Chromatopsia

Specialty: Ophthalmology.

• colored vision
• xanthopsia (yellow vision)
• erythropsia (red vision)
• cyanopia (blue vision)

Why it occurs

• Digitalis intoxication (typically causes xanthopsia or yellowish halos due to inhibition of the Na+/K+ ATPase pump in the photoreceptors)
• Recent cataract surgery with intraocular lens implantation (causes temporary cyanopia due to the sudden withdrawal of the aged lens that filtered blue light)
• Incipient diffuse vitreous or preretinal hemorrhage (causes erythropsia)
• Massive exposure to solar radiation or snow without protection from ultraviolet filters (transient post-exposure erythropsia)
• Intoxication by sildenafil or phosphodiesterase-5 inhibitors (causes cyanopia due to cross-reactivity with retinal phosphodiesterase-6)

Initial workup

Analytical determination of digoxin levels in the blood (digoxinemia) and serum electrolytes (potassium, magnesium and calcium, since hypokalemia aggravates toxicity); 12-lead electrocardiogram (ECG); Fundus evaluation under mydriasis to rule out active vitreous hemorrhage; Electroretinogram in complex cases of drug toxicity on the inner retina.

Standard management

• Specific antidigoxin antibodies — Digital antitoxin Fab, indicated intravenously in cases of severe digitalis poisoning with hemodynamic instability or ventricular arrhythmias
• Immediate suspension of suspected drugs — digoxin, sildenafil
• Oral or intravenous potassium replacement depending on the patient's hydroelectrolyte status.