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PURPOSE: This study aimed to determine the preferred protocol of corneal collagen cross-linking (CXL) in the treatment of progressive keratoconus. METHODS: Relevant studies were retrieved in PubMed, EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL). Maximum keratometry value (Kmax), best spectacle-corrected visual acuity (BSCVA), manifest refraction spherical equivalent (MRSE), and endothelial cell density (ECD) were evaluated in network meta-analysis. RESULTS: Eight randomized controlled trials (RCTs) were included. Low-level evidence suggested that aCXL with 30mW/cm2 for 3 min (aCXL-3) might be the best protocol for reducing BSCVA (65.22%) but worst protocol for reducing MRSE (51.53%). aCXL with 18mW/cm2 for 5 min (aCXL-5) might be the best protocol for reducing Kmax (39.58%) and MRSE (77.85%) but might be the worst for preserving ECD (50.98%). aCXL with 9mW/cm2 for 10 min (aCXL-10) might be the best protocol for preserving ECD (31.53%). CONCLUSION: Overall, three protocols of aCXL are comparable in therapeutic efficacy and safety for treating progressive keratoconus. Despite no direct data comparing the efficacy of each technique according to different patients' profiles, it is reasonable to state that aCXL-5 may be the best for patients at early-stage to reduce Kmax and MRSE, aCXL-3 may be the best for patients at mid-stage to improve BSCVA, and aCXL-10 may be the best for patients at late-stage to preserve DEC.
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Crosslinking Corneano , Ceratocone , Humanos , Ceratocone/diagnóstico , Ceratocone/tratamento farmacológico , Metanálise em Rede , Fármacos Fotossensibilizantes/uso terapêutico , Protocolos ClínicosRESUMO
PURPOSE: To investigate the safety of accelerated corneal collagen cross-linking (A-CXL) in patients with keratoconus on the basis of thickness analysis measurements of retinal layers and retinal morphology. STUDY DESIGN: This was a retrospective and comparative study. METHODS: The study included 64 eyes of 32 patients with keratoconus disease. One eye of the patients underwent A-CXL for progressive keratoconus (CXL group) and the fellow eye was followed due to the absence of progression. Patients with at least 1-year follow-up after A-CXL were included. Keratometry, pachymetry and corrected-distance visual acuity (CDVA) levels of the patients were compared. The segmentation analysis of the individual retinal layers of the eyes with (CXL group) and without CXL (no CXL group) was compared with spectral domain-optical coherence tomography automatic segmentation program at baseline and at the last follow-up. The thickness of the retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer, outer nuclear layer and retina pigment epithelium layer in the central 1-mm subfield defined by the ETDRS was analyzed. RESULTS: The mean age of keratoconus patients was 23.9 ± 5.4 years, patients were more likely to be male (21/11, 65.6%), and the mean follow-up duration was 13.9 ± 1.5 months. When keratometry, pachymetry and CDVA levels were compared, only a significant difference was found between CDVA at the last follow-up (0.21 vs. 0.11 LogMAR). No significant difference was observed in neither retinal morphology nor segmentation of individual retinal layers at baseline and at the final evaluation (P > 0.05). CONCLUSIONS: It has been observed that the A-CXL protocol did not cause a significant change in both retinal layer thickness and macular morphology.
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Ceratocone , Fotoquimioterapia , Adolescente , Adulto , Colágeno/uso terapêutico , Topografia da Córnea , Reagentes de Ligações Cruzadas/uso terapêutico , Feminino , Seguimentos , Humanos , Ceratocone/diagnóstico , Ceratocone/tratamento farmacológico , Masculino , Fármacos Fotossensibilizantes/uso terapêutico , Estudos Retrospectivos , Riboflavina/uso terapêutico , Raios Ultravioleta , Adulto JovemRESUMO
PURPOSE: The aim of this study is to compare the long-term follow-up outcomes of traditional and accelerated corneal cross-linking (CXL) for keratoconus. METHODS: This retrospective comparative cohort study included patients with keratoconus who underwent corneal cross-linking (CXL) between August 2008 and December 2016. Patients treated before August 2013 underwent the traditional Dresden protocol, and those treated subsequently received the accelerated protocol, i.e., 0.1% riboflavin soaking for 10 min, followed by pulsed UV-A irradiation at 30 mW/cm2 for 8 min, and a total irradiation power of 7.2 J/cm2. The primary outcome was the success rate in halting the disease progression. The postoperative changes in visual acuity, keratometry readings, endothelial cell count and complications following accelerated CXL and conventional CXL were compared. RESULTS: This study evaluated 113 eyes over a mean follow-up period of 37.61 ± 16.34 months. It was found that 89.6% and 95.7% of the eyes were successfully treated with the traditional and accelerated protocols, respectively (p = 0.239). The corrected-distance visual acuity improved in both groups, but it was significantly better following the accelerated protocol (p = 0.037). Traditional protocol group had more postoperative complications than the accelerated group (8.9% versus 2%), although not reaching statistically significant difference (p = 0.142). There were no significant differences in the topographic (p = 0.122) and refractive (p = 0.570) outcomes. CONCLUSION: Accelerated CXL and conventional CXL are both safe and effective, and the long-term follow-up showed that the accelerated protocol was similar to the standard one in terms of halting keratoconus and achieving visual outcomes. Because of its potential benefits, the accelerated protocol may be considered for the treatment of progressive keratoconus.
