[ARTIFICIAL CORNEA: FROM THE BEGINNING TO THE FUTURE]

INTRODUCTION

Corneal disease is among the leading reversible causes of blindness worldwide. Corneal transplantation is a successful and curative treatment for most of these cases. However, in certain indications it is not amendable for standard corneal transplantation, the only available option to restore functional vision is keratoprosthesis (KPro) implantation. KPros may also offer an alternative to the global shortage of donor corneas, limiting the access to transplantations. However, current KPros face many challenges, including surgical complexity that requires skilled surgeons and vast resources as well as unique surgical and post-operative complications. Although several artificial corneas have been proposed over the years, two implants are mostly used in the clinical setting today. The first, the Boston KPro, consists of a front plate with an optical stem and a back plate snapped together with donor corneal tissue in-between, which is then sutured to the patient's cornea. The second, the Osteo-odonto-keratoprosthesis (OOKP), uses biological tissue of the alveolar bone to support an optical cylinder within the eye. The indications, surgical techniques, and complication profile of the two procedures are different and will be discussed in this review. Extensive research continues to improve the accessibility and technological developments of KPros in the search for a potential breakthrough in the treatment of these difficult cases.

Corneal pseudoectasia: a case series

OBJECTIVE

To raise awareness of conditions that can tomographically mimic corneal ectasia and describe the actions required to avoid misdiagnosis.

METHODS

We report a retrospective case series of seven patients presenting at two tertiary care centers in Israel with a presumed diagnosis of keratoconus or post-refractive ectasia. Upon further examination, the ectasia diagnosis was reconsidered and eventually ruled out.

RESULTS

Included were ten eyes of seven patients. Cases included bilateral diffuse Salzmann's nodular degeneration, ophthalmoplegia with strabismus which precluded proper fixation during the acquisition of tomography images, two cases of incorrect Pentacam parameter settings, a patient with a history of hyperopic laser-assisted in situ keratomileusis (LASIK) treatment in one eye and myopic LASIK in the fellow eye, a case of old post-photorefractive keratectomy (PRK) stromal haze, and a patient with posterior polymorphous corneal dystrophy.

CONCLUSIONS

Tomography patterns mimicking corneal ectasia can appear in patients without ectatic pathology. The comprehensive ophthalmologist should be aware of such cases as they may substantially alter the treatment course and prognosis of these patients.

Best Disease: Global Mutations Review, Genotype-Phenotype Correlation, and Prevalence Analysis in the Israeli Population

Purpose

To review all reported disease-causing mutations in BEST1, perform genotype-phenotype correlation, and estimate disease prevalence in the Israeli population.

Methods

Medical records of patients diagnosed with Best disease and allied diseases from nine Israeli medical centers over the past 20 years were collected, as were clinical data including ocular findings, electrophysiology results, and retina imaging. Mutation detection involved mainly whole exome sequencing and candidate gene analysis. Demographic data were obtained from the Israeli Bureau of Statistics (January 2023). A bibliometric study was also conducted to gather mutation data from online sources.

Results

A total of 134 patients were clinically diagnosed with Best disease and related conditions. The estimated prevalence of Best disease was calculated to be 1 in 127,000, with higher rates among Arab Muslims (1 in 76,000) than Jews (1 in 145,000). Genetic causes were identified in 76 individuals (57%), primarily showing autosomal-dominant inheritance due to BEST1 mutations (58 patients). Critical conserved domains were identified consisting of a high percentage of dominant missense mutations, primarily in transmembrane domains and the intracellular region (Ca2+ binding domain) of the BEST1 protein.

Conclusions

This study represents the largest cohort of patients with Best disease reported in Israel and globally. The prevalence in Israel is akin to that in Denmark but is lower than that in the United States. Critical conserved domains within the BEST1 protein are pivotal for normal functioning, and even minor missense alterations in these areas lead to a dominant disease manifestation. Genetic testing is indispensable as the gold standard for Best disease diagnosis due to the variable clinical presentation of the disease.

Pathogen Surveillance for Acute Infectious Conjunctivitis

Importance

Acute infectious conjunctivitis is a common ocular condition with major public health consequences.

Objective

To assess regional variations and microbial etiologies of acute infectious conjunctivitis to guide treatment.

Design, Setting, and Participants

In this cross-sectional study, patients with presumed acute infectious conjunctivitis were enrolled in the study at 5 sites (Honolulu, Hawaii; Los Angeles, San Francisco, and San Diego, California; and Petah-Tikva, Israel) from March 2021 to March 2023. Patients with allergic or toxic conjunctivitis were excluded.

Main Outcomes and Measures

Pathogens were identified by unbiased RNA deep sequencing.

