Refractive errors among medical students in Jordan: prevalence, types and possible risk factors.

Aim: This study aims to determine the prevalence of refractive errors among medical students in Jordan. Materials & methods: Cross-sectional model through an online questionnaire was conducted. The questionnaire was distributed randomly to 700 medical students. Results: Females participated more than males. It was revealed that 525 (75%) of the total students were found to have a refractive error. Myopia was the most common type. About 79.0% of students have a positive family history of refractive errors which was more significant in students with refractive errors. Spectacles were the most common used method of treatment. Conclusion: The prevalence of refractive errors was high among medical students in Jordan. A positive family history was associated with students having refractive errors.

Many reports have studied refractive errors and their risk factors in different groups and ethnicities. Also, types of refractive errors were found to have a different prevalence in different age groups. Whilst refractive errors in medical students have been studied in many countries, the prevalence of refractive errors has never been studied in Jordanian medical students before. In this study, we found that myopia (with or without astigmatism) was the most common type of refractive error in medical students.

Rate of Endothelial Cell Loss and Graft Survival in Descemet Membrane Endothelial Keratoplasty in Eyes Requiring a Rebubble.

PURPOSE: We aimed to compare the rate of 6-month endothelial cell loss (ECL) and 6-month graft survival in eyes that did not require a postoperative rebubble with eyes that did require a postoperative rebubble after Descemet membrane endothelial keratoplasty (DMEK) surgery. METHODS: A consecutive series of DMEK surgeries performed from September 2013 to March 2020 was retrospectively analyzed. Eyes that did not require a rebubble for graft detachment were compared with eyes with 1 rebubble and eyes with 2 or more rebubbles for 6-month ECL and graft survival. A subanalysis of the rebubble rate for different indications for transplantation was also performed. RESULTS: One thousand two hundred ninety-eight eyes were included in this study. The 6-month ECL for eyes with no rebubbles, 1 rebubble, and ≥2 rebubbles was 29.3% ± 16.2% (n = 793), 36.4% ± 18.6% (n = 97, P = 0.001), and 50.1% ± 19.6% (n = 28, P < 0.001), respectively. The 6-month graft survival rate for eyes with no rebubbles, 1 rebubble, and ≥2 rebubbles was 99.5%, 97.8% ( P = 0.035), and 81.8% ( P < 0.001), respectively. When compared to the rebubble rate for DMEK for Fuchs dystrophy (156/1165 eyes = 13.4%), the rebubble rates were statistically higher for DMEK for failed penetrating keratoplasty (28.5%, P = 0.021) and pseudophakic bullous keratopathy (28.0%, P = 0.036). CONCLUSIONS: Eyes undergoing any rebubble procedure in the postoperative period after DMEK have an increased risk of endothelial cell loss and graft failure at 6 months postoperative. DMEK in eyes for failed penetrating keratoplasty and failed DMEK had the highest rebubble rate, with the former reaching statistical significance.

Younger Donor Tissue in Descemet Membrane Endothelial Keratoplasty Surgery: Clinical Outcomes.

PURPOSE: To determine whether using younger donor tissue for Descemet membrane endothelial keratoplasty (DMEK) surgery influences clinical outcomes. METHODS: Scroll tightness, unscrolling time, rebubble rate, and preoperative and 3- and 6-month postoperative endothelial cell density (ECD) and endothelial cell loss (ECL) were compared for 661 DMEK grafts prepared from younger (aged younger than 50 yrs, n = 81) and older donors (aged 50 yrs or older, n = 580) with Student t test, χ2 test, or Mann-Whitney U test. RESULTS: There was no difference in overall unscrolling time (younger donors: 3.1 ± 3.1 min, older donor: 2.9 ± 2.7 min, P = 0.503). Experienced faculty surgeons, compared with fellows, had a significantly lower unscrolling times for both younger donors (2.4 ± 2.3 vs. 4.6 ± 3.9 min, P = 0.002) and older donors (2.5 ± 2.1 vs. 3.7 ± 3.3 min, P <0.001). Rebubble rates were not statistically different between younger (12.3%) and older donors (15.0%, P = 0.527). Three-month ECD was higher in grafts from younger compared with that in those from older donors (2138 ± 442 vs. 1974 ± 470 cells/mm2, P = 0.024). Six-month ECD was similar for younger (1972 ± 509 cells/mm2) and older donors (1947 ± 460 cells/mm2, P = 0.585). There was no difference in 3- or 6-month ECL comparing younger (3-mo: 24.3% ± 13.4%; 6-mo: 31.1% ± 15.2%) with older donors (3-mo: 25.9% ± 15.5%, P = 0.489; 6-mo: 27.8% ± 15.1%, P = 0.231). CONCLUSIONS: DMEK grafts prepared from younger donors exhibited similar unscrolling times, rebubble rates, and 3- and 6-month ECL compared with older donors. Experienced surgeons might begin to accept DMEK grafts from younger donors with confidence.

