OCT Examination

for early diagnosis

OCT examination (Optical Coherence Tomography) is one of the most revolutionary and important diagnostic tools in modern ophthalmology. With this procedure, we obtain an extremely detailed cross-sectional image of the layers of the retina and the optic nerve head (optic disc) painlessly and without radiation exposure. Images of the central part of the retina are called macula OCT, while images of the optic nerve are called optic disc OCT. It enables the detection of serious eye diseases even in the asymptomatic, early stage that would otherwise remain hidden.

What exactly is OCT examination and what should you know about it?

OCT examination is a non-invasive imaging procedure using light waves, during which we obtain a detailed image of the eye’s tissues using completely harmless, low-energy laser light. It is primarily used to examine retinal diseases, but can also be applied to other parts of the eye to a certain extent.

Painless: Does not require anesthesia; it is a painless procedure.
Radiation-free: Completely safe, can be repeated any number of times, does not use X-rays.
Cellular-level resolution: With more advanced devices, the ten layers of the retina can be clearly distinguished, enabling the identification of tiny, microscopic changes.
3D imaging: The device captures tens of thousands of images per second, which the computer can also convert into a three-dimensional image.
Precise measurement: Thanks to the highly detailed images, micrometer-scale differences can be identified in time.
Speed: The examination, performed in a seated position, takes only a few minutes.

When and why do we use OCT examination?

In a modern practice, it is part of the routine ophthalmological examination, as it is a useful supplementary examination in several cases.

Non-invasive routine examination: a quick examination that can be repeated any number of times without side effects.
Early diagnosis: with the device, retinal diseases can be detected at such an early stage when they may not yet cause symptoms or the symptoms are not typical. This allows diagnosis to occur before the changes cause severe, permanent, or serious damage to the retina.
Follow-up examinations: It can be used very reliably for precise monitoring of the disease course. In addition, it is necessary to assess the condition of the retina or optic nerve head in detail before diseases or treatments that are known to cause or lead to retinal damage.
Monitoring treatment effectiveness: a precise and reliable procedure for assessing effectiveness and documenting changes in condition during the treatment of retinal or optic nerve diseases.

How does OCT examination work?

Patients often ask what preparations are necessary for the images to be taken. The process is extremely simple and comfortable.

Steps of OCT examination

The patient sits comfortably in front of the device, resting their chin and head. We ask them to look at the light point visible in the device throughout the examination, and if its position changes, to follow it.

We make the necessary adjustments on the device and start the imaging. The device emits a flashing light beam, with the help of which a detailed image of the retinal layers is created.

After completing the images of one eye, we direct the examination head to the other eye and perform the examination on it as well.

The images taken during the examination are immediately visible, which the specialist thoroughly examines, evaluates, and establishes the diagnosis by comparing the findings with the clinical picture.

Is pupil dilation necessary for OCT?

Although modern OCT examinations often provide excellent images without pupil dilation, in certain cases—especially with very narrow pupils or more advanced cataracts—the use of pupil-dilating eye drops is recommended to improve image quality. The drops temporarily make vision blurry and light sensitivity may occur, which completely subsides within a few hours. It is important to know that driving is prohibited after pupil dilation.

In which eye diseases is OCT examination important?

OCT examination plays an indispensable role in the early diagnosis and monitoring of many serious eye diseases. It provides critical information in numerous diseases of the retina and optic nerve head; the most common abnormalities are summarized below:

Glaucoma

It detects thinning and damage to the optic nerve fibers even before vision loss. It is the most important early diagnostic tool. Alongside visual field testing, optic disc OCT is important for assessing the effectiveness of established glaucoma treatment, i.e., the progression of the disease.

Age-related macular degeneration (AMD)

It detects fine changes, deposits, or abnormalities caused by vascular growth on the retina. Macula OCT helps distinguish between dry and wet forms, which is critical for treatment. Changes in macular edema can also be measured, which serves to assess treatment effectiveness.

