Purpose: Increased intraocular pressure (IOP) is a frequent complication after penetrating keratoplasty and can be due to reduced trabecular meshwork outflow facility. Descemet stripping endothelial keratoplasty (DSEK) is a lamellar technique for replacing pathologic corneal endothelium and may be associated with a lower risk of postoperative IOP rise. In a prospective clinical study we studied IOP and outflow facility before and after DSEK.
Methods: In 23 eyes of 23 patients before, 1 day, 6 weeks, and 3, 6, and 12 months after DSEK, IOP was measured using Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). Trabecular meshwork outflow facility (C-value) was assessed by impression tonography with the Schioetz tonometer. Central corneal thickness was measured by Haag-Streit pachymetry. Best spectacle corrected visual acuity, ocular surface fluorescein staining, and corneal sensation were also recorded.
Results: Mean IOP showed a trend toward increase from preoperatively to 1 year postoperatively, which was not statistically significant (GAT: 13.5±3.3 to 15.3±4.7 mm Hg; DCT: 13.7±2.9 to 16.7±4.8 mm Hg; Schioetz: 12.4±2.8 to 15.3±2.9 mm Hg). Outflow facility increased significantly from 0.19±0.03 before to 0.29±0.05 mm/Δmm Hg/min at 1 year after DSEK (P=0.002). Best spectacle corrected visual acuity increased significantly from 0.98±0.48 to 0.36±0.17 logMAR (P=0.0004). Corneal sensitivity was unchanged and corneal staining significantly decreased from the preoperative to 1 year postoperative period (P=0.01). Mean central corneal thickness changed significantly from 650±59 to 621±73 μm (P=0.002).
Conclusions: IOP as measured by GAT, DCT, and Schioetz tends to increase during the first year after DSEK in eyes without previous glaucoma, whereas trabecular meshwork outflow facility as measured by Schioetz tonography improves. These findings are likely to be due to a progressive increase of corneal rigidity affecting transcorneal pressure measurements of both IOP and trabecular meshwork outflow facility.
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http://dx.doi.org/10.1097/IJG.0000000000000208 | DOI Listing |
JCI Insight
January 2025
Gavin Herbert Eye Institute-Center for Translational Vision Research, Depar, University of California Irvine School of Medicine, Irvine, United States of America.
Elevation of intraocular pressure (IOP) due to trabecular meshwork (TM) dysfunction, leading to neurodegeneration, is the pathological hallmark of primary open-angle glaucoma (POAG). Impaired axonal transport is an early and critical feature of glaucomatous neurodegeneration. However, a robust mouse model that accurately replicates these human POAG features has been lacking.
View Article and Find Full Text PDFInvest Ophthalmol Vis Sci
December 2024
Department of Ophthalmology, Duke University, Durham, North Carolina, United States.
Intraocular pressure (IOP) elevation is the primary risk factor and currently the main treatable factor for progression of glaucomatous optic neuropathy. In addition to direct clinical and living animal in vivo studies, ex vivo perfusion of anterior segments and whole eyes is a key technique for studying conventional outflow function as it is responsible for IOP regulation. We present well-tested experimental details, protocols, considerations, advantages, and limitations of several ex vivo model systems for studying IOP regulation.
View Article and Find Full Text PDFInquiry
November 2024
Kyung Hee University, Seoul, Republic of Korea.
This study analyzes hospital bed capacity and resource allocation using inflow and outflow indices to identify disparities in bed utilization. The COVID-19 pandemic highlighted the need for effective healthcare management, particularly in the allocation of specialized beds such as those in intensive care units (ICU). Despite a high bed-to-population ratio, South Korea faces regional disparities in bed distribution, especially in Seoul, which accounts for 12.
View Article and Find Full Text PDFSci Rep
November 2024
Solar Physics Laboratory, NASA/GSFC, Mail Code 671, Greenbelt, MD, 20771, USA.
The solar wind is a continual outflow of plasma and magnetic field from the Sun's upper atmosphere-the corona-that expands to fills the solar system. Variability in the near-Earth solar-wind conditions can produce adverse space weather that impacts ground- and space-based technologies. Consequently, numerical fluid models of the solar wind are used to forecast conditions a few days ahead.
View Article and Find Full Text PDFPharmaceuticals (Basel)
September 2024
Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA.
Background: Hydrogen sulfide (HS)-releasing compounds can reduce intraocular pressure in normotensive rabbits by increasing aqueous humor (AH) outflow through the trabecular meshwork. In the present study, we investigated the contribution of endogenous HS and the role of intramurally generated prostaglandins in the observed increase in AH outflow facility in an ex vivo porcine ocular anterior segment model.
Material And Methods: Porcine ocular anterior segment explants were perfused with Dulbecco's Modified Eagle's Medium maintained at 37 °C and gassed with 5% CO and 95% air under an elevated pressure of 15 mmHg for four hours.
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