Dispersion of retinal pigment epithelial cells from experimental retinal holes

An endoscopic overview of the anterior vitreous base in retinal detachment and anterior proliferative vitreoretinopathy

PURPOSE

Anterior proliferative vitreoretinopathy (PVR) is an important cause of persistent or recurrent retinal detachment (RD). Endoscopy provides 360° panoramic viewing of the vitreous cavity and high-magnification viewing of the anterior vitreous base (AVB). This study describes the 'in vivo' anatomy and pathoanatomy of the AVB using an ocular endoscope in RD and anterior PVR.

METHODS

An intraoperative analysis of over 2000 consecutive eyes undergoing vitrectomy for RD operated with endoscopy-assisted vitrectomy was performed. It was recorded in notes dictated during surgery and in standardized operative reports. Around 1500 surgical videotapes, with the exclusion of diabetic retinopathy and trauma, selected by reviewing the OR reports and notes were retrospectively reviewed.

RESULTS

Seven endoscopic criteria associated with anterior PVR complicating RD are described: 'en bloc' stiff anterior vitreous retraction, ciliary detachment, seeding of the AVB by abundant pigmented and/or white granulations, anterior tissue displacement, stiff 'wrinkling' at the vitreoretinal juncture, persistent shallow ciliary/RD under perfluorocarbon liquids and traction-related retinal surface haemorrhages. Causes responsible for failure of conventional vitrectomy for RD are highlighted. Findings in case of hypotony and cyclitic membranes are described.

CONCLUSIONS

Endoscopy is a significant adjunct to our understanding of the development of anterior loop traction by obviating the two constitutive parts of the AVB, anterior and posterior, their interconnections and their respective connections to the anterior segment and to the retina. It provides a unique evaluation and thorough eradication of the anterior vitreous cortex as a scaffold for anterior PVR. It might be an adjunct to the prevention of anterior PVR.

Treatment of retinal breaks with autologous serum in an experimental model

PURPOSE

The standard treatment for retinal breaks is thermal adhesion. Breaks in the posterior pole (i.e., macular holes) recently have been treated using vitrectomy and the recombinant cytokine transforming growth factor-beta. This has been shown to achieve closure of the retinal breaks by stimulating localized fibrocellular proliferation. Serum has been shown to contain chemoattractants and mitogens for many types of cells. The authors studied the clinical and histologic effect of autologous serum application to retinal breaks in an experimental model.

METHOD

Twenty-four rabbits underwent pars plana lensectomy, vitrectomy, retinectomy, fluid-air exchange, application of test solution (12 with Hank's buffered salt solution and 12 with autologous serum), and air-gas exchange. Clinical examination with indirect ophthalmoscopy was performed, and animals were killed 5, 14, and 28 days after treatment. Tissue sections through the retinectomy were studied by light microscopy, electron microscopy, and immunocytochemistry.

RESULTS

None of the serum-treated eyes showed retinal detachment at the site of the retinectomy by evaluation with indirect ophthalmoscopy at each of the time points. In contrast, in control eyes retinal detachment developed at the retinectomy site from 0% at day 5 to 50% at day 14 and 75% at day 28. By light microscopy, serum-treated eyes contained multilayers of fibroblast-like cells adhering the retinectomy edges to the underlying retinal pigment epithelium and choroid. The control eyes had nonadherent retinal edges at the retinectomy site with little sign of fibrocellular response. Results were confirmed by electron microscopy. The fibroblast-like cells by immunocytochemistry contained vimentin, cytokeratin 18, and/or glial fibrillary acidic protein.

CONCLUSION

This study suggests that serum induces a localized fibrocellular response at the retinectomy edges compared with control eyes. This response, characterized by light microscopy, electron microscopy, and immunocytochemistry, appears to involve a mixed population of glial, retinal pigment epithelial, and/or fibroblastic cells. These cells seem to enhance adhesion and subsequent reattachment of the edges of the retinectomies at the time points studied when compared with controls.