Abstract
Purpose:
To investigate the changes of corneal endothelial density (CED) at the central cornea and to determine risk factors.
Methods:
Data on corneal endothelial density were reviewed for 49 patients (49 eyes, 241 measurements) who underwent anterior tube shunt surgery by a single surgeon at a single center. In addition to the age at surgery and sex, the type of tube used (Molteno vs. Baerveldt), postoperative period, length of tube in the anterior chamber, angle between tube and the corneal endothelium, tube insertion site (anterior vs. posterior to Schwalbe's line), and jet flow of aqueous humor (yes vs. no) were considered as risk factors for a decrease of central CED. Tube length and angle were measured by anterior segment optical coherence tomography (AS-OCT). The tube insertion site was observed by gonioscopy and AS-OCT. We assumed that jet flow of aqueous humor would start just after release of the tube ligature (7-0 nylon) with an argon laser. Mixed-effect multiple linear regression analysis was employed to analyze unbalanced panel data. Institutional review board approval was obtained from the Japanese Red Cross Medical Center and this study was consistent with the Declaration of Helsinki.
Results:
The mean postoperative period (± standard deviation) was 4.6 (±2.9) years, with a mean of 4.9 (±2.4) CED measurements. After adjusting for other variables, CED decreased significantly every year after surgery (β: -115.1 per year, 95% confidence interval (CI): -142.0 to -88.2). Factors associated with CED reduction were tube ligature release (β: -245.9, 95%CI: -417.1 to -74.7), tube angle (β: -16.2 per 1 degree with narrowing, 95%CI: -31.1 to -1.3), and tube position (β: -445.5, 95%CI: -829.7 to -61.3). In contrast, the age, sex, tube, and tube length did not show a statistically significant association with CED reduction.
Conclusions:
Anterior tube shunt surgery is associated with a decrease of CED. Peripheral cell loss due to rubbing the cornea with a tube could stimulate endothelial migration and reduce the central CED. Jet flow of aqueous humor could also contribute to CED reduction.
Keywords: 481 cornea: endothelium •
464 clinical (human) or epidemiologic studies: risk factor assessment