ABSTRACT
BACKGROUND: Central corneal thickness (CCT) can be measured by using contact and non-contact methods. Ultrasound pachymetry (US pachymetry) is a contact method for measuring CCT and is perhaps the most commonly used method. However, non-contact methods like scanning slit topography (Orbscan II), slit-lamp optical coherence tomography (SL-OCT), and specular microscopy are also used. Not many studies have correlated the measurement of CCT with all four modalities. The purpose of this study was to compare and correlate the CCT measurements obtained by US pachymetry with SL-OCT, specular microscopy, and Orbscan. METHOD: This is a prospective, comparative study done in an institutional setting. Thirty-two eyes of 32 subjects with no known ocular disease and best-corrected visual acuity of 20/20 were enrolled. CCT measurements were obtained using SL-OCT, specular microscopy, scanning slit topography (Orbscan), and US pachymetry. Three measurements were made with each instrument by the same operator. Mean, standard deviation, and coefficient of variation were calculated for CCT measurements acquired by the four measurement devices. Bland-Altman plot was constructed to determine the agreements between the CCT measurements obtained by different equipment. RESULTS: The mean CCT was 548.16±48.68 µm by US pachymetry. In comparison, CCT averaged 546.36±44.17 µm by SL-OCT, 557.61±49.92 µm by specular microscopy, and 551.03±48.96 µm by Orbscan for all subjects. Measurements by the various modalities were strongly correlated. Correlations (r (2)) of CCT, as measured by US pachymetry compared with other modalities, were: SL-OCT (r (2)=0.98, P<0.0001), specular microscopy (r (2)=0.98, P<0.0001), and Orbscan (r (2)=0.96, P<0.0001). All modalities had a linear correlation with US pachymetry measurements. CONCLUSION: In subjects with healthy corneas, SL-OCT, specular microscopy, and Orbscan (with correction factor) can be used interchangeably with US pachymetry in certain clinical settings. The four modalities showed significant linear correlations with one another.
ABSTRACT
The development of optical coherence tomography (OCT) technology has helped to usher in a new era of in vivo diagnostic imaging of the eye. The utilization of OCT for imaging of the anterior segment and ocular surface has evolved from time-domain devices to spectral-domain devices with greater penetrance and resolution, providing novel images of anterior segment pathology to assist in diagnosis and management of disease. Ocular surface squamous neoplasia (OSSN) is one such pathology that has proven demonstrable by certain anterior segment OCT machines, specifically the newer devices capable of performing ultra high-resolution OCT (UHR-OCT). Distinctive features of OSSN on high resolution OCT allow for diagnosis and differentiation from other ocular surface pathologies. Subtle findings on these images help to characterize the OSSN lesions beyond what is apparent with the clinical examination, providing guidance for clinical management. The purpose of this review is to examine the published literature on the utilization of UHR-OCT for the diagnosis and management of OSSN, as well as to report novel uses of this technology and potential directions for its future development.
Subject(s)
Conjunctival Neoplasms/pathology , Eye Neoplasms/pathology , Neoplasms, Squamous Cell/pathology , Tomography, Optical Coherence/methods , Conjunctival Neoplasms/therapy , Eye Neoplasms/therapy , Humans , Neoplasms, Squamous Cell/therapyABSTRACT
PURPOSE: To evaluate the repeatability and comparability of anterior chamber depth (ACD) and central corneal thickness (CCT) measurements obtained by Galilei dual Scheimpflug analyzer (Ziemer, Port, Switzerland) and slit-lamp optical coherence tomography (SL-OCT; Heidelberg Engineering, Dossenheim, Germany). METHODS: ACD and CCT were measured by Galilei and SL-OCT in 68 eyes of 68 healthy young subjects. Each measurement was performed 3 times by a single examiner, and the repeatability of 3 consecutive measurements was analyzed. ACD and CCT measurements were compared between the 2 devices. RESULTS: Both Galilei and SL-OCT showed high repeatability (ICCs > or = 0.994) for ACD and CCT measurements. The mean ACD and CCT measured by Galilei were greater than SL-OCT measurements by 0.11 +/- 0.09 mm and 14.01 +/- 7.38 microm, respectively. The 95% limit of agreement values for ACD and CCT measurements were 0.36 mm, 27.66 microm, respectively, and were highly correlated (correlation coefficients > or = 0.89, p < 0.001). CONCLUSIONS: Although the repeatability of each device was high, ACD and CCT obtained by Galilei and SL-OCT were significantly different. These differences should be considered when interpreting ACD and CCT measurements obtained by the 2 devices.
Subject(s)
Anterior Chamber , Eye , Tomography, Optical CoherenceABSTRACT
Objective To explore the agreement of anterior chamber angle examination by slit lamp optical coherence tomography (SL-OCT) and gonioscope.Design Case series.Participants Thirteen patients with primary glaucoma (26 eyes) and 8 normal persons(16 eyes).Methods Anterior chamber angle was measured with SL-OCT and gonioscope in turns for temporal,nasal,superior and inferior quadrant.Results of two methods were analyzed and the data were analyzed with Pearson correlation coefficient and Kappa value.Main Outcome Measures Anterior chamber angle.Results The Pearson correlation coefficient of the two methods was 0.86(P=0.00)and the Kappa value is 0.75 (P=0.00).The specificity and sensitivity of detecting occludable angle were 94.7% and 89.4%.Conclusions Anterior chamber angle examination with SL-OCT and gonioscope are well consistent.The specificity and sensitivity for SL-OCT in detecting occludable angle is satisfying.SL-OCT can be regard as an objective assistant method for the diagnosis of angle closure glaucoma.
