This document provides an overview of the general approach and examination for neurological causes of vision loss. It discusses evaluating for monocular versus binocular visual loss and whether the loss is transient or persistent. The examination involves assessing visual acuity, color vision, visual fields, pupils, eye examination, and funduscopy. For transient monocular visual loss, causes like emboli, vasculitis, and giant cell arteritis are discussed. Persistent monocular loss localizes to the eye or optic nerve. Binocular transient loss is often due to migraines or TIAs, while persistent binocular loss results from retrochiasmal strokes. Progressive vision loss indicates a compressive lesion. Specific conditions like optic neuritis, NA

1. Approach to Neurological
Causes of Vision Loss
Presenter: Dr. Kshitij Bansal
Senior Resident
Department of Neurology
GMC, Kota

2. General Approach
• Decide whether it is monocular or binocular.
• Transient/persistent
Examination –
• Visual acuity with pinhole
• Colour vision: Pseudoisometric colour plates- Early optic nerve disease may manifest as a
reduction in saturation or brightness of colours.

3. General Approach
• Field testing – Confrontation in both eyes separately.
• An abrupt change across the horizontal axis in one eye suggests optic nerve disease, and an abrupt
change across the vertical meridian in both eyes indicates visual loss of intracranial origin.
• Kinetic ( Goldmann) perimetry
• Automated static perimetry.

5. General Approach
• Pupil – RAPD localise lesion to optic nerve. Exceptions include central or large-branch retinal
artery occlusions and large retinal detachments.
• Local eye examination – Ophthalmologist’ domain. Gross examination can be done including
proptosis, congestion.
• ‘‘If you can’t see in, the patient can’t see out.’’
• Fundus – Disc – o –centric. Habit of seeing macula as well.

8. Transient Monocular Visual Loss
• Transient visual loss is often caused by abnormalities of the retinal vasculature, eg, intra- luminal
particulate matter, such as calcific or platelet fibrin emboli from the heart, or refractile cholesterol
emboli from the carotid arteries or aortic arch.
• Infections, such as syphilis, or systemic inflammatory disorders, such as sarcoidosis, may cause
vasculitis with arterial or venous sheathing and exudate deposition.
• Painful transient monocular visual loss should suggest giant cell arteritis, ocular ischemic syndrome,
carotid artery dissection, or angle-closure glaucoma.

13. Persistent Monocular Visual Loss
•Persistent monocular visual loss must localize to the eye itself or the optic nerve anterior to its junction with
the chiasm.
•The classic features of a unilateral optic neuropathy:
1. central visual loss
2. clear view through the ocular media to the optic nerve,
3. a relative afferent pupillary defect, and
4. a swollen or pale optic nerve head.
•Some optic neuropathies may spare central visual acuity.
•In up to 50% of patients with nonarteritic anterior ischemic optic neuropathy, for example, visual acuity is
good despite altitudinal visual field loss.
•In other acute optic neuropathies, such as most cases of retrobulbar idiopathic optic neuritis, the optic nerve

14. Case 1
• A 33-year-old woman was referred for an 8-day history of progressive decreased vision in her left eye.
One day prior to the onset of visual loss, she had experienced pain over her left forehead that
worsened with eye movements. Her past medical history was unremarkable, and she was on no
medication. On examination, visual function was normal in the right eye. In the left eye, visual acuity
was 20/400 with no color perception and a dense relative afferent pupillary defect. Visual field testing
showed a large dense central scotoma. Motility was full. The fundi were normal, as was the remainder
of the examination.

15. The fundi were normal

16. Diagnosis?

17. • At 2-month follow-up, vision in the left eye was much improved, and her visual field was now normal.
The left optic disc was pale temporally.
• This patient’s symptoms followed the typical course of retrobulbar optic neuritis. The MRI documented
the presence of white matter lesions, and although she never had any other neurologic symptoms, she
was at high risk for the subsequent development of multiple sclerosis.

18. Case 2
• A 37-year-old woman presented with visual loss in the right eye. Her past medical history was unremarkable, and
she was on no medication. Five weeks prior to presentation, she had reported irritation and itchiness of the right
eye, which improved with artificial tears. Five days later, she had noticed decreased vision in the inferior visual
field in the right eye, which worsened over 4 to 5 days. She had no eye pain, pain with eye movement, or
headaches. She denied any neurologic symptoms. She had a brain MRI that showed no optic nerve
enhancement, but showed one small nonenhancing periventricular T2 high signal lesion.
• D/D?
• She was diagnosed with a right optic neuropathy by her optometrist, presumably related to a right optic neuritis.
She did not receive treatment. Her vision failed to improve during the following 4 weeks.
• On neuro-ophthalmic examination, visual acuity was 20/20 in both eyes and color vision was normal, but mild red
desaturation was present in the right eye. Orbits, slit-lamp examination, and intraocular pressures were normal. A
right relative afferent pupillary defect was present. Eye movements and eyelids were normal. Humphrey visual
fields showed an inferior arcuate defect in the right eye. Funduscopic examination showed mild disc edema in
the right eye with a small cup-disc ratio in both eyes.

