Central corneal thickness and intraocular pressure measures in human corneas with endothelial guttata: an observational quality control study

Abstract

Purpose:The aim of the present study was to assess central corneal thickness (CCT) and intraocular pressure (IOP) in eyes where the corneas were affected by different degrees of severity of endothelial pseudo-guttata or guttata. Methods: In a prospective, case series observational study, non-contact tonometry and non-contact specular microscopy (NCSM) with pachymetry for central corneal thickness measures were undertaken as routine procedures on predominantly older patients without a history of corneal problems or contact lens wear. For those showing any signs of corneal endothelial abnormalities, images of the central cornea endothelium were further processed to measure the area (as a percentage) occupied by the guttata. Results: Abnormal endothelial images were obtained from 43 patients (seven with bilateral changes) with an average age of 67.5 years. Between 1.5 and 54.9 per cent of the endothelial images were affected by guttata, which were assigned grade 1 (20 eyes), grade 2 (18 eyes) or grade 3 (11 eyes). When assessed by grade, the central corneal thickness increased and the measured IOP decreased as the guttata became more numerous and confluent. Regression analyses revealed only a weak association between central corneal thickness (p = 0.044, r = 0.149) or the measured IOP (p = 0.090, r = -0.244) and the extent of the guttata (percentage). With the apparently contrasting IOP and central corneal thickness effects, no significant IOP-CCT relationship was noted (p Ն 0.268, r Յ 0.160). Conclusions: Where corneas have mild-to-modest non-dystrophic endothelial guttata, there may be a less predictable effect of corneal thickness on the outcome of tonometry.

Peripheral nasal‐temporal corneal asymmetry in relation to corneal thickness: a Scheimpflug imaging study

“…Slit‐lamp biomicroscopy and anterior segment optical coherence tomography (OCT, Topcon 3D OCT2000, http://www.topconmedical.com) were used to confirm a healthy cornea and anterior segment. Non‐contact specular microscopy (Topcon SP2000) was performed to ensure there were no notable corneal endothelial abnormalities . The study adhered to the tenets of the Declaration of Helsinki and the protocol was approved at the respective institutional ethical review boards at Glasgow Caledonian University and the University of Valladolid.…”

Assessment of the reliability of endothelial cell-density estimates in the presence of pseudoguttata

“…This number, of 45 complete cells/image, is somewhat arbitrary but was selected after consideration of several factors. First, and foremost, single endothelial images affected by moderateto-severe (pseudo)guttata are unlikely to include the 75 to 100 complete cells [10] that are often recommended for routine ECD assessments in non-guttate endothelia [6]. It could be argued that a simple solution to such a problem would be that more than one image should be taken, e.g., of the central corneal region, ensuring that there was no substantial overlap between the images.…”

“…These dark (as opposed to light-reflective regions in specular microscopy or confocal microscopy) can be generally referred to as corneal (endothelial) guttata or pseudoguttata. True corneal guttata would generally be considered as being associated with a progressive endothelial dystrophy (e.g., Fuch's), while pseudoguttata can have similar appearances but be due to other reasons and have no obvious familial link [10][11][12][13][14]. Regardless of the reliability of being able to define the cause of endothelial guttate changes, there have been a variety of studies of the endothelial cell density in corneas affected with guttata or pseudoguttata [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”