Results

In all, 52 patients (mean [range] age, 48 [7-80] years; 31 females [60%]) were enrolled at 5 sites (6 patients from Honolulu, 9 from San Diego, 11 from Los Angeles, 13 from San Francisco, and 13 from Petah-Tikva). RNA deep sequencing detected human adenovirus species D in one-quarter of patients (13 of 52). A wide range of pathogens, including human coronavirus 229E, SARS-CoV-2, and herpes simplex virus type 1, was also identified, as well as several bacteria and fungi. Moreover, 62% (32 of 52) of patients presented with purulent discharge, while only 8% (4 of 52) of patients had confirmed bacterial pathogens.

Conclusion and Relevance

In this cross-sectional study, pathogens associated with acute infectious conjunctivitis varied between all 5 sites in the US and Israel. Purulent discharge was a common presenting sign in this study, with a low specificity for bacteria-associated conjunctivitis, suggesting that further diagnostic workup may be necessary to inform antibiotic stewardship. Additional research on cost-effectiveness of using RNA deep sequencing is needed to ascertain whether it is better to monitor patients clinically until resolution of disease.

Formation of protein adducts with Hydroperoxy-PE electrophilic cleavage products during ferroptosis

Ferroptosis is an iron dependent form of cell death, that is triggered by the discoordination of iron, lipids, and thiols. Its unique signature that distinguishes it from other forms of cell death is the formation and accumulation of lipid hydroperoxides, particularly oxidized forms of polyunsaturated phosphatidylethanolamines (PEs), which drives cell death. These readily undergo iron-catalyzed secondary free radical reactions leading to truncated products which retain the signature PE headgroup and which can readily react with nucleophilic moieties in proteins via their truncated electrophilic acyl chains. Using a redox lipidomics approach, we have identified oxidatively-truncated PE species (trPEox) in enzymatic and non-enzymatic model systems. Further, using a model peptide we demonstrate adduct formation with Cys as the preferred nucleophilic residue and PE(26:2) +2 oxygens, as one of the most reactive truncated PE-electrophiles produced. In cells stimulated to undergo ferroptosis we identified PE-truncated species with sn-2 truncations ranging from 5 to 9 carbons. Taking advantage of the free PE headgroup, we have developed a new technology using the lantibiotic duramycin, to enrich and identify the PE-lipoxidated proteins. Our results indicate that several dozens of proteins for each cell type, are PE-lipoxidated in HT-22, MLE, and H9c2 cells and M2 macrophages after they were induced to undergo ferroptosis. Pretreatment of cells with the strong nucleophile, 2-mercaptoethanol, prevented the formation of PE-lipoxidated proteins and blocked ferroptotic death. Finally, our docking simulations showed that the truncated PE species bound at least as good to several of the lantibiotic-identified proteins, as compared to the non-truncated parent molecule, stearoyl-arachidonoyl PE (SAPE), indicating that these oxidatively-truncated species favor/promote the formation of PEox-protein adducts. The identification of PEox-protein adducts during ferroptosis suggests that they are participants in the ferroptotic process preventable by 2-mercaptoethanol and may contribute to a point of no return in the ferroptotic death process.

ABCD progression display for keratoconus progression: a sensitivity-specificity study

OBJECTIVE

To evaluate the sensitivity and specificity of the ABCD progression display for keratoconus progression.

METHODS

Data was collected from patients that underwent at least two Pentacam assessments 6 months apart. Sensitivity and specificity were calculated for the ABCD progression display. Progression was defined by criterion 1: change in two ABCD parameters above 80% confidence interval (CI) or criterion 2: change in one ABCD parameter above 95%CI. Receiver operating characteristic analysis compared the area under the curve (AUC) of all ABCD parameter combinations.

RESULTS

Thirty eyes were evaluated over a median time of 10.3 months. Progression by criterion 1 resulted in a sensitivity of 61.9% and specificity of 88.9%. Progression by criterion 2 resulted in higher sensitivity (80.9%) and specificity (100%). Pairwise comparisons of the ROC curves show that the AUC achieved by criterion 2 was significantly higher than criterion 1 (0.905 vs. 0.754, p = 0.0332). Evaluation of all ABCD combinations with a significant change of 80% or 95% CI did not show superiority over criterion 1 or 2 regarding progression detection. The D parameter had a very low AUC (0.5-0.556).

CONCLUSIONS

The ABCD progression display can assess keratoconus progression with high sensitivity and specificity, thus assisting the patients' decision-making process. The D parameter did not contribute to the sensitivity or specificity of this classification.

