The cornea is the outer, transparent surface of the eye, which comes into contact with the lacrimal layer. Apart from its protective role, the cornea is responsible for about 3/4 of the refractive power of the eye.
The cornea consists of the following layers:
The cells of the corneal endothelium act as a pump, thus keeping the cornea dehydrated and clear. The number of endothelial cells decreases naturally with age. Other causes of reduced numbers and changes in endothelial cell structure include corneal dystrophies and surgical trauma, e.g. after cataract surgery or valve implantation to treat glaucoma.
Endothelial cells do not have a regenerative capacity. The result of endothelial cell disfunction in advanced cases is the development of corneal edema, leading to corneal clouding and decreased vision, with or without pain.
Endotheliometry allows us to evaluate both the number and morphology of corneal endothelial cells. It is particularly useful both in preoperative assessment and in monitoring the postoperative course as well as in the diagnosis and monitoring of corneal dystrophies.
Endotheliometry of a patient with endothelial Fuchs dystrophy before cataract surgery.
Cataract is the clouding of the crystalline lens of the eye. A cataract occurs due to age, but also due to trauma, radiation, systemic disease, inflammation and medication (e.g. corticosteroids).
The Anterior Segment Optical Coherence Tomography(AS-OCT) is a non-invasive examination, which uses principles of ultrasound technology to obtain many high-resolution images within a few seconds without radiation and without contact. The first AS-OCT devices became commercially available in the mid-2000s.
AS-OCT can be used for differential diagnosis of ocular surface pathology, assessment of the angle of the anterior chamber, assessment of corneal thickness, pre- and post-operative assessment in corneal transplantation, etc.
CCT (central corneal thickness) measurement with AS-OCT
Ultrasoundbiomicroscopy (UBM) is a specialized method, with which structures of the anterior segment are depicted. Its comparative advantage lies in the fact that it can depict structures both in front and behind the iris. It is especially useful for evaluating the pathology of the iris, the angle and the ciliary body.
UBM with double-angle imaging mechanism: iris plateau and multiple posterior iris cysts
“The role of ultrasoundbiomicroscopy (UBM) in the diagnosis of an episode of acute elevation inintraocular pressure” Alonistiotis D., Oikonomou D., Hristov P., Boutsora U., Leontaras I., Risi-Koziona A., Theodosiadis P.
B’ University Ophthalmology Clinic NKUA, “ATTIKON”University General Hospital
57th PanhellenicOphthalmologyCongress 2024
Examples of anterior segment eye diseases
