Optical coherence tomography (OCT) is a diagnostic technique, by which it is possible to detect eye diseases at very early stages of their progress. Often, when doing OCT examinations, the eye disease is diagnosed for a patient who seemingly has no complaint of visual and eye health. Frequently effective treatment at the onset of a disease contributes to the highest expected and reachable result.

As a result of OCT measurement it is possible to obtain high resolution image in the examinations of front part of eye – cornea, opening of angles of anterior chamber, iris, sclera, conjunctiva, as well as of back part – retina and choroid.

Due to the fact that diagnostic device allows obtaining images with non-dilated pupil or slightly dilated pupil, the procedure is quick and painless; it is possible to perform eye examinations in patients with diabetes, glaucoma, neurological, cardiovascular diseases, in children and the elderly.

The exam is fast (3 minutes), safe, ease and patient friendly. The obtained scans, images and examinations are available immediately. When examining repeatedly, it is possible to compare the dynamics. The device is unique in that the image is created by a laser beam. Consequently, the method is comfortable for both the patient and the physician, since, during examination, the eyes are not dazzled. During the examination, the automatic re-scan function and eye tracking function adapt to changes in the condition and movements of eye; this is a very important aspect in patients with poor eyesight or poor gaze fixation.

Clinical applications: diagnosis of retinal conditions (macular disorders, detachments of the neurosensory retina and retinal pigment epithelium (e.g. central serous retinopathy or age-related macular degeneration); Optic neurophaties (optic nerve disorders such as glaucoma); Visualization of anterior segment (cornea, anterior chamber, iris and angle); Patient with elevated eye pressure, ischemic lesions (angina pectoris, stent patients ), high blood pressure, oncology diseases, diabetic patients and wearers of contact lenses to control cornea health and many others.

OCT-A is a non-invasive imaging technique that provides three-dimensional visualization of perfused vasculature of the retina and choroid. In contrast to standard structural OCT, OCT-A analyzes not only the intensity of the reflected light bust also the temporal changes in the reflection caused by moving particles, such as erythrocytes flowing through vessels. The core principle of OCT-A is the detection of signal changes over time, caused by intravascular motion of blood cells. These changes are acquired and assesses via repeated acquisitions of the image at the same location.

Clinical applications: to assess chorioretinal microvasculature and to diagnose retinal disorders (e.g. diabetic retinopathy, dry or wet age-related macular degeneration, central serous corioretinipathy, vascular occlusions, choroidal neovascular membranes); Optic nerve disorders such as glaucoma; Assessment of uveitis and many other conditions.

Endothelial microscopy is the quantitative and qualitative evaluation of the eye front transparent layer – corneal – internal cell layer endothelium. For this purpose a cutting edge automated non-contact light-reflecting TOMEY EM-4000 microscope and modern digital data processing are applied. An accurate diagnostics of the endothelium can help to identify not just the reason for changes, but also to plan treatment of frequent eye diseases – glaucoma, uveitis, Fuchs endothelial dystrophy. These diseases can cause changes in the endothelial structure and functionality, which can result in the development of the corneal oedema and vision deterioration. Also wearing contact lenses and intraocular surgeries can cause changes in the endothelium and contribute to the development of oedema in the cornea. There are no age restrictions to undergo measurement. Measurement may be done on small children as well;

The device performs measurement very quickly and painless, during the procedure there are no whatsoever unpleasant sensations, it is not necessary to remain for a long time in a forced position. During examination the patient remains seated at the device with a supported chin.

Clinical applications: cataract patients with polanned surgery; After any surgery to evaluate changes in the condition of the cornea; Prior refractive surgery (to evaluate the cell density and patients indications to surgery); Prior and after corneal transplantation surgeries; After glaucoma surgeries (specifically with implantation of filtration elements). 

Often, patients, questioned about eye pressure measuring, argue away that their blood pressure is correct. However, these are two quite different measurements, the parameters of which do not necessarily mean features regarding one thing and the other. Regularly monitored blood pressure allows for avoiding different general diseases, infarct, blood stroke, but the measurements of internal eye pressure enable timely detection and elimination of vision problems that may have irreversible effects of loss of vision.

The circulation of transparent fluid is constantly going in the eye. The liquid that washes and nourishes the avascular structures of the eye, as well as removes the metabolic end products is produced by the special gland – the ciliary body. In the tissues between the cornea and the sclera, there is a drainage area through which this fluid is discharged back into circulatory system. The pressure in the eye depends on the amount of produced fluid and removed fluid. It is too much or the fluid does not flow away, the pressure increases. The blockage of eye drainage system builds up fluid pressure that in turn may cause damage to optic nerve. If the optic nerve is damaged, blindness may occur. Excessive eye pressure also adversely affects other eye tissues. High pressure worsen metabolism in the eye. It pushes on the lens ligatures, weakens them, resulting in impaired vision, looking at different distances, the eye pupil becomes less mobile.

The cause of overproduction of aqueous humor may be hereditary, for example, if one of the blood relatives has or has glaucoma. The peculiarity of eye structure is sometimes the cause of high eye pressure when the angle of anterior chamber is narrowed or closed and the fluid cannot flow freely.