20. • This patient had an anterior right optic neuropathy (ie, decreased visual acuity, red desaturation, visual
field defect, ipsilateral relative afferent pupillary defect, and mild disc edema).
• The absence of pain, the absence of optic nerve enhancement on the MRI, and the absence of
spontaneous recovery of vision argued against an optic neuritis as the cause of her optic neuropathy.
• The mild disc edema in the setting of a small cup-disc ratio was very suggestive of a nonarteritic
anterior ischemic optic neuropathy despite her young age and absence of known vascular risk factors.
• An accurate diagnosis was crucial because a false diagnosis of optic neuritis would have likely
resulted in a number of costly tests (eg, lumbar puncture and repeat MRI) and a possible wrong
diagnosis of presumed high risk for the development of multiple sclerosis given the finding of an
incidental small white matter T2 hyperintensity on her brain MRI.

22. Persistent Monocular Visual Loss
• Important to differentiate between Macula and optic nerves.
• Both optic nerve lesions and macular lesions can reduce central acuity, and both can cause central
scotomas on visual fields.
• Both may also affect color vision, although the amount of color vision deficit for any given visual acuity
deficit is usually greater for an optic neuropathy than a maculopathy.
• Maculopathies are rarely painful, as compared to optic neuropathy, especially idiopathic optic neuritis
in which pain, particularly pain exacerbated by eye movement, is a common feature.
• Classically, maculopathies cause visual distortions and vision is slow to recover after bright light,
features not usually found among optic neuropathies.

25. Retinal Artery and Retinal Vein Occlusion
• Ophthalmic artery and central and branch retinal artery occlusions are typically acute and painless.
• When a retinal artery becomes occluded, the normally transparent retina supplied by that artery
becomes white and edematous.
• There may be segmentation of the arteriolar blood column (boxcarring), a reduction of the arteri- olar
lumens, and sometimes visible emboli.
• These acute retinal infarctions should be evaluated urgently in a stroke unit similar to acute cerebral
infarctions.
• Occlusion of the central retinal vein produces a dramatic funduscopic appearance in which the retinal
veins are markedly dilated with diffuse haemorrhages involving the inner layers of the retina.
• Cotton wool spots (small infarctions of the nerve fiber layer) and swelling of the optic nerve head are
also present.

26. Extensive superficial splinter and blot hemorrhages
surround the disc and extend into all quadrants of the
retina. Considerable retinal edema is present. The disc
is edematous with blurred margins but the central cup
can still be visualized. The veins are engorged and
tortuous. Several small cotton wool spots (micro
infarctions) can be seen adjacent to the disc.

27. Transient Binocular Visual Loss

28. • Other than transient visual obscuration in patient of bilateral papilledema, it is always due to transient
dysfunction of visual cortex.
• Visual migraine aura – M/C cause in age < 40 years
• TIA – old patients. Needs thorough cardiac/ vertebrobasilar workup.
• PRES – a/w headache, altered mental status. Seen in preeclampsia, Cyclosporine chemotherapeutic
agents
Transient Binocular Visual Loss

29. Migrane
• Transient binocular visual loss commonly appears in the visual prodrome, or aura, of migraine.
• Typically patients see a small scotoma in homonymous portions of the visual field, surrounded by
jagged, luminous, shimmering edges.
• The scotoma enlarges over several minutes, then gradually disappears, characteristically followed by a
hemicranial throbbing headache on the side opposite the involved hemifield.
• The visual loss may progress to a complete homonymous hemianopia.

30. Cerebral Hypoperfusion
• In older patients, episodes of transient, complete binocular visual loss may represent a TIA in the
distribution of the basilar artery or the posterior cerebral arteries.
• Cardiac disease and disease of the more proximal vertebral-basilar system must be considered as
embolic sources.
• TIA can also manifest as transient homonymous hemianopia.
• Hemianopic events of ischemic origin are typically sudden in onset, unlike those of migraine.
• Associated headache may be present, especially over the brow contralateral to the visual field loss.

