Distribution of 50-layer corneal densitometry values and related factors

To investigate the distribution of 50 layers of corneal densitometry and related factors.

Clinical data, including age, sex, central corneal thickness, corneal keratometry, and diopters, were collected from 102 healthy participants (102 eyes) in this retrospective study. The cornea was divided into 50 layers, and densitometry of each layer at 19 points was measured by the Pentacam. The value versus the depth curve was plotted. Paired-sample t test and one-way analysis of variance were used to compare densitometry in different regions or depth. Statistical significance was defined as P < .05.

The densitometry values of the Bowman membrane (10-14% depth), anterior stroma (14-30% depth), epithelium (0-10% depth), and Descemet membrane (94-98% depth) decreased sequentially, and the densitometry values of the middle and posterior stroma (30-94% depth) and endothelium (98-100% depth) were the lowest. The higher the degree of astigmatism, the higher the second densitometry peak (R = 0.277, P < .001). The densitometry values of the vertex and superior parts of the cornea were higher than those in the periphery and inferior parts, respectively (all P < .001). In the Bowman membrane, the densitometry is lowest in the inferior nasal part, while in the Descemet membrane, it is lowest in the inferior temporal part.

Two densitometry peaks appeared near the Bowman membrane and Descemet membrane. For different depths, the distribution of densitometry within a layer is different. We provide a methodological reference and data basis for corneal research based on local changes in densitometry, and help understand the details of corneal structure from an optical perspective through detailed layering and zoning analysis of densitometry.