Post-thaw cell viability assessment is very important in cryopreservation because it is the main assessment method used to optimize cryopreservation protocols for each cell type; hence, having standardized accurate, quick, and reliable assays for post-thaw cell viability measurements is of utmost importance. The trypan blue exclusion assay and nucleic-acid-binding fluorescence-based assays are two different methods for cell viability assessment. Both assays identify cells with damaged membranes by whether they let a compound enter the cell. In this study, these two assays are compared in the context of cryopreservation and the impacts of important cryopreservation parameters on the differences in measurements are investigated. H9c2 myoblasts were cryopreserved with different freezing protocols. Cell membrane integrities were measured immediately after thaw as well as after cryoprotectant removal by a hemocytometer-based trypan blue dye exclusion assay and a dual fluorometric SYTO 13/GelRed assay; and the results were compared. This study quantifies how (i) the absence or presence of different cryoprotectants, (ii) different cell-cryoprotectant incubation conditions, and (iii) the presence or removal of cryoprotectants after thaw affect the differences between these two viability assays.
To assess the pseudophakic anterior chamber depth (PP-ACD) or effective lens position (ELP) change after cataract surgery in patients with pseudoexfoliation syndrome (PEX).Consecutive eyes with PEX and cataract underwent standard phacoemulsification and were implanted with single-piece acrylic posterior chamber intraocular lenses (IOLs). Eyes with severe PEX and with axial length (AL) greater than 24 mm or less than 22 mm were not included. Eyes with capsular complication or unstable bags that needed capsular tension ring insertion were excluded. The SRK-II formula was applied to calculate IOL power for postoperative emmetropia. PP-ACD or ELP was measured using anterior segment optical coherence tomography. Data obtained at one and six months post operation were evaluated during analysis.Twenty-six eyes of 26 subjects (mean age: 72 years; range: 60-84 years) were studied. PP-ACD was deepened (mean change: 0.08 mm) and a concurrent hyperopic shift (0.3 D) was observed postoperatively between month 1 and month 6 (P values ≤0.002). PP-ACD and postoperative refraction changes were correlated with age and AL (P values < 0.025), respectively. Increased hyperopic shift and PP-ACD deepening in eyes with posterior capsule opacification (PCO) was noted postoperatively at six months, but the difference was not statistically significant (P values = 0.15 and 0.2, respectively).After cataract surgery in eyes with PEX syndrome, a significant backward movement of the IOL occurs postoperatively in the first six months, which is associated with a concurrent small hyperopic shift.
To evaluate the safety and bioavailability of complete and half-dose of intravitreal ziv-aflibercept (IVZ) in an experimental model.Thirty-two eyes of 16 male rabbits received one IVZ injection under anesthesia and the operating microscope. All right and left eyes received 1,250 μg/0.05 mL and 625 μg/0.05 mL of ziv-aflibercept, respectively. Then, rabbits were randomly allocated to four groups (four rabbits in each group). The rabbits were euthanized at predesignated intervals (at 24, 168, 336, and 720 hours), and the eyes were enucleated. Indirect ophthalmoscopy, vitreous sampling, and electrophysiological recordings were obtained before euthanization. Histological examination was performed after enucleation. Vitreous samples were evaluated by enzyme-linked immunosorbent assay to measure the concentration of aflibercept.No serious drug-related ocular inflammation and toxicity or systemic adverse events were identified. Electroretinogram findings showed no significant difference to the baseline measurements. Remaining vitreal concentrations of ziv-aflibercept injection for the 625 μg/mL group were 416 μg/mL, 349 μg/mL, 124 μg/mL, 41.2 μg/mL, and 18.1 μg/mL (± 10 μg/mL) and for the 1,250 μg/mL group were 833 μg/mL, 737 μg/mL, 284 μg/mL, 87.3 μg/mL, and 38.2 μg/mL (± 10 μg/mL), at zero, 24, 168, 336, and 720 hours after injection, respectively. The vitreous concentration of aflibercept was analyzed by one-compartment model. The area under curve from time 0 to the end point (AUC last) was 147,637 hours × μg/mL for the complete dose group (1,250 μg/0.05mL) and 68,498 hours × μg/mL for the half-dose group (625 μg/0.05 mL). The assessed vitreous half-life of ziv-aflibercept was 113 hours in both groups.IVZ proved to be safe and well tolerated, even in the complete dose group. It seems to be a cost-effective therapeutic option for the treatment of retinal vascular diseases. However, the long-term safety and efficacy of intravitreal ziv-aflibercept remain unknown. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:785-790.].
