Refractive outcomes of high-magnitude astigmatism correction using femtosecond LASIK versus transepithelial PRK

PURPOSE

To compare the outcomes of femtosecond laser assisted in situ keratomileusis (FS-LASIK) with transepithelial photorefractive keratectomy (T-PRK) for the correction of high-grade astigmatism.

METHODS

Medical records of patients with astigmatism of 2 diopters (D) or higher, who were treated with FS-LASIK or T-PRK in 2013 through 2014 at a private practice laser clinic, were retrospectively analyzed. Efficacy, safety, predictability and vector analysis of astigmatism correction were compared between the treatment groups.

RESULTS

The study included 93 eyes treated with FS-LASIK and 186 eyes treated with T-PRK. No significant differences in postoperative spherical equivalent (-0.10 ± 0.7 D and -0.11 ± 0.7 D, respectively, p = 0.958) and postoperative refractive astigmatism (0.79 ± 0.54 D and 0.82 ± 0.63 D, respectively, p = 0.685) were demonstrated. A significant advantage of FS-LASIK over T-PRK was seen for the efficacy (1.00 ± 0.18 and 0.86 ± 0.22, respectively, p < 0.001) and safety (1.03 ± 0.17 and 0.89 ± 0.21, respectively, p < 0.001) indices. Results remain statistically significant in a multivariate analysis model. Vector analysis for the astigmatism correction showed no significant difference between the surgery methods in the surgically induced astigmatism, difference vector, correction index and index of success.

CONCLUSION

Both procedures demonstrated desirable post-operative SE outcomes for high-grade astigmatism correction. However, FS-LASIK achieved better results than T-PRK in the efficacy and safety parameters.

Changes in anterior segment parameters following insertion of ExPRESS mini glaucoma implant vs. trabeculectomy

PURPOSE

To compare changes in anterior segment parameters following ExPRESS Mini Glaucoma Shunt surgery vs. trabeculectomy using the Pentacam rotating Scheimpflug camera.

METHODS

In this prospective, comparative study, 27 patients with glaucoma treated at the Rabin Medical Center from 2009 to 2013 were enrolled in this prospective comparative study: 19 participants (19 eyes) underwent ExPRESS shunt implantation and 12 (13 eyes) underwent trabeculectomy. Changes in anterior chamber parameters at postoperative day 1 and postoperative month 3 were evaluated on Scheimpflug images.

RESULTS

Intraocular pressure decreased significantly from baseline in both groups. The decrease in both groups was similar at postoperative month 3 (p=0.82). ExPRESS surgery caused a transient increase in posterior corneal astigmatism (p=0.008) and a transient decrease in anterior chamber depth (p=0.016) and volume (p=0.006) on postoperative day 1. At postoperative month 3, these parameters were no longer statistically significant (p=0.65, p=0.51, and p=0.57 respectively). Trabeculectomy caused a transient increase in anterior and posterior corneal astigmatism on postoperative day 1 (p=0.003 and p=0.005, respectively), which were not evident at postoperative month 3 (p=1.0 and p=1.0, respectively). At postoperative month 3, both ExPRESS and trabeculectomy showed similar changes in anterior chamber parameters.

CONCLUSIONS

Both ExPRESS mini glaucoma implant and trabeculectomy significantly decreased intraocular pressure and had transient effects on anterior segment parameters, with minor differences between the methods.

Dupilumab-induced ocular surface disease (DIOSD) in patients with atopic dermatitis: clinical presentation, risk factors for development and outcomes of treatment with tacrolimus ointment

Aim

To identify risk factors for the development of dupilumab-induced ocular surface disease (DIOSD) in adult patients with atopic dermatitis (AD) and describe outcomes of treatment.

Methods

A retrospective institutional cohort study performed at the Rabin Medical Center, Petach Tikva, Israel. Adult patients with AD who received dupilumab from March 2018 to June 2019 were included. Demographics, AD severity scores, blood IgE levels, previous atopic keratoconjunctivitis (AKC), dermatological response to dupilumab, ophthalmological evaluation and treatment were noted. Univariate and multivariate analyses were used to identify risk factors for DIOSD.

