Effect of Central Corneal Thickness on Dynamic Contour Tonometry and Goldmann Applanation Tonometry in Primary Open-angle Glaucoma

Abstract

To compare the dependence of dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) on central corneal thickness (CCT) in primary open-angle glaucoma. Methods: In a prospective study, the interocular (right vs left eye) difference in intraocular pressure measured by DCT and GAT was compared with the interocular CCT difference in 125 patients with primary open-angle glaucoma. Results: Dynamic contour tonometry measurements (mean±SD, 19.4±4.1 mm Hg) were significantly (P=.004) higher than GAT measurements (mean ± SD, 15.5 ± 3.4 mm Hg), correlating significantly with each other (r 2 =0.82, PϽ.001). The interocular difference in intraocular pressure correlated significantly with the interocu-lar CCT difference for GAT (r=0.30, P =.001) and DCT (r=0.23, P =.02) readings. Dynamic contour tonometry and GAT intraocular pressure differences significantly increased with older age (slope, 0.033 [95% confidence interval, 0.002-0.064] mm Hg/y; P=.03) but not with thicker CCT (slope, 0.006 [95% confidence interval, −0.003 to 0.017] mm Hg/µm; P =.22). Conclusions: In this series, GAT and DCT measurements were dependent on CCT in patients with primary open-angle glaucoma. Because intraocular pressure differences between DCT and GAT were independent of CCT, DCT and GAT are susceptible to similar measurement biases depending on CCT.

Comparative study of intraocular pressure measured by non-contact, rebound and goldmann applanation tonometer and their correlation with corneal thickness and true IOP in a general population

“…29 Although NCT is also widely used the correlation observed between measurements obtained using this type of tonometry and conventional applanation tonometry has never been particularly good (Vernon 1995 21,[30][31][32][33] Several studies have evaluated the RBT and most of these have detected slight overestimation with respect to GAT and a similar influence of corneal thickness on its [34][35][36][37] Studies conducted by (Grieshaber MC et al, Kamppeter BA et al, Kaufmann C et al) have reported a significant positive correlation between GAT and CCT which is similar to our findings. [38][39][40] On the other hand, studies conducted by Schneider E et al, Kniestedt C et al, Ku JY et al found no correlation between GAT values and central corneal thickness which is contrary to what we found. [41][42][43] Y.…”

Comparative study of intraocular pressure measured by non-contact, rebound and goldmann applanation tonometer and their correlation with corneal thickness and true IOP in a general population

“…29 Although NCT is also widely used the correlation observed between measurements obtained using this type of tonometry and conventional applanation tonometry has never been particularly good (Vernon 1995 21,[30][31][32][33] Several studies have evaluated the RBT and most of these have detected slight overestimation with respect to GAT and a similar influence of corneal thickness on its [34][35][36][37] Studies conducted by (Grieshaber MC et al, Kamppeter BA et al, Kaufmann C et al) have reported a significant positive correlation between GAT and CCT which is similar to our findings. [38][39][40] On the other hand, studies conducted by Schneider E et al, Kniestedt C et al, Ku JY et al found no correlation between GAT values and central corneal thickness which is contrary to what we found. [41][42][43] Y.…”

Comparison of dynamic contour tonometry with Goldmann applanation tonometry in glaucoma practice

“…No correlation was found between the difference between DCT and GAT measurements and CCT. This is in agreement with findings of previous studies (Pache et al 2005;Barleon et al 2006;Grieshaber et al 2007). Kotecha et al (2005) analysed treated and untreated eyes separately and found an association between the DCT-GAT difference and CCT and age in untreated eyes, but not in treated eyes.…”

Dynamic Contour Tonometry and Goldmann Applanation Tonometry: Correlation with Intracameral Assessment of Intraocular Pressure

“…A number of studies have confirmed that DCT overestimates IOP in comparison with GAT, but the differences range from 0.1 to 4.4 mmHg (18, 22). We found a mean difference of 4.0±1.6 mmHg, which is similar to the findings of Martinez-de-la-Casa et al (4.4±2.6 mmHg) and those of Grieshaber et al (3.9±2.3 mmHg) (22, 17). However, the mean difference found in these studies is considerably higher than that generally reported in the literature, usually within 2.5 mmHg (14, 23, 24).…”