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Ceratocone , Fotoquimioterapia , Estudos de Coortes , Colágeno/uso terapêutico , Topografia da Córnea , Reagentes de Ligações Cruzadas/uso terapêutico , Humanos , Ceratocone/diagnóstico , Ceratocone/tratamento farmacológico , Fármacos Fotossensibilizantes/uso terapêutico , Estudos Retrospectivos , Riboflavina/uso terapêutico , Raios UltravioletaRESUMO
BACKGROUND: To investigate the efficacy and safety of the retention ring-assisted continuous application of 0.1% riboflavin in pulsed-light accelerated corneal collagen cross-linking on the progression of keratoconus. METHODS: The medical records of 20 eyes of 18 patients with progressive keratoconus who received collagen cross-linking at Seoul National University Hospital were retrospectively reviewed. Isotonic 0.1% riboflavin was continuously applied for 10 min using an 8.0-mm retention ring before the irradiation and accelerated cross-linking was applied with 30-mW pulsed-ultraviolet light at a wavelength 365 nm for eight minutes (1 s on/1 s off; 30 mW/cm2, cumulative dose of 7 .2J/cm2) without further intermittent application of riboflavin. Visual acuity, refractive error, topographic index, corneal thickness, and endothelial cell density were evaluated before the operation and at 1, 3, 6, and 12 months. RESULTS: The best corrected visual acuity in logMAR improved from preoperative 0.43 to 0.17 in 12 months (p = 0.050). Maximum keratometry decreased from 51.8 D to 50.4 D at 6 months (p = 0.015) and 50.1 D at 12 months (p = 0.0003). Astigmatism decreased from preoperative 5.5 D to 4.1 D at 12 months (p < 0.0001). Thinnest corneal thickness decreased at three and 6 months but recovered in 12 months (p > 0.05). Endothelial cell density decreased at postoperative 1 month (p = 0.02) but gradually recovered in 12 months (p > 0.05). CONCLUSIONS: Retention ring-assisted continuous application of riboflavin for 10 minutes in pulsed-light accelerated cross-linking is a comparably safe and effective treatment for halting the progression of keratoconus in 12 months when compared to outcomes of the standard Dresden protocol shown in previous reports.
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Reagentes de Ligações Cruzadas/uso terapêutico , Ceratocone/tratamento farmacológico , Fotoquimioterapia/métodos , Riboflavina/administração & dosagem , Adolescente , Adulto , Colágeno/metabolismo , Perda de Células Endoteliais da Córnea/patologia , Progressão da Doença , Feminino , Humanos , Soluções Isotônicas/administração & dosagem , Ceratocone/fisiopatologia , Masculino , Fotoquimioterapia/instrumentação , Fármacos Fotossensibilizantes/uso terapêutico , Erros de Refração/fisiopatologia , Estudos Retrospectivos , Raios Ultravioleta , Acuidade Visual/fisiologia , Adulto JovemRESUMO
PURPOSE: To compare the one-year efficacy of accelerated and standard 5.4 J/cm2 protocols of cross-linking (CXL) in the treatment of progressive keratoconus. METHODS: In this systematic review, two members of the research team searched Scopus, Pubmed, ISI, Ovid, Science Direct, and Cochrane databases independently for publications between January 2010 and December 2016. The majority of retrieved studies were not randomized clinical trials (RCT), or the second arm of the RCT was either untreated or customized CXL. The outcomes of interest were uncorrected distance visual acuity, corrected visual acuity, manifest refraction spherical equivalent, maximum keratometry in the central 3 mm, minimum keratometry in the central 3 mm, and corneal thickness in the apex or thinnest point at baseline and 1 year after CXL. RESULTS: Of the 453 papers found in the preliminary search, 23 papers were included in the final analysis. Analysis of variance of one-year changes showed that longer irradiation times were associated with a greater corneal flattening effect, although there was no difference in terms of improvement in vision or refraction. CONCLUSIONS: In other words, efficacy is comparable among different CXL protocols, so it is recommended to use the standard method in cases where maximum flattening is expected, such as young people and severe cases.