Overproduction of aqueous humor may be caused by high blood pressure, atherosclerotic changes in blood vessels, diabetes mellitus, thyroid and other endocrine diseases affecting blood circulation, as well as long term use of medications. Excessive pressure trends to result from injury when the aqueous humor is prevented from outflow, after inflammation or surgery. Sometimes high eye pressure is detected in patients with watering eyes. More often high eye pressure can be observed in patients, but the pressure in eye may be also low. In both cases, changes in eye pressure are equally unfavorable and may affect the quality of vision.

If the ciliary body produces too less fluid and the pressure is low, the eye nourishing is impaired. This may indicate serious damage to the structure of the eye, such as retinal breakdown and detachment of retina that can result in significant deterioration of vision or even blindness. The attention to measurements of eye internal pressure should also be paid after eye injuries and inflammations involving a fluid producing ciliary body. If it becomes less active and does not produce enough fluid, eye hypotonia may develop and the retina can be detached.

In the Latvian American Eye Center tonometers of Finnish Company Icare Finland are used to measure the IOP of patients. These tonometers are devices of new generation applying unique so called “rebound” technology that makes IOP measuring quick, painless and accurate.

A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions. Visual field testing can be performed clinically by keeping the subject’s gaze fixed while presenting objects at various places within their visual field. The normal eye can detect stimuli over a 120º range vertically and a nearly 160 degree range horizontally. From the point of fixation, stimuli can typically be detected 60º superiorly, 70º inferiorly, 60º nasally, and 100 degrees temporally, though the true extent of the visual field depends on several features of the stimulus (size, brightness, motion) as well as the background conditions.

Clinical applications: assessment and diagnostics of glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits.

Corneal pachymetry is the process of measuring the thickness of the cornea. And a pachymeter is a medical device to performe the measurement.

Clinical applications: prior to refractive surgery; Keratoconus screening; In screening for patients suspected of developing glaucoma and other conditions.

Corneal topography is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye. Since the cornea is normally responsible for some 70% of the eye’s refractive power, its topography is of critical importance in determining the quality of vision and corneal health.The three-dimensional map is therefore a valuable aid to the examining ophthalmologist or optometrist and can assist in the diagnosis and treatment of a number of conditions.

Clinical applications: Refractive surgery (To screen candidates for normal corneal shape, patterns and ruling out suspicious or keratoconic patterns; Post operatively, topography can help to assess the dioptric change created at corneal level); Keratoconus (Early screening of keratoconus suspects is one of the most useful roles of topography; In cases with established keratoconus, the role of topography is paramount for monitoring progression and doing a timely collagen cross linking, and in contact lens fitting); Post surgery astigmatism (Post cataract surgery and post keratoplasty corneal astigmatism can be studied with the topographer and selective suture removal or other interventions can be planned); Effect of corneal and ocular surface disorders; Contact lens fitting.

Because the eye is a superficial fluid filled structure, ultrasound is an easy to use modality for visualization of ocular pathology and anatomy [1]. The principles of ocular ultrasound are the same as other applications of this technology. Sound waves are generated at a frequency greater than 20,000 Hz (20 kHz), and reflected back to the transducer by tissue in its path.

Clinical applications: it can be used for a detection of a wide-range of pathological structures, including retinal or choroidal detachment, foreign bodies, calcium, tumors and other.

The fundus of the eye is the interior surface of the eye opposite the lens and includes the retina, optic disc, macula, fovea and posterior pole. Specialized fundus cameras consisting of an intricate microscope attached to a flash enabled camera are used in fundus photography. Fundus photography is used to inspect anomalies associated to diseases that affect the eye, and to monitor their progression.

Clinical applications: assessment and/or to follow up on the condition/disease such as diabetes, age-macular degeneration (AMD), glaucoma, and neoplasm of the choroid, cranial nerves, retinal or eyeball, patients with constant headaches, diastolic pressure greater than or equal to 120mmHg and patients with sudden visual loss, arterial hypertension.

Fluorescein angiography (FA) allows study of the circulation of the retina and choroid in normal and diseased states. Photographs of the retina are taken after intravenous injection of sodium fluorescein, an orange-red crystalline hydrocarbon. Fluorescein is injected into a vein in the arm/hand and enters the ocular circulation via the ophthalmic artery 8–12 seconds later, depending on the rate of injection and the patient’s age and cardiovascular status. Fluorescence occurs when a molecule is excited by light of a certain wavelength that raises the molecule to a higher energy state and then allows it to release a photon of light to bring it back to its original state. To image this fluorescence, special excitation and barrier filters are required. 

Clinical application:  to find and diagnose eye disease including macular edema (swelling in the retina that distorts vision); diabetic retinopathy (damaged or abnormal blood vessels in the eye caused by diabetes); macular degeneration and other macular disorders; ocular melanoma and other.

Indocyanine Green Angiography (ICG) is a diagnostic procedure that uses ICG dye to examine the blood flow in the choroid – the layer of blood vessels which lies underneath the retina. Indocyanine Green dye is injected into a vein in the arm/hand. As the dye passes through the blood vessels of your eye, photographs are taken to record the blood flow. The choroidal vessels are hidden beneath a layer of pigmented cells. Infrared light given off by ICG dye can be imaged through the pigmented layer using special filters.

Clinical applications: detection of choroidal neovascularization (a common component of age related macular degeneration); multiple inflammatory conditions; chronic central serous chorioretinopathy; choroidal hemangiomas and posterior uveitis.