Impact of Advanced Image-Guided Systems on Correction of Corneal Astigmatism During Femtosecond Laser-Assisted Cataract Surgery.

PURPOSE: To determine the effectiveness of the correction of corneal astigmatism utilizing the Alcon Image Guidance system (Ft. Worth, Texas) versus manual marking in the orientation of femtosecond laser-assisted astigmatic keratotomy incisions. SETTING: This study was based in a private practice in Albany, New York, USA. DESIGN: Retrospective review of patients undergoing FLACS from January 2018 to June 2022. METHODS: Patients who underwent FLACS with Image Guidance (IG) and without IG were investigated. Variables including pre-operative K values, cylinder, spherical equivalent (SE), and visual acuity (VA) were collected, as well as the cyclorotation angle delta registered by IG, post- operative refractive cylinder, SE, and VA. The primary outcome was post-operative refractive cylinder in patients with IG compared to those without IG. RESULTS: A total of 160 eyes were included, with 103 eyes who had IG and 57 eyes who did not have IG. Post-operative cylinder was similar in those with IG (0.31 +/- 0.36 D) compared to those without IG (0.31 +/- 0.37 D) (p=0.97). Average cyclorotation in the IG group was 2.82 ± 3.03 degrees. When cyclorotation was stratified into three groups (<2.8 degrees, 2.8-8.5 degrees, >8.5 degrees), no differences were found in post-operative refractive cylinder (p=0.35). CONCLUSIONS: Patients who underwent FLACS with Image Guidance had similar post-operative cylinder outcomes compared to those without Image Guidance. This study suggests that the accommodation of cyclotorsion using an advanced image guidance system is similar to that obtained with manual marking techniques in patients having 2 diopters or less of astigmatism corrected.

Comparison of Persistent Epithelial Defect Treatment With Sutureless Cryopreserved and Dehydrated Amniotic Membrane.

PURPOSE: To compare cryopreserved sutureless amniotic membrane (C-SAM) and dehydrated SAM (D-SAM) outpatient treatment outcomes for persistent epithelial defects (PEDs), analyze risk factors for treatment failure, and identify adverse events. DESIGN: Retrospective, interventional comparative clinical study. METHODS: This study was a multicenter retrospective interventional cohort from 2 tertiary corneal referral practices from 2016 to 2020. The inclusion criteria were as follows: (1) PEDs treated (2) outpatient with (3) either C-SAM or D-SAM. PEDs were defined as epithelial defects present for ≥7 days after failing prior conservative therapy. The primary outcome measure was the resolution or improvement of a PED. The secondary outcomes included analysis of treatment failures and identification of adverse events. A total of 220 PEDs from 204 eyes (197 patients) treated with either C-SAM or D-SAM met the inclusion criteria. RESULTS: A total of 100 PEDs (45.5%) resolved after single amniotic membrane administration, 46.5% (59 of 127) in the C-SAM group and 44.1% (41 of 93) in the D-SAM group (P = .727). Forty-nine PEDs neither improved nor resolved without a significant difference between the C-SAM (21.3%) and D-SAM groups (23.7%, P = .673). There was no statistically significant difference for PED resolution, PED improvement, PEDs that did not resolve/improve, or those requiring surgery between the 2 groups for initial SAM. CONCLUSIONS: C-SAM and D-SAM were both effective for treating PEDs with comparable outcomes for resolution, improvement, and need for additional surgical intervention. Specific differences in adverse events may help dictate clinical use. Inflammatory disease was a risk factor for nonresolution of all PEDs.

Effects of hibernation on bone marrow transcriptome in thirteen-lined ground squirrels.

Mammalian hibernators adapt to prolonged periods of immobility, hypometabolism, hypothermia, and oxidative stress, each capable of reducing bone marrow activity. In this study bone marrow transcriptomes were compared among thirteen-lined ground squirrels collected in July, winter torpor, and winter interbout arousal (IBA). The results were consistent with a suppression of acquired immune responses, and a shift to innate immune responses during hibernation through higher complement expression. Consistent with the increase in adipocytes found in bone marrow of hibernators, expression of genes associated with white adipose tissue are higher during hibernation. Genes that should strengthen the bone by increasing extracellular matrix were higher during hibernation, especially the collagen genes. Finally, expression of heat shock proteins were lower, and cold-response genes were higher, during hibernation. No differential expression of hematopoietic genes involved in erythrocyte or megakaryocyte production was observed. This global view of the changes in the bone marrow transcriptome over both short term (torpor vs. IBA) and long term (torpor vs. July) hypothermia can explain several observations made about circulating blood cells and the structure and strength of the bone during hibernation.

Von Willebrand factor is reversibly decreased during torpor in 13-lined ground squirrels.

During torpor in a hibernating mammal, decreased blood flow increases the risk of blood clots such as deep vein thrombi (DVT). In other animal models platelets, neutrophils, monocytes and von Willebrand factor (VWF) have been found in DVT. Previous research has shown that hibernating mammals decrease their levels of platelets and clotting factors VIII (FVIII) and IX (FIX), increasing both bleeding time and activated partial thromboplastin time. In this study, FVIII, FIX and VWF activities and mRNA levels were measured in torpid and non-hibernating ground squirrels (Ictidomys tridecemlineatus). Here, we show that VWF high molecular weight multimers, collagen-binding activity, lung mRNA and promoter activity decrease during torpor. The VWF multimers reappear in plasma within 2 h of arousal in the spring. Similarly, FIX activity and liver mRNA both dropped threefold during torpor. In contrast, FVIII liver mRNA levels increased twofold while its activity dropped threefold, consistent with a post-transcriptional decrease in FVIII stability in the plasma due to decreased VWF levels. Finally, both neutrophils and monocytes are decreased eightfold during torpor which could slow the formation of DVT. In addition to providing insight in how blood clotting can be regulated to allow mammals to survive in extreme environments, hibernating ground squirrels provide an interesting model for studying.