To assess the safety and outcome of single-piece posterior chamber intraocular lens (PC-IOL) implantation in the ciliary sulcus following posterior capsular rupture during cataract surgery.Patients with posterior capsular rupture during cataract surgery with a single-piece acrylic IOL implanted into the ciliary sulcus were studied. Complete ocular examinations were performed after 6 months postoperatively.Twenty-four eyes were included. Mean follow-up duration was 8.33 ± 2.33 months. There was no significant difference between preoperative and postoperative keratometric cylinder or intraocular pressure. Visual acuity of 87.50% of patients was ≥20/40 after surgery. Complications included foveopathy (10 eyes), iris transillumination defect (4 eyes), iris chafing (2 eyes), pigmented keratic precipitate (KP) (4 eyes), clinical IOL tilt (6 eyes), endothelial pigment dusting (14 eyes), IOL pigment dusting (17 eyes), iris bowing (6 eyes), IOL decentration (4 eyes), and IOL tilt detected with ultrasonography biomicroscopy (UBM) (4 eyes). IOL pigment dusting was significantly higher in eyes with short axial lengths, high IOL power, small sulcus-to-sulcus (STS) diameter, large STS IOL diameter mismatch, and small anterior chamber depth and angle. Significant relationships were observed between pigmented KP with small STS diameter and large STS IOL diameter mismatch, UBM and clinical IOL tilt with large anterior chamber depth and between iris transillumination defect and STS IOL diameter mismatch.This implantation is associated with higher incidence of complications. Single-piece acrylic IOLs are not designed for sulcus implantation. However, they may be used in eyes with longer axial length if the 3-piece IOL is not available.
Abstract Background: This study aimed to measure Peri-papillary Choroidal Thickness (PCT) and Retinal Nerve Fiber Layer Thickness (RNFLT) in mild to moderate axial myopic eyes and compare their average values with those of normal control participants. Methods: Twenty-five mild to moderate axial myopic eyes were included in this study. The data of 27 normal eyes were also considered as the control group. Subjects underwent a refractive error examination and axial length measurements. Then, the RNFLT, as well as the choroid borders (outer and inner) were measured. Optical Coherence Tomography (OCT) measurement of both eyes was done using Spectral Domain Optical Coherence Tomography (SD-OCT). Results: The average PCT of the eyes of the myopic subjects and normal controls was 161.7±29.6 and 166.18±39.8 μm, respectively. All the regional values of PCT and its average were not significantly different between myopic and the control eyes. However RNFLT values were significantly lower in the superior (p=0.004), inferior (p=0.01), and nasal (p<0.001) sectors among the myopic eyes in comparison with the control eyes. There was a negative association between axial length and choroidal thickness in temporal r=0.12 (p=0.023), superiorr=-0.2(p=0.04), nasal [r=-0.34 (p<0.001] and inferior [r=-0.32 (p=0.001)] segments, respectively that of them it was not statistically significant for the temporal segment. Conclusion: Although RNFLT values were lower in the most regions of myopic eyes versus the controls, no significant difference was statistically found in the PCT using Enhanced Depth Imaging Optical Coherence Tomography (EDI-OCT) from mild to moderate axial myopic cases and the control eyes. The choroidal thickness in temporal, superior, nasal segments were negatively correlating with axial length.
A high-reliability organization (HRO) is a separate paradigm can indicate medical error reduction and patient safety improvement. Hospitals, as vital organizations in the health care system, can transform to HROs to achieve optimal performance and maximum safety in order to manage unpredicted events efficiently. Therefore, the aim of this research was to determine the knowledge of managers and staffs of Farabi Eye Hospital, Tehran, Iran about HROs model, and the extent of HROs establishment in this hospital in 2015-2016.In this descriptive-analytical and cross-sectional study, data were collected through HROs questionnaire and checklist. Validity of questionnaire and checklist was confirmed by expert panel, and the questionnaire reliability by Alpha-Cronbach method with 0.85. The collected data were analyzed with Spearman's correlation coefficient and Mann-Whitney test using the SPSS software version 19.Most of the respondents were familiar with HROs model to some extent and only 18.8% had a high level of knowledge in this regard. In addition, there was no significant correlation between the knowledge of staffs and managers with establishment of HROs model in Farabi eye hospital.Managers and staffs of Farabi Eye Hospital did not have a high knowledge level of the model of HROs and had little information about the functions and characteristics of these organizations. Therefore, we suggest HROs training courses and workshops should be established in this hospital to increase the knowledge of the managers and staffs for better establishment of HROs model.
