Rate of riboflavin diffusion from intrastromal channels before corneal crosslinking

McQuaid, Rebecca; Mrochen, Michael; Vohnsen, Brian

doi:10.1016/j.jcrs.2015.09.032

Cited by 7 publications

(3 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Proposed benefits of an HPMC-based riboflavin solution compared to a dextran-based solution include absence of intraoperative corneal thinning [ 8 – 11 ], increased diffusion rate [ 12 ], and convenience of use [ 10 , 13 ]. These advantages primarily focus on intraoperative effects of HPMC-based and dextran-based riboflavin solutions.…”

Section: Introductionmentioning

confidence: 99%

Corneal collagen crosslinking in patients treated with dextran versus isotonic hydroxypropyl methylcellulose (HPMC) riboflavin solution: a retrospective analysis

et al. 2018

View full text Add to dashboard Cite

BackgroundCorneal collagen crosslinking (CXL) is a widely used treatment for halting the progression of keratoconus. Although initial studies of CXL were performed with a riboflavin solution containing dextran, recent protocols for CXL have indicated the use of a riboflavin solution containing isotonic hydroxypropyl methylcellulose (HPMC). This study was performed to investigate differences in visual outcomes and Scheimpflug (Pentacam) analysis in patients who have undergone epithelium-off CXL with riboflavin solution containing either 20% dextran versus 1.1% HPMC.MethodsAll patients in this non-randomized, non-masked, retrospective cohort analysis were treated at Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA. Thirty-seven eyes of 33 patients were crosslinked with a dextran solution and 19 eyes of 19 patients crosslinked with an isotonic HPMC solution, both using an epithelium-off 30-min, 3 mW/cm2 protocol. All patients had a diagnosis of keratoconus or post-refractive surgery ectasia. Best spectacle corrected visual acuity (BSCVA) and Pentacam parameters were compared at all follow up visits (1, 6, 12, and 24 months). Differences between groups treated with HPMC and dextran were compared using student’s t-test. Differences between treated eye and fellow eye were calculated and compared between HPMC and dextran groups using paired t-test.ResultsPatients treated with a dextran solution had significantly greater improvement in BSCVA at 1, 6, and 24 months (p < 0.05) compared to the isotonic HPMC-treated group. Kmax increased in both groups at 1 month; however, HPMC-treated patients had a greater increase compared to dextran-treated patients (p = 0.01). Kmax decreased in both groups at 6 and 12 months, although this finding was only significant in the HPMC-treated group at 12 months.ConclusionsOur data suggest that crosslinking with the dextran solution may result in significantly better visual outcomes (demonstrated by visual acuity) compared to the isotonic HPMC riboflavin solution. Dextran solutions may have other potential advantages intrinsic to its biochemical properties facilitating more efficient crosslinking. Further research and long-term evidence regarding the use of dextran versus HPMC riboflavin solutions in collagen crosslinking is necessary.

show abstract

Section: Introductionmentioning

confidence: 99%

Corneal collagen crosslinking in patients treated with dextran versus isotonic hydroxypropyl methylcellulose (HPMC) riboflavin solution: a retrospective analysis

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Though this value has been reported for FMN, values are inconsistent. 49,62,63 Thus, we calculated this parameter along with n through the combination of the Cottrell and Levich equations (Figs. 3a-3b).…”

Section: Kinetic Properties Of Flavin Electron Transfer At P3ht-im + ...mentioning

confidence: 99%

Electrochemical Characterization of Biomolecular Electron Transfer at Conductive Polymer Interfaces