Long-Term Evaluation of Pseudoexfoliation Syndrome Post-Cataract Extraction

The study aimed to examine the effect of cataract extraction on ophthalmologists' ability to detect pseudoexfoliation (PXF) syndrome. A total of 31 patients admitted for elective cataract surgery were enrolled in this prospective comparative study. Prior to surgery, patients underwent slit-lamp examination and gonioscopy conducted by experienced glaucoma specialists. Subsequently, patients were re-examined by a different glaucoma specialist and comprehensive ophthalmologists. Pre-operatively, 12 patients were diagnosed with PXF on the basis of a Sampaolesi line (100%), anterior capsular deposits (83%), and pupillary ruff deposits (50%). The remaining 19 patients acted as controls. All patients were re-examined 10-46 months post-operatively. Of the 12 patients with PXF, 10 (83%) were correctly diagnosed post-operatively by glaucoma specialists and 8 (66%) by comprehensive ophthalmologists. There was no statistically significant difference in PXF diagnosis. However, detection of anterior capsular deposits (p = 0.02), Sampaolesi lines (p = 0.04), and pupillary ruff deposits (p = 0.01) were significantly lower post-operatively. Diagnosis of PXF is challenging in pseudophakic patients as the anterior capsule is removed during cataract extraction. Therefore, PXF diagnosis in pseudophakic patients relies mainly on the presence of deposits at other anatomical sites, and careful attention to these signs is required. Glaucoma specialists may be more likely than comprehensive ophthalmologists to detect PXF in pseudophakic patients.

Evaluating Changes in Apparent Chord Mu after Pharmacological Pupil Dilatation

INTRODUCTION

Preoperative measurements of apparent chord mu length above 0.6 mm have been associated with higher risks for photic phenomena after cataract surgery with multifocal intraocular lenses (MFIOLs).

METHODS

This retrospective study evaluated patients scheduled for elective cataract surgery at a single tertiary medical center between 2021 and 2022. Pupil diameter and apparent chord mu length were analyzed for eyes with biometry measurements from IOLMaster 700 (Carl Zeiss Meditec, AG) under photopic light conditions, before and after pharmacological pupil dilatation. Exclusion criteria were visual acuity worse than 20/100, prior intraocular surgery, refractive surgery, iris-related procedures, or pupil abnormalities affecting dilatation. Apparent chord mu lengths before and after pupil dilatation were compared. In addition, multivariate linear regression analysis, using a stepwise method, was conducted to assess possible predictors of apparent chord values.

RESULTS

Included were 87 eyes of 87 patients. Mean chord mu length increased after pupillary dilatation from 0.32 ± 0.17 mm to 0.41 ± 0.17 mm for right eyes (p < 0.001) and from 0.29 ± 0.16 mm to 0.40 ± 0.22 mm for left eyes (p < 0.001). Seven eyes (8.0%) had an apparent chord mu of 0.6 mm and above pre-dilatation. Fourteen eyes (16.1%) with an apparent chord mu under 0.6 mm pre-dilatation had apparent chord mu of 0.6 mm or above post-dilatation.

CONCLUSION

Apparent chord mu length significantly increases after pharmacological pupillary dilatation. Pupil size and dilatation status should always be considered during patient selection for a planned MFIOL using apparent chord mu length as a reference marker.

The first-in-human implantation of the CorNeat keratoprosthesis

OBJECTIVES

To describe the first clinical implantation of the CorNeat™ keratoprosthesis, which utilizes a polymeric scaffold for biointegration within ocular tissue.

METHODS

The CorNeat keratoprosthesis was implanted in the right eye of a patient with bilateral corneal opacification and neovascularization secondary to multiple failed grafts. The following surgical technique was used: 360 degree peritomy; epithelial scraping and corneal marking; pre-placement of three corneo-scleral sutures through the implant; central trephination using a 7 mm trephine and host cornea removal; keratoprosthesis placement and sutures tightening while fitting the corneal edge into the posterior groove of the CorNeat keratoprosthesis; and repositioning of the conjunctiva over the implant skirt and fixation with sutures and Fibrin sealant.

RESULTS

Twelve months postoperatively visual acuity improved to 1/16 from hand movement. The keratoprosthesis was properly positioned. Tactile intraocular pressure was assessed as normal. Regional, mostly nasal, conjunctival retraction of 4-5 mm over the nano-fibre skirt was seen throughout follow-up. The anterior chamber was quiet and well-formed. No other postoperative complications were observed.

CONCLUSION

This initial case may imply a potential breakthrough in the treatment of corneal disease not amenable to standard corneal transplant. Long follow-up and additional implantations are desired to prove the long-term safety and efficacy of this device.

Post-refractive surgery of Israeli Defense Forces recruits in 2005-2018-prevalence, combat unit drop-out rates and utilization of eye-care services

PURPOSE

To assess the number of recruits for military service in the Israeli Defense Force (IDF) who underwent refractive surgery prior to enlistment and examine whether the procedure affected their ability to accomplish combat training.

SETTING

Medical records of IDF recruits.

DESIGN

Retrospective analysis of medical records of recruits with ametropia who underwent or did not undergo refractive surgery prior to enlistment.

