Basic sciences are the key to the comprehension and management of lacrimal system disorders in a right perspective. Electron microscopy adds one such dimension to this perspective. Ultrastructural features of lacrimal system and its disorders are sparsely documented in the literature.1–8 Most of the studies used combinations of scanning (SEM) and transmission electron microscopic (TEM) techniques. The earliest detailed work was by Radnot in 19721 followed by Adenis in 19802 and series of landmark papers later by Paulsen.3,4 The entire lacrimal system has been recently revisited and mapped using the SEM.5 The earlier papers predominantly focused on the TEM features of the cilia, their distribution and possible functions.1,2 Mechanisms of tear outflow and acquired lacrimal obstructions were proposed based on a few ultrastructural studies on functional anatomy of lacrimal sac epithelium and cavernous body of the lacrimal sac and nasolacrimal duct.3,4
The basic pathogenesis of punctal stenosis at an ultrastructural level was found to be chronic inflammation, increased recruitment of fibroblasts with irregular laying of collagen and subsequent fibrosis. Mononuclear inflammatory infiltrate mostly restricted to areas around fibroblasts could represent close cellular interactions which may influence the pathogenesis. Similarly TEM studies on the dacryocystorhinostomy scars demonstrated bony ingrowths with metabolically active osteoblasts and provided useful insights into the post-surgical healing.
The study of biofilms on lacrimal stents in the recent past has given newer insights into possible infections and chronic inflammation, both of which could be detrimental to the outcomes of surgery. Subsequent focused biofilm studies on different segments of the stents, intraluminal features, biofilm quantification and behaviors following prolong retention of stents have added to the knowledge and insights into possible physical modifications to the existing stents.6
Ultrastructural effects of mitomycin C (MMC) on nasal mucosa using varying techniques have been studied by very few.7,8 The ultrastructural effects have been classified based on their effects on various components of nasal mucosa like epithelial, glandular, vascular and collagenous tissues and documented the differences between topical applications versus circumostial injection of MMC (COS-MMC).8
All these electron microscopic studies have further enhanced our understanding at sub cellular levels and contributed to generation of newer ideas in an effort to demystify the pathogenesis of obstructions in the drainage pathways, intra-operative use of adjuncts and post-operative wound healing. The challenge of the future is to take the pathogenesis and management of lacrimal disorders a notch higher and electron microscopy will play a major supportive role in this quest.
References
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