Lesson 7: Top 6 Artefacts 2 Copy

3. Incomplete segmentation: Segmentation refers to the computer deciding where the borders of the retinal nerve fibre layer tissue lie.

It may then display it as two coloured lines. If you donu2019t see the two-coloured lines going all the way from the left to the right of the printout, you have incomplete segmentation, which means the machine was unable to completely draw the coloured lines and unable to determine the complete borders of the retinal nerve fibre layer.

In this situation, the machine may not be able to calculate the correct thickness of the retinal nerve fibre layer.

4. Peripapillary-atrophy-associated error: Peripapillary atrophy is a common abnormality that can occur in the vicinity of the optic nerve.

It is often seen in older patients and patients who have glaucoma. Usually, the OCT scan circle is larger than most Peripapillary-atrophy, so most scans are not affected by it.

However, in patients who have really large areas of Peripapillary-atrophy, the OCT machine will scan over it.

Because certain layers of the retina are missing in an area of Peripapillary-atrophy, the machine will wrong thickness values of the retinal nerve fibre layer.