Results

Sixteen of 37 patients who were included in the study (43%) had new or exacerbated symptoms of ocular surface disease starting at 2 weeks following the first treatment. Three patients reported transient dry eye sensation which lasted 2 weeks; nine patients reported chronic dry eye sensation, and four patients (25%) had marked blepharoconjunctivitis. The presence of severe AD was the strongest predictor of DIOSD. Not a single patient with moderate AD had DIOSD. In multivariate analysis, prior AKC was a risk factor for DIOSD (R2=15.78, OR=23.28, p=0.005) while a family history of atopy was protective of DIOSD (R2=6.22, OR=0.13, p=0.05). All four patients with blepharoconjunctivitis had resolution of signs, and symptoms within days of starting periocular 0.03%–0.1% tacrolimus ointment.

Conclusions

DIOSD is common in patients with AD receiving dupilumab. While most cases are mild, some patients can develop blepharoconjunctivitis which responds well to tacrolimus ointment. AD severity, and previous AKC are risk factors for DIOSD.

Comparative analysis of biomechanical parameters of the corneas following Descemet membrane endothelial keratoplasty and contralateral healthy corneas

PURPOSE

To compare the biomechanical properties of the unilateral operated corneas in patients who had undergone Descemet membrane endothelial keratoplasty (DMEK) for pseudophakic bullous keratopathy (PBK) with those of the contralateral normal corneas.

METHODS

This was a retrospective cohort study conducted at university hospitals (Department of Ophthalmology, Rabin Medical Center, Petach Tikva, Israel, and S. Fyodorov Eye Microsurgery State Institution, Moscow, Russia). Forty eyes of 20 patients who underwent DMEK for unilateral PBK 3.5 to 36 months ago and with normal fellow eyes were included in the study. An ocular response analyzer was used to measure the corneal biomechanical properties in the operated and normal fellow eyes. The main outcome measures were corneal hysteresis (CH) and corneal resistance factor (CRF).

RESULTS

The mean CH (8.4 ± 1.5 mmHg vs. 8.2 ± 1.5 mmHg, P = 0.707) and the mean CRF (8.7 ± 1.6 mmHg vs. 8.3 ± 1.6 mmHg, P = 0.419) values did not show any statistically significant difference between the operated and the normal fellow eyes.

CONCLUSIONS

In our study, the corneas that underwent DMEK for PBK showed normal values for biomechanical parameters. These findings support the previous studies that have reported near complete visual, functional, and ultra-structural rehabilitation of the corneas following DMEK.

Comparison of Subconjunctival Aflibercept and Betamethasone for the Treatment of Formed Corneal Neovascularization in a Rabbit Model

AIM

To compare the efficacy of aflibercept (Eylea®), a potent antivascular endothelial growth factor (VEGF) agent, with betamethasone (Celestone®) and placebo for the treatment of formed corneal neovascularization in a rabbit model.

METHODS

A central corneal chemical burn was created in the right eye of 24 New Zealand albino rabbits. Four weeks later, the rabbits were randomly divided into 4 equal groups for subconjunctival injection of aflibercept, betamethasone, aflibercept+ betamethasone, or saline (control). Digital photographs taken at weekly intervals were rated by 2 masked observers for extent, centricity, and density of corneal neovascularization according to a predefined scale. The percentage of corneal surface involved by neovascularization was quantified by image analysis software (Fiji-J). The change in corneal neovascularization from treatment administration (4 weeks after injury) to 4 weeks later (8 weeks after injury) was assessed. The rabbits were then euthanized, and their eyes were enucleated and processed for histopathological and immunofluorescence studies.

RESULTS

There was no significant difference in the change in corneal neovascularization after treatment among the 4 groups according to the digital images (p > 0.15) or histological evaluation with hematoxylin and eosin (p > 0.08). On immunofluorescence assay, a lower VEGF concentration was observed in all treatment groups compared to the control group.

CONCLUSIONS

In this rabbit model, corneal neovascularization induced by chemical burn failed to regress with treatment with aflibercept, betamethasone, or their combination.

Iron catalysis of lipid peroxidation in ferroptosis: Regulated enzymatic or random free radical reaction?

