Histological Section as Compared to the OCT Image 

Although the Photoreceptor Integrity Line, or the PIL (defined as the junction between the inner and outer segments) is barely visible in most histological sections, it is highly prominent in normal SD OCTs. The PIL, as shown above, should be continuous throughout the entire scan in normal eyes. The PIL is considered by some as a mere artifact that is due to the difference in the index of refraction of the inner and outer segments but this artifact is remarkably useful in SD OCT interpretation.*

*The Photoreceptor Integrity Line (PIL) as Revealed by SD OCT is available at: http://www.lulu.com