Aplication of <i>in Vivo</i>Confocal Microscopy in Ophtalmology—Overview

Confocal microscopy is a method which has been increasingly used over the last decade in the study of the anterior ocular surface. The method allows testing and in vivo high resolution imaging of the structures of the anterior eye segment, at a cellular level, which is close to the histological examination of tissues. The data provided by this method allow for a better understanding of both the functional and pathological processes occurring in the anterior ocular surface not only for scientific purposes but also in clinical practice. The aim of the present work is to summarize the current knowledge and applications of confocal microscopy of the anterior ocular surface.

Optical Coherence Tomography Parameters in Preperimetric Open-Angle Glaucoma

Purpose: To evaluate the measurements of the peripapillary retinal neurofiber layers (RNFL) and the ganglion cells complex (GCC) obtained by Optical Coherence Tomography (OCT) in eyes with preperimetric open-angle glaucoma. Methods: One hundred and forty eyes of 75 patients (21 male and 54 female), 80 eyes with preperimetric glaucoma (PPG) (45 patients) and 60 normal eyes (30 subjects) were included in this study. Automated visual field examination was done to all participants using Humphrey field analyzer, program 30-2. The GCC thickness and peripapillary RNFL thickness were measured using RTVue-100 (Optivue, Inc., Fremont, CA). The areas under ROC (receiver operating characteristic)—curves (AUCs) were defined for all examined GCC and RNFL parameters. Results: GCC of the eyes with PPG was significantly thinner than GCC of the normal eyes: (89.58 vs 97.82 microns, P < 0.001). There was no significant difference between upper and lower GCC halves in both study groups. We found a reduction of RNFL thickness in glaucomatous eyes (P < 0.001) compared with normals. AUCs for GCC parameters in eyes with PPG were larger than AUCs for RNFL parameters. Conclusion: Our study showed that the peripapillary RNFL and GCC thickness are lower in preperimetric glaucoma than in normal eyes. Despite the fact that GCC measurements (especially GLV) show better AUC than peripapillary measurements, we suggest that two scans (GCC and ONH) put together are superior in detecting early structural glaucomatous damage. Several diagnostic parameters should be considered in the clinical diagnosis of preperimetric glaucoma.

Anterior Segment Optical Coherence Tomography Indices and Their Value in Diagnosing Corneal Ectasia

Purpose: To determine the diagnostic value of the anterior segment optical coherence tomography (AS-OCT) indices in differentiating normal from ectatic corneas. Material and Methods: Two groups of patients—with corneal ectasia and normal controls were compared. Each group consists of 80 eyes of 43 age and sex-matched patients. All of them underwent corneal topography with OCULUS Keratograph 5M and corneal pachymetry with AS-OCT with RTVue-100. The indices generated by the AS-OCT pachymetric scans were analyzed. Results: There was a statistically significant difference for all the examined indices between the two groups with p values <0.001 and a confidence interval of 95%. The minimal corneal thickness (Min) was the best performing index according to the ROC analysis with an area under the curve of 0.976 and a combination of sensitivity and specificity of 0.925 and 0.911 respectively, and a “cut-off” value of 484 microns, followed by the indices of focal thinning—Min-Med and Min-Max with an area under the curve of 0.973 and 0.971 and sensitivity/specificity of 0.938/0.962 and 0.938/0.937 respectively. The rest of the examined parameters had an area under the curve in the range between 0.950 for the central corneal thickness and 0.814 for the outer superior segment. Conclusion: The anterior segment OCT indices showed excellent capability in differentiating ectatic from normal corneas.