Accelerated corneal crosslinking with 20'-soaking hydroxypropyl methyl cellulose/riboflavin vs conventional crosslinking with 30'-soaking dextran/riboflavin.

PURPOSE: To evaluate and compare functional and structural outcomes of accelerated corneal crosslinking (A-CXL) using riboflavin with hydroxypropyl methyl cellulose (HPMC) vs conventional corneal crosslinking (C-CXL) using riboflavin with dextran. SETTING: American University of Beirut Medical Center, Beirut, Lebanon. DESIGN: Retrospective analysis. METHODS: Retrospective analysis of 83 eyes of 73 patients with mild to moderate keratoconus. First group (n = 44 eyes) underwent C-CXL using a 30-minute riboflavin/dextran soaking between June 2014 and March 2016. Second group (n = 39 eyes) underwent A-CXL using a 20-minute riboflavin/HPMC soaking between April 2016 and December 2017. Patients were evaluated preoperatively and at 1, 3, and 12 months postoperatively. Main outcome measures were simulated keratometry (simK), maximum axial keratometry (Kmax), demarcation line depth, and haze intensity measured using optical coherence tomography-based image analysis software. RESULTS: Demarcation line (DL) was 298.30 ± 64.60 µm and 335.61 ± 99.76 µm for C-CXL and A-CXL groups, respectively ( P = .04). Haze profile was similar for both groups. The mean simK values were reduced from 46.93 ± 3.50 and 46.44 ± 2.93 preoperatively to 46.18 ± 3.65 and 45.54 ± 2.78 at 12 months postoperatively, for C-CXL and A-CXL, respectively ( P = .003 for both groups). The mean Kmax decreased from 52.46 ± 4.82 and 51.50 ± 3.87 preoperatively to 51.30 ± 4.42 and 50.30 ± 3.52 postoperatively, for the C-CXL and A-CXL, respectively ( P < .001 for both groups). There was no difference in the simK and Kmax changes between the C-CXL and A-CXL groups ( P = .814 and P = .913), visual acuity, and refraction between the 2 groups ( P > .05). CONCLUSIONS: A-CXL with a 20-minute riboflavin/HPMC soaking produced deeper DL and similar corneal haze, topographic, refractive, and visual results to C-CXL with a 30-minute riboflavin/dextran soaking.

Comparison of topographic outcomes between HPMC based and vitamin E TPGS based riboflavin solutions after corneal cross-linking.

PURPOSE: To compare the visual and topographic results between patients who underwent epithelium-off cross-linking using riboflavin solutions compounds hydroxypropyl methylcellulose (HPMC) 1.1% and D-alpha-tocopheryl polyethylene-glycol 1000 succinate (VE-TPGS). METHODS: In this study, 37 eyes treated with HPMC and 29 eyes treated with VE-TPGS were evaluated retrospectively. Spherical equivalent (SE), refractive cylinder, corrected distance visual acuity tests (CDVA), corneal topography indices (flat and steep meridians' keratometry (K1 and K2)), maximum keratometry (K max), central, thinnest, and apical corneal thicknesses, the front and back keratoconus vertex index (KVf, KVb), and the surface asymmetry index of the front and back surface (SIf, SIb), and endothelial cell density were compared at baseline and postoperative follow-up visits (1, 3, 6, and 12months). RESULTS: At the end of the 12th-month, K1, K2, and Kmax were decreased in both groups. In comparison to baseline, there was a decline in the HPMC group in the 3rd- month Kmax change, an increase was observed in the VE-TPGS group. In the 12th-month KVb change, an increase was observed in the HPMC group compared to the baseline, while a decrease was observed in the VE-TPGS group. The other parameters did not show a statistically significant difference between the groups (p > 0.05). CONCLUSION: At the end of 12 months, both riboflavins were effective in stopping the progression of keratoconus and were safe for endothelium. Although both riboflavins provide a decrease in keratometry values, it can be said that VE-TPGS is superior to HPMC in correcting the ectasia on the posterior corneal surface.

Polymorphisms in glia maturation factor ß gene are markers of cellulose ether effectiveness in prion-infected mice.

Anti-prion effects of cellulose ether (CE) are reported in rodents, but the molecular mechanism is fully unknown. Here, we investigated the genetic background of CE effectiveness by proteomic and genetic analysis in mice. Proteomic analysis in the two mouse lines showing a dramatic difference in CE effectiveness revealed a distinct polymorphism in the glia maturation factor ß gene. This polymorphism was significantly associated with the CE effectiveness in various prion-infected mouse lines. Sequencing of this gene and its vicinity genes also revealed several other polymorphisms that were significantly related to the CE effectiveness. These polymorphisms are useful as genetic markers for finding more suitable mouse lines and exploring the genetic factors of CE effectiveness.

Effect of Riboflavin Solution With Hydroxypropyl Methylcellulose and Eyelid Speculum on Pachymetry Changes During Accelerated Collagen Crosslinking.

PURPOSE: To assess corneal thickness changes with isotonic riboflavin (RF) solution with hydroxylpropyl methylcellulose in patients undergoing accelerated corneal collagen crosslinking (CXL) with and without an eyelid speculum. METHODS: Fifty-two eyes of 48 patients with progressive keratoconus were enrolled in this study. The patients in this study were divided into 2 groups: in group 1 an eyelid speculum was removed during 20-minute RF (0.1%) + hydroxylpropyl methylcellulose (Mediocross M; Avedro Inc, Waltham, MA) instillation, and in group 2 the eyelid speculum was retained in place during the entire CXL procedure. All patients underwent accelerated CXL using continuous ultraviolet-A (UVA) light exposure at 9 mW/cm for 10 minutes; total energy dose was 5.4 J/cm. Intraoperative ultrasound pachymetry measurements were obtained before and after epithelial removal, after RF loading, and after UVA light exposure at 5 and 10 minutes. RESULTS: The preoperative pachymetric measurements decreased in both groups after the removal of epithelium [group 1 (n = 26): -25 µm, group 2 (n = 26): -31 µm, P = 0.234]. Although the thinnest pachymetry significantly increased after soaking in both group 1 (52.26 µm) and group 2 (27.88 µm, P < 0.001), closure of the eyelids during RF instillation further increased the pachymetry readings (P < 0.0001). The corneal thickness remained stable in both groups during UVA irradiation at 5 and 10 minutes (P > 0.05). CONCLUSIONS: Closure of the eyelids further induces corneal swelling that may offer an advantage to improve safety of the procedure particularly in thin corneas.

Randomized Study of Collagen Cross-Linking With Conventional Versus Accelerated UVA Irradiation Using Riboflavin With Hydroxypropyl Methylcellulose: Two-Year Results.

PURPOSE: To compare the clinical outcome 2 years after corneal collagen cross-linking (CXL) with conventional and accelerated ultraviolet A (UVA) irradiation using riboflavin with hydroxypropyl methylcellulose. METHODS: Prospective randomized controlled study. Forty patients with keratoconus (40 eyes) were randomized to either CXL using conventional 3 mW/cm UVA irradiation for 30 minutes (CXL30 group) or accelerated 9 mW/cm UVA irradiation for 10 minutes (CXL10 group). In both groups, a solution of 0.1% riboflavin with 1.1% hydroxypropyl methylcellulose (methylcellulose-riboflavin) was used. Uncorrected distance visual acuity, corrected distance visual acuity (CDVA), and Scheimpflug tomography were performed at baseline and after 24 months. RESULTS: Both groups had statistically significant improvement in CDVA and maximum keratometric reading compared with baseline; however, with no statistically significant difference in the change between the 2 groups. No significant changes in flattest, steepest and mean keratometry (K1, K2 and K mean) were found in either of the groups. There were no statistically significant changes in ECD in either group after 2 years or in the difference in the change between the 2 groups. A literature review showed comparative clinical outcome after accelerated CXL compared with conventional CXL; however, in several studies, there was a tendency for less pronounced corneal flattening after accelerated CXL. CONCLUSIONS: Improvement in visual acuity and maximum keratometric reading 2 years after CXL was found after both conventional and accelerated UVA irradiation using methylcellulose-riboflavin. This suggests that when using riboflavin with methylcellulose, the less time-consuming accelerated protocol is a valuable and effective option in CXL treatment.

Demarcation line depth after contact lens-assisted corneal crosslinking for progressive keratoconus: Comparison of dextran-based and hydroxypropyl methylcellulose-based riboflavin solutions.

PURPOSE: To compare the demarcation line depth after contact lens-assisted corneal crosslinking (CXL) for progressive keratoconus using dextran-based and hydroxypropyl methylcellulose (HPMC)-based riboflavin solutions. SETTING: Advanced Eye Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India. DESIGN: Retrospective case series. METHODS: Patients with preoperative epithelium-on (epi-on) minimum corneal thickness between 350 µm and 450 µm having contact lens-assisted CXL for progressive keratoconus were crosslinked with isoosmolar 0.1% riboflavin in 20% dextran 500 or HPMC 1.1%. The primary outcome measure was the mean demarcation line depth measured 1 month postoperatively on anterior-segment optical coherence tomography. The secondary outcome measure was change in endothelial cell density (ECD) 6 months from baseline. RESULTS: The study comprised 21 patients (21 eyes, 9 in the HPMC group and 12 in the dextran group). The mean demarcation line depth was deeper in the HPMC group (308.22 µm ± 84.19 [SD]) than in the dextran group (235.33 ± 64.87 µm) (P < .04). This difference remained significant (P = .02) even after controlling for the preoperative lesser epi-on minimum corneal thickness in the HPMC group (385.56 ±13.81 µm) versus the dextran group (413.08 ± 29.58 µm) (P < .02). The ECD 6 months after contact lens-assisted CXL was comparable to the baseline levels in both groups (P = .19 and P = .09, respectively). CONCLUSION: During contact lens-assisted CXL, HPMC-based riboflavin seemed to be associated with a deeper demarcation line than dextran-based riboflavin, although both solutions were safe for the endothelium at 6 months.

Accelerated 15 mW pulsed-light crosslinking to treat progressive keratoconus: Two-year clinical results.

PURPOSE: To assess the clinical and microstructural results of accelerated 15 mW pulsed-light corneal crosslinking (CXL) to treat progressive keratoconus. SETTING: Siena Crosslinking Center, Siena, Italy. DESIGN: Prospective case series. METHODS: After epithelium removal (with Epi-Clear) and 10 minutes stromal soaking with riboflavin 0.1% hydroxypropyl methylcellulose solution, all eyes had 15 mW/cm2 pulsed-light epithelium-off accelerated CXL for 6 minutes of ultraviolet-A (UVA) irradiation (1 second on/1 second off), maintaining a total UVA exposure of 12 minutes at a fluence of 5.4 J/cm2. The 2-year follow-up examination included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, Scheimpflug tomography, in vivo confocal microscopy (IVCM), and spectral-domain optical coherence tomography (SD-OCT). RESULTS: The study comprised 132 eyes of 96 patients (mean age 23.7 years ± 4.3 [SD]) with stage II keratoconus. The change in UDVA and CDVA was statistically significant, from 0.51 ± 0.106 logarithm of the minimum angle of resolution (logMAR) at baseline to 0.309 ± 0.074 logMAR (P = .0001) and 0.271 ± 0.144 logMAR at baseline to 0.135 ± 0.100 logMAR (P = .0023), respectively. Coma values measured by Scheimpflug analysis showed a statistically significant improvement beginning with the first postoperative month (P = .0004). The IVCM scans documented basal epithelial healing occurring 72 hours after treatment associated with the presence of subepithelial nerves. The SD-OCT scans performed in the central 6.0 mm of corneal diameter documented a demarcation line at a mean depth of 280 ± 32 µm. CONCLUSION: The 15 mW/cm2 pulsed-light epithelium-off accelerated CXL was effective and safe, stabilizing keratoconus progression through 2 years of follow-up.

The improvement of dry eye after cataract surgery by intraoperative using ophthalmic viscosurgical devices on the surface of cornea: The results of a consort-compliant randomized controlled trial.

BACKGROUD: This study aimed to investigate the protective effect of intraoperative used hydroxypropyl methylcellulose (HPMC 2%) on the ocular surface after cataract surgery. METHODS: A total of 149 eyes (149 patients) diagnosed with age-related cataract, age 69.19 ±â€Š9.74 years, were enrolled in this prospective, parallel-design, continuous, randomised controlled study. Patients were randomly assigned to receive HPMC 2% (study group) or balanced salt solution (control group) during the surgery to moisturize the cornea surface. The Ocular Surface Disease Index, Schirmer test without topical anesthetics, tear break-up time, and corneal fluorescein staining were assessed preoperatively, 1 day, 1 week, and 1 month after the surgery, respectively. RESULTS: The Schirmer test value of male patients in the study group at 1 week postoperation was higher than that of male patients in the control group (P = .019). For patients diagnosed with dry eye before the surgery, Schirmer test value in the male patients in the study group at 1 month after surgery was higher than that in the male patients in the control group (P = .037). Furthermore, for the cluster of preoperative dry eye patients whose surgical time was longer than median, corneal fluorescein staining of the patients in the study group was superior to that of the patients in the control group (P = .032). CONCLUSION: Intraoperative use of HPMC 2% on the cornea surface could improve clinical outcomes of tear film and ocular surface health to some degree, especially in the patients diagnosed with dry eye before the surgery, male patients, and patients whose surgical time was relatively longer.

Assessment of Photodynamic Inactivation against Periodontal Bacteria Mediated by a Chitosan Hydrogel in a 3D Gingival Model.

Chitosan hydrogels containing hydroxypropyl methylcellulose (HPMC) and toluidine blue O were prepared and assessed for their mucoadhesive property and antimicrobial efficacy of photodynamic inactivation (PDI). Increased HPMC content in the hydrogels resulted in increased mucoadhesiveness. Furthermore, we developed a simple In Vitro 3D gingival model resembling the oral periodontal pocket to culture the biofilms of Staphylococcus aureus (S. aureus), Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), and Porphyromonas gingivalis (P. gingivalis). The PDI efficacy of chitosan hydrogel was examined against periodontal biofilms cultured in this 3D gingival model. We found that the PDI effectiveness was limited due to leaving some of the innermost bacteria alive at the non-illuminated site. Using this 3D gingival model, we further optimized PDI procedures with various adjustments of light energy and irradiation sites. The PDI efficacy of the chitosan hydrogel against periodontal biofilms can significantly improve via four sides of irradiation. In conclusion, this study not only showed the clinical applicability of this chitosan hydrogel but also the importance of the light irradiation pattern in performing PDI for periodontal disease.

Liver retraction system by C3-muco-adhesive polymer films for laparoscopic surgery.

BACKGROUND: Conventional laparoscopic instruments used for retraction may cause trauma at the retraction site. Alternative retraction/lifting especially of heavy solid organs such as the liver may be obtained by other means. The present study was designed to explore the use of C3-muco-adhesive polymers (C3-MAPs), which exhibit strong binding to the liver shortly after application to the organ and which retain strong adhesion for sufficient time, to enable sustained retraction during laparoscopic operations. METHODS AND MATERIALS: C3-muco-adhesive polymers were produced specifically for the study. In an ex vivo experimental set-up, discs of C3-MAPs were placed on the surface of porcine livers for adhesion and retraction studies involving objective measurements by tensiometry. RESULTS: Experiments were carried out on 14 porcine livers. The force required to detach the C3-MAPs from the liver exceeded 2.0 N 30 s after application. The adhesion force by C3-MAPs files was sufficient to enable sustained retraction force necessary for exposure of the gall bladder, which was achieved by a mean retraction force of 4.85 N (SD = 0.63). This was sustained for a mean of 130 min (range 17.0-240.0). In the adhesion studies, the forces at 30 s required to detach the polymer discs from the liver exceeded 20 N (upper limit of the load cells of the Instron). The duration of the adhesion enabled sustained optimal gall bladder exposure for periods ranging from 17 to 240 min, with a mean of 130 ± 91 min. CONCLUSIONS: The results of the present study demonstrate that the adhesion and retraction properties of the engineered C3-MAP films are sufficient to enable complete exposure of the gall bladder for a period exceeding 1 h, confirming their potential for atraumatic retraction in laparoscopic and other minimal-access surgical approaches.

Isotonic riboflavin and HPMC with accelerated cross-linking protocol.

PURPOSE: The aim of this study was to monitor corneal pachymetry changes during accelerated collagen cross-linking (CXL) for keratoconus while using isotonic riboflavin with HPMC. METHODS: All consecutive patients who underwent CXL for progressive keratoconus, using accelerated protocol and isotonic riboflavin with HPMC, from December 2012 to September 2013 were included in the study. The corneal pachymetry measurements were obtained at different time points: after epithelial removal, after riboflavin application for 20 minutes, and after ultraviolet A irradiation for 10 minutes at 9 mW/cm. RESULTS: A total of 14 eyes of 14 consecutive patients were included in this study. The mean age of the patients was 19 ± 8 years. There were 8 left eyes and 6 right eyes. After epithelial debridement, the thinnest pachymetric readings were between 324 and 452 µm (average, 401.4 ± 40.7 µm). No significant difference (P = 0.80) was found between the deepithelialized corneal thickness and after 20 minutes of isotonic riboflavin with HPMC (pachymetric average, 405.3 ± 37.5 µm). Pachymetric average after ultraviolet A irradiation was 419.29 ± 20.60 µm. There was no statistical significant change in the corneal thickness after the irradiation (P = 0.24). CONCLUSIONS: During corneal CXL using isotonic riboflavin and HPMC with accelerated cross-linking protocol, no significant decline in the corneal thickness was demonstrated.