0
selected
-
1.
Epithelial remodeling after corneal crosslinking using higher fluence and accelerated treatment time.
Haberman, ID, Lang, PZ, Broncano, AF, Kim, SW, Hafezi, F, Randleman, JB
Journal of cataract and refractive surgery. 2018;(3):306-312
Abstract
PURPOSE To evaluate changes in regional corneal epithelial thickness after corneal crosslinking (CXL) using higher fluence (7.2 J/cm2) and accelerated treatment time (4 minutes) in eyes with progressive keratoconus using spectral-domain optical coherence tomography (SD-OCT) and to correlate focal epithelial and focal anterior curvature changes. SETTING Academic medical center in the United States. DESIGN Prospective case series. METHODS Patients had anterior segment SD-OCT (RTVue-100) with focal stromal and epithelial measurements and Scheimpflug imaging before and 1, 3, 6, and 12 months after accelerated CXL. RESULTS Twenty-seven eyes from 20 patients were evaluated. Before the accelerated CXL, the epithelium was thinnest in the inferior inner and outer temporal regions, whereas at 12 months postoperatively, the epithelium was significantly thinned in multiple inferior and nasal regions by 1.1 to 3.2 μm (P < .05, all measurements), with no significant changes from 6 to 12 months. Epithelial thickness standard deviation across the central 6.0 mm was significantly reduced by 3 months (1.4 μm, P = .09) and remained stable at 12 months (P = .009). Change in epithelial thickness was poorly correlated to change in anterior curvature (r = -0.035). CONCLUSIONS Significant epithelial remodeling occurred after accelerated CXL in eyes with progressive keratoconus, with improved regularity across the central 6.0 mm, by 6 months after treatment. There was poor correlation between focal epithelial thickness and anterior curvature changes, with wide variability between patients. Establishing the pattern of epithelial remodeling after CXL might help optimize future custom treatment protocols.
-
2.
Collagen cross-linking with photoactivated riboflavin (PACK-CXL) for the treatment of advanced infectious keratitis with corneal melting.
Said, DG, Elalfy, MS, Gatzioufas, Z, El-Zakzouk, ES, Hassan, MA, Saif, MY, Zaki, AA, Dua, HS, Hafezi, F
Ophthalmology. 2014;(7):1377-82
Abstract
PURPOSE To investigate the efficacy and safety of corneal collagen cross-linking (CXL) with photoactivated riboflavin (photoactivated chromophore for infectious keratitis [PACK]-CXL) in the management of infectious keratitis with corneal melting. DESIGN Prospective clinical trial. PARTICIPANTS Forty eyes from 40 patients with advanced infectious keratitis and coexisting corneal melting. METHODS Twenty-one patients (21 eyes) underwent PACK-CXL treatment in addition to antimicrobial therapy. The control group consisted of 19 patients (19 eyes) who received only antimicrobial therapy. MAIN OUTCOME MEASURES The slit-lamp characteristics of the corneal ulceration, corrected distance visual acuity, duration until healing, and complications were documented in each group. The Mann-Whitney U test was used for statistical analysis. P values less than 0.05 were considered statistically significant. RESULTS The average time until healing was 39.76 ± 18.22 days in the PACK-CXL group and 46.05 ± 27.44 days in the control group (P = 0.68). After treatment and healing, corrected distance visual acuity was 1.64 ± 0.62 in the PACK-CXL group and 1.67 ± 0.48 in the control group (P = 0.68). The corneal ulceration's width and length was significantly bigger in the PACK-CXL group (P = 0.004 and P = 0.007). Three patients in the control group demonstrated corneal perforation; infection recurred in 1 of them. No serious complications occurred in the PACK-CXL group. CONCLUSIONS Corneal CXL with photoactivated riboflavin did not shorten the time to corneal healing; however, the complication rate was 21% in the control group, whereas there was no incidence of corneal perforation or recurrence of the infection in the PACK-CXL group. These results indicate that PACK-CXL may be an effective adjuvant therapy in the management of severe infectious keratitis associated with corneal melting.
-
3.
Characteristics influencing outcomes of corneal collagen crosslinking for keratoconus and ectasia: implications for patient selection.
Greenstein, SA, Hersh, PS
Journal of cataract and refractive surgery. 2013;(8):1133-40
Abstract
PURPOSE To determine preoperative patient characteristics that may predict topography and visual acuity outcomes of corneal collagen crosslinking (CXL). SETTING Cornea and refractive surgery practice. DESIGN Cohort study. METHODS Crosslinking was performed in eyes with keratoconus or corneal ectasia. Multiple regression and odds ratio analyses were performed to determine independent predictors of changes in topography-derived maximum keratometry (K) and corrected distance visual acuity (CDVA) 1 year postoperatively. Preoperative characteristics included sex, age, uncorrected distance visual acuity (UDVA), CDVA, maximum keratometry (K), corneal thickness, corneal haze, disease group, and cone location. Postoperative improvement in maximum K was defined as flattening of 2.0 diopters (D) or more and worsening as steepening of 1.0 D or more. Improvement in CDVA was defined as a gain of 2 lines or more and worsening as a loss of 1 line or more. RESULTS The study comprised 104 eyes (66 keratoconus; 38 corneal ectasia). Eyes with a preoperative CDVA of 20/40 or worse were 5.9 times (95% confidence interval [CI], 2.2-6.4) more likely to improve 2 Snellen lines or more. Eyes with a maximum K of 55.0 D or more were 5.4 times (95% CI, 2.1-14.0) more likely to have topographic flattening of 2.0 D or more. No preoperative characteristics significantly predicted worsening of visual acuity or corneal topography. CONCLUSIONS Patients with worse preoperative CDVA and higher K values, particularly with a CDVA of 20/40 or worse or a maximum K of 55.0 D or more, were most likely to have improvement after CXL. No preoperative characteristics were predictive of CXL failure.