Descemet Stripping Automated Endothelial Keratoplasty: The influence of preoperative endothelial cell density and triple procedures on grafts at 5 years postoperative.

The purpose is to determine if the preoperative central endothelial cell density (ECD) in triple (phacoemulsification plus intraocular lens implantation plus DSAEK) and non-triple Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) procedures have a relationship with the 5-year postoperative ECD or percent Endothelial Cell Loss (ECL).Out of 986 consecutive DSAEK surgeries for Fuchs dystrophy, 241 eyes had 5-year ECD measurements available. Endothelial cell densities were then evaluated against preoperative ECDs to obtain measures of ECL. Triple and non-triple procedures were isolated and compared independently.One hundred eighty two eyes had undergone a triple procedure and 59 had not. The mean ECD at 5 years was 1560 ±â€Š648 cells/mm for triples and 1483 ±â€Š621 cells/mm for non-triples (P = .42). Endothelial Cell loss was 44.4% ±â€Š21.7% and 44.4% ±â€Š22.0%, respectively for eyes that underwent a triple or non-triple (P = .99). There was a moderate, but significant correlation between preoperative ECD and the ECD at 5 years after DSAEK for both triples (r = 0.39, P < .001), and non-triples (r = 0.32, P = .01), respectively.In Descemets stripping automated endothelial keratoplasty grafts, higher preoperative donor ECD was correlated with higher ECD at 5 years postoperatively but was unaffected by a concurrent cataract surgery in the triple procedure.

Donor DMEK Tissue Characteristics: Association With Rebubble Rate and 6-Month Endothelial Cell Loss.

PURPOSE: To determine whether specific donor characteristics influence postoperative rebubble rate and 6-month endothelial cell loss (ECL) in Descemet membrane endothelial keratoplasty (DMEK). METHODS: A retrospective analysis of a consecutive series of 857 DMEK surgeries using eye bank-prepared donor tissue was performed between September 2013 and April 2018. DMEK graft characteristics including donor age, preoperative endothelial cell density (ECD), preservation time, death-to-preservation time, and donor diabetes status were analyzed for correlation with rebubble rate and 6-month postoperative ECL. Subgroup analyses of donor age, preoperative ECD, preservation time, death-to-preservation time, preparation-to-surgery time, and diabetes severity were also performed. Statistically significant relationships between donor characteristics and rebubble rate or 6-month postoperative ECL were determined using Pearson correlation, one-way analysis of variance, t test, and χ analysis. RESULTS: The overall rate of rebubble after 857 surgeries performed by 7 surgeons during the study period was 12.6%. There was no significant relationship between postoperative rebubble rate and donor age, preoperative ECD, preservation time, death-to-preservation time, preparation-to-surgery time, or donor diabetes status. The subgroup analysis of these characteristics also yielded no significant relationship with rebubble rate. There was also no significant relationship between 6-month postoperative ECL and analyzed donor factors. CONCLUSIONS: Donor characteristics such as higher donor age, lower preoperative ECD (<2500), longer preservation time, and donor diabetes did not increase the rebubble rate or the 6-month ECL after DMEK. These results indicate that common surgeon preferences for donor tissues that are younger, fresher, with higher cell count, and without diabetes do not translate into superior postsurgical outcomes.

The Last 200 Surgeon-Loaded Descemet Membrane Endothelial Keratoplasty Tissue Versus the First 200 Preloaded Descemet Membrane Endothelial Keratoplasty Tissue.

