Ocular and Visual System (2)

Amphiphilic medications such as amiodarone, chloroquine, clofazimine, phenothiazines, suramin

CORNEA
- Pigment deposits in corneal epithelium (verticillate keratopathy)
- Intralysosomal accumulation of lipids

Long-term systemic use of phenothiazine (AC), corticosteroids (PSC)

LENS
- Cataracts anterior cortical, (AC), posterior subcapsular, (PSC)
- Chemical deposition, photochemical oxidation

Organophosphate and carbamate insecticides, nerve gas agents such as sarin, soman, and tabun

PUPIL
- Pupil constriction (miosis)
- Anticholinesterases

Atropine or belladonna

PUPIL
- Pupil dilation (mydriasis) and photophobia
- Cholinergic antagonists

Amphetamine, cocaine, phenylephrine

PUPIL
- Pupil dilation (mydriasis) and photophobia
- Adrenergic antagonists

Acute alcohol intoxication, barbiturate toxicity, acute solvent exposure

OCULAR MOTILITY
- Diplopia (double vision), nystagmus
- Oculomotor impairment, Damage or dysfunction in vestibular/oculomotor reflex pathways

Carbon disulfide, chloroquine

Retinal pigment epithelium
- Loss of central vision (central scotoma)
- Degeneration of retinal pigment epithelium and underlying photoreceptors

Lead, methyl mercury, vigabatrin; Organophosphate and carbamate insecticides, nerve gas agents

RETINA
- Poor night (scotopic) vision and impaired dark adaptation
- Damage to and apoptosis of rod photoreceptors, Acetylcholinesterase inhibitors

Digitalis/digitoxin

RETINA
- Altered color perception, central scotoma
- Inhibition of cone photoreceptor sodium-pumps

Sildenafil and tadalafil

RETINA
- Altered color perception
- Inhibition of cone photoreceptor cGMP-phosphodiesterase

Chronic exposure to styrene and organic solvents, trimethadione, chronic high dose antibiotics

RETINA
- Impaired color discrimination (Blue/Yellow)
- Damage to cone photoreceptors and inner retina

Higher level chronic exposure to organic solvents:
Carbon disulfide
Hexane
Chronic Carbon Monoxide
Chronic Alcoholism
Ethambutol

RETINA
- Impaired color discrimination (Red/Green)
- Acquired damage to cone photoreceptors, neural retina and/or afferent visual pathway

Methyl mercury, vigabatrin

RETINA
- Loss of peripheral vision (tunnel vision, peripheral scotoma, visual field constriction)
- Degeneration of peripheral retina and nerve fiber layer

Acrylamide, carbon disulfide

RETINA
- Reduced contrast sensitivity and visual acuity
- Degeneration of the retinal ganglion cells and optic tract, microaneurysms and retinal vasculopathy

Higher level chronic exposure to organic solvents such as:
Carbon disulfide
Hexane
Ethambutol
Ethylene glycol
Isoniazid
Linezolid
Chloramphenicol
Methanol
Vigabatrin

OPTIC NERVE AND OPTIC TRACT
- Reduced contrast sensitivity and visual acuity
- Optic neuritis and/or degeneration of the optic tract, generally affecting mitochondrial ATP production

Amiodarone
Sildenafil
Tadalafil

OPTIC NERVE AND OPTIC TRACT
- Monocular and/or binocular visual loss
- Nonartereteric anterior ischemic optic neuropathy

Methyl mercury

LATERAL GENICULATE AND VISUAL CORTEX
- Central scotoma
- Degeneration of calcarine fissure of visual cortex

Lead
Chronic Exposure to Carbon Disulfide
Hexane and other Solvents
Toluene

LATERAL GENICULATE AND VISUAL CORTEX
- Visuomotor deficits and reduced contrast sensitivity
- Visual and motor cortex dysfunction