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Colágeno/uso terapêutico , Córnea/patologia , Reagentes de Ligações Cruzadas/uso terapêutico , Ceratocone/tratamento farmacológico , Fotoquimioterapia/métodos , Riboflavina/uso terapêutico , Acuidade Visual , Topografia da Córnea , Humanos , Ceratocone/diagnóstico , Fármacos Fotossensibilizantes/uso terapêuticoRESUMO
BACKGROUND: The purpose of this study was to identify differences in clinical corneal findings after standard and accelerated epithelial off cross-linking (CXL) during a long-term follow-up. METHODS: Two hundred forty-one patients (184 male) were included in this monocentric, retrospective, non-randomized and unmasked study. One hundred forty-eight eyes were treated with the accelerated protocol and 138 with the standard protocol with epithelial off CXL, if diagnosed with keratoconus and a progression in Kmax of more than one dioptre during the preceding 6 months, plus a minimal pachymetry measurement of 400 µm in keratometry (Pentacam, Oculus GmbH, Wetzlar, Germany). Exclusion criteria were previous surgery, other corneal conditions or age above 50 years. Follow-up time was 36 months with clinical examination and keratometry at every visit. Outcome measures were the observed rate of corneal changes, differences between treatment groups and correlation with keratometry measurements. RESULTS: In patients with accelerated CXL, significantly more clear corneas were seen at three (p = 0.015) and six (p = 0.002) months after surgery than following the standard protocol. The rate of clear corneas dropped from 52.2% pre-operation (OP) to a minimum of 19.3% after 6 months in the standard protocol group compared with 50.7% clear corneas pre-OP and a minimum of 40.8% in the accelerated group. In the standard protocol group, more striae were found 3 months after intervention than in the accelerated group (p = 0.05). CONCLUSIONS: In patients with accelerated CXL, fewer morphological corneal changes were observed than after conventional CXL. However, rarely, corneal changes persisted for a long time.
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Reagentes de Ligações Cruzadas/uso terapêutico , Ceratocone/tratamento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Adulto , Protocolos Clínicos , Córnea/patologia , Feminino , Humanos , Ceratocone/patologia , Ceratocone/cirurgia , Masculino , Estudos Retrospectivos , Riboflavina/uso terapêuticoRESUMO
OBJECTIVE: Bullous keratopathy (BK) is a serious corneal condition leading to impaired vision and ocular pain, due to chronic corneal edema and recurrent superficial ulceration. BK is refractory to conventional therapy. In human patients, corneal collagen cross-linking (CXL) has been used for the treatment of BK, and CXL treatment was recently described for canine patients. The aim of this study was to evaluate the clinical and pachymetric effects of accelerated CXL in dogs affected by BK. ANIMAL STUDIED: Eight dogs (10 eyes) with BK underwent accelerated CXL. PROCEDURES: CXL treatment comprised 30 min of riboflavin-dextran instillation, followed by 3 min of UVA irradiation at 30 mW/cm². Ocular pain, corneal edema, corneal ulceration, and pachymetry were evaluated 7, 14, 30, 90, and 180 days after treatment. RESULTS: Corneal ulceration and ocular pain were resolved by 1 week after CXL treatment and did not recur during the 6-month follow-up period. Corneal edema improved in the first 3 months, but worsened from months 3 to 6. Corneal thickness initially decreased, but returned to baseline by 6 months post-CXL. CONCLUSIONS: CXL is a useful treatment option for BK in dogs, despite the short-lasting effects on corneal thickness. Patient comfort improved rapidly after a single procedure, although CXL did not achieve resolution of corneal edema. Treatment protocols may be refined to produce more durable effects on corneal edema.
