Predictability of the Achieved Lenticule Thickness in Keratorefractive Lenticule Extraction for Myopia Correction.

PURPOSE: To assess the predictability between the SCHWIND ATOS femtosecond laser (SCHWIND eye-tech-solutions) read-out and achieved lenticule thickness measured using MS-39 anterior segment optical coherence tomography (ASOCT; CSO) at the corneal vertex at postoperative 1 day and 1 and 3 months of follow-up. METHODS: This retrospective case series included 130 eyes of 65 consecutive patients who were treated with SmartSight (SCHWIND eye-tech-solutions) lenticule extraction. Sixty-four percent of patients were women with a mean spherical refraction of -4.98 ± 1.19 diopters (D) and mean astigmatism of 0.53 ± 0.64 D. The measurements were performed using AS-OCT with the Phoenix Software v 4.1.1.5. Lenticule thickness was obtained by the subtraction method between preoperative and postoperative total corneal thickness. RESULTS: A lower reduction in central corneal thickness (CCT) compared to the laser read-out for all three follow-up visits can be observed. Essentially, the reduction in CCT was identical at 3 months versus 1 month. The reduction in CCT was lowest at postoperative 1 day. Examining the 1- and 3-month data (essentially equivalent), one can see a best fit of y = 0.94 x -7 µm. CONCLUSIONS: The reduction in CCT was stable from 1 month of follow-up. The stable reduction in CCT was -6% (-1.5% after accounting for design decisions) and -7 µm lower than the respective laser read-out. The findings are predictable, showing a certain level of the lenticules becoming slightly thinner than their respective laser read-outs. [J Refract Surg. 2023;39(11):728-735.].

Stereoacuity and Multifocal Intraocular Lenses - a Systematic Review.

Background: Among various visual functions, stereoacuity, or the ability to perceive depth, is the most sophisticated binocular function. Many publications discuss the influence of retinal image formation by multifocal intraocular lenses on glare and contrast sensitivity, but only a few present results of testing binocular vision in patients with multifocal intraocular lenses. Objective: This article is designed to review the results of testing binocular vision in patients with multifocal intraocular lenses implanted in cataract surgery. Methods: This article was performed based on a literature review and Internet search through scientific databases such as PubMed, Scopus, Web of Science, and Google Scholar. Results: Some reports found that patients implanted with the monofocal lens, when measured with a near addition, presented statistically significant better stereoacuity scores than those implanted with any of the multifocal intraocular lens types. When the TNO test was used for measurement, statistically significant better stereoacuity was disclosed with the refractive multifocal intraocular lens than with the diffractive-based multifocal intraocular lens design. Stereoacuity scores, even within the same types of lenses, were significantly better with the Titmus test than with the TNO test. Conclusion: Stereoacuity is not affected by multifocality-induced retinal blur as it is by other causes of image degradation such as small residual refractive error very early opacification of ocular media or dry eye. Multifocal intraocular lenses do not cause more functional aniseikonia than would be expected with a monofocal intraocular lens. Since stereoacuity is compromised with unilateral multifocal intraocular lens implantation bilateral implantation should be attempted.

Management of Post-LASIK Ectasia.

Background: Corneal ectasia is a sight-threatening complication of corneal refractive surgery characterized by progressive steepening and thinning of the cornea and subsequent loss of best-corrected visual acuity. Objective: To report the clinical outcomes following treatment of post-laser in situ keratomileusis (LASIK) induced ectasia. Methods: This is a retrospective case series of 7 patients (10 eyes) which developed post-LASIK ectasia. In these cases of postoperative ectasia, the presented clinical signs were either forme fruste keratoconus, thin cornea, posterior elevation map value > +15.0µm, or residual stromal bed < 300µm. All cases were treated with either collagen crosslinking (CXL) alone or combined with PRK or CXL and phakic intraocular implant using the Dresden protocol and a slight modification thereof. In all cases, the flap was created using the Moria M2 mechanical microkeratome (average flap thickness 118.15±12.88µm), and refractive error was corrected using the Wavelight Allegretto excimer laser. Results: Average preoperative corrected visual acuity (CDVA) was 0.75 (±0.26) Snellen. Postoperative CDVA significantly increased to 0.86 (±0.13) Snellen (p=0.04, paired t-test). One eye lost three lines of its baseline CDVA (before ectasia), while all other eyes regained lines of CDVA. All cases remained stable during the follow-up. Conclusion: Several surgical procedures are used for the management of corneal ectasia. However, the best surgical approach should be determined based on the state of progression of the disease. Although ectasia remains a potentially devastating complication after refractive surgery, most patients can regain functional visual acuity with appropriate management, and corneal transplantation is infrequently indicated.

