Some Ultrastructural Aspects of the Vitreoretinal Juncture

Abstract

The ultrastructural study of the vitreoretinal juncture was carried out by comparing two groups of patients: 6 young subjects under 25 years and 6 older subjects over 70. Retinal samples were taken from the posterior pole, the equator and the extreme periphery. Our work shows that the morphological modifications of the vitreoretinal juncture during the aging process vary following location. The most original alteration, never observed before, appears in the equatorial region: it consists of a widening of the intercell space filled with fibrils adhering to MÜller’s cells. It builds up an adhesion zone between the vitreous and the retina which is not visible during clinical investigations; it can create a tear during the posterior vitreous detachment.

In vitro phagocytosis of collagens by immortalised human retinal Müller cells

“…Comparing all experiments, cultured Müller cells phagocytose beads coated with type II collagen better than beads coated with BSA or types I and IV collagen and noncoated beads. These findings may be adduced in support of the hypothesis that Müller cells could be involved in the slow process of vitreoretinal remodelling, which has been described as interactive or degenerative remodelling, predominantly in the peripheral retina, [5,8,14,24,33,35] and which is very slowly progressive on ageing [33,35]. In a lifetime, the width of the vitreous base increases only with approximately 2 mm [35].…”

“…Gloor and Daicker [8] described atrophy of neuroglia in the same area, which caused intercellular gaps becoming filled with cords of collagen fibrils connecting vitreous and retina. Malecaze et al [14] found widening of intercellular spaces filled with fibrils adhering to Müller cells in the middle part, but the lesions were smaller than described before and not associated with gaps in the ILL. More recently, Wang et al [35] observed, mainly by scanning electron microscopy, progressive invasion of the innermost peripheral retina by bundles of collagen fibrils, initially as characteristic collagen fibres spreading out under the ILL and eventually as a dense mat of collagen in the elderly. Furthermore, collagen fibrils penetrated the ILL through localised defects and intertwined with those in the basal vitreous.…”

Visual Outcomes of Pars Plana Vitrectomy with Epiretinal Membrane Peeling in Patients with Asteroid Hyalosis: A Matched Cohort Study

“…Since AH is strongly associated with cardiovascular risk factors, it is believed that the induced vascular changes release the asteroid body-relevant ions and macromolecules more easily to the vitreous cavity. The inner limiting membrane becomes more permeable because of structural alterations [7,16,17] in aged eyes and after posterior vitreous detachment.…”

Structure of the Human Vitreoretinal Border Region

“…However, the wide range of thicknesses obtained in the various regions may hide a slight change in thickness with age. Gärtner [17,18] found an increase in thickness with age, and Malecaze et al [27] found a thickening of the basement mem brane in the posterior pole of aged human subjects. A similar increase in thickness was also found in the primate MLI [13].…”

“…degenerative crypts, increased intercellular space, detachment of basement membrane and vacuol ization. has been described by Foos [4], Gärtner [29], Malecaze et al [27]. Hogan [15] and Matsuo et al [11].…”