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OBJECTIVES: Melting keratitis is a serious condition presenting a high risk of permanent blindness and is caused by infectious or noninfectious factors. In humans, the clinical efficacy of collagen cross-linking (CXL) has been described in the treatment of refractory infectious keratitis by arresting keratomalacia. The aim of this study was to evaluate the efficacy of accelerated CXL for the treatment of melting keratitis in cats. ANIMALS STUDIED: Ten cats were treated for unilateral melting keratitis by accelerated CXL. PROCEDURE: Corneas were irradiated by UVA (370 nm) at 30 mW/cm² irradiance for 3 min after soaking with 0.1% riboflavin in 20% dextran for 30 min (D1). Follow-up was conducted 3, 7, 14, and 30 days after treatment. RESULTS: Pain improvement was noted for all cases at D4 examination. Epithelial healing was observed at D8 for 9 of 10 cases and at D15 for 1 of 10 cases. Resolution of cellular infiltration was observed for all cases at D8 examination. The corneal vascularization was reduced for 9 of 10 cats by D31. At D31, all cases presented a variable degree of corneal fibrosis, but all eyes had visual function. No recurrent infection was observed. CONCLUSION: Accelerated CXL appears to be a valuable option for the treatment of melting keratitis in cats. All the cases have reached a satisfactory outcome despite the individual differences in the conditions prior to the CXL treatment and the variable presence of infectious agents.
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Doenças do Gato/terapia , Dextranos/farmacologia , Ceratite/veterinária , Riboflavina/farmacologia , Terapia Ultravioleta/veterinária , Animais , Gatos , Córnea/irrigação sanguínea , Córnea/patologia , Córnea/efeitos da radiação , Dextranos/administração & dosagem , Ceratite/patologia , Ceratite/terapia , Estudos Prospectivos , Riboflavina/administração & dosagemRESUMO
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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Reagentes de Ligações Cruzadas/uso terapêutico , Ceratocone/tratamento farmacológico , Fotoquimioterapia , Radiossensibilizantes/uso terapêutico , Riboflavina/uso terapêutico , Raios Ultravioleta , Adolescente , Adulto , Colágeno/metabolismo , Córnea/efeitos dos fármacos , Córnea/metabolismo , Feminino , Humanos , Ceratocone/metabolismo , Ceratocone/fisiopatologia , Masculino , Refração Ocular , Acuidade Visual , Adulto JovemRESUMO
PURPOSE: To analyse long-term outcomes of standard cross-linking (SCXL), accelerated cross-linking (ACXL) and transepithelial cross-linking (TCXL) in the treatment of progressive paediatric keratoconus regarding stability, safety and efficacy. METHODS: This prospective multicentre randomized controlled trial included 97 eyes of 97 paediatric patients with stages I-III ABCD keratoconus grading system, who were randomized into three groups; SCXL group (control group, n = 32; 3 mW/cm2 × 30 min/5.4 J/cm2 ), ACXL (n = 33; 18 mW/cm2 × 5 min/5.4 J/cm2 ) and TCXL (n = 32; 18 mW/cm2 × 5 min/5.4 J/cm2 ). Subjective refraction, uncorrected and corrected visual acuity, keratometry and pachymetry measurements using corneal topography were recorded preoperatively and 1, 2 and 3 years postoperatively. RESULTS: SCXL group exhibited significant successive improvements in the mean visual, refractive and keratometric parameters throughout the entire postoperative 3 years while ACXL group exhibited significant improvements in visual and keratometric parameters in the first postoperative year that remained stable in second and third postoperative years. TCXL group exhibited significant progressive deterioration in all mean parameters compared to SCXL and ACXL (p < 0.0001). Both SCXL and ACXL revealed final 100% success rate with good stability while TCXL revealed final 22% failure rate with keratoconus progression (p < 0.0001). CONCLUSION: SCXL and ACXL were comparable in halting keratoconus progression and achieved good stability and safety; however, SCXL was more efficient than ACXL as it yielded greater significant postoperative mean visual, refractive and keratometric improvements achieving smoother corneal remodelling. Both SCXL and ACXL were much superior to TCXL. SCXL is the best CXL treatment option for paediatric keratoconus while ACXL is a good and effective alternative.
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Ceratocone , Fotoquimioterapia , Criança , Humanos , Topografia da Córnea , Ceratocone/diagnóstico , Ceratocone/tratamento farmacológico , Fotoquimioterapia/métodos , Estudos Prospectivos , Raios Ultravioleta , Acuidade VisualRESUMO
BACKGROUND: To compare one-year results of accelerated cross-linking (ACXL) treatment for progressive keratoconus in pediatric and adult age groups. METHODS: The records of patients who had undergone the ACXL procedure (9mV/cm2, 10min) for progressive keratoconus were evaluated retrospectively. The patients were divided into 2 groups, with the pediatric group aged 17years or less and the adult group aged 18years or more, for the statistical analysis. Pre- and 12-month post- ACXL best-corrected visual acuity (BCVA), maximum keratometry (Kmax), sim K1, sim K2, corneal thickness at the thinnest point (thCT), and corneal astigmatism (CA) values of the patient groups were recorded. RESULTS: Thirty-two right eyes of 32 patients were included in the pediatric group, and 32 right eyes of 32 patients were included in the adult group. A significant improvement in BCVA and a significant decrease in thCT values were present in both groups 12months after the surgery compared to the preoperative period. The decrease in Kmax, sim K1 and sim K2 values compared to the preoperative period was significant in the adult group. When the two groups were compared after 12months, only the simK1 value was significantly lower in the adult group, and there was no significant difference between the other measurements. CONCLUSIONS: There is a slight tendency toward more flattening in the adult group 12months after ACXL treatment, but this is not statistically significant.