Duality of iron as an essential cofactor of many enzymatic metabolic processes and as a catalyst of poorly controlled redox-cycling reactions defines its possible biological beneficial and hazardous role in the body. In this review, we discuss these two "faces" of iron in a newly conceptualized program of regulated cell death, ferroptosis. Ferroptosis is a genetically programmed iron-dependent form of regulated cell death driven by enhanced lipid peroxidation and insufficient capacity of thiol-dependent mechanisms (glutathione peroxidase 4, GPX4) to eliminate hydroperoxy-lipids. We present arguments favoring the enzymatic mechanisms of ferroptotically engaged non-heme iron of 15-lipoxygenases (15-LOX) in complexes with phosphatidylethanolamine binding protein 1 (PEBP1) as a catalyst of highly selective and specific oxidation reactions of arachidonoyl- (AA) and adrenoyl-phosphatidylethanolamines (PE). We discuss possible role of iron chaperons as control mechanisms for guided iron delivery directly to their "protein clients" thus limiting non-enzymatic redox-cycling reactions. We also consider opportunities of loosely-bound iron to contribute to the production of pro-ferroptotic lipid oxidation products. Finally, we propose a two-stage iron-dependent mechanism for iron in ferroptosis by combining its catalytic role in the 15-LOX-driven production of 15-hydroperoxy-AA-PE (HOO-AA-PE) as well as possible involvement of loosely-bound iron in oxidative cleavage of HOO-AA-PE to oxidatively truncated electrophiles capable of attacking nucleophilic targets in yet to be identified proteins leading to cell demise.

[PREVALENCE OF DEMODEX PARASITES IN PATIENTS WITH CHRONIC BLEPHARITIS AND HEALTHY CONTROLS IN ISRAEL]

INTRODUCTION

Previous studies demonstrated the potential pathogenic relationship between infestation of the eyelashes by the parasite Demodex and chronic blepharitis, whereas other studies did not demonstrate such relations and concluded that Demodex is a normal eyelid flora.

AIMS

This study examines the prevalence of Demodex in patients with blepharitis compared to a healthy control group in Israel, in order to further explore and establish its pathogenic role in cases of chronic blepharitis.

METHODS

A case-control study was conducted including 110 participants: 60 patients with chronic blepharitis attending a tertiary medical center and 50 subjects with no signs of blepharitis. Six to eight eyelashes were epilated from each participant and studied microscopically for the presence of Demodex by a blinded examiner. Fluorescein stain was added to the "clean" samples in order to reduce the false negative results.

RESULTS

Demodex were identified on the eyelashes of 44 patients with blepharitis (73.3%) and 20 controls (40%) (p<0.001). After adjusting for age, blepharitis was still a significant risk factor for the presence of Demodex (OR=2.96, CI 95% 1.2-7.3).

CONCLUSIONS

This study supports previous studies demonstrating pathogenic relationship between Demodex infestation of the eyelashes to chronic blepharitis. The authors recommend epilating 6-8 lashes of patients with blepharitis for microscopic identification of these parasites. Fluorescein stain may have a limited role in the recognition of Demodex in parasite free samples.

Survey of the analysis of continuous conformational variability of biological macromolecules by electron microscopy

Single-particle analysis by electron microscopy is a well established technique for analyzing the three-dimensional structures of biological macromolecules. Besides its ability to produce high-resolution structures, it also provides insights into the dynamic behavior of the structures by elucidating their conformational variability. Here, the different image-processing methods currently available to study continuous conformational changes are reviewed.

'Blue bubble' technique: an ab interno approach for Descemet separation in deep anterior lamellar keratoplasty using trypan blue stained viscoelastic device

BACKGROUND

In this study, we examined a novel variant of 'big-bubble' deep anterior lamellar keratoplasty using trypan-blue-stained viscoelastic device for the creation of a pre-descemetic bubble.

METHODS

Ten corneoscleral rims were mounted on an artificial anterior chamber (AC). The AC was filled with air through a limbal paracentesis. A Melles' triangulated spatula was inserted through the paracentesis, with its tip penetrating the AC, was then slightly retracted and pushed into the deep stroma above the roof of the paracentesis. A mixture of trypan blue and viscoelastic device (Healon, Abbott Medical Optics, Abbott Park, Illinois) was injected into this intra-stromal pocket using a 27-G cannula to create a pre-descemetic separation bubble. Bubble type and visualization of dyed viscoelastic device were noted. The method was later employed in three cases.