METHODS

Recruits were categorized into ametropes and recruits who underwent refractive surgery. Fitness and assignment to combat units and completion status of combat training were compared between the two groups.

RESULTS

The study included 334,688 (182,969 males, 151,719 females) ametropes of which 5231 (4753 males, 478 females) underwent refractive surgery prior to recruitment. Refractive surgery prevalence increased from 9/1000 ametropes in 2005 to 18.5/1000 ametropes in 2018 (r = 0.912, p < 0.001); 2643 of the operated recruits (50.5%) had their surgery at the age of 17-18. Dropout rates from combat training were significantly lower in the refractive surgery group during the study period (1.68% vs. 6.14%, respectively, p < 0.001). Soldiers in the operated group were more frequently referred to ophthalmologists than those in the ametropes group and less frequently referred to optometrists.

CONCLUSIONS

The prevalence of refractive surgery in IDF recruits has increased substantially during the last decade with more of them applying to combat units. Refractive surgery opened new possibilities for recruits who were unfit for combat duty prior to surgery and did not appear to impair the chances of successfully completing combat training.

The Effect of Anti-Inflammatory Topical Ophthalmic Treatments on In Vitro Corneal Epithelial Cells

Purpose

To compare the effect of three commonly prescribed anti-inflammatory eye drops on corneal epithelial cells in vitro.

Methods

Three different lines of human corneal epithelial cells were tested: primary cells cultured from donor tissue, commercially available primary cells, and immortalized cells. Cells were seeded on 96-well plates and treated with the following eye drops: cyclosporine 0.05%, lifitegrast 5%, and tacrolimus 0.03% or 0.1%. Exposure times tested were 30 seconds, 1 minute, 2 minutes, 1 hour, 2 hours, 4 hours, and 24 hours. Brightfield images and viability assays were analyzed 48 to 72 hours after the initiation of treatments. At least five replicates were tested per drug and time exposure.

Results

Commercially obtained primary cells showed reduced viability following 1 hour with tacrolimus 0.1% (8%; P = 0.043%) and 4 hours with tacrolimus 0.03% (17%; P = 0.042%). Lifitegrast exposure reduced primary cell viability after 4 hours (10%; P = 0.042). Cell viability in primary cells was not deleteriously affected following exposure to cyclosporine for up to 4 hours. A similar trend was observed in both primary cells cultured from donor tissue and immortalized human corneal epithelial cells, demonstrating greater decreases in cell viability in tacrolimus compared to lifitegrast and cyclosporine. Light microscopy imaging for analysis of cell morphology and confluence supported the results.

Conclusions

Tacrolimus showed the highest impact on corneal epithelium survival in vitro, and cyclosporine proved the most protective.

Translational Relevance

Comparing anti-inflammatory eye drops on corneal epithelial cells in vitro may inform eye drop selection and development for clinical purposes.

Toric Intraocular Lens Calculations With the Barrett Calculator: A Comparison of the Calculator With and Without the Integrated K Method

PURPOSE

To compare the accuracy of the Barrett Integrated K (IK) toric calculator with the standard Barrett toric calculator.

METHODS

Consecutive patients who underwent cataract extraction with implantation of a toric intraocular lens at the Rabin Medical Center, Israel, were reviewed. Errors in predicted postoperative refractive astigmatism were calculated for the Barrett toric calculator using biometry measurements only and with the IK tool using biometry and tomography. Both methods were assessed with predicted and measured posterior corneal astigmatism (PPCA and MPCA, respectively).

RESULTS

The study included 73 eyes of 59 patients. The mean centroid prediction error using PPCA (0.08 ± 0.80 D @ 78°) was significantly different compared with MPCA (0.07 ± 0.80 D @ 48°, P = .016). In addition, a significant difference between IK-PPCA (0.06 ± 0.80 D @ 80°) and IK-MPCA (0.05 ± 0.80 D @ 38°) was found (P = .023). The median absolute prediction error ranged from 0.55 D using IK-PPCA to 0.60 D using PPCA, with no significant differences between the four calculation versions. No significant differences were found between the calculators in the predictability rates within ±0.50, ±0.75, and ±1.00 D. Analysis of one eye of each patient showed similar results.

CONCLUSIONS

The IK calculator yielded comparable outcomes to the standard Barrett calculator. Although differences in the mean centroid errors were found, they were clinically insignificant and predominantly seen in the axis of the predicted astigmatism error. These minor differences were mainly attributed to the incorporation of the MPCA in the calculation. [J Refract Surg. 2022;38(9):565-571.].

Validation of the multi-metric D-index change in the assessment of keratoconus progression

PURPOSE

To validate the effectiveness of the multi-metric D-index by Pentacam in detecting keratoconus (KC) progression.

