The effect of corneal thickness on intraocular pressure measurement in patients with corneal pathology

Abstract

Background/aim: To compare intraocular pressure (IOP) measurements taken by the Goldmann applanation tonometer, the Tono-Pen and the ocular blood flow pneumotonometer in eyes with varying central corneal thickness (CCT) due to penetrating keratoplasty (PK), keratoconus (KC), and Fuchs' endothelial dystrophy (FED). Methods: IOP was measured with the Goldmann applanation tonometer, Tono-Pen XL, and OBF pneumotonometer in 127 eyes with the following corneal abnormalities. There were 56 eyes that had undergone PK, 37 eyes with KC, and 34 eyes with FED. CCT was measured using an ultrasound pachymeter after IOP determinations had been made. Results: Mean IOP measurements in all three patient groups were significantly higher when measured by OBF pneumotonometer. Linear regression analysis showed that patients with FED had a significant increase in IOP with increasing CCT of 0.18 mm Hg/10 mm using the Goldmann tonometer, 0.15 mm Hg/10 mm with the Tono-Pen, and 0.26 mm Hg/ 10 mm with the OBF pneumotonometer. In patients with KC and after PK, linear regression analysis did not show a significant effect of CCT on IOP. A multivariate linear regression model controlling for age, sex, graft size, and patient group, showed that the effect of CCT on IOP for Tono-Pen (0.13 mm Hg/10 mm CCT) and Goldmann (0.14 mm Hg/10 mm CCT) were significantly lower than for the OBF pneumotonometer (0.26 mm Hg/10 mm CCT). Conclusions: This study found that mean IOP measurements using the OBF pneumotonometer were significantly higher than those made using the Goldmann applanation tonometer or Tono-Pen in eyes with a variety of cornel pathologies. The OBF pneumotonometer was found to be most affected by variation in CCT. For all three instruments, the relation between IOP and CCT depended on the corneal pathology and was greatest for FED.

Purinergic dysregulation causes hypertensive glaucoma–like optic neuropathy

“…CCT measurement revealed that P2Y 6 KO mice showed thicker CCT at middle age. Many reports have suggested that IOP is positively correlated to CCT (67)(68)(69)(70)(71)(72)(73)(74)(75). Our present data demonstrated that mature adult P2Y 6 KO Figure 6.…”

Depth-Resolved Full-Field Measurement of Corneal Deformation by Optical Coherence Tomography and Digital Volume Correlation

“…In the present study, considering the relatively small thickness of the porcine cornea to the spatial resolution of the SS-OCT system, 24 3 -voxel sub-volumes with 50% overlap were used to perform DVC. This sub-volume size can enhance the strain spatial resolution; nevertheless, it increases strain noise level, as proposed in [45], where the noise level increases from around when the sub-volume size reduces from 36 3 to 24 3 .…”

“…Its structural integrity, shape and transparency are essential to maintain optical performance. Abnormalities in its composition or structure due to disorders or disease such as keratoconus, corneal dystrophy, glaucoma or mass lesions, to name a few, severely degrade vision [3][4][5][6][7]. Ablative laser surgery is widely used to correct refractive performance and improve visual acuity, with more than one million operations in the United States alone each year [8].…”

Espessura central da córnea e a medida da pressão intra-ocular com diferentes tonômetros

“…Para uso clínico, a leitura mais alta da PIO no TCDP deve ser considerada. Entretanto, as medidas como TCDP parecem não depender da ECC, corroborando alguns trabalhos (2)(3)(4)11,(13)(14) . Brusini e cols.…”