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Ceratocone , Fotoquimioterapia , Adulto , Criança , Colágeno/uso terapêutico , Topografia da Córnea , Reagentes de Ligações Cruzadas/uso terapêutico , Seguimentos , Humanos , Ceratocone/diagnóstico , Ceratocone/tratamento farmacológico , Ceratocone/epidemiologia , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/uso terapêutico , Estudos Retrospectivos , Riboflavina/uso terapêutico , Raios Ultravioleta , Acuidade VisualRESUMO
PURPOSE: The purpose of the present study was to assess the long-term efficiency and safety of the "epi-off" accelerated CXL (9 mW/cm2 for 10 minutes) in comparison to the standard "epi-off" CXL (3 mW/cm2 for 30 minutes) in terms of topographical and keratometric parameters, refractive data and visual outcomes at 7 years of follow-up, in progressive keratoconus. MATERIAL AND METHOD: A retrospective and comparative study was performed. A total of 183 eyes from 183 patients with documented progressive keratoconus were included in the study. The patients were divided in two groups: 93 eyes from 93 patients underwent "epi-off" standard cross-linking technique (3 mW/cm2 for 30 minutes) (S-CXL group) and 90 eyes from 90 patients underwent accelerated "epi-off" corneal CXL technique (9 mW/cm2 for 10 minutes) (A-CXL group). RESULTS: Improvements in uncorrected distance visual acuity (UDVA) were statistically significant compared to baseline values in both groups at each time-point visit (p=0.0421 at 1 year, p=0.0411 at 7 years for A-CXL and p=0.0375 at 1 year, p=0.0389 at 7 years for S-CXL). At 7 years there was a statistically significant increase in CDVA (p=0.039 in the A-CXL group and p=0.0343 in the S-CXL group at 7 years). Statistically significant reduction was noticed in Ksteep (p=0.0411 in A-CXL group and p=0.0224 in S-CXL group), Kflat (p=0.0198 in A-CXL group and p=0.008 in S-CXL group), K mean (p=0.0106 in A-CXL group and p=0.0193 in S-CXL group) and Kmax (p=0.0413 in A-CXL group and p=0.054 in S-CXL group) at 7 years, compared to baseline values, in both groups, but without any statistically difference between the two procedures, at all time-point visits (p>0.05). CONCLUSION: The long-term outcomes of "epi-off" accelerated corneal collagen crosslinking-UVA (9 mW/cm2 for 10 minutes) are similar to standard "epi-off" corneal collagen crosslinking procedure in the treatment of progressive keratoconus.
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The purpose of this study was to evaluate the effectiveness and safety of a novel buffered riboflavin solution approved for corneal cross-linking (CXL) in progressive keratoconus and secondary corneal ectasia. Following the in vivo preclinical study performed on New Zealand rabbits comparing the novel 0.25% riboflavin solution (Safecross®) containing 1% hydroxypropyl methylcellulose (HPMC) with a 0.1% riboflavin solution containing 0.10% EDTA, accelerated epithelium-off CXL was performed on 10 patients (10 eyes treated, with the contralateral eye used as control) through UV-A at a power setting of 9 mW/cm2 with a total dose of 5.4 J/cm2. Re-epithelialization was evaluated in the postoperative 7 days by fluorescein dye test at biomicroscopy; endothelial cell count and morphology (ECD) were analyzed by specular microscopy at the 1st and 6th month of follow-up and demarcation line depth (DLD) measured by anterior segment optical coherence tomography (AS-OCT) one month after the treatment. We observed complete re-epithelization in all eyes between 72 and 96 h after surgery (88 h on average). ECD and morphology remained unchanged in all eyes. DLD was detected at a mean depth of 362 ± 50 µm, 20% over solutions with equivalent dosage. SafeCross® riboflavin solution chemically-boosted corneal cross-linking seems to optimize CXL oxidative reaction by higher superoxide anion release, improving DLD by a factor of 20%, without adverse events for corneal endothelium.