MATERIALS AND METHODS

This was a retrospective study of KC patients at the Rabin Medical Center, Petah Tikva, Israel, during 2016-2018 with at least two corneal tomography examinations six months apart. Agreement between clinical diagnosis of progression (1.5D increase in mean keratometric value, 1D increase in Kmax, a 5% decrease in central corneal thickness (CCT), worsening of visual acuity by more than one line, or deterioration of manifest corneal astigmatism > 1.5D) and the D-index was evaluated. Receiver operating characteristic (ROC) analysis was used to find the D-index's optimal cutoff value to show progression.

RESULTS

We included KC eyes in the stable group (N = 7) and the progression group (N = 54). Patient demographics and tomographic parameters at baseline were similar between the groups. The D-index change was significantly higher in the progression group than in the stable group (median + 1 and 0.0, respectively, p = 0.024). Based on the ROC analysis, the optimal D-index cutoff change within at least six months was 0.32 (59.3% sensitivity and 100% specificity (area under the curve [AUC] = 0.771, Youden = 0.592). Subjects with a D-index change above this value had a 21.1-fold increase in odds for corneal ectasia progression requiring CXL (OR: 21.1, 95%CI 1.17-398.8, p = 0.038).

CONCLUSION

The multi-metric D-index can serve as a clinically feasible parameter to detect KC progression and guide patients' referral for further interventions.

Ocular Trauma Caused by Confetti Cannons

BACKGROUND

Eye trauma is an unfortunate and often preventable cause of vision loss. Confetti cannons are common causes of injury. Awareness of ocular hazards of confetti cannons remains low because of limited reports describing ophthalmic injuries following their use.

OBJECTIVES

To describe outcomes of ocular trauma caused by confetti cannons and to increase recognition of their ocular risks.

METHODS

A retrospective analysis was conducted of eye injuries caused by confetti cannons presenting to a single medical center between 2016 and 2020. Data collected included age, gender, eye injured, ocular damage, visual outcome, and details of surgeries performed.

RESULTS

Overall, six consecutive patients (2 males, mean age 19.5 ± 9.74 years) were identified and studied. In all patients only one eye was injured (3 right eyes) during a private celebration, most commonly (n=5) to a bystander while in the vicinity of a cannon operated by someone else. Most common eye injuries included corneal erosion (n=4), traumatic hyphema (n=4), and retinal edema (n=3). Mean initial logMAR visual acuity in the injured eye was 0.73 ± 0.18, improving to 0.25 ± 0.16 at the final visit (P = 0.125). Two patients underwent eye surgery due to their trauma: one to repair globe penetration and another to undergo intravitreal injection of tissue plasminogen activator and C3F8 for submacular hemorrhage, followed 8 months later by intravitreal bevacizumab injection for choroidal neovascularization.

CONCLUSIONS

Confetti cannons pose hazards that can cause severe ocular trauma resulting in permanent vision loss. Increasing awareness of device hazards is necessary to prevent eye injuries.

Descemet Membrane Endothelial Keratoplasty in Eyes With Chronic Ocular Hypotony Following Glaucoma Surgery

PURPOSE

To assess the outcomes of Descemet membrane endothelial keratoplasty (DMEK) in patients with ocular hypotony after glaucoma surgery.

DESIGN

retrospective case series.

METHODS

Setting: Multicenter retrospective case series.

PATIENTS/INTERVENTION

Hypotonic eyes with prior glaucoma surgery that underwent DMEK between January 2013 and July 2019 in Israel (2 centers) and Canada (1 center).

MAIN OUTCOME MEASURES

Pre/postoperative corrected distance visual acuity, complications, 3- to 6-month endothelial cell loss, and intraocular pressure (IOP).

RESULTS

The study included 11 DMEK procedures performed in 10 eyes of 4 males and 6 females aged 65-84 years. Indications for DMEK included 7 cases of pseudophakic bullous keratopathy, 2 cases of failed DMEK, and 1 case of failed Descemet stripping automated endothelial keratoplasty. All patients had at least 1 previous trabeculectomy operation. One patient had 2 trabeculectomy procedures and 1 tube placement procedure. Two patients had 1 previous trabeculectomy and 1 tube placement procedure. The corrected distance visual acuity improved significantly from 1.52 ± 0.68 logarithm of minimal angle of resolution preoperatively to 0.49 ± 0.32 logarithm of minimal angle of resolution 3 months postoperatively (P < .001). Rebubbling occurred in 3 of 11 procedures (27%). Endothelial cell loss 6-12 months postoperatively was 60% ± 16% (range, 41%-89%). At the last follow-up visit, 6 of 11 (54%) of the grafts were clear. The remaining 5 grafts failed at 1-4 years postoperatively. The preoperative IOP was 5.1 ± 1.6 mm Hg (range, 1-7 mm Hg). In all but one patient, the postoperative IOP did not increase to more than 13 mm Hg. In 2 cases, the IOP decreased from 5 and 7 mm Hg preoperatively to 1 mm Hg 1 year postoperatively.

