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C.H. Karabatsas, European Glaucoma Panel Group; Central Corneal Thickness (CCT) Is Not Correlated With Intraocular Pressure (IOP) Change When Switching Between Treatments . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4428.
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© ARVO (1962-2015); The Authors (2016-present)
To study whether absolute change in intraocular pressure (IOP) when switching between treatments is correlated with central corneal thickness (CCT).
This was a multicentric randomized, double masked clinical trial in 7 Europen centers. A total of 200 glaucoma or ocular hypertension patients participated. Included were patients who were controlled (IOP <22 mmHg) on the unfixed combination of Latanoprost and Timolol for at least 3 months prior to the baseline visit, or uncontrolled patients on monotherapy either with Latanoprost or Timolol who were eligible for dual therapy. The last group of patients underwent a 6 weeks wash–in phase with the non–fixed combination of Latanoprost and Timolol before baseline IOP determination and inclusion into the study. By randomization, 101 patients were switched to Bimatoprost and 99 patients were switched to Latanoprost/ Timolol fixed combination. IOP was measured at 20:00, 24:00, 05:00, 08:00, 12:00 and 16:00 hours in each visit. IOP values from baseline visit and at 12 weeks follow up visit were analyzed. For the purpose of this report 194 eyes with complete data were considered ( 99 patients on Bimatoprost and 95 patients on Latanoprost/Timolol fixed combination). CCT measurements were done prior to randomization. The mean IOP curve was used in the calculations at three time periods: total (24hour curve), daytime and nighttime. Spearman correlation coefficient was estimated for testing the correlation between CCT and absolute IOP change between baseline and week 12. In addition graphical displays were produced where the line between the plotted values was a linear regression line using the model y=a+bx. P values were considered significant when less than 0.05.
None of the correlation coefficients were statistically significant for all groups (total n=194, Bimatoprost group n=99 and Latanoprost/Timolol group n=95) and for all time periods (24–hour curve, daytime and nighttime). In graphical displays only a single graph for nighttime values in the Latanoprost/Timolol fixed combination group reached marginal significance (p=0.046).
The absolute change in IOP after switching between treatments seems to be independent of the CCT.
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