Artificial Intelligence-Based Approaches to Reflectance Confocal Microscopy Image Analysis in Dermatology

Reflectance confocal microscopy (RCM) is a non-invasive imaging method designed to identify various skin diseases. Confocal based diagnosis may be subjective due to the learning curve of the method, the scarcity of training programs available for RCM, and the lack of clearly defined diagnostic criteria for all skin conditions. Given that in vivo RCM is becoming more widely used in dermatology, numerous deep learning technologies have been developed in recent years to provide a more objective approach to RCM image analysis. Machine learning-based algorithms are used in RCM image quality assessment to reduce the number of artifacts the operator has to view, shorten evaluation times, and decrease the number of patient visits to the clinic. However, the current visual method for identifying the dermal-epidermal junction (DEJ) in RCM images is subjective, and there is a lot of variation. The delineation of DEJ on RCM images could be automated through artificial intelligence, saving time and assisting novice RCM users in studying the key DEJ morphological structure. The purpose of this paper is to supply a current summary of machine learning and artificial intelligence’s impact on the quality control of RCM images, key morphological structures identification, and detection of different skin lesion types on static RCM images.

In Vivo Confocal Microscopy Evaluation in Patients with Keratoconus

Keratoconus is the most common primary corneal ectasia characterized by progressive focal thinning. Patients experience increased irregular astigmatism, decreased visual acuity and corneal sensitivity. Corneal collagen crosslinking (CXL), a minimally invasive procedure, is effective in halting disease progression. Historically, keratoconus research was confined to ex vivo settings. In vivo confocal microscopy (IVCM) has been used to examine the corneal microstructure clinically. In this review, we discuss keratoconus cellular changes evaluated by IVCM before and after CXL. Cellular changes before CXL include decreased keratocyte and nerve densities, disorganized subbasal nerves with thickening, increased nerve tortuosity and shortened nerve fibre length. Repopulation of keratocytes occurs up to 1 year post procedure. IVCM also correlates corneal nerve status to functional corneal sensitivity. Immediately after CXL, there is reduced nerve density and keratocyte absence due to mechanical removal of the epithelium and CXL effect. Nerve regeneration begins after 1 month, with nerve fibre densities recovering to pre-operative levels between 6 months to 1 year and remains stable up to 5 years. Nerves remain tortuous and nerve densities are reduced. Corneal sensitivity is reduced immediately postoperatively but recovers with nerve regeneration. Our article provides comprehensive review on the use of IVCM imaging in keratoconus patients.

Corneal confocal microscopic characteristics of acute angle-closure crisis

Background To investigate characteristics of the acute angle-closure crisis (AACC) and fellow eyes using confocal microscopy. Methods Unilateral AACC patients hospitalized at the Xi’an People’s Hospital from October 2017 to October 2020 were recruited in this cross-sectional study. Age-matched participants scheduled for cataract surgery were enrolled as a healthy control group. Corneal epithelial cells, subepithelial nerve fiber plexus, stromal cells, and endothelial cells were examined by confocal and specular microscopy. Results This study enrolled 41 unilateral AACC patients (82 eyes) and 20 healthy controls (40 eyes). Confocal microscopy revealed that the corneal nerve fiber density, corneal nerve branch density and corneal nerve fiber length were reduced significantly in AACC eyes. The stromal cells were swollen and the size of the endothelial cells was uneven with the deposition of punctate high-reflective keratic precipitate on the surface. In severe cases, the cell volume was enlarged, deformed, and fused. The corneal subepithelial nerve fiber, stromal layer, and endothelial layer were unremarkable in the fellow eyes, and the density of the endothelial cells was 2601 ± 529 cells/mm2, which was higher than 1654 ± 999 cells/mm2 in AACC eyes (P < 0.001). Corneal edema prevented the examination of 17 eyes using specular microscopy and in only four eyes using confocal microscopy. There were no significant differences in endothelial cell density between confocal and specular microscopy in the AACC eyes (P = 0.674) and fellow eyes (P = 0.247). The hexagonal cell ratio reduced significantly (P < 0.001), and average cell size and coefficient of variation of the endothelial cells increased significantly compared with fellow eyes (P < 0.001, P = 0.008). Conclusions AACC eye showed decreased density and length of corneal subepithelial nerve fiber plexus, activation of stromal cells, increased endothelial cell polymorphism, and decreased density.

Histomorphological view of the cornea investigated by laser confocal microscopy in keratoplasty

Introduction. Corneal transplantation is the most successful and commonly performed allotransplantation procedure as compared with other organs and tissues. Over 100,000 corneal transplantations are performed worldwide every year.Purpose. This study investigated whether in vivo confocal microscopy (IVCM) can aid in the diagnosis of a graft rejection reaction by detecting changes in cellular structures and density of immune cells after penetrating keratoplasty.Materials and methods. The study included thirty-four eyes of 34 patients who underwent penetrating keratoplasty (7 eyes with corneal graft rejection, 27 without rejection). The average age of patients is 51.1 ± 13.6 years (from 23 to 76 years). The follow-up period ranged from 12 to 36 months (24.5 ± 4.84 months). Follow-up was performed at 1, 3, 6, 12 months and annually after PKP. To study the morphology of the cornea all patients underwent IVCM to assess the basal epithelium, subbasal layer, stroma and endothelium. Immune cells were identified and evaluated for the shape, length of the processes and their density.Results. Patients with corneal graft rejection demonstrated significant accumulation of corneal dendritic-like immune cells compared to patients with non-rejected grafts. In addition, the cells acquired a more mature morphology (grade 2–3). The density of dendritic cells (DC) was 809.17 ± 342.19 (p < 0.001). A positive correlation was found between DC density and graft rejection (p < 0.001). As well the patients showed signs of endothelial failure with low endothelial cell density and pleomorphism, increased light scattering and hyperreflectivity of the stroma.Conclusions. In a complex of diagnostic measures, confocal microscopy may provide a valuable clinical adjunctive tool in diagnosis and management of early corneal graft rejection.

In Vivo Confocal Microscopy of the Corneal Sub-Basal Nerve plexus in Medically Controlled Glaucoma

The present study investigated the corneal sub-basal nerve plexus (SNP) modifications in glaucoma. Ninety-five glaucomatous patients were enrolled and divided into Group 1 and 2, preserved and preservative-free mono-therapy (30 and 28 patients), and Group 3, multi-therapy (37). Thirty patients with dry eye disease (DED) and 32 healthy subjects (HC) served as controls. In vivo confocal microscopy evaluated the nerve fibers density (CNFD), length (CNFL), thickness (CNFT), branching density (CNBD), and dendritic cell density (DCD). CNFD, CNFL, and CNBD were reduced in Group 3 and DED compared to HC (p < 0.05). CNFL was reduced in Group 3 compared to Group 2 (p < 0.05), and in Group 1 compared to HC (p < 0.001). CNFD, CNBD, and CNFT did not differ between glaucomatous groups. DCD was higher in Group 3 and DED compared to HC and Group 2 (p < 0.01). Group 3 showed worse ocular surface disease index (OSDI) scores compared to Group 1, 2, and HC (p < 0.05). CNFL and DCD correlated with OSDI score in Group 3 (r = −0.658, p < 0.001; r = 0.699, p = 0.002). Medical therapy for glaucoma harms the corneal nerves, especially in multi-therapy regimens. Given the relations with the OSDI score, SNP changes seem features of glaucoma therapy-related OSD and negatively affects the patient's quality of life.