31. Case 3
• A 65-year-old woman had episodic visual loss. In her twenties and thirties, she had experienced
episodic headaches with nausea, photophobia, and phonophobia, but with no associated visual
phenomena. 2 years before the present examination she had begun to experience episodes of
bilateral visual disturbances, which she described as the appearance of gold line just off the center of
vision in both eyes. The line enlarged over approximately 5 to 10 minutes, enclosing a central area.
After 20 minutes, the process gradually broke up like a puzzle and normal vision was restored. She
denied associated headache or eye pain.
• Diagnosis?

32. • This woman presented with a typical history of migrainous visual aura without headache. The
characteristic buildup of positive visual symptomatology over time, the duration of the episodes, their
occurrence over years, the lack of other neurologic symptoms or signs, and the lack of any residual
abnormality on examination all attested to the benign nature of these events. The absence of
headaches is common after age 50.

34. Persistent Binocular Visual Loss
• Most commonly results from strokes involving the retrochiasmal visual pathways and causes
homonymous visual field defects.
• Bilateral occipital lobe infarcts can result in tubular visual field defects, checkerboard visual field
defects, or complete loss of vision in both eyes, a condition called cortical or cerebral blindness.
• Cortical blindness, especially from infarction, can be accompanied by a denial of the visual loss and
confabulation, a condition known as Anton syndrome.
• Sudden binocular visual loss can also result from bilateral ischemic optic neuropathies or from
chiasmal compression due to pituitary apoplexy.
• Pituitary apoplexy can cause headache, diplopia, ptosis, altered mental status, and hemodynamic
shock, but the presentation can be subtle such that the diagnosis is missed.

35. Progressive Visual Loss

36. Progressive Visual Loss
• Progressive visual loss is the hallmark of a lesion compressing the afferent visual pathways.
• Examples: Pituitary tumors, aneurysms, craniopharyngiomas, and meningiomas.
• Granulomatous disease of the optic nerve from sarcoidosis or tuberculosis.
• Optic nerve compression at the orbital apex from thyroid eye disease can occur with minimal orbital
signs or ocular motility disturbance.
• Hereditary or degenerative diseases of the optic nerves or retina are bilateral and are usually
diagnosed during the first two decades of life.
• The most common inherited optic neuropathy is the autosomal dominant variety, known as dominant
optic atrophy.
• There are central or cecocentral scotomas with sparing of the peripheral visual field and temporal
pallor and cupping of the optic discs. Color vision is usually abnormal.

37. Progressive Visual Loss

38. Progressive Visual Loss
• Leber hereditary optic neuropathy (LHON) is a maternally transmitted disease resulting from
mutations in the mitochondrial deoxyribonucleic acid (DNA) genes encoding subunits of respiratory
chain complex I.
• LHON can also cause sudden painless central visual loss with subsequent progression.
• The visual loss initially may be monocular or binocular, but the fellow eye is almost always affected
within a few weeks to months and certainly by 1 year.
• Visual recovery is variable and infrequent and depends on the mitochondrial DNA mutation.
• Optic disc drusen are a common cause of pseudopapilledema and can produce visual field defects
including enlargement of the physiological blind spot, arcuate defects, and generalized constriction.
• Loss of visual acuity is atypical but can result from development of a secondary choroidal neovascular
membrane, with subsequent hemorrhage into the macula, or anterior ischemic optic neuropathy.

39. Progressive Visual Loss

40. Progressive Visual Loss

41. Progressive Visual Loss
• Chronic papilledema from any cause of intracranial hypertension can produce progressive optic
neuropathy.
• The visual fields become constricted, with nasal defects occurring initially, followed by gradual
constriction, with central vision being spared until late.
• Toxic and nutritional optic neuropathies are bilateral and usually progressive.
• Nutritional variety causes gradual onset of painless visual loss, prominent dyschromatopsia,
cecocentral scotomas, and development of optic atrophy late in the disease.
• Medications that are toxic to the optic nerves, including ethambutol, amiodarone, and linezolid.
• Retinal toxins, such as vigabatrin, digitalis, chloroquine, hydroxychloroquine, and
phenothiazines.

42. Progressive Visual Loss

43. Progressive Visual Loss
• Rapidly progressive bilateral visual loss can be caused by paraneoplastic processes that affect the
retina or, less commonly, optic nerves.
• Small-cell carcinoma of the lung is the most commonly associated tumor, but gynecological,
endocrine, and breast tumors have been implicated.
• With CAR, features include photopsias, night blindness or nyctalopia, constricted visual fields, and an
extinguished electroretinogram.
• Combined treatment with chemotherapy and immunosuppression may be effective in occasional
cases.

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