Peripapillary rnfl classification

For example, quadrant and average RNFL thickness values will usually be relatively greater in individuals with very large optic discs, because thickness generally increases closer to the disc. As expected from the well-known pattern of glaucomatous optic nerve neuroretinal rim thinning, the inferior RNFL quadrant generally undergoes the greatest amount of thinning and has the greatest area under the receiver operating characteristics curve.

This loss is routinely diagnosed by the presence of thinning of the optic nerve neuroretinal rim, peripapillary retinal nerve fiber layer (RNFL), and/or inner layers of the macula.

Publications

Abstract

Purpose: To report the distribution of peripapillary retinal nerve fiber layer (RNFL) thickness in healthy young adults, investigate factors associated with RNFL thickness, and report the percentage of outside normal limits (ONL) and borderline (BL) RNFL thickness classifications based on the optical coherence tomography (OCT) manufacturer reference database.

The researchers’ linear mixed-effects model showed a statistically significant negative RNFL thickness slope in healthy subjects (-0.54μm/year). Linear mixed models were used to analyze associations. Methods: Participants of the Raine Study Generation 2 cohort (aged 18-22 years) underwent spectral domain OCT imaging with an RNFL circle scan. Although OCT analyses of macular and optic nerve neuroretinal rim thickness have become increasingly popular in recent years, RNFL analysis has been the benchmark of OCT imaging in glaucoma since its inception.2 RNFL analysis provides an alternative to the visual inspection of the optic nerve neuroretinal rim as well as a quantitative estimation of retinal ganglion cell axonal loss.

SD-OCT imaging confirms corresponding inferior RNFL thinning seen both on the thickness map and quadrant thickness (C) and inferotemporal macular thinning of the ganglion cell and inner plexiform layers (D).

Structural changes in glaucoma can be detected with different imaging tools, including optical coherence tomography (OCT).

The prevalence of ONL and BL classifications was generally higher than the expected rates of 1% and 4%, respectively, in temporal sectors and lower than expected in nasal sectors. In addition to diagnosis, these measurements are useful for monitoring disease progression.

• Physicians must consider the possibility of confounding factors and assess data in retinal nerve fiber layer reports within the context of the clinical picture.

DISEASE PROGRESSION

RNFL thickness measurements are highly reproducible, especially when acquired with spectral-domain OCT (SD-OCT) instruments.

In fact, RNFL thickness generally follows the ISNT rule (ie, inferior, superior, nasal, temporal), and a violation of the RNFL’s ISNT rule can be indicative of glaucoma. A 12º circular scan pattern containing 768 A-scans, averaged 100 times, was used to derive mean RNFL thickness. Nevertheless, quantitative data in the current RNFL analysis are limited to values obtained from cross-sectional slices of the image.

Longer axial length was associated with thinner RNFL globally, nasally, inferotemporally, superotemporally, superonasally, and inferonasally, as well as thicker RNFL temporally. The optic nerve photograph shows thinning of the inferior optic nerve neuroretinal rim (A) with a superior paracentral visual field defect (B). Results: Data were available for 1288 participants (mean age, 20.0 years).

Baseline global RNFL thickness also had a significant negative effect on RNFL thickness slope (-0.01µm/year) while baseline age had a significant positive effect on RNFL thickness slope (0.01μm/year).

The researchers noted that “The RNFL thickness slope was shallower with thinner baseline RNFL thickness and higher baseline age.”