Clinical, histological and ultrastructural studies of the posterior hyaloid membrane

James

2008

Eye

Self Cite

130

Purpose/Background Epiretinal membrane (ERM) formation is a common change resulting in disturbance of macular vision and predisposing to rhegmatogenous retinal detachment. Current treatment strategies rely chiefly on surgical removal of the membranes from the surface of the retina, allowing the retina to remodel and reattach. Improved knowledge of the pathological process behind the formation of these membranes, particularly knowledge of the cell types involved in their formation, is likely to increase our understanding of the way this group of diseases behave and to improve treatment. Methods We reviewed the histological findings of 109 surgically removed specimens and correlated these to age-related changes seen in a 32 cadaver eyes studied after corneal harvesting. The samples were studied using light microscopy and immunocytochemistry. Results In all cases of idiopathic ERMs, including cellophane maculopathy, macular hole, and vitreomacular traction syndrome, laminocytes were the exclusive cell type present. In cases of macular pucker associated with retinal tears, the membranes contain variable cohesive groups of retinal pigment epithelial (RPE) cells in addition to laminocytes. In cases of proliferative diabetic retinopathy, membranes consist almost entirely of capillaries and hyaline stromal tissue, with or without haemosiderin pigment and RPE cells and in which laminocytes and ILM were not identified. In cadaver eyes PVD was seen in 17/32 (53%) of cases, and the vitreous was attached in 14/32 (43.7%) and in one case no vitreous was present. Isolated laminocytes were present on the retinal surface in 12/18 cases with detached vitreous and in 1/14 cases with attached vitreous. In all cases laminocytes were scanty and confined to the optic nerve head, macular or subjacent macular retina. Immunohistochemistry findings indicate that laminocytes are positive for glial fibrillary acidic protein (GFAP), cytokeratin marker AE1/AE3, type II collagen, and type IV collagen. In some cases novel basement membrane formation was seen. There was a tendency for increased positivity of GFAP and AE1/AE3 with increased cellularity, and where novel basement membrane formation was present. Conclusion Laminocytes are the fundamental cell type in idiopathic ERMs. These cells are frequently found in small and dispersed numbers in eyes containing a PVD. The presence of retinal pigment cells invariable indicates proliferative retinopathy and is only seen in association with a retinal detachment or tear. Diabetic membranes are composed of neovascular stromal tissue, which is most likely to be a response to retinal hypoxia.

Section: Cadaver Eyesmentioning

confidence: 99%

Pathological changes in the vitreoretinal junction 1: epiretinal membrane formation

James

2008

Eye

Self Cite

130

“…20 However, their frequent occurrence at the vitreoretinal interface has led us to suggest that such cells (also called laminocytes) may be a normal component of the inner limiting membrane of the retina. 18 The presence of ILM components, that is, type IV collagen, and laminocytes, in the PHM of control PVD eyes confirms that, at least in some cases, vitreous detachment must occur beneath the level of the retinal ILM. Whether this is the case in all instances is less certain, as negative staining for ILM components could be due to loss of these antigens in eyes from patients who will usually have had their PVD many years before dying, and does not necessarily indicate separation has occurred above the ILM.…”

Section: Discussionmentioning

confidence: 67%

“…16,17 The ERM specimens also showed resemblance in their histological and immunocytochemical characteristics with PHM specimens obtained in a previous study. 7,18 They both contain type IV collagen and GFAP-positive cells. This supports our clinical impression that during the process of PVD in eyes with stage IV MH, dehiscence of the PHM over the macula results in remnants being left and manifesting as ERM.…”

Section: Discussionmentioning

confidence: 99%

A rationale for membrane peeling in the repair of stage 4 macular holes

Ang

James

et al. 2005

Eye

Self Cite

Aim To examine the histological and immunocytochemical characteristics of epiretinal membranes (ERM) associated with stage 4 macular holes (MH) so as to establish a vitreoretinal rationale for surgery in stage 4 MH. Method Consecutive patients with stage 4 MH undergoing vitrectomy and membrane peeling were recruited. Preoperatively, the eyes were examined for ERM formation over the macula and completeness of posterior hyaloid membrane (PHM) separation from the retina. ERM peel specimens obtained during surgery were sent for histological and immunocytochemical studies and were compared with the PHM specimens taken from a previous post-mortem study of eyes with physiological posterior vitreous detachment but without macular holes. Result A total of 13 patients with stage 4 MH fulfilled the inclusion criteria and were recruited. Preoperatively, all eyes had an ERM over the macula and incomplete separation of the PHM seen as a defect in the PHM on specular biomicroscopy. Histologically, the ERM specimens had very similar morphological characteristics to PHM, consisting of an eosinophilic membrane of varying thickness with scattered spindleshaped cells. The membranes stained positively for type IV collagen while the cells were glial fibrillary acidic protein positive. Postoperatively, successful closure of MH was achieved in all cases. Conclusion Stage 4 MH is characterised by incomplete separation of the PHM from the retina with remnants overlying the macula manifesting as ERM. Removal of the ERM is required during vitrectomy in order to relieve the tangential forces involved in the development of MH.

“…However, splitting can also occur within the cortical vitreous or within the ILL, resulting in basement membrane components being present within the detached posterior hyaloid membrane (cortical vitreous gel). 14 Aggregates of vitreous collagen or fragments of the ILL in the posterior hyaloid membrane may be seen as SVO when this is no longer attached to the inner surface of the retina. During PVD a ring of fibrous tissue becomes detached from the optic nerve and is frequently visible on the posterior hyaloid membrane; this structure, called the 'Weiss ring', is frequently visible seen as a large 'comma' or 'c-shaped' SVO.…”

Section: Svo With Pvdmentioning

confidence: 99%

Vitrectomy for primary symptomatic vitreous opacities: an evidence-based review

Ivanova

Jalil

Antoniou

et al. 2016

Eye

Floaters are a common ocular condition which form as a consequence of aging changes in the vitreous. Although in most patients the symptoms are minimal, they can cause significant impairment in vision-related quality of life in a small population of patients. Recently there has been an increase in awareness of the visual disability caused by floaters, and the evidence-base for treatment of this condition using small-gauge vitrectomy has increased. In this review, we define the term 'floaters' as symptomatic vitreous opacities (SVO). We suggest a classification dependent on the presence or absence of posterior vitreous detachment and discuss their pathogenesis and natural history. We review their impact on patients' quality of life related to visual function. We review the psychological factors that may have a role in some patients who appear to be affected by SVO to the extent that they pursue all options including surgery with all its attendant risks. We summarise the available evidence-base of treatment options available for SVO with special emphasis on the safety and efficacy of vitrectomy for this condition.