RESULTS

In all 10 corneoscleral rims, the technique successfully created a visible pre-descemetic (type 1) bubble that could be expanded up to the predicted diameter of trephination. Subsequent trephination and the removal of corneal stroma were uneventful. In two out of four clinical cases, a type 1 bubble was created, while in two others, visco-dissection failed and dyed viscoelastic was seen in the AC.

CONCLUSIONS

The presented technique holds promise of being a relatively easy to perform, predictable and well-controlled alternative for achieving a type 1 bubble during deep anterior lamellar keratoplasty surgery. The trypan-blue-stained viscoelastic device facilitates proper visualization and control of the separation bubble and assists in identifying the penetrance to the separation bubble prior to removal of the stromal cap.

Laser capsulotomy following cataract surgery: Comparing time to capsulotomy with implantation of two broadly used intraocular lenses

PURPOSE

The aim of this study is to compare the length of time from uneventful cataract surgery using one of two common posterior chamber intraocular lenses (IOLs) (hydrophilic versus hydrophobic acrylic) to laser capsulotomy.

MATERIALS AND METHODS

Retrospective analysis of all patients who underwent neodymium: yttrium-aluminum-garnet laser capsulotomy between 2011 and 2014 following uneventful phacoemulsification surgery at a tertiary university-affiliated medical center. Medical records were reviewed for demographics, ocular comorbidities, operative details, postoperative follow-up, and findings of the precapsulotomy ophthalmologic examination. Parameters, including age, sex, laterality, visual acuity, surgeon's experience, and time from cataract surgery to capsulotomy, were compared between patients who received hydrophilic (SeeLens AF, Kibbutz Hanita, Israel) or hydrophobic (AcrySof SA60AT, Alcon Laboratories, Fort Worth, TX, USA) IOLs.

RESULTS

The cohort included 222 patients (255 eyes), of which, 107 were male and 115 female, of mean age 73 ± 8 years. Mean interval from cataract surgery to laser capsulotomy was 24 months (range 2-70) and was significantly shorter in patients with SeeLens (23 ± 13 months) than AcrySof IOL implantation (28 ± 13 months, P = 0.04). Lens type remained significant in multivariate analysis after including surgeon's experience and age as potential confounders (P = 0.04).

CONCLUSION

The hydrophilic SeeLens IOL is associated with a significantly shorter time interval from cataract surgery to laser capsulotomy than the hydrophobic AcrySof IOL.

Effect of Histone Deacetylase Inhibitor, Butyroyloxymethyl-Diethyl Phosphate (AN-7), on Corneal Neovascularization in a Mouse Model

PURPOSE

To examine whether butyroyloxymethyl-diethyl phosphate (AN-7), a histone deacetylase inhibitor, inhibits chemically induced corneal neovascularization (NV) in mice.

METHODS

Corneal NV was induced in the right eye of male C57BL mice by application of a mixture of 75% silver nitrate and 25% potassium nitrate to the corneal center. Immediately thereafter, the mice were randomized into 2 groups, receiving an intraperitoneal injection of AN-7 or saline, which served as control. Corneal NV was evaluated at constant time intervals from the corneal injury by corneal photographs and the area of corneal NV was measured. Centricity and density of the corneal vascularization were graded. Corneal flat mounts blood vessels staining and histological studies were performed on day 10. Unpaired t-test was used for group comparisons.

RESULTS

The corneal neovascular area was statistically significantly reduced by AN-7 treatment on days 10 and 14 postinjury and compared with the untreated group. The centricity and density of the corneal NV between treated and untreated groups showed no significant difference at any time point.

CONCLUSIONS

Systemic treatment with AN-7 had a significant inhibitory effect on chemical burn-induced corneal NV in mice. These results suggest that AN-7 should be further evaluated for its therapeutic potential for the treatment of corneal NV.

Validation of the EORTC QLQ-BIL21 questionnaire for measuring quality of life in patients with cholangiocarcinoma and cancer of the gallbladder

Background:

There is no specific quality of life (QoL) measurement tool to quantify QoL in patients with biliary tract cancer. Quality of life measurement is an increasingly crucial trial end point and is now being incorporated into clinical practice.

