Epiphora : impact on vision, outcome of lacrimal surgery and investigations with ultra-high-frequency ultrasound

Sammanfattning: Epiphora is a common condition that often receives little attention. Excessive tear production creates an irregular and ever-changing ocular surface, affecting refraction and reducing vision. However, in a standard test situation the visual acuity is seldom affected, leading to the misinterpretation that epiphora is a minor problem. Patients report social discomfort as a result of red eyes and constant eye wiping, and the misperception that they are sad or crying. The aims of the present studies were to quantify the functional visual disability experienced by patients with epiphora, to survey current management practices, and to present the long-term outcome of two lacrimal drainage procedures. In addition, a novel imaging technique, ultra-high-frequency (UHF) ultrasound, was used to visualize the upper lacrimal drainage anatomy and the lacrimal pump. Limitations on activities in daily life due to visual disability have long been recorded in the Swedish National Cataract Register and used as an outcome measure. The tool used, a questionnaire named Catquest-9SF, was validated in this study for epiphora patients, and their visual disability was found to be in parity with those of patients awaiting cataract surgery in their second eye (Paper I). A survey of current management practices in the Nordic countries regarding acquired lacrimal drainage obstruction (ALDO) indicated that canaliculodacryocystoplasty (CDCP) is used when treating obstructions below the lacrimal sac (Paper II), a practice less common elsewhere. However, approximately half of patients with multiple obstructions or nasolacrimal duct obstructions (NLDO) treated with CDCP require additional surgery due to the recurrence of obstruction (Paper III). This proportion is significantly higher than when stenosis is confined to the canaliculi. There is no consensus regarding the use of silicone stent intubation in conjunction with dacryocystorhinostomy (DCR). The duration of intubation has received little attention as a factor contributing to outcome. A 97% long-term success rate was found with a comparatively short intubation duration of one week (Paper IV). This shows that a high success rate is possible with a one-week intubation period. I suggest that there may be an optimal duration of intubation, with which the possible positive effects are achieved while the negative effects minimized. Using UHF ultrasound and motion tracking, it was demonstrated that the motion of the lateral lacrimal sac wall is greatest in the anterior-posterior direction during blinking (Paper V). This is in contrast to an existing theory regarding the mechanics of the lacrimal pump. In conclusion, the findings presented in this thesis suggest that epiphora should be recognized as a debilitating condition affecting everyday life, and that the use of CDCP to treat NLDO should be reconsidered in the Nordic countries, as it may be an inadequate form of treatment. Furthermore, a very high success rate is possible with a short duration of intubation in DCR. Finally, the current theory regarding the lacrimal pump should be re-evaluated.