CONCLUSION

DMEK is a valid procedure for the treatment of corneal edema in hypotonic eyes after glaucoma procedures. These eyes benefit from improvement in vision after DMEK.

Outcomes of Repair of Total Graft Detachment following Descemet's Membrane Endothelial Keratoplasty

OBJECTIVE

To present the outcomes of attempts to salvage total graft detachment following Descemet's membrane endothelial keratoplasty (DMEK).

METHODS

A search of the electronic medical records of two tertiary medical centers for all patients who underwent DMEK yielded six cases of postoperative total graft detachment (2.54%). Graft salvage was attempted in all cases using repeated intracameral graft staining, unfolding, and reattachment to the stroma under 20% hexafluoride gas.

RESULTS

In all cases, a free-floating totally detached graft was identified in the anterior chamber shortly after surgery. Salvage surgery resulted in a central, well-oriented, and fully attached graft. In three cases, the primary graft failed, and in two, the corneas cleared at first but failed after 2 months and 1 year respectively. In one case, the cornea remained clear during 1 year of follow-up but had a very low endothelial cell density.

CONCLUSION

Reattachment of fully detached DMEK graft is technically possible, but graft manipulation during the primary and secondary operations is likely to damage the endothelial cells, resulting in primary or early graft failure. If graft salvage is attempted, the probability of primary or early graft failure should be discussed with the patient, and expectations should be tempered accordingly.

Transepithelial photorefractive keratectomy on the same day of the initial consultation for the correction of myopia

PURPOSE

To examine the clinical outcomes, efficacy, safety, and predictability of transepithelial photorefractive keratectomy (Trans-PRK) operations performed on the day of the first screening visit in comparison with operations scheduled at a following appointment.

METHODS

Data of consecutive patients with myopia of various degrees, who underwent Trans-PRK, were retrospectively analyzed. Findings were compared between patients who underwent Trans-PRK on the same day of first consultation to patients that underwent surgery at subsequent visits, following initial consultation on a different day.

RESULTS

The study included 599 eyes treated on the initial visit day and 1936 eyes treated on a subsequent visit. Mean final spherical equivalent was close to emmetropia in both groups (p = 0.183). Efficacy indices were 0.928 ± 0.192 in the initial-visit group and 0.945 ± 0.163 in the second-visit group (p = 0.152). Safety indices were 0.954 ± 0.156 and 0.955 ± 0.151 (p = 0.707), respectively. No differences between the groups were seen in uncorrected visual acuity (UDVA) of ⩾20/20, ⩾20/25, and ⩾20/32. Only the sub-analysis of patients reaching UDVA of 20/40 or better was slightly lower in the first-visit (95.5%) compared with the second-visit group (97.9%, p = 0.001). Results of attempted correction within ±0.50 D were: 63.3% and 69.0%, respectively (p = 0.009). Complications profiles in the two groups were comparable.

CONCLUSIONS

Trans-PRK completed on the day of the first screening appointment demonstrated a similar safety outcome compared with subsequent-visits procedures, and slightly lower, yet comparable, results regarding efficacy and predictability.

Descemet Membrane Endothelial Keratoplasty Outcomes between Young and Old Graft Recipients

Purpose: To evaluated Descemet's membrane endothelial keratoplasty (DMEK) outcomes in young and old graft recipients.Materials and Methods: Data of 164 surgeries with a median age of 76 years (interquartile range 14 years) undergoing DMEK surgery between 2016 and 2018 was reviewed. Complications, graft survival, and visual acuity gain were compared between subjects in the 25th percentile (young recipients; aged 70 years and less, n = 21) and 75th percentile (old recipients; aged 85 years and over, n = 27) over the 2-year follow-up.Results: Young recipients had a lower rate of pre-operative glaucoma (14.3% vs. 51.9%, p = .014) and pseudophakic bullous keratopathy (9.5% vs. 59.3%, p < .001), and a higher rate of Fuchs endothelial dystrophy (57.1% vs. 14.8%, p = .002) and combined cataract extraction at the time of DMEK surgery (52.4% vs. 7.4%, p = .001) when compared to old recipients. Complications (primary graft failure, pupillary block, cystoid macular edema or infectious keratitis) were independent of graft recipient age. Descemet's membrane detachment requiring re-bubbling was observed more often in young compared to the old recipients (42.9% vs. 14.8%, p = .049). Visual acuity gain between the groups remained comparable up to 1-year, whereas at 2-years old recipients showed significantly declined visual acuity gains compared to the young recipients (0.14 ± 0.68 vs. 0.74 ± 0.49, p = .012). Graft recipients aged over 85 years had a considerably higher graft failure rate over the 24-months (40.7% vs. 4.8%, p = .006) and shorter graft survival time (p = .002; log-rank) when compared to the recipients aged under 70 years. After adjusting for potential confounders such as Fuchs endothelial dystrophy, pseudophakic bullous keratopathy and glaucoma, the recipients aged over 85 remained at higher risk for graft failure (HR = 17.278, 95% CI = 1.787-167.1, p = .014).Conclusions: In aged DMEK recipients, regardless of the low incidence of early postoperative complications, the rate of postoperative graft failure was significantly higher and graft survival shorter than in younger recipients.

