What is an OCT?
OCT stands for "optical coherence tomography", it is an examination similar to an ultrasound of the eye.
The OCT performs non-invasive measurements allowing a study of the different structures of the eye. This technique is used to highlight certain lesions and pathologies.
OCT provides images of biological tissue by measuring the reflection of light (emitted by an infrared laser) on the retinal tissue.
The image resolution is 10 to 15 microns, at least twice as fine as what is accessible with conventional methods such as MRI or ultrasound ultrasound.
This makes it possible to highlight with great precision the different layers of the retina and the optic nerve.
How does the exam go ?
It takes 1 to 10 minutes for the total duration of the exam.
The patient settles down in front of the device, in a dark room.
After placing the chin and the forehead on the support of the device, the ophthalmologist or the orthoptist will ask him to fix a luminous cross while keeping both eyes wide open.
The measurement only lasts a few seconds, there is no contact with the patient's eye and the examination is safe for the eye.
During this examination, dilation of the pupil is not necessary. The light beam scans the retina and the patient fixes the light point.
At the same time, the ophthalmologist adjusts the control settings and changes the position of the cut. Finally, the result of the examination precisely assessing the density of the different layers and structures of the retina as well as its evolution compared to the examinations which may have been carried out previously will allow the ophthalmologist to establish a complete diagnosis for the patient.
Generally, both eyes are examined for an accurate comparison and diagnosis. Images are printed, explained and given to patients.
These examinations are included in the patient file and available for further studies.
Why and when to do the exam?
The ophthalmologist performs an OCT examination for various reasons:
1. The study of the macula (central retina allowing you to see the clearest): This examination is carried out in the event of a sudden or progressive drop in vision, or in monitoring retinal pathology, it will make it possible to analyze and detect lesions or loss of density of the different thicknesses of the central structure of the retina.
2. Monitoring diabetic retinopathy.
3. Analysis of the optic nerve: this examination is used in the context of monitoring and screening for glaucoma or else in the analysis of a papillary defect by analyzing
In which cases does OCT become essential?
OCT can in some cases allow early diagnosis of certain diseases (glaucoma, AMD, etc.) before symptoms are noticed by the patient. The pathology is then taken care of early, follow-up and treatments are put in place and irreversible damage can thus be avoided.
The equipment used: OCT Spectralis Sanotek HRA + OCT2
This equipment is exceptional by the combination in a small instrument of the angiographies FLUO, ICG, OCTA without injection, of the OCT Spectral 85 KHz and the faculty of MultiColor.
The high quality image is obtained by cSLO (confocal laser scanning) which is a new technology used for the examination and imaging of ocular structures and the retina.
This imagery combines the fine resolution of the confocal scanning and the spectral selectivity of a laser illumination to give precise and clear images impossible to have from a traditional photography of the fundus of the eye. More, this imaging allows the analysis of difficult cases such as eyes with cataracts.
This technology also includes a so-called AutoRescan function which automatically places the tracking scans in the same place as the last visit to allow the identification of structural changes.
Spectral OCT is very reliable thanks to the “TruTrack Active Eye Tracking ™”, an imaging technique which uses two light beams to study the fundus of the eye and reduces the effects of eye movements during analysis which allows obtain very precise analysis data.
In addition, “Heidelberg Noise Reduction” is a new exclusive technology also present in this device which eliminates the noise granted to OCT and cSLO imagery.
Peut-on conduire après un scanner des yeux ?
Le patient peut tout à fait conduire après un OCT, à part s'il a fallu dilater sa pupille pour examiner le fond de son œil, comme c'est parfois le cas" explique le spécialiste.
En cas de dilatation de la pupille, on recommande d'attendre 2 à 4 heures avant de reprendre le volant.