Microdot Accumulation in the Anterior Cornea with Aging – Quantitative Analysis with in Vivo Confocal Microscopy

Abstract

Purpose: Degenerative 'microdot' deposits in healthy and hypoxic corneas are believed to represent lipofuscin-like material aggregation in the stroma. To accurately assess microdot deposits in a clinical setting, we sought to quantify these deposits for the first time using the non-invasive clinical imaging technique of in vivo confocal microscopy (IVCM). Methods: The corneas of 102 healthy subjects aged 15-88 years were examined by IVCM and microdot density was quantified using a 6-point grading scale by two masked, trained examiners. Microdot density was analyzed with respect to age, sex and stromal depth, and inter-eye and inter-observer differences were evaluated. Results: In healthy subjects, microdot density decreased from the anterior to posterior stroma, with the greatest accumulation observed in the most anterior stroma (subepithelial region). In this region, microdot density correlated strongly with age (P < .0001), with increased microdot deposition in older subjects (>60 years) relative to younger ones (<45 years) (P < .001). Microdot density between eyes of the same subject was highly correlated (r = 0.92, P < .0001), while no association with sex was noted (P ≥ 0.05). The mean inter-observer difference in microdot assessment was 0.62 ± 0.09 grades, with a high correlation of grading between observers (r = 0.77, P < .0001). Conclusions: IVCM can be used to non-invasively quantify microdot deposits in the subepithelial corneal stroma with good inter-observer reproducibility. Microdot assessment may provide a novel means of quantifying age-related or pathologic degeneration of the corneal stroma in a clinical setting.

Advanced Anterior Eye Segment Imaging for Ichthyosis

“…They have been reported in healthy subjects and are regarded as early-stage irreversible corneal stromal alterations due to hypoxia [ 42 ]. Utheim et al reported an accumulation of microdots in the aging cornea, primarily in the subepithelial stromal region [ 43 ]. This conclusion does not align with our findings, since P5 is young (13 years old) and presented with microdot accumulation in the anterior and posterior stroma.…”

Corneal confocal microscopic characteristics of acute angle-closure crisis

“…Confocal microscopy might be superior to specular microscopy to analyze the endothelial cells in AACC with corneal edema. The confocal microscope can directly obtain images of tissues and cells in each layer of the cornea through continuous confocal scanning, detecting various elements of normal and affected corneas in multiple layers and in vivo, without fixation and staining of tissue sections [9][10][11][12][13][14]. Thus, it is a major method for exploring the pathological mechanism of ophthalmic diseases at the cellular level.…”

“…Specular microscopy should be performed for glaucoma patients to check the endothelial cell density before intraocular surgery, but corneal edema caused by acute IOP elevation often makes it impossible to analyze the endothelial cells [7,8]. Confocal microscopy is a novel non-invasive corneal imaging examination method [9][10][11]. Due to high resolution and magnification, it reveals the corneal changes at the cellular level under three-dimensional space and real-time conditions; similar results could be obtained in the cloudy corneal tissue, making it a commonly used tool for the clinical study of corneal lesions [9][10][11][12][13][14].…”

“…Confocal microscopy is a novel non-invasive corneal imaging examination method [9][10][11]. Due to high resolution and magnification, it reveals the corneal changes at the cellular level under three-dimensional space and real-time conditions; similar results could be obtained in the cloudy corneal tissue, making it a commonly used tool for the clinical study of corneal lesions [9][10][11][12][13][14].…”

“…Confocal microscopy plays a major role in evaluating keratitis and corneal nerves [9][10][11][12][13][14], but there is only one study about its use for AACC which focused on Langerhans cells and keratocytes [15]. Our study aimed to investigate corneal epithelial cells, subepithelial nerve fiber plexus, stromal cells, and endothelial cells of the AACC and fellow eyes and healthy controls using confocal microscopy.…”