Mechanical testing of lid speculae and relationship to postoperative ptosis.

AIMS: Postoperative lid malpositions are known complications of routine intraocular surgery and were previously attributed to the use of a bridle suture or the myotoxic effect of retrobulbar or peribulbar anaesthetics. However, lid malpositions are still seen under topical anaesthesia. Recent studies have implicated the lid speculum as a factor. Patients with narrower vertical palpebral apertures have been shown to develop postoperative ptosis more frequently, but the reason is unknown. This is the first study to determine the forces exerted by lid speculae over a range of palpebral apertures. METHODS: Mechanical testing was undertaken using a Bose 3200 materials testing machine. Tests were undertaken on four disposable and four reusable speculae. The force used to compress each speculum was compared over a range of displacements. A two-sample t-test was used to compare the stiffness of the two types of speculum. RESULTS: The stiffness of the reusable speculum was significantly greater than the disposable speculum (P=0.002). The stiffness of each speculum was greatest at the range of displacement corresponding to the narrower palpebral apertures. CONCLUSIONS: Different speculae exert significantly different forces on patients' eyelids during surgery. The patients who experience the greatest compression from the speculae are those with the smallest palpebral apertures. This may explain why these patients are more likely to develop postoperative lid malpositions.

Amantadine for dyskinesia in Parkinson's disease.

BACKGROUND: Abnormal involuntary movements known as dyskinesias are amongst the most disabling side-effects of levodopa therapy. It is thought that amantadine, an NMDA-receptor antagonist, may reduce dyskinesias in patients with Parkinson's disease without worsening Parkinsonian symptoms. OBJECTIVES: To compare the efficacy and safety of adjuvant amantadine therapy versus placebo in treating dyskinesia in patients with Parkinson's disease, already established on levodopa, and suffering from motor complications. SEARCH STRATEGY: Electronic searches of The Cochrane Controlled Trials Register (The Cochrane Library Issue 3, 2001), MEDLINE (1966-2001), EMBASE (1974-2001), SCISEARCH (1974-2001), BIOSIS (1993-2001), GEROLIT (1979-2001), OLDMEDLINE (1957-1965), LILACS (1982-2001), MedCarib (17th Century - 2001), PASCAL (1973-2001), JICST-EPLUS (1985-2001), RUSSMED (1973-2001), DISSERTATION ABSTRACTS (2000-2001), SIGLE (1980-2001), ISI-ISTP (1990-2001), Aslib Index to Theses (2001), Clinicaltrials.gov (2001), metaRegister of Controlled Trials (2001), NIDRR (2001) and NRR (2001) were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of amantadine were contacted. SELECTION CRITERIA: Randomised controlled trials comparing amantadine with placebo in the treatment of dyskinesia in patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS: Data was abstracted independently by NC and KD onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS: Three randomised controlled trials were found comparing amantadine with placebo in the treatment of dyskinesia in patients with idiopathic Parkinson's disease. Three trials were excluded on the basis that they had no control group and a further three did not state whether they randomised the treatment that participants received. The included trials were double-blind cross-over studies involving a total of 53 patients. All three studies failed to present data from the first arm, instead presenting results as combined data from both treatment arms and both placebo arms. Two trials had no wash-out interval between the treatment periods. In view of the risk of a carry-over effect into the second arm, the results of these trials were not analysed. The final trial had a one week wash-out interval but only examined 11 participants. One study reported side-effects of amantadine in 8 of the 18 participants, including confusion and worsening of hallucinations. Another reported reversible edema of both feet in one of eleven participants. REVIEWER'S CONCLUSIONS: Due to lack of evidence it is impossible to determine whether amantadine is a safe and effective form of treatment for levodopa-induced dyskinesias in patients with Parkinson's disease.

Beta-blocker therapy for tremor in Parkinson's disease.

BACKGROUND: The tremor of Parkinson's disease can cause considerable disability for the individual concerned. Traditional antiparkinsonian therapies such as levodopa have only a minor effect on tremor. Beta-blockers are used to attenuate other forms of tremor such as Essential Tremor or the tremor associated with anxiety. It is thought that beta-blockers may be of use in controlling the tremor of Parkinson's disease. OBJECTIVES: To compare the efficacy and safety of adjuvant beta-blocker therapy against placebo for the treatment of tremor in patients with Parkinson's disease. SEARCH STRATEGY: Electronic searches of MEDLINE, EMBASE, SCISEARCH, BIOSIS, GEROLIT, OLDMEDLINE, LILACS, MedCarib, PASCAL, JICST-EPLUS, RUSSMED, DISSERTATION ABSTRACTS, SIGLE, ISI-ISTP, Aslib Index to Theses, The Cochrane Controlled Trials Register, Clinicaltrials.gov, metaRegister of Controlled Trials, NIDRR, NRR and CENTRAL were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of beta-blockers were contacted. SELECTION CRITERIA: Randomised controlled trials of adjuvant beta-blocker therapy versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS: Data was abstracted independently by two of the authors onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS: Four randomised controlled trials were found comparing beta-blocker therapy with placebo in patients with idiopathic Parkinson's disease. These were double-blind cross-over studies involving a total of 72 patients. Three studies did not present data from the first arm, instead presenting results as combined data from both treatment arms and both placebo arms. The risk of a carry-over effect into the second arm meant that these results were not analysed. The fourth study presented data from each arm. This was in the form of a mean total score for tremor for each group. Details of the baseline scores, the numbers of patients in each group and standard deviations were not provided, meaning that the magnitude and significance of any changes due to therapy could not be calculated. One study reported a substantial fall in heart rate in 14 of the 22 patients, with one patient withdrawing after his heart rate dropped to 56 beats per minute (baseline heart rate was not reported). REVIEWER'S CONCLUSIONS: In view of this lack of evidence, it is impossible to determine whether beta-blocker therapy is effective and safe for the treatment of tremor in Parkinson's disease. The high frequency of bradycardia in one trial raises some concerns about the prescription of beta-blockers to normotensive elderly patients but the study was too small for the true degree of risk to be calculated.