Methods:

This International Multicentre Phase IV Validation Study assessed the QLQ-BIL21 module in 172 patients with cholangiocarcinoma and 91 patients with cancer of the gallbladder. Patients completed the questionnaire at baseline pretherapy and subsequently at 2 months. Following this, the psychometric properties of reliability, validity, scale structure and responsiveness to change were analysed.

Results:

Analysis of the QLQ-BIL21 scales showed appropriate reliability with Cronbach's α-coefficients >0.70 for all scales overall. Intraclass correlations exceeded 0.80 for all scales. Convergent validity >0.40 was demonstrated for all items within scales, and discriminant validity was confirmed with values <0.70 for all scales compared with each other. Scale scores changed in accordance with Karnofsky performance status and in response to clinical change.

Conclusions:

The QLQ-BIL21 is a valid tool for the assessment of QoL in patients with cholangiocarcinoma and cancer of the gallbladder.

Relating the Structure of HIV-1 Reverse Transcriptase to Its Processing Step

Abstract By treating an enzyme as a coarse-grained uniform block of material, utilizing only the α-Carbon positions, the normal modes of motion can be obtained. For reverse transcriptase the slower of these motions are suggestive of being involved in the processing step, where the RNA or DNA strand is copied onto a new DNA strand at a polymerase site, and the RNA strand is subsequently cut up at the distant Ribonuclease H site. The slowest mode of motion involves hinge bending about a site midway between the polymerase and Ribonuclease H sites, suggesting that it can push or pull the RNA strand between these two sites. Pulling the nucleic acid strand would require tight binding to the RNase H site. The next slowest mode involves a hinge that opens and closes the protein like a clamp, which could facilitate the release of the nucleic acids for their step-wise progression. The third mode could rotate the substrate. An overall description of the step-wise processing step would involve close coordination among these steps. Results suggest that the smaller p51 subunit serves only as ballast to support the various modes of motion involving the different parts of the p66 subunit.

A 10-year survey: prevalence of ocular surface squamous neoplasia in clinically benign pterygium specimens

PURPOSE

It is essential to assess the yield of routine histopathological examination of pterygium specimens excised from clinically benign pterygium. The purpose of this study was to determine the rate of histopathologically identified ocular surface squamous neoplasia (OSSN) in clinically benign pterygium specimens.

MATERIALS AND METHODS

This retrospective consecutive study consisted of patients from the cornea services of the ophthalmology departments of Meir Medical Center, Kfar Sava, and Rabin Medical Center, Petah Tikva, Israel. Included patients were those with clinically benign pterygium who underwent pterygium excision between January 2002 and December 2011. The pterygium specimens were sent for histopathological examination and the pathology reports were reviewed for evidence of OSSN.

RESULTS

Overall, pathology reports of 682 eyes of 585 sequential patients were included in the study. There was a male predominance of cases (59%). Patients' age ranged from 16 to 87 years with an average age of 56 years. Six hundred and forty-three cases were primary (94%) and 39 cases were recurrent (6%).

CONCLUSIONS

Cases of clinically benign pterygium diagnosed and excised by an experienced corneal expert are less likely to harbor OSSN. The yield of routine histopathological examination of such specimens may be low.

Accuracy of Scheimpflug Holladay equivalent keratometry readings after corneal refractive surgery in the absence of clinical history

BACKGROUND AND OBJECTIVE

To identify the most accurate combination of Pentacam's equivalent keratometry readings (EKR) and intraocular lens power formula when the clinical history is unavailable.

PATIENTS AND METHODS

A total of 18 patients underwent cataract surgery after refractive surgery. The Pentacam 4.5- and 3.0-mm EKR were combined with the SRK II, SRK/T, Hoffer-Q, and Holladay I and II formulas.

RESULTS

The smallest deviation from the predicted value was achieved by combining the 4.5 EKR with the Holladay II formula (mean arithmetic deviation, -0.2 ± 0.4 dpt).

CONCLUSION

The 4.5-mm EKR + Holladay II formula can accurately calculate intraocular lens power in patients with previous refractive surgery.

