iontophoresis (T-ionto CL) and standard corneal cross-linking (standard CL) for the treatment of progressive keratoconus 12 months after the operation. DESIGN Prospective randomized controlled clinical trial. PARTICIPANTS Thirty-four eyes of 25 participants with progressive keratoconus were randomized into T-ionto CL (22 eyes) or standard CL (12 eyes). METHODS T-ionto CL was performed using an iontophoresis device with dextran-free 0.1% riboflavin-5-phosphate solution with enhancers and by irradiating the cornea with a 10 mW/cm2 ultraviolet A device for 9 minutes. Standard CL was performed according to the Dresden protocol. MAIN OUTCOME MEASURES The primary outcome measure was stabilization of keratoconus after 12 months through analysis of maximum simulated keratometry readings (Kmax, diopters). Other outcome measures were corrected distance visual acuity (CDVA, logarithm of the minimum angle of resolution [logMAR]), manifest spherical equivalent refraction (D), central corneal thickness (CCT, micrometers) and endothelial cell density (ECD). Follow-up examinations were arranged at 3 and 7 days and 1, 3, 6, and 12 months. RESULTS Twelve months after T-ionto CL and standard CL, Kmax on average flattened by -0.52±1.30 D (P = 0.06) and -0.82±1.20 D (P = 0.04), respectively. The mean change in CDVA was -0.10±0.12 logMAR (P = 0.003) and -0.03±0.06 logMAR (P = 0.10) after T-ionto CL and standard CL, respectively. The manifest spherical equivalent refraction changed on average by +0.71±1.44 D (P = 0.03) and +0.21±0.76 D (P = 0.38), respectively. The CCT and ECD measures did not change significantly in any group at 12 months. Significant differences in the outcome measures between treatments were found in the first week postoperatively. No complications occurred in the T-ionto CL group; 1 eye (8%) had sterile corneal infiltrates, which did not affect the final visual acuity, in the standard CL group. CONCLUSIONS Significant visual and refractive improvements were found 12 months after T-ionto CL, though the average improvement in corneal topography readings was slightly lower than the Dresden protocol in the same period.
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A Preliminary In Vitro Study on the Efficacy of High-Power Photodynamic Therapy (HLLT): Comparison between Pulsed Diode Lasers and Superpulsed Diode Lasers and Impact of Hydrogen Peroxide with Controlled Stabilization.
Caccianiga, G, Baldoni, M, Ghisalberti, CA, Paiusco, A
BioMed research international. 2016;:1386158
Abstract
Aim. In periodontology lasers have been suggested for the photodynamic therapy (PDT): such therapy can be defined as the inactivation of cells, microorganisms, or molecules induced by light and not by heat. The aim of this study was to evaluate results of PDT using a 980 nm diode laser (Wiser Doctor Smile, Lambda SPA, Italy) combined with hydrogen peroxide, comparing a pulsed diode laser (LI) activity to a high-frequency superpulsed diode laser (LII). Materials and Methods. Primary fibroblasts and keratinocytes cell lines, isolated from human dermis, were irradiated every 48 h for 10 days using LI and LII combined with SiOxyL(+) ™ Solution (hydrogen peroxide (HP) stabilized with a glycerol phosphate complex). Two days after the last irradiation, the treated cultures were analyzed by flow cytofluorometry (FACS) and western blotting to quantify keratin 5 and keratin 8 with monoclonal antibodies reactive to cytokeratin 5 and cytokeratin 8. Antimicrobial activity was also evaluated. Results. Both experimental models show the superiority of LII against LI. In parallel, stabilized HP provided better results in the regeneration test in respect to common HP, while the biocidal activity remains comparable. Conclusion. The use of high-frequency lasers combined with stabilized hydrogen peroxide can provide optimal results for a substantial decrease of bacterial count combined with a maximal biostimulation induction of soft tissues and osteogenesis.
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10.
Standard corneal collagen crosslinking versus transepithelial iontophoresis-assisted corneal crosslinking, 24 months follow-up: randomized control trial.
Bikbova, G, Bikbov, M
Acta ophthalmologica. 2016;(7):e600-e606
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Abstract
PURPOSE To compare the results of standard corneal crosslinking (CXL) and transepithelial iontophoresis-assisted CXL after 24 months follow-up. MATERIAL AND METHODS Corneal crosslinking (CXL) was performed in a series of 149 eyes of 119 patients with keratoconus I-II of Amsler classification. Depending on the CXL method, patients were divided into two groups: (1) 73 eyes with standard CXL and (2) 76 eyes with transepithelial iontophoresis-assisted CXL. Depending on the group, epithelium removal or administration of riboflavin solution by iontophoresis for 10 min was performed, after which standard surface UVA irradiation (370 nm, 3 mW/cm2 ) was performed at a 5-cm distance for 30 min. RESULTS A statistically significant difference in corrected distance visual acuity (CDVA) was observed between the two groups, with a better outcome in the second group after 6 months (p = 0.037); however, no significant difference was found 24 months after treatment (p = 0.829). Stabilization and regression of keratometry values were achieved in both groups, but standard CXL was more effective. The average demarcation line depth in the standard CXL group was 292 ± 14 μm after 14 days and 172 ± 16 μm in the transepithelial iontophoresis-assisted CXL group. No demarcation line was detected after 1 month and 3 months in 45% and 100% of the eyes in the second group respectively. CONCLUSION Transepithelial iontophoresis-assisted collagen crosslinking showed to be less effective than standard CXL after 24 months of follow-up, possibly due to a more superficial formation of corneal collagen crosslinks, however the stopping of disease progression was achieved 24 months after procedure.