Abstract
Purpose: :
Understanding the rheological properties of chopped vitreous may aid in anticipating their effects on device performance during vitrectomy and may provide insight into vitreoretinal diseases. We sought to compare the rheological properties of chopped human vitreous from various patient ages and disease states.
Methods: :
We measured the rheological properties of the vitreous of 65 consecutive eyes undergoing pars plana vitrectomy. At the start of the vitrectomy, the vitrector tip was placed approximately 5 mm posterior to the center of the lens and a vitrectomy sample of 1 cc was taken under air. The compliance and viscosity of these samples were characterized with a shear rheometer using a protocol that had been validated for precision and reproducibility.
Results: :
Vitreous from 65 eyes was analyzed and a complete data set for 55 and 27 eyes was obtained for compliance and viscosity data, respectively. There was no relationship between patient age and compliance or viscosity. Viscosity (units in mPa•s) was greater in patients with proliferative diabetic retinopathy (42.8 ± 2.6, n = 3) than patients without diabetic retinopathy (35.6 ± 9.5, n = 22, p = 0.015). Viscosity was also greater in patients with vitreomacular traction or full-thickness macular hole (40.9 ± 3.4, n = 4) than in patients without these pathologies (34.6 ± 11.6, n = 23, p = 0.045). Analyses of phakic status, presence of diabetes without regard to retinal disease, and other vitreoretinal pathologies (tractional retinal detachment, rhegmatogenous retinal detachment, epiretinal membrane, and vitreous hemorrhage) did not reveal statistically significant differences. No statistically significant differences in compliance were detected.
Conclusions: :
In this group of patients, chopped vitreous from eyes with proliferative diabetic retinopathy and vitreomacular traction/full-thickness macular hole had greater viscosity than vitreous from eyes without these pathologies. Understanding these differences in viscosity may influence surgical technique and may give insight into vitreoretinal diseases.
Keywords: vitreoretinal surgery • vitreous