Glaucoma is usually measured through a series of tests that evaluate, among other things, the integrity of the optic nerve and the intraocular pressure (IOP). But researchers are now pointing to an OCT modality that may be able to identify early stages of the disease in an unexpected structure: the cornea. According to researchers, the corneal speckle of glaucoma suspects has a similar relationship between the parameters of scattering exhibited in glaucoma patients and is distinguishable from that of healthy controls.
The investigators say that this finding shows that using OCT to measure speckle “can shed more light on the structural characteristics of corneal tissue and their relationship to glaucoma progression.” They add that “corneal tissue should be given more consideration in future histopathology studies of glaucoma.”
To determine this, investigators looked at 64 subjects separated into three groups; those with diagnosed primary open-angle glaucoma (18 patients), glaucoma suspects with normal levels of IOP and uncompromised visual field (24) and age-matched controls (22). The team looked at each patient’s corneal speckle using OCT as we as their IOP, visual fields, Heidelberg Retinal Tomography, retinal nerve fiber layer thickness and biometry.
When measuring IOP, visual field parameters, mean retinal fiber layer thickness and central corneal thickness, the glaucoma suspects all looked similar to the healthy controls and were significantly different than the confirmed glaucoma cases. However, the parameters of the corneal speckle were not significantly different between the groups, but they showed a markedly higher and statistically significant coefficient of determination for glaucoma patients and suspects than that for the control group. This, the researchers say indicates “that glaucoma suspects have similar relationship between the corneal scatterer cross section and scatterer density to that exhibited in the glaucoma patients but markedly different from that of healthy controls.”
|Iskander D, Kostyszak M, Jesus D, et al. Assessing Corneal Speckle in Optical Coherence Tomography. Optom Vis Sci. 2020;97(2):62-7.|