Free vibrations of a taut cable with an attached linear viscous damper are investigated in detail using an analytical formulation of the complex eigenvalue problem. This problem is of considerable practical interest in the context of stay-cable vibration suppression in bridges. An expression for the eigenvalues is derived that is independent of the damper coefficient, giving the range of attainable modal damping ratios and corresponding oscillation frequencies in every mode for a given damper location without approximation. This formulation reveals the importance of damper-induced frequency shifts in characterizing the response of the system. New regimes of behavior are observed when these frequency shifts are large, as is the case in higher modes and for damper locations further from the end of the cable. For a damper located sufficiently near the antinode in a given mode, a regime of solutions is identified for which the damping approaches critical as the damper coefficient approaches a critical value. A regime is developed to indicate the type of behavior in each mode for any given damper location.

The purpose of this study is to present the first report of a case of primary frosted branch angiitis from the UK and to review the characteristics of this rare disease. Primary frosted branch angiitis causes characteristic florid translucent retinal perivascular sheathing of both arterioles and venules in association with variable uveitis, retinal oedema and visual loss, normally with good recovery. A total of 57 cases have been reported in the world literature. Atypical, typically focal frosted branch angiitis may also occur secondary to other causes of intraocular inflammation, especially cytomegalovirus retinitis. Primary frosted branch angiitis has a characteristic presentation but a variable course, typically affecting children or young adults. The disease is likely to represent a common immune pathway in response to multiple infective agents. The optimal treatment is unclear.

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The uveitis casemix in this region reflects a predominantly white Caucasian population in a temperate country, but with changing characteristics owing to increasing immigration, enhanced diagnostic techniques, changes in referral pattern, and some real changes in disease incidence.

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SummaryThe varying clinical appearance within a group of 103 patients with Fuchs' Hetero chromic Uveitis (FHU) is discussed. Bilateral cases accounted for 7.8% of patients. Cataract was found in 80.2% of cases after 8.8 years mean follow-up, and glaucoma affected 26.2% of patients. The most important diagnostic criteria are the typical pattern of iris atrophy and depigmentation, the characteristic intraocular inflam mation, and complicated cataract. These are described in detail. The correct diag nosis of FHU is important because it affects future management and prognosis. The presence or absence of macroscopic heterochromia is not a helpful component of the ocular examination and should play little part in diagnosis. FHU does not necessarily present in its classical form, and may first resemble acute anterior uveitis or pars planitis. The syndrome may be the end stage of a number of different conditions.

Purpose To assess the effectiveness of anti-tuberculous treatment in patients with chronic uveitis and either active systemic or latent tuberculosis (TB) in a non-endemic community. Methods Retrospective study of patients with chronic uveitis, non-ocular evidence of latent or active TB and no other identified cause of uveitis who underwent a 6-month course of standard anti-tuberculous chemotherapy. Response to treatment was assessed at 6 and 12 months after initiation of treatment. Results A total of 27 patients were included of whom 59% were female. In all, 19 were Asian, 4 Caucasian, and 4 Black. More than half of patients had a history of contact with another person treated for TB. Inflammation resolved after chemotherapy in 70.3% of patients, 18.5% had a change in the nature of their inflammation and 11.1% had no benefit. Conclusions There were no uveitis features characteristic of TB uveitis and a wide range of manifestations was seen ranging from non-granulomatous anterior uveitis to occlusive retinal vasculitis. TB is not endemic in the United Kingdom, therefore consideration of ethnicity, immigration, and history of TB contact remain important to direct investigations. In a patient with uveitis and latent TB, a full 6-month course of antituberculous chemotherapy is recommended although it may not be curative of the uveitis.

A retrospective analysis was carried out of all patients attending the casualty department of Southampton Eye Hospital during 1 February to 31 July 1983. During the six month period 8092 patients made a total of 13 544 visits. Of these patients, 6178 were attending the hospital for the first time and 1914 had previously been seen in the outpatient clinic; many did not fall into the category of "accident and emergency." Some 37% of patients were managed by the ophthalmic nurse alone.The findings show that the department was providing a service far in excess of its defined function, which suggests that the structure of the acute ophthalmic services may require change. Certainly the value of the ophthalmic nurse was beyond question, her active participation in management allowing the doctor more time with the more complex clinical problems and thus enhancing efficiency. IntroductionThe casualty department at Southampton Eye Hospital provides a 24 hour service for acute ophthalmic conditions in south west