Global motions exhibited by proteins in micro- to milliseconds simulations concur with anisotropic network model predictions

The Anton supercomputing technology recently developed for efficient molecular dynamics simulations permits us to examine micro- to milli-second events at full atomic resolution for proteins in explicit water and lipid bilayer. It also permits us to investigate to what extent the collective motions predicted by network models (that have found broad use in molecular biophysics) agree with those exhibited by full-atomic long simulations. The present study focuses on Anton trajectories generated for two systems: the bovine pancreatic trypsin inhibitor, and an archaeal aspartate transporter, GltPh. The former, a thoroughly studied system, helps benchmark the method of comparative analysis, and the latter provides new insights into the mechanism of function of glutamate transporters. The principal modes of motion derived from both simulations closely overlap with those predicted for each system by the anisotropic network model (ANM). Notably, the ANM modes define the collective mechanisms, or the pathways on conformational energy landscape, that underlie the passage between the crystal structure and substates visited in simulations. In particular, the lowest frequency ANM modes facilitate the conversion between the most probable substates, lending support to the view that easy access to functional substates is a robust determinant of evolutionarily selected native contact topology.

Comparison between femtosecond laser mushroom configuration and manual trephine straight-edge configuration deep anterior lamellar keratoplasty

AIM

To compare outcomes and complications of femtosecond laser (FSL) mushroom configuration and manual trephine (MT) straight-edge configuration deep anterior lamellar keratoplasty (DALK).

METHODS

A cohort of 19 consecutive eyes that underwent FSL DALK was compared with 19 consecutive eyes that underwent MT DALK. Surgery was performed for eyes with keratoconus, corneal ectasia and scarring. Patient demographics, best-corrected visual acuities (BCVAs), refraction and complications were compared.

RESULTS

Groups were comparable for age, gender and preoperative BCVA. Rates of intraoperative and postoperative complications were low and comparable between the groups. These included intraoperative Descemet's membrane (DM) perforation which did not require conversion to penetrating keratoplasty; stromal rejection successfully treated with topical steroids; postoperative DM detachment; delayed epithelial healing and increased intraocular pressure which resolved with topical anti-glaucoma drops. At 3 months, the mean BCVA was significantly better in the FSL group compared with the MT group (p=0.00002). At 6 months and 1 year, there was no significant difference between mean BCVA between the two groups. Mean spherical equivalent, cylindrical astigmatism and keratometric cylinder preoperatively and at 3, 6 and 12 months postoperatively were similar between the two groups.

CONCLUSIONS

FSL or trephine DALK are viable options for keratoconus, ectasia and corneal scars. Earlier visual recovery occurs with FSL mushroom configuration compared with MT straight-edge DALK.

Zig Zag versus Top Hat configuration in IntraLase-enabled penetrating keratoplasty

AIM

To compare the outcomes with IntraLase-enabled keratoplasty using (IEK) Top Hat (TH) versus Zig Zag (ZZ) configuration.

METHODS

Retrospective comparative series of 24 eyes that underwent TH and 10 eyes that underwent ZZ IEK.

RESULTS

There were no significant differences in LogMar Best-spectacle corrected visual acuity (TH- IEK=0.3; ZZ-IEK=0.18, p=0.18), spherical equivalent (TH-IEK=-3.55±3.7 dioptres (D); ZZ-IEK=-2.69±4.85 D, p=0.60), manifest cylinder (TH- IEK=3.79±2.43 D; ZZ- IEK=4.61±3.29 D, p=0.45), topographic astigmatism (TH-IEK=3.67±2.34 D; ZZ-IEK=4.26±1.1 D, p=0.63), total higher-order aberrations (TH- IEK=8.26±3.53; ZZ-IEK=8.1±4.71, P=0.92), endothelial cell density change from baseline (TH- IEK= -41.55%±15.86; ZZ-IEK=-25.45%±30.66, p=0.22) or time to suture removal in months (TH- IEK=7.48±4.07; ZZ- IEK=6.93±2.71, p=0.75). There was no difference in requirements for astigmatic keratectomy (TH-IEK=54.2%±13; ZZ-IEK=50%±5, OR=1.18) or complications (TH-IEK=25%±6; ZZ-IEK=30%±3, OR=0.78).

CONCLUSIONS

TH-IEK and ZZ-IEK have comparable visual and refractive outcomes, wound healing and endothelial cell counts at 1-year.

