Screening for glaucoma in a Brisbane general practice — the role of tonometry

Objectives: (1) To pilot, and evaluate, a tonometry training intervention for general practitioners; (2) to evaluate the efficacy of three types of tonometer (Perkins, Schiotz and Tonopen) in the hands of these general practitioners; (3) to evaluate the predictive value of tonometry in screening for glaucoma in a general practice population; and (4) to evaluate the acceptability of tonometry to general practice patients. Design: After being trained, three general practitioners recruited 73 of their patients over 50 years of age to attend for measurement of intraocular pressure by tonometry. Intraocular pressure was initially measured by an ophthalmologist using the Goldmann applanation tonometer, and then recorded in random order by GPs using three types of tonometer — the Perkins, Schiotz and Tonopen. Setting: A group general practice in a middle-class suburb in southern Brisbane. Outcome measures: (1) Comparison of measurements on the Perkins, Schiotz and Tonopen tonometers with that of the ‘gold standard’, the Goldmann Applanation tonometer; (2) Prevalence of disc and perimetric abnormality suggestive of glaucoma among those patients with increased intraocular pressure; and (3) the acceptability of contact tonometry to general practice patients. Results: There was considerable variability between intraocular values obtained across doctors and across instruments (6% to 95% of values within 4 mm of the ‘gold standard’). The Schiotz tonometer provided the most uniform assessment of intraocular pressure across the groups. Nineteen of the 73 patients (26%) had intraocular pressures ≥21 mmHg using the ‘gold standard’. Of these, 18 were followed up with funduscopy, gonioscopy, repeat measurement of intraocular pressure and visual field assessment. Five had persistent elevations of intraocular pressure ≥21 mmHg on subsequent assessment, and two had mild abnormalities of cup—disc ratio with normal fields on testing with Humphrey computerised perimetry. Conclusion: No one hand-held tonometer proved highly accurate in the hands of all three doctors. Even measured optimally, increased intraocular pressure alone was a poor predictor of glaucoma. Of the population screened, two patients (3%) showed evidence of mild cup-disc abnormality requiring follow-up.     

Pre-operative Predictors of Weight Loss at 1-Year after Lap-Band® Surgery

Background: The authors studied a range of preoperative factors for their predictive value of effectivenes of Lap-Band? placement, using the percentage of excess weight loss at 1-year as the outcome measure (%EWL1). Methods: All factors were measured and recorded prior to surgery. Factors included: patient demographics, family, medical and weight history. Laboratory measures and the responses to the SF36 Health Survey were also assessed. Factors were assessed for correlation with %EWL1. Results: The group (N=440, F:M 383:57) had mean age 40.0 ± 9.5 years, weight of 126 ± 25 kg, and BMI 45.6 ± 7.5 kg/m2 pre-operatively. At 1-year follow-up, the group had mean weight 97.6 ± 20 kg, BMI 35.6 ± 6.3 kg/m2, and %EWL1 45.8 ± 17%. Increasing age (R=-0.13, p<0.01) and preoperative BMI (R=-0.22, p<0.001) were significantly associated with less %EWL1 and all other factors were controlled for these before assessing significance. Important factors associated with a lower %EWL1 included: hyperinsulinemia (R=-0.36, p<0.001), insulin resistance (R=-0.33, p<0.001) and disease associated with insulin resistance, poor physical ability, pain, and poor general health responses to the SF-36 Health Survey. Patients who consumed alcohol regularly had a better rate of weight loss (R= 0.23, p<0.005). Factors that had no influence included gender, a history of mental illness and measures of mental health, previous bariatric surgery, and a history of many medical conditions associated with obesity. Conclusion: Important physical factors have been found to influence the rate of weight loss.Those with increased age, pain, physical disability and insulin resistance have a great deal to gain from weight loss. Although this study has identified factors that are associated with less weight loss, we have not found any factor that predicts an unacceptably low weight loss and thus provides a contraindication to Lap-Band? placement. The findings of this study allow us to set more realistic goals for the rate of weight loss in specified sub-groups of our patients.