BPM1 regulates RdDM-mediated DNA methylation via a cullin 3 independent mechanism.

KEY MESSAGE: BPM1 interacts with components of the DDR complex and stimulates DNA methylation at CHH sites, suggesting its involvement in the RdDM methylation pathway. The best-known function of MATH-BTB proteins, including Arabidopsis BPM proteins, is their role as substrate-specific adaptors of CUL3-based E3 ligases in the ubiquitin-proteasome pathway. This paper reports a new CUL3-independent role of BPM1 in RNA-directed DNA methylation (RdDM). Using quantitative and qualitative Y2H, pull down, microscale thermophoresis and FRET-FLIM, we demonstrate that BPM1 interacts with DMS3 and RDM1, components of the chromatin remodeling DDR complex involved in the recruitment of the RdDM methylation machinery. All three proteins colocalized predominantly in the nucleus. The MATH domain, which specifically binds proteins destined for degradation, was not essential for interactions with DMS3 and RDM1. In plants overexpressing BPM1, endogenous DMS3 protein levels were stable, indicating that BPM1 does not induce proteasomal degradation. In RDM1-overexpressing plants, RDM1 was not ubiquitinated. Together, these results suggest that BPM1 does not mediate the degradation of DMS3 and RDM1. Additionally, overexpression of BPM1 caused increased global methylation levels as well as CHH methylation in promoters of two RdDM-regulated genes, FWA and CML41. Overall, BPM1 seems to have a stimulating effect on RdDM activity, and this role appears to be unrelated to its known function as a Cul3-based E3 ligase adaptor.

Influence of Clinically Active Graves' Ophthalmopathy on Spherical Equivalent and Visual Acuity.

Purpose: Clinical experience regarding the fluctuations of the refractive error of the eye during the different stages of Graves' ophthalmopathy observed through outpatient clinic frequent check-ups points towards an underestimated and often overlooked problem. Published data about it are sparse. The clinical manifestations of Graves' ophthalmopathy can be understood from the perspective of "compartment syndrome" and literature implies how such changes can affect the refractive error and consequently, the visual acuity. The purpose of the study was to explore how the clinical activity score of Graves' ophthalmopathy affects refractive error and visual acuity. Patients and Methods: The study was prospective and observational, including 60 eyes of 30 patients with clinically active Graves' ophthalmopathy. All the patients were monitored and evaluated over a period of 36 months by the clinical activity score, spherical equivalent and visual acuity. All the observed parameters were statistically analyzed. Results: The mean values of spherical equivalent and visual acuity throughout the observed period showed continuous fluctuation. Repeated measure analysis of variance showed statistically significant differences in visual acuity and spherical equivalent over the observed period. There was a statistically significant positive correlation between visual acuity and clinical activity score. The correlation between spherical equivalent and clinical activity score was also positive but not statistically significant. Conclusion: A decrease in the clinical activity score is either the result of a spontaneously resolving course of Graves' ophthalmopathy or a consequence of treatment, so lowering in fluctuation of refractive error and improved visual acuity may be associated with a reduction in orbital inflammation.

Taking the Wheel - de novo DNA Methylation as a Driving Force of Plant Embryonic Development.

