Glaucoma study

Slit-lamp examination of the anterior segment of the eyeball (biomicroscopy) – Slit-lamp examination is part of routine ophthalmic examination. It allows to assess the structure of the eye structures. The slit lamp consists of a source of strong light, which can be directed at individual structures of the eyeball, and a biomicroscope, which allows the examiner to magnify the image (6-40x), but also to see stereoscopically (spatially). The test is completely safe and can be repeated many times, since the eye is illuminated with normal visible light, which is not harmful to it.

Testing of intraocular pressure (tonometry, IOP) – measurement of pressure in the eye made with a tonometer. Blood pressure should be measured at every visit to the ophthalmologist. Tonometry performed before deciding on laser vision correction is designed to determine whether the procedure poses any risk to the patient. Modern non-contact tonometers measure not only corneal thickness and intraocular pressure, but also the biomechanical properties of the cornea when an air pulse is applied to it.

Examination of the fundus after pupil dilation – also known as ophthalmoscopy, funduscopy or fundus viewing; details here.

Visual field examination (perimetry) – an examination of the visual field, during which possible visual field defects appearing in the eye in the course of developing glaucoma are detected. Many times, two or even three examinations are necessary to obtain reliable results of visual field evaluation. Perimetry signals the development of the optic nerve atrophy process. Dual-frequency perimetry (FDT) shows changes in the visual field earlier than traditional computer perimetry.

Examination of the angle of seepage (gonioscopy) – examination of the angle of seepage to determine whether the angle is open or closed performed with a gonioscope inserted directly into the eye. This test requires anesthesia of the eyeball. It can also be performed using optical coherence tomography of the eye (SL-OCT) – this test is non-invasive and does not require anesthesia.

Corneal thickness test (pachymetry) – a measurement of the thickness of the cornea at its center, made by non-contact or touch using an ultrasound probe. No pupil dilation is required for the test. Evaluation of corneal thickness is a mandatory test in patients with glaucoma and ocular hypertension, and is also performed before surgical procedures, including laser procedures, on the cornea, as well as in the diagnosis of corneal cone and other corneal disorders. The test has a major impact on the assessment of intraocular pressure values. Tactile pachymetry is performed using ultrasonic pachymeters. The test requires contact between the camera tip and the patient’s cornea. It is painless because the patient’s cornea is anesthetized beforehand with a drop. Non-contact pachymetry is performed as part of corneal tomography using an ultrasound camera. In this case, there is no contact between the camera and the cornea.

Optical nerve tomography (e.g. OCT or GDx or HRT) – OCT is optical coherence tomography of the eye. The OCT eye tomograph has a resolution 10 times greater than that of an ultrasound machine, so the result of the OCT examination can be compared with a histological image of the retina (that is, the examination has the same value as if the doctor were examining a tissue slice taken surgically). The test is non-contact, performed on an outpatient basis, and takes a few minutes. GDX is a scanning laser polarimetry that, together with OCT, can determine the thickness of the retinal nerve fiber layer damaged by glaucoma. HRT is a laser tomography of the retina that evaluates the optic nerve disc. During the HRT examination, the doctor delineates the optic nerve disc. The correct delineation of its boundaries determines whether the camera will automatically classify a given disc image as normal, suspicious or damaged by glaucoma.

Imaging studies of the anterior segment of the eye (e.g., OCT or UBM) – OCT as above. UBM is an ultrabiomicroscopy that accurately analyzes the shape and size of the angle of seepage, as well as the thickness and position of the lens.