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In adults, the management of keratoconus has evolved in recent years to achieve a well-codified treatment algorithm. The technique of cross-linking (CXL) has allowed us to stabilize the progression of keratoconus and has been largely developed. It is very effective, with few postoperative complications. Currently, there is no specific keratoconus management protocol for children. As we already know that keratoconus usually evolves more rapidly in children, we might consider whether a stabilizing treatment should be proposed as first-line therapy at the time of diagnosis. We carried out a retrospective study including patients less than 18 years of age with keratoconus who consulted the ophthalmology department at Edouard Herriot hospital in Lyon between 2013 and 2017. The main study parameter was whether or not CXL was performed. The other parameters were gender, age, ethnicity, eye rubbing, presence or absence of atopic disease, maximum keratometry (Kmax), minimal pachymetry, best corrected visual acuity (BCVA) and spherical equivalent. Forty-eight eyes of 34 patients were included. We found that two-thirds of the patients were Caucasian boys. Half of the patients had allergies, and over 60% of patients rubbed their eyes regularly. Only six percent of patients had a family history of keratoconus. The mean age of the patients was 14 (7-18) years at the time of diagnosis. Thirty-four eyes of 22 patients underwent CXL, for a total of 71% of our cohort. No postoperative complications occurred. After CXL, there was no significant difference in minimum pachymetry (455.6±37.25µm vs. 453.45±42.6µm after treatment (P=0.71)) or Kmax (50.23±7.17D vs. 50.99±7.01D after treatment (P=0.058)). There was a significant improvement in BCVA (from 0.30±0.3LogMar to 0.17±0.17LogMar after CXL (P=0.024)) and spherical equivalent (-1.91±2.1D to -2.54±1.89D after treatment (P=0.009)). The mean duration of follow-up was 32.2 months (12-59). CXL shows long-term disease stabilization in children with keratoconus. Nevertheless, this technique is indicated only for progressive keratoconus. Early diagnosis and management are essential in this population where the disease is rapidly changing. Treatment of atopy and performance of corneal topography when a child has irregular astigmatism should become automatic for early detection of this disease.
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Ceratocone , Fotoquimioterapia , Adolescente , Adulto , Criança , Colágeno/uso terapêutico , Topografia da Córnea , Reagentes de Ligações Cruzadas/uso terapêutico , Epitélio , Seguimentos , Humanos , Ceratocone/tratamento farmacológico , Masculino , Fármacos Fotossensibilizantes/uso terapêutico , Estudos Retrospectivos , Riboflavina/uso terapêutico , Raios Ultravioleta , Acuidade VisualRESUMO
INTRODUCTION: To compare the results of an accelerated corneal cross-linking (CXL) protocol (9 mW/cm2, 10 min) with the standard CXL protocol (3 mW/cm2, 30 min) in patients with Down syndrome (DS) who have keratoconus (KC). METHODS: Twenty-seven 10- to 20-year-old patients with DS who had bilateral progressive KC were enrolled in a contralateral randomized trial and completed 2 years of follow-up examinations. Fellow eyes were randomly allocated to the accelerated CXL group or the standard CXL group. The main outcome measure was change in maximum keratometry (Kmax) centered on the steepest point (zonal Kmax - 3 mm) with a non-inferiority margin of 1.0 diopter (D). Vision and refraction tests, ophthalmic examinations, and corneal tomography were performed at baseline and at 6, 12, and 24 months after CXL. Failure was defined as an increase of ≥ 1.0 D in zonal Kmax - 3 mm within a 12-month period. RESULTS: The mean age (± standard deviation) of the patients was 15.71 ± 2.40 years. The within-group change in zonal Kmax - 3 mm was not significant after 2 years in either group, and within-group zonal Kmax - 3 mm remained stable. At 2 years after CXL, the mean change in the zonal Kmax - 3 mm was - 0.02 ± 0.81 D and - 0.31 ± 0.86 D in the accelerated CXL and standard CXL groups, respectively (P = 0.088). At 1 year of follow-up, three patients in the accelerated CXL group showed treatment failure (mean change in zonal Kmax - 3 mm + 2.12 ± 0.11 D); no patients in the standard CXL group showed treatment failure. At 2 years of follow-up, these three patients showed a decrease of - 0.43 ± 0.18 D in zonal Kmax - 3 mm from a baseline value of 55.11 ± 0.32 D. The 2-year trends of the inferior-superior asymmetry and vertical coma were statistically significantly different between the two groups, with the accelerated CXL protocol showing superiority in patients with higher baseline values. CONCLUSION: In young patients with Down syndrome, the accelerated CXL protocol was able to halt disease progression and may be an alternative for the standard CXL protocol. In advanced KC, the efficacy of the accelerated approach was delayed and appeared later in the follow-up. In asymmetric cornea, the accelerated CXL resulted in centralization of the corneal cone. TRIAL REGISTRATION: Iranian Registry of Clinical Trials, IRCT20100706004333N3.
