Glaucoma examination

Anterior segment examination with a slit lamp (biomicroscopy) – slit lamp examination is part of a routine ophthalmological examination. It allows for the assessment of the eye’s structural components. A slit lamp consists of a strong light source that can be directed at individual structures of the eyeball, and a biomicroscope that enables the examiner to magnify the image (6–40x) and also provides stereoscopic (3D) vision. The examination is completely safe and can be repeated multiple times, as the eye is illuminated with normal visible light, which is not harmful to it.

Intraocular pressure measurement (tonometry, IOP) – measurement of pressure in the eye performed using a tonometer. Pressure should be measured during every visit to an ophthalmologist. Tonometry performed before deciding on laser vision correction aims 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 after an air impulse.

Fundus examination after pupil dilation – also known as ophthalmoscopy or funduscopy; details here.

Visual field examination (perimetry) – a visual field examination that detects any defects in the visual field that appear in the eye during the progression of glaucoma. Often, two or even three examinations are necessary to obtain reliable visual field assessment results. Perimetry signals the development of optic nerve atrophy. Frequency doubling perimetry (FDT) shows changes in the visual field earlier than traditional computerized perimetry.

Drainage angle examination (gonioscopy) – an examination of the drainage angle to determine if it is open or closed, performed using a goniolens placed directly on the eye. This examination requires local anesthesia of the eyeball. It can also be performed using optical coherence tomography of the eye (SL-OCT) – this examination is non-invasive and does not require anesthesia.

Corneal thickness measurement (pachymetry) – measurement of corneal thickness at its center, performed non-invasively or invasively using an ultrasound probe. Pupil dilation is not required for this examination. Assessment of corneal thickness is a mandatory examination for patients with glaucoma and ocular hypertension, and it is also performed before surgical procedures, including laser procedures, on the cornea, as well as in the diagnosis of keratoconus and other corneal diseases. The examination has a significant impact on the assessment of intraocular pressure values. Contact pachymetry is performed using ultrasonic pachymeters. The examination requires contact between the device tip and the patient’s cornea. It is painless because the patient’s cornea is anesthetized beforehand with drops. Non-contact pachymetry is performed as part of corneal tomography using an ultrasound device. In this case, there is no contact between the device and the cornea.

Optic nerve tomographic examinations (e.g., OCT, GDx, or HRT) – OCT stands for Optical Coherence Tomography of the eye. An OCT eye tomograph has 10 times higher resolution than an ultrasound device, which is why the OCT examination result can be compared to a histological image of the retina (meaning the examination has the same value as if a doctor were examining a tissue sample taken surgically). The examination is non-invasive, performed on an outpatient basis, and takes several minutes. GDX is scanning laser polarimetry, which, along with OCT, allows for determining the thickness of the retinal nerve fiber layer, which is damaged by glaucoma. HRT is Heidelberg Retina Tomography, which assesses the optic nerve head. During the HRT examination, the doctor delineates the optic nerve head. The accurate delineation of its boundaries determines whether the device automatically classifies a given image of the disc as normal, suspicious, or damaged by glaucoma.

Anterior segment imaging (e.g., OCT or UBM) – OCT as above. UBM stands for Ultrabiomicroscopy, which precisely analyzes the shape and size of the drainage angle, as well as the thickness and position of the lens.