Pathology of the lacrimal system and its treatment

© 2011 Dr. Alan A. McNabThe lacrimal system comprises the lacrimal glands, the tear film and the lacrimal drainage system (the lacrimal puncta, canaliculi, lacrimal sac and nasolacrimal duct). The lacrimal system is essential in maintaining a healthy ocular surface and therefore optimal visual function. This thesis presents a compilation of papers on the lacrimal system, its pathology and surgical treatment. The lacrimal system is subject to a wide variety of congenital anomalies, some with a clearly established genetic basis. This thesis commences with a small series of papers describing congenital anomalies of the lacrimal drainage system. The lacrimal glands comprise the main lacrimal gland and the accessory lacrimal glands. The main lacrimal gland is analogous to the salivary glands in terms of the range of pathological processes that occur within it. Several papers in this thesis are devoted to pathological entities occurring in the lacrimal gland. Infection within the lacrimal system is a common clinical entity. Two brief papers describe less common infections of the lacrimal system. The commonest cause of lacrimal drainage system obstruction is so-called Primary Acquired Naso-lacrimal Duct Obstruction (PANDO). However there is a large variety of secondary causes of lacrimal obstruction and the third section of the thesis presents several papers on this group of conditions. Tumours of the lacrimal outflow system are rare and their management presents a number of challenges. This thesis includes three significant publications on the pathology, clinical features and surgery of these rare tumours. The largest section of the thesis comprises papers published on various aspects of the surgical management of the lacrimal excretory system, including anaesthetic techniques, methods to reduce blood loss, secondary haemorrhage after dacryocystorhinostomy (DCR) and late failure of DCR. The final section of the thesis comprises reproductions of book chapters written on lacrimal surgery, which include sections on the management of more complex and challenging lacrimal cases where previous surgery has failed or where lacrimal obstruction occurs in the canalicular system. Their inclusion serves also to emphasise the importance of the role of the surgeon as educator