effect; the mechanism of this is unknown but is associated with prolongation of the QT interval.3 There is little doubt that in the two cases reported here amiodarone exerted an antiarrhythmic effect within a few hours of the first oral dose. Possibly previous treatment with other antiarrhythmic agents had in some way sensitised the myocardium to the effects of amiodarone. The prolongation of the QT interval suggests that in our patients oral amiodarone produced an acute pharmacological effect similar to that seen after intravenous administration. Our observations cannot be explained on the basis of current knowledge of the pharmacokinetics of oral amiodarone and highlight the need for further investigation of its mode of action. IRosenbaum MB, Chiale PA, Halpern MS, et al. Clinical efficacy of amiodarone as an antiarrhythmic agent. Am J Cardiol 1976;38:934-44. 2 Vaughan Williams EM. The discovery of the anti-arrhythmic action of amiodarone. In: Amiodarone in cardiac arrhythmias. London: Royal Society of Medicine, 1978:1-11. (International Congress and Symposium Series, No 16.) 3 Marcus FI, Fontaine GH, Frank R, Grosgogeat Y. Clinical pharmacology and therapeutic applications of the antiarrhythmic agent, amiodarone.

SUMMARYEthmoidal sinnses intervening between the lacrimal sac and the nose can cause confusion when performing a dacryocystorhinostomy (OCR). This study aimed to assess the frequency of entry into ethmoidal sinuses when performing a OCR and to identify any helpful distinguishing features, at surgery, between the ethmoi dal and nasal spaces. Ethmoidal sinuses were initially entered in 23 of 50 standard OCRs (46%) in which the ostium was formed via the lacrimal fissure. Nasal mucosa was found to be 2 to 3 times thicker than ethmoidal sinus mucosa and less friable. Being aware of the risk of entering an ethmoidal sinus and of the anatomical differences between ethmoidal and nasal tissue greatly aids location during surgery and allows edge-to-edge suturing of sac mucosa to nasal mucosa in all cases.For a successful dacryocystorhinostomy (DCR) it is important to make an adequate ostium into the nose.Indeed it is recommended that all bone between the lacrimal sac and the nasal mucosa be removed, such that no bone is left within 5 mm of the common canaliculus. Thus following DCR, the sac and duct should no longer exist as separate anatomical structures but instead be incorporated into the nose.1 For this to be achieved the surgeon has to be able to identify his or her exact anatomical location at all steps of the operation. One cause for failure of a DCR is making an opening into an ethmoidal sinus rather than the nose and anastomos ing the lacrimal sac to ethmoidal sinus mucosa.1,2 In this study we observed how frequently, when making the ostium, an ethmoidal sinus was initially entered using a standard DCR technique? We also compared nasal and ethmoidal mucosa and found that the For illustrative purposes we biopsied the mucosa in six representative cases. RESULTSAn ethmoidal sinus was entered initially in 23 of the 50 consecutive adult cases (46%). Macroscopically the ethmoidal mucosa was seen to be much thinner and more friable than nasal mucosa, in every case.

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Aims-To describe a method of securi indwelling O'Donohughe's lacrimal tul in dacryocystorhinostomy using two 3 mm Watski sleeves Methods-The operative technique us to secure the sleeves into position on 1 lacrimal tubes is described. Forty sev procedures with a follow up ranging fr( 3 to 30 months (mean 10 months) E reviewed. Results-The tubes and sleeves were M tolerated. Upward prolapse of the tul occurred only once and the tubes wt easily repositioned in this case. Conclusion-Securing lacrimal tul with Watski sleeves in dacryocystorhii stomy is a simple, cheap, and effect procedure. (BrJ Ophthalmol 1995; 79: 664-666) Dacryocystorhinostomy and canalictu surgery provide a very high rate of perman relief of the watery eye, with a failure rate of] than 10% of cases.