Reconciling visual field defects and retinal nerve fibre layer asymmetric patterns in retrograde degeneration: an extended case series

Abstract

BackgroundAccurate diagnosis in patients presenting with lesions at various locations within the visual pathway is challenging. This study investigated functional and structural changes secondary to such lesions to identify patterns useful to guide early and effective management.MethodsOver 10,000 records from patients referred for optic nerve head assessment were reviewed and 31 patients with a final diagnosis of likely neuropathic lesions posterior to the eye were included in the current study. Fundus photographs, optic coherence tomography images and visual field tests were evaluated for changes with respect to retinal nerve fibre layer topography and prediction of structure‐function paradigms. Emerging clinical patterns were examined for their consistency with the likely anatomical origin of the underlying insult in the presence of varying diagnoses.ResultsData from patients with lesions along the visual system allowed identification of retinal nerve fibre layer asymmetry correlated with visual field defects and ganglion cell analysis. Bilateral discordance in retinal nerve fibre loss easily discernible from an altered pattern of the temporal‐superior‐nasal‐inferior‐temporal curve was characteristic for post‐chiasmal lesions. These sometimes‐subtle changes supported diagnosis in cases with multiple aetiologies or with ambiguous visual field analysis and/or ganglion cell loss.ConclusionIntricate knowledge of the retinal architecture and projections allows coherent predictions of functional and structural deficits following various lesions affecting the visual pathway. The integration of adjunct imaging and retinal nerve fibre layer thinning will assist clinicians to guide clinical investigations toward a likely diagnosis in the light of significant individual variations. The case series presented in this study aids in differential diagnosis of retrograde optic neuropathies by using retinal nerve fibre layer asymmetric patterns as an important clinical marker.

An evidence‐based approach to the routine use of optical coherence tomography

“…Unlike in AMD and DR, OCT imaging of treatment‐naïve eyes with glaucoma does not necessarily yield ‘classic’ signs, and instead displays significant overlap with other disorders affecting the optic nerve head, such as retinal vascular occlusions and ischaemic optic neuropathies (Figure B–D) . This further reinforces the idea of glaucoma as a disease of statistical abnormality (for example, statistically depressed visual field or OCT results) .…”

The value of visual field testing in the era of advanced imaging: clinical and psychophysical perspectives

“…The anatomy of the optic chiasm and of the visual pathway beyond, means that, in general, visual field defects are bilateral . Patterns of visual field loss – pre‐chiasmal, chiasmal or post‐chiasmal – are useful for guiding subsequent neuroimaging …”

“…The anatomy of the optic chiasm and of the visual pathway beyond, means that, in general, visual field defects are bilateral. 146 Patterns of visual field lossprechiasmal, chiasmal or post-chiasmalare useful for guiding subsequent neuroimaging. [147][148][149] Chiasmal defects are characteristically bitemporal (Figure 8), with a bias toward either superior (for example, pituitary adenoma) or inferior (for example, craniopharyngioma) bitemporal defects, depending on aetiology.…”

“…[147][148][149] Chiasmal defects are characteristically bitemporal (Figure 8), with a bias toward either superior (for example, pituitary adenoma) or inferior (for example, craniopharyngioma) bitemporal defects, depending on aetiology. 146,150 Visual field losses in the far superotemporal and inferotemporal regions of the field may at first be subtle and the wider and symmetrical 30-2 test grid may be required.…”

“…152,153 Defects higher along the visual pathway (for example, cortical lesions) are typically more congruous. 154,155 Lesions of the axons travelling in the optic radiations or cortical areas postlateral geniculate nucleus can give rise to trans-synaptic retrograde degeneration of the retinal ganglion cells (see Zangerl and colleagues 146 for a full review). Retrograde degeneration manifests as retinal nerve fibre layer or retinal ganglion cell loss mirroring the visual field defects that respect the vertical midline.…”