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Simultaneous corneal cross-linking (CXL) has been proposed as an adjunct therapy to corneal refractive procedures to prevent future ectasia, especially when performed in borderline corneas. This review analyses the currently available literature (minimum follow-up 6 months) on corneal refractive surgery and simultaneous CXL (PRK Xtra, LASIK Xtra, and SMILE Xtra) to evaluate the overall results including the safety, efficacy, and potential complications associated with these procedures. A comprehensive literature search of various electronic databases (PubMed, PubMed Central, Cochrane database, and MEDLINE) was performed up to 20th May 2020. Four relevant studies were found for PRK Xtra, 12 for LASIK Xtra, and 3 for SMILE Xtra. The total number of eyes included in this review was 1,512: 294 for PRK Xtra, 221 for PRK-only, 446 eyes for LASIK Xtra, 398 eyes for LASIK-only, 91 for SMILE Xtra and 62 for SMILE-only. Current literature suggests that refractive surgery and simultaneous CXL is generally safe and delivers comparable results in terms of visual and refractive outcomes than refractive surgery alone. However, there is no consensus on a standard cross-linking protocol, and complications such as diffuse lamellar keratitis, central toxic keratopathy, and corneal ectasia following Xtra procedures have been reported. It is therefore suggested that surgeons exercise caution in case-selection and counsel their patients regarding the potential risks and benefits with Xtra procedures. Also, further studies are required to standardize the UV-A irradiation protocols and to evaluate the long-term effect on safety, refractive predictability, and stability of these procedures.
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Ceratomileuse Assistida por Excimer Laser In Situ , Miopia , Colágeno , Córnea/cirurgia , Humanos , Miopia/cirurgia , Acuidade VisualRESUMO
Purpose: To compare the subclinical inflammatory response (as measured by anterior chamber flare) induced after standard (3 mW/cm2, 30 min) and accelerated (18 mW/cm2, 5 min) corneal cross-linking (CXL). Methods: In this comparative, non-randomized study, patients with progressive keratoconus who underwent standard or accelerated CXL were studied. Laser flare photometery (FM-600; Kowa, Tokyo, Japan) was used to measure anterior chamber flare preoperatively and at 1 week, 1 month, 3 months, and 6 months after the procedure. Results: Sixty eyes of 60 patients were studied; 30 eyes in each group. Mean baseline flare values were 4.15 ± 1.19 and 4.57 ± 2.17 ph/ms in standard and accelerated groups, respectively (p = 0.228).and after surgery increased in all follow-up measurements in the both groups similarly (P > 0.05). Conclusion: Both standard and accelerated CXL results in induction of a subclinical inflammatory response that persists up to 6 month. The response was similar between the two groups.
Assuntos
Câmara Anterior/diagnóstico por imagem , Colágeno/farmacologia , Reagentes de Ligações Cruzadas/farmacologia , Ceratocone/terapia , Procedimentos Cirúrgicos Oftalmológicos/métodos , Fotoquimioterapia/métodos , Riboflavina/uso terapêutico , Adolescente , Adulto , Córnea/patologia , Córnea/cirurgia , Topografia da Córnea , Feminino , Seguimentos , Humanos , Ceratocone/diagnóstico , Masculino , Fármacos Fotossensibilizantes/uso terapêutico , Estudos Prospectivos , Fatores de Tempo , Resultado do Tratamento , Raios Ultravioleta , Acuidade Visual , Adulto JovemRESUMO
Purpose: Laser in-situ keratomileusis (LASIK), photorefractive keratectomy (PRK) and small-incision lenticule extraction (SMILE) are safe and effective refractive surgical procedures. However, complications include regression of treatment and iatrogenic keratectasia which can be severe and sight-threatening. In order to reduce these complications, simultaneous corneal cross-linking (CXL) is currently being added to these refractive procedures. This review analyses current long-term literature (≥ 1 year follow-up) on refractive surgery and simultaneous CXL (LASIK Xtra, PRK Xtra and SMILE Xtra) to determine its overall safety and efficacy.Methods: A comprehensive literature search of various electronic databases (PubMed, PubMed Central and MEDLINE) was performed up to 9th February 2019. Efficacy and safety indices are calculated where possible.Results: Ten relevant studies were found for LASIK Xtra, 4 for PRK Xtra and 1 for SMILE Xtra. The total number of eyes included in this review was 1,189: 347 eyes for LASIK Xtra, 300 eyes for LASIK-only, 298 for PRK Xtra, 204 for PRK-only, 40 for SMILE Xtra and none for SMILE-only. Current studies show that refractive surgery and simultaneous CXL produces comparable or better results in terms of refractive and keratometric stability than refractive surgery alone. However, case reports of complications such as corneal ectasia, diffuse lamellar keratitis and central toxic keratopathy have also recently been published.Conclusions: Simultaneous accelerated CXL and refractive surgery is effective for the treatment of myopia. However, it is as yet unclear if the additional CXL step reduces the incidence of iatrogenic keratectasia. Further long-term comparative studies would be useful in evaluating safety and efficacy of this procedure. More research should also be performed to titrate the UV-A irradiation settings for an optimal outcome.
