Glaucoma masqueraders: Diagnosis by spectral domain optical coherence tomography

Abstract

Background: Advances in optic nerve and retinal imaging have dramatically changed the care of glaucoma patients, complementing the importance of the clinical exam of the optic nerve and automated perimetry in making the diagnosis of glaucoma. Computerized imaging, however, does not replace the clinical exam, as there can be overlap in the appearance of non-glaucomatous optic neuropathies with glaucoma.

Methods: The spectral domain optic coherence tomography (SD-OCT) images of five patients with non-glaucomatous optic nerve pathology are presented.

Cases: The first patient had bilateral temporal thinning on OCT imaging and subsequent positive syphilis testing. The second patient had a glaucomatous-appearing inferior arcuate scotoma and associated superior thinning on OCT; these findings were due to buried optic nerve head drusen, clearly appreciated on OCT of the optic nerve head. Bilateral diffuse macular thinning, with preservation of the superior and inferior fiber bundles, was seen in the third patient, who had multiple sclerosis, with no clinical history of optic neuritis. Dense and marked thinning of a macular half, respecting the horizontal meridian, is seen in two patients, one patient with non-arteritic anterior ischemic optic neuropathy and lastly, in a patient with hemi-retinal vein occlusion.

Conclusion: SD-OCT of the optic nerve and retina complements the essential clinical examination of patients with glaucomatous and non-glaucomatous optic neuropathies.

Keywords: Glaucoma; Macular OCT; OCT; Optic neuropathy.

Figure 1

Optic neuropathy secondary to treponemal infection. Optic nerve images of the right (OD) and left (OS) eyes are displayed, adjacent to the Pattern Deviation plots from the patient’s visual field (VF). The RNFL analysis and scan are shown for each eye. The color retinal thickness maps (revealing differences of 10–15 microns) of each eye are flanked by the Asymmetry Analyses comparing the superior to inferior macular half. Note the inferior nasal defect on the VF in the left eye, and the corresponding thinning of the superior quadrant of the RNFL (arrow), suggestive of a glaucomatous defect. Also note the significant loss of the superior half of the parafoveal thickness (arrow). However, the bilateral temporal thinning is unusual in mild-moderate glaucoma.

Figure 2

Optic nerve head drusen with associated visual abnormalities. Optic nerve images of the right (OD) and left (OS) eyes are displayed, adjacent to the Pattern Deviation plots from the patient’s VF. The RNFL analysis and scan are shown for each eye. The color retinal thickness maps of each eye are flanked by the Asymmetry Analyses comparing the superior to inferior macular half. Elevation of the nasal disc is due to drusen (arrow). Note the superior nasal defect in the RNFL with the corresponding inferior visual field defect. There is a superior arcuate-shaped area of thinning in the macula (arrow).

Figure 3

Optic nerve head drusen. The right optic nerve, with an oblique optical section through the optic nerve head, is displayed. The drusen appears dark on the OCT (arrow).

Figure 4

Multiple Sclerosis-associated optic neuropathy. Optic nerve images of the right (OD) and left (OS) eyes are displayed, adjacent to the Pattern Deviation plots from the patient’s VF. The RNFL analysis and scan are shown for each eye. The color retinal thickness maps of each eye are flanked by the Asymmetry Analyses comparing the superior to inferior macular half. There is bilateral temporal thinning of the RNFL, with relative preservation of the superior and inferior bundles. On the macular scan, note extensive loss of the parafoveal ganglion cells and the papillomacular bundle.

Figure 5

Non-arteritic anterior ischemic optic neuropathy. The optic nerve image of the left (OS) eye is displayed, adjacent to the Pattern Deviation plot from the patient’s VF. The RNFL scan and analysis are shown for that eye. The retinal thickness map (shown in color) of that eye is shown with the Asymmetry Analysis (black-and-white square map to the right of the color map) comparing the superior to inferior macular half. There is superior and temporal thinning of the RNFL with an associated inferior altitudinal visual field defect. The retinal thickness of the superior half of the macula is diffusely and markedly thin, respecting the horizontal meridian.

Figure 6

Hemi-retinal vein occlusion. The optic nerve image of the left (OS) eye is displayed, adjacent to the Pattern Deviation plot from the patient’s VF. The RNFL scan and analysis are shown for that eye. The retinal thickness map (shown in color) of that eye is shown with the Asymmetry Analysis comparing the superior to inferior macular half (black-and-white square map to the right of the color map). Note the superior altitudinal defect on the visual field, with the corresponding inferior thinning of the RNFL and macula. The inferior macula is markedly thin, less than 200 microns.