Halos around lights

Specialty: Ophthalmology.

• colored halos
• light diffraction
• ophthalmic luminous circles

Why it occurs

• Senile cataract in development (changes in the refractive index of the lens)
• Corneal epithelial edema secondary to acute crisis of ocular hypertension
• Progressive Fuchs endothelial dystrophy
• Prolonged use or overuse of poorly fitting contact lenses
• Accentuated irregular astigmatism or apical keratoconus
• Previous corneal refractive surgery (sequence of aberrant spherical aberrations)

Initial workup

Urgent Goldmann applanation tonometry (to quantify intraocular pressure); