Epithelium Off Research Articles

Comparison of Corneal Stromal Demarcation Line Depth in Epi-off and Epi-on Corneal CrossLinking Using Anterior Segment Optical Coherence Tomograph

Objective: To compare the corneal stromal demarcation line depth after Epithelium-On and Epithelium-Off corneal crosslinking in patients with keratoconus using anterior segment Optical Coherence Tomography (AS-OCT).
 Study design: Quasi-experimental study.
 Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi Pakistan from Jun 2018 to Jun 2019.
 Methodology: This study included patients (60 eyes) with progressive keratoconus treated with procedure CXL (corneal cross linkage). There were 30 eyes in each group. Two different protocols of Corneal cross linkage were performed, and patients were divided into two groups according to protocol: 1) epithelium-on Corneal cross-linkage, 2) epithelium-off Corneal crosslinkage. In the First-Group, epithelium-on Corneal cross-linkage,corneal epithelium was not removed, riboflavin solution was instilled on the cornea for one hour, and the cornea was exposed to Ultraviolet A rays. In Epithelium off Corneal cross-linkage,after epithelium was removed by spatula, riboflavin solution was instilled for 30 minutes, and Ultraviolet-A rays were focused on the cornea. After one month of the procedure, Anterior segment Optical Coherence Tomography was performed.Demarcation line depth was measured in treated corneas in all patients from both groups, and findings were compared.
 Results: The stromal demarcation line depth was similar in both groups, and there was no statistical difference between the groups. The mean value of demarcation line depth was 277.13±107.09 цm (p>0.05).
 Conclusion: Corneal stromal demarcation line depth after both procedures was similar in both groups after one month of Corneal cross-linkage, so it was concluded that epithelium-on Corneal cross-linkage was comparable to epithelium-off Corneal cross-linkage.

Nonhealing epithelial defect after collagen cross-linking for keratoconus with vernal keratoconjunctivitis

Here we report a case of nonhealing epithelial defect after corneal collagen cross-linking (C3R) in a 24-year-old young adult with progressive keratoconus and concomitant vernal keratoconjunctivitis (VKC). Epithelium off C3R with hypoosmolar riboflavin and ultraviolet -A irradiation was done in the right eye for progressive keratoconus. The preoperative minimum corneal thickness was 388 microns. Chronic VKC was stabilized with mast cell stabilizer and lubricants before C3R. The patient presented with nonhealing epithelial defect until 1-month post cross-linking due to possible limbal stem cell deficiency (LSCD) and underlying VKC with giant papillae. Amniotic membrane grafting was done twice for ocular surface stabilization which occurred at the end of 7 weeks. Final best-corrected visual acuity at 1 year was 6/12 with nebular corneal scarring. Preemptive management of giant papillae and proper stabilization of the ocular surface is essential before C3R. In cases of keratoconus with VKC, LSCD should be strongly suspected and reactivation of VKC with a prolonged course of epithelial healing can be a possible complication after C3R.

AN AYURVEDIC APPROACH FOR BALANOPOSTHITIS – A CASE STUDY

An inflammatory condition of male genitalia called Balanoposthitis is made of two words in which Balanitis means inflammation of glans penis and Posthitis means inflammation of prepuce internal part of skin genitalia (prepuce) and is common in uncircumcised population. It primarily occurs due to unretractable foreskin, poor personal hygiene, peeling off of epithelium, secretions from the glands provide damp, warm environment for growth of different organisms which makes the area susceptible for various infections. In the present case study a male patient presented with pain, redness, whitish discharge, greyish-whitish scales over glans penis, mild swelling in groin region and pain in the groin region. It is very much evident that any health issue that affects reproductive organ can also impact various aspects of life, causing anxiety stress, relationship problems or poor self-esteem. But routine examination of penis can create awareness if something wrong is detected. The basic focus of management in Balanoposthitis is to control the acute infection and prevent recurrence along with appropriate hygiene measures. In this case patient of Vat-Pittaj prakruti was successfully managed on Ayurvedic principles, by balancing the vitiated Kapha and Pitta dosha with Shaman chikitsa and encouraging results were found without any untoward effect during the 4 week course of management. Traditional system of medicine is a known wealth of herbs and has potential to manage various ailments of modern era.

Transepithelial versus Epithelium off Crosslinking for Treating Keratoconus among Jordanians

Background: The progression of keratoconus is stabilized with the help of corneal collagen cross-linking (CXL) supported through photosynthesized riboflavin. Objective: This study aims to compare the effectiveness of the transepithelial procedure and epithelium off procedure of corneal collagen crosslinking among keratoconus patients in Jordan. Methods: The study recruited 80 patients suffering from progressive keratoconus, from a tertiary care setting in Jordan. These participants were randomly divided into two groups; group 1 with 40 participants subjected to transepithelial (Corneal collagen cross-linking) CXL; and 40 participants in group 2 received conventional epithelium off CXL. Results: Improvement was observed in the mean contact lens, which corrected distance visual acuity (CDVA) from logMAR 0.332 ± 0.09 (group 1), 0.35 ± 0.09 (group 2) to 0.241 ± 0.07 (group 1), 0.21 ± 0.07 (group 2), respectively at the end of follow-up (12 months). The mean pachymetry improved from 429.81 ± 18.96 μm (group 1), 430.08 ± 17.05 μm (group 2) to 436.5 ± 15.49 μm (group 1), 436.44 ± 12.53 μm (group 2), respectively, after twelve months. Additionally, the mean Sim K astigmatism declined from 7.0 ± 2.0 (group 1), 6.73 ± 1.98 (group 2) to 5.97 ± 1.88 (group 1), 5.53 ± 0.08 (group 2) respectively at twelve months post-treatment. Majority of the patients in group 2 experienced more pain as compared to group 1 participants. Conclusion: The effectiveness of a cross-linking procedure related to keratometry readings and corneal thickness showed that conventional (epithelium off) CXL method is more effective than transepithelial CXL.

The effects of corneal collagen cross‐linking and the discrepancy between epithelium on and epithelium off treatment – Results from the Portsmouth population cohort

The effects of corneal collagen cross‐linking and the discrepancy between epithelium on and epithelium off treatment – Results from the Portsmouth population cohort

Recent Innovations in Collagen Corneal Cross-linking; a Mini Review.

Background:The introduction of corneal cross-linking (CXL) with ultraviolet-A (UVA) and Riboflavin photosensitizer (Vit B2) from Seiler et al., revolutionized the treatment of Keratoconus and other corneal ectatic diseases.Today, the commonly known epithelium off Dresden protocol is in clinical use for the last 15 years with great success and regarded by many as the golden standard.Methods:With several studies demonstrating its simplicity, efficacy and safety this revolutionary method, paved the way for new therapies and strategies in the treatment of corneal ectatic diseases and changed our understanding in corneal biomechanics. Recent scientific and technological advances enabled the creation of various modifications of the initial CXL protocol and the formation of new ones.Conclusion:This work highlights the recent advances of CXL, such as the role of oxygen, higher fluence and shorter irradiation times as well as the various clinical applications and updates of this method.

Transepithelial corneal crosslinking in treatment of progressive keratoconus: 12 months' clinical results.

Objective:The purpose of this study was to evaluate the safety and efficacy of transepithelial corneal collagen cross linking (TE-CXL) with modified riboflavin and accelerated UVA irradiance in thin corneas with pachymetry less than 400 microns at thinnest point, untreatable by epithelium off corneal collagen cross linking (CXL) in adult Pakistani population with progressive keratoconus.Methods:This quasi experimental study included twenty six eyes of 26 patients with progressive keratoconus who underwent accelerated transepithelial CXL in Armed forced institute of ophthalmology with 12 months follow up. Modified riboflavin, ParaCel ((riboflavin 0.25%, Benzalkonium chloride, EDTA, Trometamol, hydroxypropyl methylcellulose) and vibeX Xtra (riboflavin 0.25%) (Avedro, USA)) were applied to cornea in two stages. Uncorrected and Corrected Distant Visual Acuities (UDVA, CDVA), spherical equivalent (SE), astigmatism, pachymetry at thinnest point (Pachy thin), apex keratometry (Kmax), simulated and steep keratometry (Sim K, steep K) were measured at baseline and at 3, 6 and 12 months post operatively. The cornea was then exposed to accelerated UVA irradiance of 9mW/cm2 for 10 min (total dose 30 mW/cm2).Results:The mean age of the patient was 24.54±5.16 years. UDVA, CDVA, SE, astigmatism significantly improved at all postoperative test points (p=0.000, 0.004, 0.000, 0.004 respectively). Kmax and pachy thin were significantly reduced over baseline at 1 year (p=0.000, 0.004 respectively). Topographic indices Sim K and steep K did not show significant changes. No intra or post-operative complications were reported.Conclusion:Transepithelial accelerated CXL with modified riboflavin is a safe and effective procedure which halt disease progression in thin corneas with progressive keratoconus.

An investigation into corneal enzymatic resistance following epithelium-off and epithelium-on corneal cross-linking protocols

The aim of this study was to investigate corneal enzymatic resistance following epithelium off and on riboflavin/UVA cross-linking (CXL). One hundred and fourteen porcine eyes were divided into four non-irradiated control groups and seven CXL groups. The latter comprised; (i) epithelium-off, 0.1% iso-osmolar riboflavin, 9 mW UVA irradiation for 10 min, (ii) disrupted epithelium, 0.1% hypo-osmolar riboflavin, 9 mW UVA for 10 min, (iii) epithelium-on, 0.25% hypo-osmolar riboflavin with 0.01% benzylalkonium chloride (BACS), 9 mW UVA for 10 min, (iv) epithelium-on, 5 min iontophoresis at 0.1 mA for 5 min with 0.1% riboflavin solution, 9 mW UVA for 10 min or (v) 12.5 min, (vi) epithelium-on, prolonged iontophoresis protocol of 25 min with 1.0 mA for 5 min and 0.5 mA for 5 min with 0.25% riboflavin with 0.01% BACS, 9 mW UVA for 10 min or (vii) 12.5 min. Enzymatic resistance was assessed by daily measurement of a corneal button placed in pepsin solution and measurement of corneal button dry weight after 11 days of digestion. This study revealed that the enzymatic resistance was greater in CXL corneas than non-irradiated corneas (p < 0.0001). Epithelium-off CXL showed the greatest enzymatic resistance (p < 0.0001). The prolonged iontophoresis protocol was found to be superior to all other trans-epithelial protocols (p < 0.0001). A 25% increase in UVA radiance significantly increased corneal enzymatic resistance (p < 0.0001). In conclusion, although epithelium-on CXL appears to be inferior to epithelium-off CXL in terms of enzymatic resistance to pepsin digestion, the outcome of epithelium-on CXL may be significantly improved through the use of higher concentrations of riboflavin solution, a longer duration of iontophoresis and an increase in UVA radiance.

Differential molecular signature of ectatic and non‐ectatic areas from Keratoconus patient corneas

PurposeTo evaluate if the gene expression profile of corneal epithelium from the cone area in Keratoconus (KC) differs from the peripheral non‐ectatic areas.Hypothesis: The ectasia in Keratoconic cornea is localized to the cone while the peripheral areas are apparently normal. Hence we hypothesized that within the cone of a KC patient cornea, the structural weakness may be a function of localized gene expression differencesMethodsStudy group contained 54 KC patients undergoing epithelium off corneal collagen crosslinking (CXL) and 9 non‐ectatic subjects undergoing photo refractive keratectomy (PRK) as controls. The cone vs periphery distinction is based on keratometry and location of the cone based on elevation map. Using a 4.5 mm trephine centered on the cone, epithelium was scraped separately for cone and rest as periphery. In non‐ectatic controls, the central 4.5 mm area was taken as cone. Gene expression profiling was performed for each pair of cone and periphery samples by quantitative PCR.ResultsLysyl oxidase levels were significantly reduced in the cone of KC patients (p = 0.002). Structure related genes COL1 (p = 0.01) and COL4 (p = 0.008) were also reduced significantly in KC patient cones. The cytokines IL6, TGFβ and TNFα did show an increased trend; regulatory cytokine IL10 did not show significant trend. Matrix remodeler MMP9 showed an increasing trend at the cone while its inhibitor TIMP1 showed a reducing trend that was not significant(p = 0.09).ConclusionsEctasia in KC may be driven by local molecular factors at the cone that possibly spreads to other parts of cornea as disease progresses.

Differential molecular signature of ectatic and non‐ectatic areas from Keratoconus patient corneas

PurposeTo evaluate if the gene expression profile of corneal epithelium from the cone area in Keratoconus (KC) differs from the peripheral non‐ectatic areas.HypothesisThe ectasia in Keratoconic cornea is localized to the cone while the peripheral areas are apparently normal. Hence we hypothesized that within the cone of a KC patient cornea, the structural weakness may be a function of localized gene expression differences.MethodsStudy group contained 54 KC patients undergoing epithelium off corneal collagen crosslinking (CXL) and 9 non‐ectatic subjects undergoing photo refractive keratectomy (PRK) as controls. The cone vs periphery distinction is based on keratometry and location of the cone based on elevation map. Using a 4.5 mm trephine centered on the cone, epithelium was scraped separately for cone and rest as periphery. In non‐ectatic controls, the central 4.5 mm area was taken as cone. Gene expression profiling was performed for each pair of cone and periphery samples by quantitative PCR.ResultsLysyl oxidase levels were significantly reduced in the cone of KC patients (p = 0.002). Structure related genes COL1 (p = 0.01) and COL4 (p = 0.008) were also reduced significantly in KC patient cones. The cytokines IL6, TGFβ and TNFα did show an increased trend; regulatory cytokine IL10 did not show significant trend. Matrix remodeler MMP9 showed an increasing trend at the cone while its inhibitor TIMP1 showed a reducing trend that was not significant(p = .09).ConclusionsEctasia in KC may be driven by local molecular factors at the cone that possibly spreads to other parts of cornea as disease progresses.

Recovery of corneal sensitivity after collagen crosslinking with and without epithelial debridement in eyes with keratoconus

To evaluate the changes in corneal sensitivity after corneal collagen crosslinking (CXL) with the epithelium off (epi-off) and with the epithelium on (epi-on) in eyes with keratoconus. Prospective interventional case series. Eye Clinic, A. Fiorini Hospital, Terracina (Latina), Rome, Italy. On the basis of the corneal pachymetry at the area of topographic steepening, eyes treated with CXL were divided in 2 groups: those with a corneal thickness of 400 μm or more (epi-off) and those with a corneal thickness of less than 400 μm (epi-on). Corneal sensitivity was measured using a contact esthesiometer (Cochet-Bonnet) before treatment and 1 and 7 days and 1, 3, 6, 9, and 12 months after treatment. The study evaluated 50 CXL-treated eyes in 50 patients (25 epi-on and 25 epi-off) from January 7, 2012, to December 15, 2012. In the epi-off group, corneal sensitivity was statistically significantly reduced for up to 3 months after CXL and gradually returned to normal levels. In the epi-on group, corneal sensitivity was statistically significantly reduced for up to 7 days but was not statistically significantly different from preoperative values at other measurement times. At 7 days, the corneal sensitivity was statistically significantly lower in the epi-off eyes than in the epi-on eyes. Epi-off and epi-on CXL both caused hypoesthesia, but corneal sensitivity subsequently recovered completely. The corneal hypoesthesia was more pronounced in eyes in which the epi-off technique was used, and the recovery time was shorter for eyes treated using epi-on CXL. No author has a financial or proprietary interest in any material or method mentioned.

Trans-epithelial versus conventional corneal collagen crosslinking: A randomized trial in keratoconus.

Purpose:The purpose was to compare transepithelial versus epithelium off technique of corneal collagen crosslinking (CXL) in patients of keratoconus.Materials and Method:Totally, 40 eyes (40 patients) with progressive keratoconus were subjected to transepithelial CXL (20 eyes; Group I), and conventional CXL (20 eyes; Group II). Patients were evaluated for uncorrected distance visual acuity, best corrected visual acuity (BCVA), slit lamp-biomicroscopy, keratometry, 9-point pachymentry, orbscan II, and endothelial cell count at baseline and post CXL at 1, 3, and 6 months.Results:The two groups were similar with respect to the evaluated parameters both at baseline and at the end of 6 months. There was an improvement in mean BCVA from Log Mar 0.327 ± 0.1 (Group 1), 0.36 ± 0.08 (Group 2) to 0.23 ± 0.08 (Group 1; P < 0.001), 0.22 ± 0.06 (Group 2; P < 0.001), respectively, at 6 months. Mean Sim K astigmatism decreased from 6.6 ± 1.93 D (Group 1), 6.64 ± 1.93 D (Group 2) to 5.14 ± 1.86 D (Group 1; P = 0.001), and 4.77 ± 0.06 (Group 2; P = 0.001), respectively, at 6 months. The mean pachymetry increased from 432.05 ± 19.36 μm (Group 1), 429.91 ± 16.66 μm (Group 2) to 447.8 ± 16.09 μm (Group 1; P < 0.001), 440.25 ± 11.18 um (Group 2; P = 0.002), respectively, at 6 months. All cases showed stabilization of keratoconus two eyes in epithelium off group developed persistent stromal haze. Most of the patients in Group II experienced pain and photophobia during first 2 days, but not of Group I.Conclusion:Trans-epithelial technique offers visual and topographic outcomes similar to the conventional method with superior patient comfort postintervention.

Corneal haze and visual outcome after collagen crosslinking for keratoconus: A comparison between total epithelium off and partial epithelial removal methods.

Background:Keratoconus is an asymmetric, bilateral, progressive noninflammatory ectasia of the cornea that affects approximately 1 in 2000 of the general population. This may cause a significant negative impact on quality of life. Corneal collagen crosslinking (CXL) is one of the recently introduced methods that have been used to decrease the progression of keratoconus, in particular, as well as other corneal-thinning processes.Materials and Methods:A total of 44 keratoconic eyes of 22 patients were enrolled in this randomized prospective study, after obtaining informed consent. In the first group, the corneal epithelium were totally removed and in the second group, the central 3 mm of epithelium was kept intact and partial removal was performed. After collagen crosslinking in both groups, comprehensive ophthalmologic examination was performed on all patients before and 6 months after the surgery. This article is registered at www.clinicaltrial.gov with registration number NCT01809977.Results:The difference between the two groups was not statistically significant regarding postoperative corneal haziness, refraction, and visual acuity (P > 0.05). However, comparison of pre- and postoperative parameters within each group revealed that total removal of the cornea has resulted in significant improvement of K-max (P value: 0.01) and Q-value (P value: 0.009); while eyes in partial removal group had better improvement of corrected vision (P value: 0.006). Both methods had significant and similar increase in optical corneal density (P < 0.0001).Conclusion:In our study, keeping the central corneal epithelium intact was not beneficial for decreasing corneal haziness, however, this method caused better improvement in corrected vision. Total epithelium off technique resulted in better improvement of K-max and Q-value.

Riboflavin/Ultraviolet A Crosslinking of the Paracentral Cornea

The depth of corneal crosslinking (CXL) does not seem homogeneous within the treatment area but shows a reduction toward the periphery of the cornea. This study was undertaken to investigate this reduction effect and to look for possible solutions. Ten corneas were investigated by means of an optical coherence tomography system (SS-100; Tomey, Nagoya, Japan) 1 month after standard CXL (epithelium off, 0.1% riboflavin for 30 minutes, ultraviolet A radiation 365 nm, 3 mW/cm). The depth of the demarcation line was measured as a function of the radial distance from the apex. These curves were compared with a theoretical curve derived from a standard model of photopolymerization. The CXL depth 3 mm away from the center decreases on average to 65% of the central depth (range: 52%-78%). Polymerization theory predicts this decay, however, underestimates the effect. The intended depth of CXL using current light sources is achieved only within the central area of the cornea. To provide CXL to the peripheral cornea, the ultraviolet beam either should have an improved intensity profile or may have to be decentered.