PURPOSE: The purpose of this study was to compare the clinical outcomes from using eye bank-prepared, endothelium-out preloaded Descemet membrane endothelial keratoplasty (DMEK) tissue with those obtained with endothelium-out surgeon-loaded DMEK tissue using the same surgical technique at 1 site. METHODS: This study retrospectively reviewed 400 consecutive cases of DMEK from March 2016 to April 2018. The last 200 cases using surgeon-loaded tissue were compared with the first 200 cases using preloaded tissue. Statistical analysis was performed using the Wilcoxon signed-rank test, binomial logistic regression, Kruskal-Wallis 1-way analysis of variance, Student t test, or Pearson χ tests. RESULTS: Comparing surgeon-loaded versus preloaded DMEK tissue, respectively, no statistical difference was found in the mean 6-month postoperative values for endothelial cell loss (32.9% ± 18.5% vs. 29.9% ± 16.4%, P = 0.31), best corrected visual acuity (20/26 vs. 20/25, P = 0.54), or change in central corneal thickness (-14.4% ± 8.9% vs. -15.6% ± 11.7%, P = 0.43). The mean 1-year endothelial cell loss was also not significantly different (37.6% ± 17.2% vs. 33.2% ± 14.8%, P = 0.07). Overall, the rebubble rate for surgeon-loaded tissue was 17.5% and 12.5% for preloaded tissue, a statistically nonsignificant difference. Operative outcomes for mean tissue scroll tightness (1-4) and tissue unscroll time (minutes) for surgeon-loaded and preloaded tissue were similar between groups (2.4 vs. 2.2, P = 0.12 and 3.5 vs. 3.3 minutes, P = 0.50). CONCLUSIONS: Tissue that is trephinated, stained, and loaded into an injector by the eye bank and then shipped to the surgeon had no difference in clinical outcomes compared with tissue where the surgeon performs these steps. The safety and speed of using preloaded tissue should be considered by DMEK surgeons.

Patent Blue V as an Alternative Stain for DMEK Grafts: Safety, Stain Retention, and Feasibility.

PURPOSE: To determine whether Patent Blue V (PB) can be used as an alternative dye for staining Descemet membrane endothelial keratoplasty (DMEK) grafts. METHODS: DMEK grafts from donor corneas were stained with 2.5% PB for 4 minutes (n = 2), 2.5% PB for 10 minutes (n = 2), or 0.06% trypan blue (TB) for 4 minutes (n = 1). The stain intensity of the grafts was compared initially and at different time points over a 15-minute period of balanced salt solution wash using a grading scale based on a serial dilution series of PB. Three additional grafts were stained with 2.5% PB for 10 minutes and used in mock surgeries to assess stain retention after injection and manipulation in a donor eye model for 25 minutes. To assess the safety of PB, DMEK grafts were prepared from 10 pairs of corneas where one cornea was stained with 0.06% TB for 4 minutes and the mate cornea was stained with 2.5% PB for 10 minutes. The grafts were preloaded and stored for 5 days in Optisol-GS at 2°C to 8°C, and endothelial cell loss was quantified using Calcein-AM staining and FIJI segmentation by 2 masked readers. RESULTS: PB stain intensities were lighter than TB-stained grafts. Grafts stained with 2.5% PB for 10 minutes retained sufficient color for the 25-minute duration of mock surgery. The average endothelial cell loss for PB versus TB grafts was 21.6% ± 5.3% versus 20.2% ± 5.4% (P = 0.202) as determined by reader 1 and 23.6% ± 4.8% versus 21.2% ± 5.8% (P = 0.092) as determined by reader 2. CONCLUSIONS: PB is a viable alternative dye in DMEK grafts for applications where TB may not be available or approved for use.

Endothelial keratoplasty: The relationship between recipient anterior chamber depth and endothelial cell loss.

PURPOSE: To determine the relationship between anterior chamber depth (ACD) and percent endothelial cell loss (ECL) after Descemet Stripping Automated Endothelial Keratoplasty (DSAEK). METHOD: In 78 eyes receiving triple procedure (DSAEK combined with cataract extraction and posterior chamber intraocular lens (PCIOL) implantation), ACD was measured preoperatively with an intraocular lens (IOL) Master and ECL was calculated with specular microscopy at 6 months, 1, 2, 3, and 4 years postoperatively. ACD and ECL from all 78 eyes were compared using correlation analysis and students t test. Eyes were then separated into 2 groups based on ACD, group 1 with ACD < 3mm and group 2 with ACD ≥ 3mm. Students t test was then performed to compare group 1 and group 2 ECL at 6 months, 1, 2, 3, and 4 years postoperative. RESULTS: Mean ACD for all 78 eyes was 2.93 ±â€Š0.43 mm. Mean ECL was 32.7%, 27.6%, 29.6%, 32.5%, and 37.2% at 6 months, 1, 2, 3, and 4 years. No significant correlation between ACD and ECL was observed at any time point for the combined analysis of 78 eyes (P > .05). At 2 and 4 years postoperative, mean ECL was 32.6% ±â€Š16.1% and 43.0% ±â€Š23.2% in eyes with ACD < 3mm and 25.3% ±â€Š13.0% and 29.6% ±â€Š18.2% in eyes with ACD ≥ 3 mm (P = .041 at 2 years and .008 at 4 years). CONCLUSION: ACD and ECL were not directly correlated; however, there may be a threshold ACD in which shallower anterior chambers preoperatively result in greater donor ECL over time.

