Click on the images to know more
Click on the images to know more
To know a patient’s peripheral vision, he must perform a visual field examination. The visual field is the space perceived by an eye that fixes a stationary point. It is important to mention that visual acuity of the central vision can be normal even in the presence of a loss of field of vision. However, it is possible that a glaucoma patient with pronounced deficits in his visual field can still read without any problem. (Devices available to test the visual field: Humphrey, FDT Matrix and Octopus).
The tearlab is a test that analyzes the tear film of the eye. The lacrimal film is the protective layer of the ocular surface and is made of three main elements: liquid, aqueous humour and mucins (sticky proteins). The osmolarity test of the tearlab gives the doctor a significant measure of the health and the stability of the tear film structure. This examination system represents a significant step forward for the diagnosis and the treatment of ocular dryness : osmolarity measurement of the lacrimal film becomes a monitoring tool and gives a measure of the treatment’s impact.
The UBM (Ultrasound bio-microscope) takes microscopic ultrasound scanning of the anterior chamber and the irido-corneal angles using the most advances and versatile technology of high frequency ultrasound available today. This device makes it possible to easily obtain and analyse quickly some high-resolution videos and digital images of the anterior chamber. This exam gives precise measurements of the eye’s structure as well as a detailed overview of the tissues condition. The results are used to establish a diagnosis, visualize the presence of cysts and tumors and detect abnormalities in the eye’s structure.
The B-scan is an important exam to evaluate the inside of the eye including the retina. Using the principles of ultrasounds, a probe directs high frequency waves inside the eye. The waves are reflected in the inner structures of the eye and are converted into images viewed on a screen. With this exam the ophthalmologist can evaluate the inside of the eye in cases where the takes are limited by cataracts, corneal scars or other ocular conditions. The results of this exam allow the ophthalmologist to make a distinction between the pathologies of the vitreous body, the retina, the choroid (a layer of tissue under the retina, the optic nerve and the anterior segment.
The specular microscope is an instrument used to analyse the cornea’s endothelial cells (posterior layers) which maintains the balance of its fluid and its clarity. These cells do not regenerate and are usually damaged by eye injuries, diabetes, glaucoma, cornea diseases, surgery and excessive contact lens wear. In a preoperative assessment, this exam determines if the surgery as a risk of damaging the patient’s cornea and adjusts the surgical technique accordingly. This test is carried out without contact. It consists of taking photos of the cells to evaluate their density and their format.
The OCT-Cirrus is a high-speed and high-resolution optical ultrasound used for 3D imaging and retinal and optic nerve analysis. This exam detects the early loss of ganglion cell in glaucoma and retinal pathologies. The macula that holds more than 50$ of the retinal ganglions cells is the ideal location to detect the early loss of these cells and track changes over time. The retina is mad e of three ganglion cell layers that thins out as the cells die. This device can also take images and precise measurements of the anterior segment including: the cornea, the anterior chamber as well as the irido-corneal angles. Therefore it is an important exam to make a diagnosis of the plateau of the iris or iris cysts.
HRT Heidelberg Retinal Tomography is a diagnostic test used for the accurate documentation and observation of the head of the optic nerve for the diagnosis and treatment of glaucoma. The HRT uses a special laser to take 3-dimensional photos of the optic nerve and the surrounding retina. The typical damage of the optic nerve is called “excavation”. Due in part to eye’s high-pressure, the optic nerve cells die and disappear. When they disappear in sufficient quantity this produces a hollow in the optic nerve “excavation”. So the physician with the assistance of this diagnostic test seeks to determine the presence and extent of the excavation. This machine is equipped with analysis software to evaluate the progress of the excavation over time. This is why the test is done at a certain interval (example every 6 months or every year).
Corneal topography is an exam used to measure the shape and integrity of the cornea. A corneal topographer projects a series of luminous rings on the surface of the cornea, which in turn reflects the image in the instrument. After analyzing the rings of light, the computer generates a topographic map of the cornea. These images are used to diagnose corneal aberrations or pathologies. This device is used to help diagnose corneal pathologies. This exam is also carried out (in conjunction with the biometry) in the preoperative assessment of cataract surgery. It provides not only the aberrations of the cornea but also a keratometry which gives the measure of the eye’s astigmatism. Specifically, it is the radius of curvature of the cornea, which is measured with the difference between K1 and K2 (K1-K2). The measurement of the axis determines the angle at which astigmatism is present.
Automatic refractometry is an exam to measure the refraction of light by the eye. Ocular refraction is the change of direction of a light ray that passes through the eye in different media. This ray ends up converging on the retina, meaning the layer of cells lining the bottom of the eyeball, which is intended to transform the luminous energy into a nerve impulse which is then decoded by the brain in the form of images. The automatic refractometry allows the diagnosis of refractive disorders. It can be hyperopia, myopia or astigmatism. The automatic refractometer also has the ability to measure corneal radii of curvature (keratometry).
Every device commonly used to measure intraocular pressure is based on the same principle: it measures the force needed to deform the eye and deduces the pressure. It is like pressing a balloon to see if it is well inflated. The ORA measures intraocular pressure with a blast of air. However this measurement is distorted if the cornea, on which the devices are supported, has an abnormal thickness. This is why physicians use both measurements (corneal thickness and IOP) to determine true intraocular pressure.
The biometry is a high precision device that allows the measurement of the length of the patient’s eye as well as the cornea’s curvature, data used to determine the strength of the intra ocular lens that will be used during the cataract surgery.
At the Clinique Bellevue, the ophthalmic angiography is performed using the HRA Spectralis device and the Visucam. This examination makes it possible to see the various retinal pathologies with the help of a contrasting coloring liquid. The dye is injected into the patient’s hand and flows to the blood vessels of the retina. This dye allows us to see if there are blood leaks in the retina and also where they are located. When the fluid reaches the retina, the technician takes several photos in the span of 5 minutes, which will be analyzed by the ophthalmologist
The Goldmann tonometer allows us to take intraocular pressure with a slight contact (comparable to a contact lens) on the patient’s eye, which is desensitised by numbing eye drops.