Diabetic retinopathy

With macula OCT, we obtain a detailed, precise image of macular edema at the site of sharp vision at a very early stage. It is an indispensable diagnostic tool for timing and monitoring laser treatment or injection therapy and for assessing treatment effectiveness.

Macular edema

Swelling of the central part of the retina can develop as a result of diabetes, inflammation, or circulatory disorders, and may also occur after cataract surgery, among other causes. In these cases, macula OCT helps establish the diagnosis and severity of macular edema, determine the treatment plan, and provide follow-up.

Epiretinal membrane

A thin membrane can develop at the macula for various reasons, which can pull the retina and thus distort vision. Macula OCT imaging plays an important role in assessing surgical cases of epiretinal membrane.

CSCR Disease

Unlike macular edema, in CSCR the fluid accumulation is not in the retinal layers but between the 9th and 10th layers, subretinally. Macula OCT imaging helps distinguish the condition from other cases involving edema and is important in establishing a precise treatment plan for micropulse laser treatment and assessing effectiveness.

Macular hole, vitreous traction

The examination also plays a key role in other abnormalities of the macula, such as macular hole or macular vitreous adhesion or vitreous traction. In such cases, macula OCT allows precise assessment of the current structure of the retina and thus clarifies the cause of sudden vision loss.

When is OCT examination generally recommended?

The examination is recommended not only in cases of vision problems. During screening examinations, it is also a useful supplementary examination in asymptomatic patients, especially in high-risk groups.

As a screening examination: OCT examination is recommended every 2 years for those aged 18–65 in the absence of complaints.
Over 40 years of age: For early diagnosis of various retinal conditions, such as glaucoma or age-related macular degeneration (AMD), especially if similar diseases have occurred in the family.
In case of diabetes: At least once a year, for screening of diabetic macular edema.
In case of symptoms: For examining fine abnormalities of the macula in cases of sudden vision loss, distorted vision (e.g., straight lines appearing wavy), or noticing a blurry spot.
During follow-up examination: After ophthalmological diseases, ophthalmic surgeries, ophthalmic laser treatments, or intravitreal injection therapies, to monitor the disease course and measure treatment effectiveness.

Summary of OCT examination

For precise diagnosis, OCT examination is often necessary, which is now indispensable in modern, responsible ophthalmological care. Thanks to imaging, the ophthalmologist can precisely quantify the thickness of the retinal layers, aiding in the detection of the earliest changes.

Frequently Asked Questions (FAQ) about OCT examination

No, the procedure is completely painless and contactless.

OCT examination generally takes 5 minutes. Afterward, your doctor reviews the images and compares the results with other elements of the ophthalmological examination.

OCT examination can be performed without pupil dilation, but in certain cases, better quality images can be obtained with dilation.

No, OCT examination only takes images of the macula; the resulting images must be evaluated by a highly trained ophthalmologist. General ophthalmologists can also evaluate the images to a limited extent.

A diagnosis should not be made based on a single printed image, as it shows only a thin slice of the retina. The printed image serves only to document the magnitude of the disease, not to establish a diagnosis. The OCT image must be evaluated together with the results of the slit-lamp fundus examination to correctly determine the condition.

Roughly yes, but not in detail or completely. The limitation is partly that we are comparing only one image, and partly that the devices have slightly different normal ranges, so fine changes can only be assessed using the same type of device.

No. Since it works with light waves and there is no radiation exposure, it can be repeated indefinitely and has no negative side effects. Vision may be worse for a few seconds after the measurement, and glare may also occur.

It does not require special preparation. Since pupil dilation may be necessary, it is advisable to arrive with an escort or choose public transport, as driving is temporarily contraindicated.

ℹ️ If your vision is important to you and you have a known eye disease, or if you belong to the risk groups mentioned above, request an appointment at our practice for a comprehensive ophthalmological examination combined with an OCT examination!

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