Agreement of Corneal Endothelial Cell Analysis Between Konan-Noncon Robo SP-6000 and Tomey EM-3000 Specular Microscopes in Healthy Subjects

PURPOSE

To compare corneal endothelium parameters taken by two common noncontact specular microscopes in healthy subjects.

METHODS

Healthy participants visiting the outpatient eye clinic at the Rabin Medical Center, Petah Tikva, Israel, were recruited prospectively. All participants underwent three consecutive corneal endothelial cell photographs with both the Konan-Noncon Robo SP-6000 and the Tomey EM-3000 specular microscopes. Endothelial cell density (ECD) was evaluated using the manual center technique in both machines. Bland-Altman graphs were used to assess the agreement between the devices, and intraclass correlation coefficient (ICC) served to assess intraobserver variability for each device.

RESULTS

Recruited were 49 healthy subjects with a mean age of 48.9±15.6 years, 49 right eyes were included. The mean ECD was comparable between the Tomey EM-3000 and the Konan-Noncon Robo SP-6000 (2,713.2±242.4 vs. 2,700.8±300.5 cells/mm2, respectively, P=0.47) with a mean difference of 12.4 cells/mm2 (0.67%), a mean ECD absolute difference of 93.3 cells/mm2, and low 95% limits of agreement of -222.0 to +246.9 cells/mm2. A folded empirical distribution function curve showed that all differences fell within 525.4 cells/mm2, centered around a median of 13.3 cells/mm2. Intraclass correlation coefficient was high for both the Konan-Noncon Robo SP-6000 (0.93, 95% confidence interval [CI]: 0.89-0.95) and the Tomey EM-3000 (0.88, 95% CI: 0.82-0.93).

CONCLUSIONS

The difference in endothelial cell measurements between the Konan SP-6000 and the Tomey EM-3000 specular microscopes through the center and the L-count analyzing techniques, respectively, is clinically small and not statistically significant. Nevertheless, caution should be taken when used interchangeably because ECD difference between the two machines can be as high as 525.4 cells/mm2.

High Agreement between Barrett Universal II Calculations with and without Utilization of Optional Biometry Parameters

Purpose: To examine the contribution of anterior chamber depth (ACD), lens thickness (LT), and white-to-white (WTW) measurements to intraocular lens (IOL) power calculations using the Barrett Universal II (BUII) formula. Methods: Measurements taken with the IOLMaster 700 (Carl Zeiss, Meditec AG, Jena, Germany) swept-source biometry of 501 right eyes of 501 consecutive patients undergoing cataract extraction surgery between January 2019 and March 2020 were reviewed. IOL power was calculated using the BUII formula, first through the inclusion of all measured variables and then by using partial biometry data. For each calculation method, the IOL power targeting emmetropia was recorded and compared for the whole cohort and stratified by axial length (AL) of the measured eye. Results: The mean IOL power calculated for the entire cohort using all available parameters was 19.50 ± 5.11 diopters (D). When comparing it to the results obtained by partial biometry data, the mean absolute difference ranged from 0.05 to 0.14 D; p < 0.001. The optional variables (ACD, LT, WTW) had the least effect in long eyes (AL ≥ 26 mm; mean absolute difference ranging from 0.02 to 0.07 D; p < 0.001), while the greatest effect in short eyes (AL ≤ 22 mm; mean absolute difference from 0.10 to 0.21 D; p < 0.001). The percentage of eyes with a mean absolute IOL dioptric power difference more than 0.25 D was the highest (32.0%) among the short AL group when using AL and keratometry values only. Conclusions: Using partial biometry data, the BUII formula in small eyes (AL ≤ 22 mm) resulted in a clinically significant difference in the calculated IOL power compared to the full biometry data. In contrast, the contribution of the optional parameters to the calculated IOL power was of little clinical importance in eyes with AL longer than 22 mm.

The Effect of COVID-19 on Israeli Ophthalmology Departments: Directors' Perspectives

BACKGROUND

The coronavirus disease-2019 (COVID-19) pandemic presented a major medical management challenge to ophthalmology departments throughout Israel.