To evaluate the visual outcomes, pseudoaccommodation, and wavefront aberrometry after implantation of Wichterle IOL-Continuous Focus (WIOL-CF®, Gelmed International, Kamenne Zehrovice, Czech Republic) by i-Trace aberrometry.In this retrospective interventional case series study, after cataract surgery with implantation of accommodative WIOL-CF®, the patients were evaluated with i-Trace aberrometer for measurement of modulation transfer function (MTF), point spread function (PSF), total aberrations, higher order aberrations (HOAs) at far and near and pseudoaccommodation. The pre and postoperative visual acuity at near and distance were also measured.Forty eyes of 20 patients (aged 40-77 years) were enrolled in this study with mean follow-up time of up 13.10 ± 5.52 months. The mean logMAR corrected distance visual acuity (CDVA) improved from 0.20 ± 0.14 preoperatively to 0.10 ± 0.09 at the last follow-up after surgery (P = 0.002). The results were 60% J1, 70% J2, 85% J3, 90% J4, 95% J5 and 100% for J6. The mean pseudoaccommodation, range of accommodation volume, and average of peak accommodation were -2.52 ± 1.56 diopters (D), 1.50 to 5.25 D and -3.25 ± 1.25 D, respectively. The mean MTF at 5 cycles per degree at far was 0.200 ± 0.10 and for near was 0.207 ± 0.10. PSF at far and near was 0.0002 and 0.001, respectively. The mean root mean square (RMS) value of HOAs; total, coma spherical aberration, trefoil, and secondary astigmatism were 1.08 ± 0.48 μm, 0.89 ± 0.45 μm, -0.33 ± 0.23 μm, 0.25 ± 0.17 μm, and 0.15 ± 0.13 μm for far and 0.88 ± 0.49 μm, 0.73 ± 0.46 μm, -0.25 ± 0.22 μm, 0.19 ± 0.16 μm and 0.11 ± 0.10 μm for near, respectively. There was a decrease in HOAs at near relative to far (P < 0.05).WIOL-CF® seems to be an acceptable accommodative intraocular lens (IOL) in terms of uncorrected near and distant visual outcomes, MTF and HOA.
Glaucoma is the second leading cause of preventable blindness in the World1, and gravely affects quality of life.2 It affects approximately 60 million people worldwide; 1-2% of the population over 40 years and 10% of people aged over 70.3 It has been estimated that the toll of bilateral blindness due to primary glaucoma will increase to 11 million people by 2020.1 In developed countries, at least half of glaucoma patients are unaware of their disease and this estimate is likely to be higher in developing countries. World Glaucoma Week: WGW (http://www.wgweek.net/) is recognized annually on the second week of March (this year, March 9-15) in order to create and maintain global awareness and initiative for glaucoma control.
According to the World Health Organization (WHO), glaucoma is an emerging cause of blindness in Iran.4 Estimated prevalence rates in Iran are 0.5% for those under 50 years and up to 5% in older populations.3,5 These figures are comparable to other population-based studies in Asia and are lower in comparison to those of Middle-Eastern countries.1
Health actions are broadly categorized in four major groups of primordial, primary, secondary and tertiary prevention. Classic ophthalmic examples for these categories, in the same order include sanitation improvement and environmental hygiene to reduce Chlamydia trachomatis-infested flies as a part of strategies for trachoma control, tight control of blood sugar in diabetic patients to prevent retinopathy, access to and delivery of cataract surgery, and provision of black pupil contact lenses for patients with blind disfigured eyes. Parenthetically, it is noteworthy that these designations are relative and may change based on what one considers as the attributing health condition.
The popular expression for secondary prevention is “screening” which itself means separation and sorting. Why “secondary”? Because the disease is already present, and we are trying to diagnose it at an asymptomatic “pre-clinical” phase (see below). Why “prevention”? Because there is potential to avoid undesirable outcomes. In this sense, one should take care not to confuse screening with surveys, as the former is a health measure and the latter is a research effort for the generation of epidemiological evidence.
We are on the verge of being able to diagnose glaucoma at early and even subclinical phases with certainty. Optic nerve imaging and nerve-fiber layer thickness analysis in terms of data capture and analytical algorithms have advanced tremendously in recent years. But in order to apply a diagnostic test for glaucoma screening, it should be practical as well as accurate for the given population; i.e. demonstrate near perfect negative predictive value (i.e. no glaucoma missed) and a positive predictive value of better than 20% (i.e. at least one true glaucoma in 5 referrals). These performance indicators are predicated on the intrinsic susceptibility and selectivity of the test, such as sensitivity and specificity, respectively, as well as the disease prevalence.