Qualitative Investigation of Corneal Changes after Accelerated Corneal Collagen Cross-linking (A-CXL) by In vivo Confocal Microscopy and Corneal OCT

Purpose: To assess qualitative micro-morphological corneal changes by confocal microscopy and corneal OCT after accelerated corneal crosslinking (A-CXL) in keratoconic patients. Study design: Prospective non-randomized pilot study. Methods: 20 eyes of 20 patients, aged between 13 and 26 years (mean 22.6 years) underwent A-CXL by the KXL UV-A source (Avedro Inc. Waltham MA, USA). Patients were divided into 4 groups according to different riboflavin solutions and UV A powers.15 patients underwent epithelium-off A-CXL: 5 (Group 1) by riboflavin 0.1% plus dextran 20% at 12 mW/cm2 for 10 min; 5 (Group 2) at 30 mW/cm2 for 4 min; 5 (Group 3) by dextran-free riboflavin 0.1% plus HPMC at 30 mW/cm2 for 4 min and 5 (Group 4) by riboflavin 0.25% plus EDTA, BAK, TRIS epithelium-on A-CXL for 2 min and 40 sec. Micro-morphological analysis was assessed by in vivo HRT II confocal microscopy and corneal OCT. Results: Epithelium regenerated into 3 days. Sub-epithelial nerves disappeared after treatment regenerating into 6 months. Epithelium off A-CXL penetration, measured evaluating keratocytes loss at confocal microscopy and demarcation lines at corneal OCT, resulted at 180 μm on average in the Group 1, 160 μm in the Group 2, 150 μm in the Group 3. Epithelium-on A-CXL (Group 4) revealed a penetration at 80 μm on average. No endothelial damage was recorded in all groups. Conclusion: A-CXL shortened conventional CXL procedure under 20 minutes, being well tolerated. Its clinical efficacy needs to be determined in the mid-long term follow-up and in a large cohort of patients.

In Vivo Imaging of Riboflavin Penetration During Collagen Cross-linking With Hand-held Spectral Domain Optical Coherence Tomography

To compare the effect of complete versus grid-like epithelial removal on riboflavin penetration during collagen cross-linking (CXL) in vivo using hand-held spectral domain optical coherence tomography (OCT, Bioptigen Inc). In this prospective, observational, comparative case series, patients with progressive keratoconus undergoing CXL with riboflavin and ultraviolet A (UVA) light were enrolled. Twenty eyes (20 patients) undergoing CXL using 0.1% riboflavin and UVA light (365 nm) were imaged intraoperatively at 30 and 60 minutes after starting the procedure, using hand-held spectral domain OCT. In 10 eyes, the epithelium was removed completely in the central 7-mm zone (complete removal group) whereas in the remaining 10 eyes, the epithelium was removed in a grid pattern, leaving behind intact islands of epithelium (grid-like removal group). The depth of hyperreflective band (representing penetration of riboflavin) in the anterior corneal stroma was measured. In the complete removal group, the hyper-reflective band was homogenous, extending to a mean depth of 54.2±5.2 μm and 72.4±7.1 μm at 30 and 60 minutes, respectively (P<.001). In the grid-like removal group, the mean depth of the hyperreflective band was uneven, being significantly more in the "epithelium off" areas (56.90±4.66 μm and 74.2±6.7 μm at 30 and 60 minutes, respectively) (P<.001) compared to the "epithelium on" areas (18.9±2.3 μm and 24.7±2.3 μm at 30 and 60 minutes, respectively) (P<.001). Epithelial removal appears to be an essential step prior to performing CXL, as an intact epithelium appears to block penetration of riboflavin in the anterior corneal stroma.

Influence of native crude fibers on the true digestibility of nitrogen and the amino acids

In several test series with rats, the influence of native crude fibres (straw meal and pea hulls) on the amount of metabolic fecal nitrogen (MFN) was tested. It could be ascertained that native crude fibres increase MFN. The influence of the increased MFN on the true digestibility of nitrogen and the amino acids was investigated in test series with casein diets. The casein diets were supplemented with native crude fibres. Generalising, we can state that native crude fibres--due to their structure (lignin)--fix amino acids and thus withhold them from absorption. They do not, however, increase the MFN by mechanical action (increase of the scraping off of intestinal epithelium).