In Vivo Choroidal Neovascularization and Macrophage Studies Provide Further Evidence for a Broad Role of Prostacyclin in Angiogenesis.

PURPOSE: The purpose of these studies was (1) to investigate the ability of human M1 phenotype macrophages to secrete vascular endothelial growth factor (VEGF) and the influence of prostacyclin receptor (IP) stimulation (2) to evaluate the contribution of the proangiogenic prostanoid prostacyclin to experimental choroidal neovascularization Methods: Human macrophages derived from primary blood mononuclear cells were functionally biased toward the M1 phenotype by using tumor necrosis factor α (TNFα). Experimental choroidal neovascularization was produced by laser photocoagulation. Antagonist drugs RO-3244794 (IP antagonist) and GW 627368 (EP4 antagonist) were administered according to an optimal dosing regimen that was predetermined by bioavailability studies. RESULTS: IP receptor stimulation had diametrically opposed effects on VEGF release compared with reported data on cytokine/chemokine secretion from human macrophages. For example, the IP agonist cicaprost stimulated VEGF secretion although it inhibits monocyte chemoattractant protein-1 (MCP-1) secretion: both would favor a proangiogenic effect. The IP receptor antagonist RO-3244794 produced an ∼20% statistically significant reduction in the neovascularized lesion area in the choroidal neovascularization model, which was a similar level to that produced by the EP4 antagonist GW 627368. Combining the 2 drugs produced a statistically significant reduction in neovascularization but only of slightly greater magnitude than that obtained with each antagonist administered alone. CONCLUSIONS: IP receptor stimulation potently and highly efficaciously promoted VEGF release from human M1 macrophages, indicating a possible contribution of the M1 macrophage subtype to VEGF-induced choroidal neovascularization. Studies in living animals suggest that prostacyclin and its target IP receptor contribute to choroidal neovascularization, although to a more modest extent than might have been expected.

Preloaded Descemet Membrane Endothelial Keratoplasty Donor Tissue: Surgical Technique and Early Clinical Results.

PURPOSE: To describe the technique, advantages, and early complication rates of using Descemet membrane endothelial keratoplasty (DMEK) donor tissue that is prestained and preloaded into an injector at the eye bank and delivered in a storage medium to the surgeon for transplantation 1 to 2 days later. METHODS: A total of 111 eyes with endothelial failure underwent DMEK using donors that were prestripped, prestained, S-stamped, and preloaded into a Straiko modified Jones tube and delivered in an Optisol-filled viewing chamber 1 to 2 days later. Scroll tightness, time to unscroll and center the tissue, postoperative rebubble rate, and graft failure rate were recorded. Endothelial cell density was measured at 3 and 6 months. RESULTS: All tissues remained well stained with easy visualization at the time of surgery (n = 111). The mean scroll tightness was 2.2 (range: 1-4). The mean time to center and unscroll the tissue was 3.5 minutes (range: 0.5-11.25 min). There was no primary graft failure. There were 16 cases with the placement of another bubble postoperatively (with a 14.4% rebubble rate). Of those 16 cases, 2 required a second rebubble. Endothelial cell loss at 3 and 6 months postoperatively was 26.7% (n = 63 eyes) and 30.9% (n = 67 eyes), respectively. CONCLUSIONS: This is the first report of the clinical use of prestained, preloaded tissue for DMEK. The characteristics and handling of the tissue were not different from those of surgeon-loaded tissue. Because punching, staining, and loading the graft intraoperatively is not necessary, the surgery time and risk of damaging donor tissue are reduced when using preloaded tissue.