Comparative study of intraocular pressure measured by non-contact, rebound and goldmann applanation tonometer and their correlation with corneal thickness and true IOP in a general population

“…29 Although NCT is also widely used the correlation observed between measurements obtained using this type of tonometry and conventional applanation tonometry has never been particularly good (Vernon 1995 21,[30][31][32][33] Several studies have evaluated the RBT and most of these have detected slight overestimation with respect to GAT and a similar influence of corneal thickness on its [34][35][36][37] Studies conducted by (Grieshaber MC et al, Kamppeter BA et al, Kaufmann C et al) have reported a significant positive correlation between GAT and CCT which is similar to our findings. [38][39][40] On the other hand, studies conducted by Schneider E et al, Kniestedt C et al, Ku JY et al found no correlation between GAT values and central corneal thickness which is contrary to what we found. [41][42][43] Y.…”

Comparison of dynamic contour tonometry with Goldmann applanation tonometry in glaucoma practice

“…No correlation was found between the difference between DCT and GAT measurements and CCT. This is in agreement with findings of previous studies (Pache et al 2005;Barleon et al 2006;Grieshaber et al 2007). Kotecha et al (2005) analysed treated and untreated eyes separately and found an association between the DCT-GAT difference and CCT and age in untreated eyes, but not in treated eyes.…”

Dynamic Contour Tonometry and Goldmann Applanation Tonometry: Correlation with Intracameral Assessment of Intraocular Pressure

“…A number of studies have confirmed that DCT overestimates IOP in comparison with GAT, but the differences range from 0.1 to 4.4 mmHg (18, 22). We found a mean difference of 4.0±1.6 mmHg, which is similar to the findings of Martinez-de-la-Casa et al (4.4±2.6 mmHg) and those of Grieshaber et al (3.9±2.3 mmHg) (22, 17). However, the mean difference found in these studies is considerably higher than that generally reported in the literature, usually within 2.5 mmHg (14, 23, 24).…”

Comparative study of intraocular pressure measured by non-contact, rebound and goldmann applanation tonometer and their correlation with corneal thickness and true IOP in a general population

“…29 Although NCT is also widely used the correlation observed between measurements obtained using this type of tonometry and conventional applanation tonometry has never been particularly good (Vernon 1995 21,[30][31][32][33] Several studies have evaluated the RBT and most of these have detected slight overestimation with respect to GAT and a similar influence of corneal thickness on its [34][35][36][37] Studies conducted by (Grieshaber MC et al, Kamppeter BA et al, Kaufmann C et al) have reported a significant positive correlation between GAT and CCT which is similar to our findings. [38][39][40] On the other hand, studies conducted by Schneider E et al, Kniestedt C et al, Ku JY et al found no correlation between GAT values and central corneal thickness which is contrary to what we found. [41][42][43] Y.…”

Comparison of dynamic contour tonometry with Goldmann applanation tonometry in glaucoma practice

“…No correlation was found between the difference between DCT and GAT measurements and CCT. This is in agreement with findings of previous studies (Pache et al 2005;Barleon et al 2006;Grieshaber et al 2007). Kotecha et al (2005) analysed treated and untreated eyes separately and found an association between the DCT-GAT difference and CCT and age in untreated eyes, but not in treated eyes.…”

Dynamic Contour Tonometry and Goldmann Applanation Tonometry: Correlation with Intracameral Assessment of Intraocular Pressure

“…A number of studies have confirmed that DCT overestimates IOP in comparison with GAT, but the differences range from 0.1 to 4.4 mmHg (18, 22). We found a mean difference of 4.0±1.6 mmHg, which is similar to the findings of Martinez-de-la-Casa et al (4.4±2.6 mmHg) and those of Grieshaber et al (3.9±2.3 mmHg) (22, 17). However, the mean difference found in these studies is considerably higher than that generally reported in the literature, usually within 2.5 mmHg (14, 23, 24).…”