During plant embryogenesis, regardless of whether it begins with a fertilized egg cell (zygotic embryogenesis) or an induced somatic cell (somatic embryogenesis), significant epigenetic reprogramming occurs with the purpose of parental or vegetative transcript silencing and establishment of a next-generation epigenetic patterning. To ensure genome stability of a developing embryo, large-scale transposon silencing occurs by an RNA-directed DNA methylation (RdDM) pathway, which introduces methylation patterns de novo and as such potentially serves as a global mechanism of transcription control during developmental transitions. RdDM is controlled by a two-armed mechanism based around the activity of two RNA polymerases. While PolIV produces siRNAs accompanied by protein complexes comprising the methylation machinery, PolV produces lncRNA which guides the methylation machinery toward specific genomic locations. Recently, RdDM has been proposed as a dominant methylation mechanism during gamete formation and early embryo development in Arabidopsis thaliana, overshadowing all other methylation mechanisms. Here, we bring an overview of current knowledge about different roles of DNA methylation with emphasis on RdDM during plant zygotic and somatic embryogenesis. Based on published chromatin immunoprecipitation data on PolV binding sites within the A. thaliana genome, we uncover groups of auxin metabolism, reproductive development and embryogenesis-related genes, and discuss possible roles of RdDM at the onset of early embryonic development via targeted methylation at sites involved in different embryogenesis-related developmental mechanisms.

The protein turnover of Arabidopsis BPM1 is involved in regulation of flowering time and abiotic stress response.

KEY MESSAGE: Protein degradation is essential in plant growth and development. The stability of Cullin3 substrate adaptor protein BPM1 is regulated by multiple environmental cues pointing on manifold control of targeted protein degradation. A small family of six MATH-BTB genes (BPM1-6) is described in Arabidopsis thaliana. BPM proteins are part of the Cullin E3 ubiquitin ligase complexes and are known to bind at least three families of transcription factors: ERF/AP2 class I, homeobox-leucine zipper and R2R3 MYB. By targeting these transcription factors for ubiquitination and subsequent proteasomal degradation, BPMs play an important role in plant flowering, seed development and abiotic stress response. In this study, we generated BPM1-overexpressing plants that showed an early flowering phenotype, resistance to abscisic acid and tolerance to osmotic stress. We analyzed BPM1-GFP protein stability and found that the protein has a high turnover rate and is degraded by the proteasome 26S in a Cullin-dependent manner. Finally, we found that BPM1 protein stability is environmentally conditioned. Darkness and salt stress triggered BPM1 degradation, whereas elevated temperature enhanced BPM1 stability and accumulation in planta.

Changes in Endothelial Cell Count Up to Three Years After Implantation of Toric Implantable Collamer Lenses.

PURPOSE: To determine the temporal effect of toric implantable collamer lens (TICL) implantation and location on corneal endothelial cell density (ECD) over a period of 36 months after surgery. METHODS: ECD [number of cells per square millimeter estimated using the Specular Microscope SP-1P (Topcon Europe Medical B.V., Netherlands)] data were collected from cases deemed suitable for the TICL (VTICMO, VTICM5; STAAR Surgical, Nidau, Switzerland). The preoperative refractive error (sphere and cylinder) ranged from -1.00 to -22.25 diopter sphere and from -0.50 to -5.50 diopter cylinder. ECD was evaluated at preoperative and all postoperative sessions. RESULTS: Key findings were as follows: the mean ECD (±SD, 95% confidence interval) was 2720 cells/mm (±272, 2620-2820 cells/mm) preoperatively, which was reduced to 2372 cells/mm (±325, 2250-2490 cells/mm) at 36 months postoperatively (P < 0.001). Linear regression revealed the following significant correlations between the (1) log of the change in ECD (y1) and log of preoperative ECD (x1) at 2 years postoperatively, y1 = 2.513x1-6.2816 (n = 62, r= 0.3503, P = 0.005); (2) mean ECD (y2) and log time (in months, x2), y2= 2543.7-36.997x2-38.99x2 (r=-0.9654, n = 7, P = 0.0004); and (3) mean axial distance between the front surface of the crystalline lens and the TICL back surface (y3) and time postoperatively (in months, x3), y3 = 0.1035x3-5.2808x3 +473.18 (r = 0.8512, n = 7, P = 0.015). CONCLUSIONS: Expected ECD loss after TICL implantation by 2 years postoperatively is predictable. On average, over 3 years after implantation, there is (1) an initial rapid decline in ECD, followed by a gradual fall in the rate of cell loss, and (2) a gradual fall in the distance between the TICL and the crystalline lens by 2 years postoperatively, followed by a reversal by the third year.