-
4.
UVA-riboflavin photochemical therapy of bacterial keratitis: a pilot study.
Makdoumi, K, Mortensen, J, Sorkhabi, O, Malmvall, BE, Crafoord, S
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2012;(1):95-102
Abstract
BACKGROUND The aim of this work as to investigate the photochemical interaction used in corneal crosslinking (CXL) as the primary therapy for bacterial keratitis. METHODS A prospective non-randomized study was conducted including 16 patients with a clinical diagnosis of bacterial keratitis. No patient had any prior antibiotic treatment for the current infection. Photography and microbial culturing of the infected cornea were performed. Riboflavin was topically administered for 20 min and ultraviolet light (UVA) exposure settings for treatment of keratoconus were used. After the procedure, clinical examinations were done at least once daily until signs of improvement had been established. The frequency of examinations was thereafter reduced. Antibiotic therapy was initiated if infectious progression was suspected. The trial was registered at ISCRTN.org (no: 21432643). RESULTS All eyes responded to the photochemical treatment with improvement in symptoms and signs of reduced inflammation. Epithelial healing was achieved in all cases. Antibiotic administration was necessary in two cases. One patient required a human amniotic membrane transplant. CONCLUSIONS This trial illustrates that photosensitization of riboflavin using UVA at 365 nm has the potential to induce healing in patients with microbial keratitis. The results from the treatment of these 16 patients with corneal ulcers indicate that UVA-riboflavin photochemical therapy merits a controlled study in order to assess its efficacy and safety compared to antibiotics.
-
5.
Topical riboflavin attenuates ultraviolet B- and ultraviolet A-induced immunosuppression in humans.
Damian, DL, Matthews, YJ, Halliday, GM
Photodermatology, photoimmunology & photomedicine. 2010;(2):66-9
Abstract
BACKGROUND Riboflavin (vitamin B(2)) plays a key role in cellular energy metabolism. We have observed previously that nicotinamide (vitamin B(3)), which is also centrally involved in cellular energy restoration after UV irradiation, is highly immune protective in humans. We thus hypothesized that riboflavin might also confer immune protection. METHODS We irradiated healthy, nickel-allergic volunteers with narrowband UVA (385 nm) and UVB (300 nm) at separate sites on the lower back. These areas were treated with riboflavin solution or vehicle at 24 h and again at 30 min before UV exposure. Forty-eight hours after irradiation, volunteers were patch tested with nickel-containing Finn chambers, at both irradiated and nonirradiated sites, with and without prior riboflavin treatment. The resulting contact hypersensitivity reactions at each site were then measured 72 h later with a reflectance erythema meter in order to determine and compare the immune suppressive effects of each intervention. RESULTS We observed that low doses of both UVB and longwave UVA1 were immune suppressive in humans. Topical riboflavin conferred immune protection against both wavebands. CONCLUSIONS Riboflavin is immune protective in humans, and this may reflect the role of the B group vitamins in cellular energy restoration after UV exposure.
-
6.
Are effects of MTHFR (C677T) genotype on BMD confined to women with low folate and riboflavin intake? Analysis of food records from the Danish osteoporosis prevention study.
Abrahamsen, B, Madsen, JS, Tofteng, CL, Stilgren, L, Bladbjerg, EM, Kristensen, SR, Brixen, K, Mosekilde, L
Bone. 2005;(3):577-83
Abstract
We have previously found BMD and fracture risk to be significantly associated with the MTHFR (C677T) polymorphism in healthy postmenopausal women in the first years after menopause. Since then, other cohort studies have suggested that sufficient intake of riboflavin and/or folate may have the potential to prevent development of low BMD in women with the TT genotype. This could to some extent explain why this polymorphism is associated with low BMD or fracture in some study populations and not in others. It would also indicate that fractures associated with the TT genotype could be preventable by vitamin B supplementation. We have, therefore, reviewed baseline food record data from our original study to determine if BMD and fracture associations with the MTHFR genotype depended on the intake of folate, riboflavin, or other members of the vitamin B complex, associated with homocysteine metabolism. We analyzed genotype, BMD, and dietary records from 1700 healthy postmenopausal women who participated in the DOPS study. For the assessment of fracture risk, we used longitudinal observations from 854 women in the control group who remained compliant with their initial allocation of no treatment. Riboflavin intake was significantly correlated with femoral neck (FN) BMD in women with the TT genotype (r = 0.24, P < 0.01). FN and lumbar spine (LS) BMD were only associated with the MTHFR genotype in the lowest quartile of riboflavin intake. At the FN, similar threshold effects were shown for folate, vitamin B12, and vitamin B6. Among these vitamin B complex members, stepwise regression analysis identified riboflavin as the only significant predictor of FN BMD in the TT genotype. In conclusion, we confirm reports that BMD in the MTHFR TT genotype is only significantly reduced in the lowest quartile of riboflavin, B12, B6, and folate intake, at least at the time of menopause. Vitamin B supplementation would only be expected to benefit BMD in about 2% of the population, i.e., those with the TT genotype and low vitamin B intake.