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Introduction to the RetinaLyze Glaucoma algorithm

RetinaLyze Glaucoma is an algorithm, which enables safe, efficient and quick investigation of potential pathological changes like color variations in the optic nerve head, which could indicate early signs of eye disease like Glaucoma in both clinical and retail settings. The purpose of the RetinaLyze Glaucoma algorithm is to make it accessible to perform and receive investigations for haemoglobin (Hb) levels in the optic nerve head (ONH) by means of colour fundus images (colourimetry), which can indicate early signs of Glaucoma.

The algorithm analyzes fundus images and gives instant and easily understandable results. The entire process involves only the image from fundus cameras – no visual field analyzer/perimetry, OCT or tonometer is necessary.

RetinaLyze Glaucoma is a new feature, which is available in the RetinaLyze WebApp from Q2 2018 and is also available in the RetinaLyze API.

Before you continue reading about the RetinaLyze Glaucoma algorithm, it would be a great idea to familiarize yourself with the eye disease, Glaucoma. Read more below.

How to use RetinaLyze Glaucoma

Who to screen

Anyone is at risk of getting glaucoma and should be screened. However, the risk of getting glaucoma gets higher as you age, especially after the age of 40.¹

Anyone with a family history of glaucoma and/or high eye pressure (IOP) also have an increased risk for glaucoma. Read about other risk factors and how often to screen different patients in the article about glaucoma here.

Initiating the analysis in the RetinaLyze WebApp

Please read the general Get Started guide before continuing, if you are new to the RetinaLyze Webapp.

Upload the fundus photo as usual (manually or automatically)
Initiate the analysis by clicking on "Run Glaucoma analysis"

Automatic detection of the border/rim of the ONH

In order to begin screening, the algorithm needs to properly identify the optic nerve head (ONH). After initiating the analysis, the system will automatically detect the ONH rim/border. This process requires no involvement from the user.

The optimal result is achieved, when the border is set slightly inside the apparent edge of the ONH (i.e. where the inner limit of the Elschnig Scleral Ring lies).

In some cases, the algorithm may ask you to take another fundus image (displaying this error).

In very rare cases, the algorithm may set the border of the ONH incorrectly. If you do not agree with the border, simply capture a new fundus image and analyze that.

Understanding the results

The result of the automated analysis is displayed in two parts.
One is a colour-representation of the severity of the changes found (Red, Yellow or Green), the other is an overlay showing the measured level of hemoglobin in the ONH.

Colour summary of result

Green result

Green indicates that no color variations in the optic nerve head have been found i.e. the hemoglobin level is within the normal range.

Yellow result

Yellow indicates that there are indications of color variations which could indicate early signs of Glaucoma i.e. the hemoglobin level is slightly outside the normal range. The yellow result should be treated as a red result, if one or more of the following statements are true. The patient/client:

Has family history of glaucoma
Has an elevated IOP (Intraocular pressure), or there is a difference of 4 mmHg or greater between right and left eye
Shows indications of optic disc damage on an OCT scan
Shows visual field defects on a visual perimeter analysis

If none of the above are true, treat the yellow result as a green result.

Red result

Red indicates that there are indications of color variations which could indicate early signs of Glaucoma i.e. the hemoglobin level is outside the normal range.

Glaucoma overlay/Hemoglobin Map

Please see the 'How does the RetinaLyze Glaucoma algorithm work?'-section in the RetinaLyze Glaucoma FAQ-article for an explanation of the overlay.

Communicating the results & Taking action

In general

The RetinaLyze Glaucoma algorithm and the result should be considered a tool for a screening or diagnostic process, and not a diagnosis in itself. A diagnosis for glaucoma, should always be carried out by an ophthalmologist e.g. following the NICE-guidelines.

The screening and information provided by the RetinaLyze Glaucoma algorithm does not replace a consultation with an ophthalmologist, who will be able to give the patient/client a more complete assessment of their vision and general eye health.

Green result

It's important to convey the following:

A screening, not diagnosis, has been performed for signs of glaucoma.
No indication of signs of glaucoma has been found and the client doesn't need to be referred to an ophthalmologist for further examination for glaucoma.
If the client is already attending regular checkups with an ophthalmologist, has a scheduled appointment with an ophthalmologist, has been diagnosed with or treated for retinal eye-diseases or shows signs/has symptoms of eye diseases, they should keep attending their appointment(s) and/or seek medical attention, since green results may be false negatives.

An example of a formal communication of a Green result to the customer could be the following:

"RetinaLyze has performed a screening for signs of Glaucoma on a photo of your retina.

RetinaLyze Glaucoma measures the hemoglobin level in the optic disc. The measurement can be used as an indication that the optic disc isn't getting the nourishment that it needs. These symptoms could be caused by Glaucoma.

The hemoglobin level is within the normal range.

On the basis of this analysis, there has not been found any reason to contact an ophthalmologist earlier than already scheduled."

Yellow result

It's important to convey the following:

A screening, not diagnosis, has been performed for signs of glaucoma.
An indication of signs of glaucoma has been found.
If the client has family history of glaucoma, has an elevated IOP, shows indications of optic disc damage on an OCT scan or shows visual field defects on a visual perimeter analysis, the client should be referred to an ophthalmologist for further examination for glaucoma.
If the client is already attending regular checkups with an ophthalmologist, has a scheduled appointment with an ophthalmologist, has been diagnosed with or treated for retinal eye-diseases or shows signs/has symptoms of eye diseases, they should keep attending their appointment(s) and/or seek medical attention, since green results may be false negatives.

An example of a formal communication of a Yellow result to the customer could be the following:

"RetinaLyze has performed a screening for signs of Glaucoma on a photo of your retina.

RetinaLyze Glaucoma measures the hemoglobin level in the optic disc. The measurement can be used as an indication that the optic disc isn't getting the nourishment that it needs. These symptoms could be caused by Glaucoma.

The hemoglobin level is slightly outside the normal range.

On the basis of this analysis, it is recommended to contact an ophthalmologist within months for further examination if you have a family history of glaucoma.
If you do not have a history of glaucoma, you do not need to bring forward your visit to the ophthalmologist, but it is recommended to get the screening again in a year's time or discuss this with your ophthalmologist at your next routine visit."

Red result

It's important to convey the following:

A screening, not diagnosis, has been performed for signs of glaucoma.
An indication of signs of glaucoma has been found.
The client should be referred to an ophthalmologist for further examination for glaucoma within months.
If the client notices symptoms of glaucoma, they should seek medical attention earlier.
If the client is already attending regular checkups with an ophthalmologist, has a scheduled appointment with an ophthalmologist, has been diagnosed with or treated for retinal eye-diseases or shows signs/has symptoms of eye diseases, they should keep attending their appointment(s) and/or seek medical attention, since green results may be false negatives.

An example of a formal communication of a Red result to the customer could be the following:

"RetinaLyze has performed a screening for signs of Glaucoma on a photo of your retina.

RetinaLyze Glaucoma measures the hemoglobin level in the optic disc. The measurement can be used as an indication that the optic disc isn't getting the nourishment that it needs. These symptoms could be caused by Glaucoma.

The hemoglobin level is outside the normal range.

On the basis of this analysis, it is recommended to contact an ophthalmologist within months for further examination."

Have more questions?

If you would like to know more about the RetinaLyze Glaucoma algorithm or have more questions, please have a look at the FAQ about the RetinaLyze Glaucoma below.

Go to the RetinaLyze Glaucoma FAQ

SOURCES

Glaucoma