Effect of erythropoietin on healing of corneal epithelial defects in rabbits

BACKGROUND/AIM

Corneal epithelial defects may heal slowly in patients with diabetes, limbal stem cell deficiency, extensive chemical burns or anesthetized corneas. Studies have shown that erythropoietin, a glycoprotein hormone that promotes red blood cell proliferation and inhibits apoptosis of erythroid progenitors, may also exert a cytoprotective, antiapoptotic effect on nonhematopoietic cells. The aim of the study was to examine the effect of erythropoietin on the healing process of corneal epithelial erosions in rabbit eyes.

METHODS

Fifteen New Zealand albino rabbits were divided into 3 groups following induction of unilateral uniform corneal epithelial erosions. The first group received local treatment with erythropoietin-containing cellulose-based gel 4 times daily; the second group received treatment with cellulose-based gel without erythropoietin 4 times daily, and the third group received no treatment. The healing process was monitored twice daily using cobalt-blue-filtered slit lamp photography and digital images of fluorescein-stained corneas until complete re-epithelization was achieved. Following re-epithelization, corneas were removed for histologic processing. One-way analysis of variance and Mann-Whitney tests were used for statistical analysis.

RESULTS

Mean ± SD time to complete re-epithelization was 55 ± 2.19 h in the group treated with erythropoietin-containing cellulose-based gel, 66.5 ± 14.25 h in the group treated with gel only and 62.2 ± 9.09 h in the untreated group (p = 0.16, not significant). There was no significant difference among the groups in the time to complete re-epithelization or the rate of epithelial healing. Histologic corneal evaluation revealed stromal vascularization in 2 of the 6 erythropoietin-treated rabbits and in neither of the control groups.

CONCLUSION

Erythropoietin has no beneficial effect on the rate of healing of corneal epithelial erosions in rabbit eyes, and corneal stroma neovascularization seems to be a significant adverse effect.

The use of ophthalmic viscosurgical devices during donor's corneal harvesting

PURPOSE OF THE STUDY

To evaluate the protective effect of Biolon (sodium-hyaluronate 1%) use on corneal endothelium, during donor's corneal harvesting.

MATERIALS AND METHODS

A prospective, randomized, double blind, comparative study was performed on 120 corneas donated from 60 donors. One cornea from each donor (n = 60) was harvested using intracameral injection of ophthalmic viscosurgical device (OVD), and the fellow cornea with no use of OVD (n = 60, control group). Endothelial cell density (ECD) values were obtained at the center of each corneal graft with a specular microscope one day after harvesting.

RESULTS

ECD in the OVD group were 2839 ± 412.5 cells/mm(2) and in the control group 2748 ± 429.7 cells/mm(2). (p = 0.03). Distribution curve of the difference in ECD between the OVD and no OVD eyes showed that 47% of the donors had > 100 cells/mm2 difference, and 32% of donors had >200 cells/mm(2) difference in favor of the OVD group.

CONCLUSIONS

Intracameral OVD injection during corneal graft harvesting may protect the endothelium from the mechanical damage induced during the procedure. Further investigation is needed before routine the use of intracameral OVD should be considered in this setting.

Corneal graft failure following Nd:YAG laser membranotomy for inadvertent retained descemet's membrane after penetrating keratoplasty

Retained Descemet's membrane (DM) following penetrating keratoplasty (PKP) is a rare finding that may reduce visual acuity following opacification or endanger the graft endothelium. The association between Nd:YAG laser membranotomy and corneal graft failure is reported. Five of 1,350 patients (0.37%) undergoing PKP for pseudophakic bullous keratopathy or graft failure between 1986 and 2008 presented with inadvertent retained DM located close to the graft endothelium. The membrane opacified within 3 to 4 months, reducing the patients' vision. Nd:YAG laser membranotomy was performed using low energy and few pulses. Patients' visual acuity improved from 6/40 to 6/90 before treatment to 6/15(-) to 6/20 at 2 weeks following membranotomy. However, the corneal graft decompensated within 6 to 8 weeks following this procedure, necessitating repeat PKP, with removal of the retained DM. Nd:YAG laser membranotomy may lead to corneal graft failure due to shockwave damage created by the laser pulses, focused near the endothelial surface.