Rizwan Malik | PubMed Health

PubMed2006

Development and evaluation of a linear staircase strategy for the measurement of perimetric sensitivity.

Perimetric sensitivity of patients with glaucoma has traditionally been measured in logarithmic (dB) units, but linear sensitivity correlates better with conventional structural measures of glaucomatous damage. Monte Carlo simulations of perimetric algorithms were used to assess potential effects of logarithmic steps on bias and variability when perimetric sensitivity was represented in linear units, and to assess the potential benefits of algorithms using linear steps. Simulations predicted that linear staircases could reduce the sensitivity-dependence of bias, variability and efficiency. These predictions were supported by a perimetric study of 21 patients with glaucoma and 20 age-similar controls who made repeat visits over several weeks.

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PubMed2006

Refractory glaucoma--tube or diode?

BACKGROUND: The aim of the present study was to assess the relative effectiveness of tube surgery and cyclodiode laser in terms of achieving intraocular pressure control. METHODS: A retrospective study was undertaken to compare patients undergoing double plate Molteno tube implantation with patients undergoing diode cyclophotocoagulation. Intraocular pressure (IOP) was documented at 7 days prior to surgery and postoperatively at various time points. Surgical success was defined as a final IOP between 6 (inclusive) and 21 mmHg (inclusive), without the use of topical medication, while 'qualified' success was defined as IOP within the same range with the use of topical medication. RESULTS: Twenty-eight diode patients and 26 tube patients were included for the study. An average follow up of 150 weeks (range = 21-322 weeks) was available. Mean preoperative IOP was 37 +/- 12 mmHg for the tube group and 39 +/- 16 mmHg for the diode group (t = 0.51, P = 0.61). The final IOP was 17 +/- 12 mmHg for the tube group and 21 +/- 13 mmHg for the diode group (t = 0.35, P = 0.73). Surgical success was achieved in 46% of tube eyes and 11% of diode eyes, while qualified success was achieved in 81% of tube eyes compared with 64% of eyes in the diode group. Two eyes which underwent diode became phthisical. CONCLUSIONS: IOP control may be achieved in a greater number of patients with tube surgery. The possible benefits of IOP control in diode patients need to be weighed against the risks of long-term visual loss and the need for multiple re-treatments in this group.

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