advertisement

Editors Selection IGR 8-4

Imaging: Retinal nerve fibre layer

Comment by Nic Reus on:

15312 Quantifying retinal nerve fiber layer thickness in whole-mounted retina, Huang XR; Knighton RW; Shestopalov V, Experimental Eye Research, 2006; 83: 1096-1101

Find related abstracts

Various optical measurement techniques (e.g., scanning laser polarimetry [SLP] and optical coherence tomography [OCT]) are available to assess the retinal nerve fiber layer (RNFL) in glaucoma. Their measurements of RNFL thickness may be validated by comparing them to measurements of RNFL thickness in conventional histologic sections. However, it is difficult to match a histologic section to an SLP or OCT image. In addition, only a limited number of nerve fiber bundles can be assessed histologically. Moreover, the process is very time consuming. Huang et al. (1012), in this case report study, present a method that uses confocal laser scanning microscopy (cLSM) to allow a 3-dimensional histologic analysis of the retina. To this end, retinas of rats and pigs were whole-mounted. Their retinal nerve fiber bundles were stained with phalloidin and their ganglion cell bodies with DAP fluorescent counterstain of nuclei. cLSM was then used to take en face serial images at different depths. Subsequently, cross-sectional images were constructed from these measurements.

The en face cLSM image showed the same pattern of nerve fiber bundles and blood vessels as seen in measurements that had been obtained beforehand with either reflectometry or polarimetry, allowing good registration of measurements. The cross-sectional images provided thickness measurements of the RNFL over the entire field-of-view . Of note, RNFL thickness measured with cLSM was thicker than that measured in conventional histologic sections, which may have been due to tissue dehydration in the histologic sections. Not only can the cLSM method be used to validate various imaging techniques, it may also be an easy and precise way to study RNFL damage in animal models. A drawback of the currently presented method may be that it is not able to measure very thick nerve fiber bundles, such as occur in human RNFL, due to low signal-to-noise ratios at increasing depths in the retina.

• ← Previous
• Next →