Assuntos
Colágeno/farmacologia , Cirurgia da Córnea a Laser/métodos , Reagentes de Ligações Cruzadas/uso terapêutico , Lasers de Excimer/uso terapêutico , Miopia/cirurgia , Fotoquimioterapia/métodos , Acuidade Visual , Córnea/efeitos dos fármacos , Córnea/cirurgia , Seguimentos , Humanos , Ceratomileuse Assistida por Excimer Laser In Situ/métodos , Miopia/tratamento farmacológico , Ceratectomia Fotorrefrativa/métodos , Fatores de TempoRESUMO
PURPOSE: To compare results between standard and accelerated corneal collagen cross-linking (CXL) for the treatment of progressive keratoconus. METHODS: We performed literature searches in PubMed, Cochrane Library, Web of Science, ISRCTN registry, ClinicalTrials.gov, and EMBASE for studies comparing conventional Dresden (C-CXL) and accelerated CXL (A-CXL). Outcomes were clinical results and changes in corneal properties. Weighted mean differences were used to evaluate the effects. RESULTS: Here, 22 studies with 1158 eyes (C-CXL: 577 eyes; A-CXL: 581 eyes) were included. At the last follow-up, C-CXL was superior regarding minimum keratometry (p < 0.00001) and demarcation line depth (p < 0.00001), whereas A-CXL should be favoured when considering minimum corneal thickness (p = 0.0005). No differences in uncorrected and corrected distance visual acuity (p = 0.09 and 0.98), spherical equivalent (p = 0.11), spherical and cylindrical error (p = 0.29 and 0.32), maximal and average keratometry (p = 0.05 and 0.65), central corneal thickness (p = 0.15), corneal biomechanical properties (p ≥ 0.21 respectively), time of reepithelialization (p = 0.76), subbasal nerve density (p = 0.69), endothelial cell density (p = 0.30) and morphology (p ≥ 0.40 respectively) were found among both groups. CONCLUSION: Consideration of less corneal thinning favours A-CXL, whereas the deeper demarcation line and greater changes in minimum keratometric values in C-CXL may indicate a higher treatment efficacy. Altogether, C-CXL, as well as A-CXL, provides successful results in the strengthening of corneal tissue.
Assuntos
Colágeno/uso terapêutico , Córnea/patologia , Reagentes de Ligações Cruzadas/uso terapêutico , Ceratocone/tratamento farmacológico , Fotoquimioterapia/métodos , Riboflavina/uso terapêutico , Acuidade Visual , Topografia da Córnea , Humanos , Ceratocone/patologia , Fármacos Fotossensibilizantes/uso terapêutico , Resultado do TratamentoRESUMO
Collagen corneal cross-linking (CXL) is an invasive pharmacological treatment strategy used for corneal ectatic disorders and is currently the only treatment capable of halting the progression of the disease. In the past 20 years, the conservative management of progressive corneal ectasia has changed, thanks to this procedure that produces strengthening of the corneal tissue through the photochemical reaction generated by the combined action of riboflavin and ultraviolet A radiation. Many modified protocols have been implemented to halt the progression of the disease and to delay or prevent visual loss and surgical procedures such as corneal transplantation. Because of the variety of different protocols that are currently used, the results that are being reported are very variable, and could generate some confusion in relation to the true efficacy of the procedure. The aim of this review was to provide an overview of the aforementioned protocols that are designed to maintain the efficacy of CXL in halting the progression of the disease but avoiding the major limitations of the procedure.