Chronic glaucomas (open and closed angle) classically fulfill screening criteria. They have a long natural course with a latent “pre-clinical” phase of reportedly 5 to 14 years,6,7 the major pathogenic factor, i.e. high intraocular pressure, is treatable, they are diagnosable, and the significance of their public health impact has been documented.
While our resources are limited, health issues and the required actions are almost infinite. Here is where economic evaluation helps us with rational priority setting. These evaluations function in two dimensions including what to screen and how to screen.8 Limited studies, mostly in developed nations, addressed glaucoma screening cost-effectiveness. Advanced modeling and a variety of vision-related quality of life indices were used to estimate the gains over a 20 year time span as compared to that of the existing scenario in the target health care system.9-13 The hypothetical screening staff were either optometrists or technicians, and screening tests comprised of ophthalmoscopy, tonometry and perimetry14 in the population over 40 years. Unanimously, all evaluations concluded that population-based screening is not cost-effective. Projected incremental cost-effectiveness ratios (ICER) for developed countries exceeded predetermined thresholds for one additional quality-adjusted life year (QALY) gained; for instance, the ICER in the UK was more than £30,000 per QALY, which is very costly.10 Corresponding figures are £15,000 per QALY for photography-based diabetic retinopathy screening by technicians15 and £16,500 for amblyopia screening at 3 years of age.16
Results of economic evaluations depend on the socio-economical context, healthcare infrastructure (existing feasible alternatives and access to providers) and epidemiological factors. In the UK, an ICER of £20,000/QALY or less is considered cost-effective, and is judged as an effective use of public resource.17 For developing countries like Iran where there is neither an established threshold nor estimates on cost-effectiveness, WHO proposes using the gross domestic product (GDP). In this sense, the average GDP per capita in Iran over the past five years was about $10,000.18 Therefore, glaucoma screening would be highly cost-effective for an ICER less than $10,000/QALY, relatively cost-effective if it is between 1-3 times the GDP per capita, and not cost-effective for an ICER more than $30,000/QALY.19
Considering the relatively lower glaucoma prevalence in Iran, one may infer that population-based screening for chronic glaucoma is not cost-effective either. But as mentioned, other contextual factors like the screening personnel, applied diagnostic technology, existing health system capacity, etc. influence these evaluations.
A more frugal alternative is “targeted screening” in which people at higher baseline risk of the disease are chosen. Established risk factors can form the framework for this approach. In case of chronic glaucoma, these include age and family history (race may not be applicable to Iran). The estimated odds ratio per decade of increase in age is 1.6 for Asians.20 The prevalence of open angle glaucoma in the under 55 age group is less than 1%, while it is significantly greater in individuals older than 70 years (3% in Asians).3,5,21 Figures for Whites follow the same pattern. The adjusted odds ratio of first degree family history of glaucoma is 3 and the lifetime risk is 9 times more for siblings and offspring.22,23 In the UK, it is predicted that glaucoma screening might be cost-effective in a 50-year-old cohort at a prevalence of 4% with a 10 year screening interval.10
What do ophthalmologists routinely do? They perform “opportunistic case finding”!24 It has been reported that half of the patients with a recent diagnosis of glaucoma had undergone an eye examination in the preceding 12 months but still had been missed.25 On the other hand, it has been shown that glaucoma is more common in clinical populations.26 This opportunity for “clinical screening” should be well embraced by clinicians. It is emphasized that this is intended to detect glaucoma in subjects with no complaint of visual loss and in non-specific referrals like dry eye syndrome, etc.15 This capacity can be hugely extended to primary eye care services such as optometry and general practices.
PRELIMINARY POLICY STATEMENTS
Population-based screening for chronic glaucoma may not be currently cost-effective for Iran.
Targeted screening in families who had a glaucoma case in first degree relatives older than 50 years is recommendable.
Social marketing and occasional campaigns (on World Glaucoma Week, for instance) should be performed to create awareness and encourage people to seek care.
Clinical screening should be approached on multiple levels; optometrists, general/family physicians, and ophthalmologists should rule out glaucoma in their referrals. For this purpose, required guidelines and equipment should be developed and supplied.
Alternative screening programs should be tested and evaluated in population labs. Specifically, teleophthalmology and modern information technology tools and protocols should be explored.
The future is bright, as personalized (molecular and genomic-based) medicine may soon provide us with constitutional probabilities for a wide spectrum of health conditions including glaucoma. Alternatively, biomarkers may help us assess risks for glaucoma or directly diagnose it at clinical and population levels; then we can reconsider our approach towards glaucoma screening more precisely.
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