Agee¹,

Gill²,

Pace³

et al. 2023

J. Electrochem. Soc.

View full text Add to dashboard Cite

Bio-electrochemical systems (BESs) are promising for renewable energy generation but remain hindered by inefficient electron transfer at electrode surfaces. As the toolbox of bio-anode materials increases, rigorous electrochemical characterization of emerging materials is needed. Here, we holistically characterize the electrochemical interaction of flavin mononucleotide (FMN), an electron shuttle in biological systems and a cofactor for oxidoreductase enzymes, with the bio-inspired mixed conducting polymer poly{3-[6′-(N-methylimidazolium)hexyl]thiophene} (P3HT-Im+). The behavior of this polymer is compared to the equivalent polymer without the histidine-like imidazolium. We find improved conductivity and charge storage in imidazolium-containing polymers beyond what is explained by differences in the electroactive area. The P3HT-Im+ further shows internal charge storage but with negligible faradaic contribution, indicating that charge storage capacity may translate to improved biocatalysis non-intuitive ways. Finally, one-electron transfer is observed between FMN and glassy carbon, while a bio-similar two-electron transfer is observed for the P3HT-Im+. To our knowledge, this is the first example of a concerted two-electron transfer between FMN and an electrode interface, which we attribute to the bio-inspired, histidine-like imidazolium functional groups in the polymer. These studies demonstrate the importance of bio-relevant materials characterization when such materials are deployed in BESs.

show abstract

“…Swine are increasingly being used in ophthalmology and vision science research to model various ocular diseases (Stricker-Krongrad et al, 2016), develop surgical techniques (Tasaka et al, 2013; Ibarz et al, 2016; McQuaid et al, 2016; Nanavaty and Kubrak-Kisza, 2017; Speri et al, 2017; Tandogan et al, 2016), novel therapies and intervention strategies (Umazume et al ., 2013; Scott et al, 2015; Wang et al, 2016; Lin et al, 2017; Drozhz- hyna et al, 2017; Cong et al, 2018) to prevent vision loss in humans due to similar ocular anatomy and physiology (Beauchemin, 1974; De Schaepdrijver et al, 1992; Gerke et al, 1995; Bartholomew et al, 1997; Ninomiya and Inomata, 2006; Acosta et al ., 2009; Sanchez et al ., 2011). Although studies (Bartholomew et al, 1997; Faber et al, 2008; Jay et al, 2008) have examined anatomical features of the domestic swine cornea, none have compiled a characterization of miniature corneal morphology at both the light and electron microscopic level.…”

mentioning

confidence: 99%

Anatomic Studies of the Miniature Swine Cornea

Abhari

Eisenback

Kaplan

et al. 2018

The Anatomical Record

View full text Add to dashboard Cite

The domestic swine eye resembles the human eye both anatomically and physiologically. Xenotransplantation of the swine cornea to humans in need of full keratoplasty shows promise as a potential therapeutic strategy to restore vision in individuals with advanced corneal disease, especially those residing in developing nations. That said, we characterized the morphology of corneas from miniature swine, which are smaller in size, easier to handle, and more cost-effective compared to domestic swine. Eyes (N = 15) were harvested from miniature swine from different age groups: 1 month (N = 3), 2 month (N = 3), 4 month (N = 3), 8 month (N = 3), as well as 24 month old adult domestic swine (N = 3). They were immediately submerged in fixative and processed for histological examination at the light and transmission electron microscopic level. Gross anatomic measurements of the cornea were significantly less (P value ≤ 0.05) in miniature swine versus domestic swine. Corneal strata exhibited morphological characteristics similar to the domestic swine cornea. Adult miniature swine corneas show similar overall corneal thickness at 8 months of age versus domestic swine. Miniature swine exhibit similar corneal morphology with the domestic pig and humans, with the exception of Bowman’s layer, which is absent in pigs. Therefore, miniature pigs may be a useful resource of corneal tissue for humans in need of full keratoplasty, as well as serve as a large eye model for ophthalmology residents to develop surgical skills and for development and testing of ocular therapeutic strategies that translate to humans.

show abstract

Rate of riboflavin diffusion from intrastromal channels before corneal crosslinking

Abstract: In this study, riboflavin had a faster stromal diffusion when injected into a corneal channel than when applied as drops to the anterior corneal surface. Further numerical modeling might allow optimization of the channel structure for any specific choice of riboflavin.

Cited by 7 publications

References 20 publications

Corneal collagen crosslinking in patients treated with dextran versus isotonic hydroxypropyl methylcellulose (HPMC) riboflavin solution: a retrospective analysis

Corneal collagen crosslinking in patients treated with dextran versus isotonic hydroxypropyl methylcellulose (HPMC) riboflavin solution: a retrospective analysis

Electrochemical Characterization of Biomolecular Electron Transfer at Conductive Polymer Interfaces

Anatomic Studies of the Miniature Swine Cornea

Contact Info

Product

Resources

About