Research Article: Macular choroidal thickness and peripapillary retinal nerve fiber layer thickness in normal adults and patients with optic atrophy due to acute idiopathic demyelinating optic neuritis

Date Published: June 1, 2018

Publisher: Public Library of Science

Author(s): Kyung-Ah Park, Daye Diana Choi, Sei Yeul Oh, Rayaz A. Malik.

http://doi.org/10.1371/journal.pone.0198340

Abstract

To evaluate the association between macular choroidal thickness and peripapillary RNFL thickness in patients with optic atrophy due to acute idiopathic demyelinating optic neuritis and in normal controls using spectral domain optical coherence tomography (SD-OCT).

We performed SD-OCT peripapillary RNFL circular scan centered on the optic disc with horizontal and vertical crosshair scans through the fovea using the enhanced depth technique in 62 eyes with optic atrophy due to acute idiopathic demyelinating optic neuritis and 86 eyes of normal controls. The association between RNFL thickness and macular choroidal thickness measurements was assessed.

The mean age was 43 ± 14 years (mean ± SD) in patients with optic atrophy and 45 ± 16 years in healthy controls (p = 0.791). There was a significant association between nasal peripapillary RNFL thickness and choroidal thickness at 3.0 mm nasal to the foveal center in patients with optic atrophy in multivariate analysis (estimate = 1.398, p = 0.011). In controls, there were significant associations between global average, superior, and inferior peripapillary RNFL thickness and choroidal thickness at 3.0 mm superior to the foveal center (estimate = -60.112, p = 0.044, estimate = 15.821, p = 7.312, and estimate = 15.203, p = 7.222, respectively).

Our SD-OCT data revealed that there was a significant association between peripapillary RNFL thickness and macular choroidal thickness in patients with optic atrophy due to acute idiopathic demyelinating optic neuritis and in controls, although the mechanism remained unclear. The difference in the pattern of association between patients with optic atrophy and controls suggests that optic atrophy caused by acute idiopathic demyelinating optic neuritis could affect the pattern of association between peripapillary RNFL thickness and macular choroidal thickness.

Partial Text

Optical coherence tomography (OCT) is a noninvasive and objective method for quantitating axonal and neuronal loss in patients with various types of optic neuropathies and disorders of the central nervous system[1–3]. Peripapillary retinal nerve fiber layer analysis has become one of the most useful tools for evaluating optic nerve damage in optic neuropathies. Recently, in addition to measurement of nerve fiber layer thickness, choroidal thickness has been investigated in various optic neuropathies including glaucoma, anterior ischemic optic neuropathy, and optic neuritis (ON)[4–12]. Several studies have reported that peripapillary choroidal thickness is thinner in glaucomatous eyes compared to that in normal eyes[6, 7]. However, the result is controversial[4, 5]. Peripapillary and macular choroidal thicknesses are also related to anterior ischemic optic neuropathy[8–11]. One study has reported that peripapillary RNFL thinning in non-glaucomatous optic atrophy is associated with peripapillary choroidal thinning[12]. Another population-based study on 478 non-glaucomatous adults has revealed that thinner peripapillary choroidal thickness is associated with thinner peripapillary RNFL thickness[11]. However, the association between macular choroidal thickness and peripapillary RNFL thickness in patients with optic atrophy due to ON or in normal controls is currently unclear. Therefore, the objective of this study was to evaluate the association between macular choroidal thickness and peripapillary RNFL thickness in patients with optic atrophy due to acute idiopathic demyelinating ON and in normal controls. Such evaluation might provide a better understanding of the relationship between structural parameters that might be useful for assessing optic nerve damage using OCT in various optic neuropathies.

This retrospective study was approved by the Institutional Review Board of Samsung Medical Center (Seoul, Republic of Korea). It was performed at a single center according to the tenets of the Declaration of Helsinki. This study included the following two groups of participants: 46 patients (62 eyes) with optic atrophy caused by acute idiopathic demyelinating ON and 47 healthy controls (86 eyes), who visited the general or neuro-ophthalmology clinic between April 1, 2011 and March 31, 2016. Most of healthy controls were hospital workers who underwent routine ocular examination.

The mean age was 43 ± 14 years (mean ± SD) in patients with optic atrophy and 45 ± 16 years in healthy controls (p = 0.791). Twenty-nine (63%) patients with optic atrophy and 26 (55%) healthy controls were women. The mean spherical equivalent refractive error was -1.2 ± 2.1 diopters in patients with optic atrophy and -0.6 ± 1.5 diopters in controls (p = 0.144). Peripapillary RNFL thickness measurements and descriptive statistics of functional and vision test are summarized in Table 1. Significant differences were observed between eyes with optic atrophy and control eyes in all clinical parameters and in peripapillary RNFL thicknesses.

In this study, significant differences in peripapillary RNFL thicknesses were observed between eyes with optic atrophy and control eyes, but not in macular choroidal thickness. One previous study has reported that peripapillary choroidal thickness in patients with non-glaucomatous optic atrophy caused by ON is thinner than that in controls globally and at temporal, temporal-superior, and nasal-inferior regions[12]. In our study, there was no significant difference in macular choroidal thickness between patients with optic atrophy and healthy controls. Our data suggest that optic atrophy caused by acute idiopathic demyelinating ON does not induce significant macular choroidal damage which can cause changes in choroidal thickness.

 

Source:

http://doi.org/10.1371/journal.pone.0198340

 

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