OBJECTIVES

To examine the managerial challenges, actions taken, and insights of directors of ophthalmology departments in Israel during the COVID-19 pandemic.

METHODS

We conducted a cross sectional survey of directors of ophthalmology departments during the COVID-19 pandemic while the Israeli population was quarantined.

RESULTS

All 21 directors answered the survey. The majority of the COVID-19 admissions were located in the center of Israel (53%) and Jerusalem (30%). E-communication took a central role in coping with the pandemic with 80% of the directors satisfied with this form of communication; 75% reported a reduction in clinical and surgery volume of at least 25%, and 40% reported reallocations of manpower. Most of the medical staff used gloves, a face shield, disposable robe, and a mask with no uniformity across departments. Cross satisfaction was noted regarding a hospital's ability to equip the departments. Lack of preparation for post-pandemic era was reported by all directors, but one (95%). Directors sought guidelines and uniformity regarding outpatient referral to the hospital (p = 0.035).

CONCLUSIONS

Guidelines via safe digital platforms aid in management decisions and uniformity across departments. Advanced preparation is needed to prevent adverse clinical outcomes and to maintain treatment continuum. Our results can be used to guide and help improve the preparedness of ophthalmology departments during COVID-19 and for future pandemics.

Real-time intraoperative ultrasound biomicroscopy for determining graft orientation during Descemet's membrane endothelial keratoplasty

PURPOSE

To evaluate the intraoperative use of ultrasound biomicroscopy (UBM) during Descemet's membrane endothelial keratoplasty (DMEK) to determine graft's orientation.

METHODS

Prospective interventional study of eight eyes of seven patients who underwent DMEK. Following the identification of correct graft orientation using 'Blue cannula tip' sign during DMEK surgery, UBM was used to ascertain graft's orientation. The rate of successful DMEK graft orientation determined by the UBM was registered and verified postoperatively by anterior segment-optical coherence tomography (OCT). Intra- and postoperative complications, postoperative clearance of the cornea, corrected distance visual acuity and endothelial cell loss were also noted.

RESULTS

The study included five males and two females aged 54-82 years with corneal oedema due to Pseudophakic bullous keratopathy (n = 5), Fuchs' endothelial dystrophy (n = 2). In all cases, the technique allowed proper determination of the graft's orientation. In one case, 'blue cannula tip' sign showed correct orientation while UBM identified an upside-down graft. The graft was inverted in the anterior chamber using fluid jets, and repeat 'blue cannula tip' sign and UBM examination both showed correct orientation. In all cases, postoperative anterior segment-OCT demonstrated correct graft orientation.

CONCLUSIONS

Use of intraoperative UBM to determine graft orientation during DMEK correlated with proper graft orientation, as was verified postoperatively by anterior segment-OCT. The use of UBM can be particularly helpful in cases of poor graft visibility due to opaque corneal stroma, pigment or blood in the anterior chamber during surgery, or when the blue tint of the graft fades rapidly, which may preclude proper determination of graft's orientation.

Femtosecond laser assisted in situ keratomileusis (FS-LASIK) yields better results than transepithelial photorefractive keratectomy (Trans-PRK) for correction of low to moderate grade myopia

INTRODUCTION

The purpose of this study was to compare the outcomes of transepithelial photorefractive keratectomy (Trans-PRK) with femtosecond laser assisted in situ keratomileusis (FS-LASIK) for the correction of low to moderate myopia.

METHODS

A retrospective cohort study design was used. The study group included patients with myopia less than -6.0 D, with or without concomitant astigmatism under 2.0 D, who were treated with FS-LASIK or Trans-PRK in 2013 through 2014. Background, clinical and outcome data were collected from the patient files. A comparison between eyes treated with FS-LASIK or Trans-PRK was performed.

RESULTS

The Trans-PRK group was comprised of 1793 eyes and the FS-LASIK group of 666 eyes. Mean ± SD spherical equivalent (SE) refraction prior to surgery was -3.43 ± 1.27 D in the Trans-PRK group and -3.18 ± 1.34 D in the FS-LASIK group (p < 0.001). Efficacy index values were 0.95 ± 0.14 in the Trans-PRK group and 0.98 ± 0.12 in the FS-LASIK group (p < 0.001), and corresponding safety index values were 0.96 ± 0.13 and 0.99 ± 0.12 (p < 0.001). Distance from target refraction was 0.45 ± 0.42 D in Trans-PRK group and 0.43 ± 0.38 D in the FS-LASIK group (p = 0.537); 71.6% and 74.2% of eyes were within ±0.5 D of attempted correction, respectively (p = 0.193).

CONCLUSIONS

Both Trans-PRK and FS-LASIK demonstrated excellent results, mostly comparable with the current literature. FS-LASIK achieved better results than Trans-PRK surgery in the efficacy and safety parameters.

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.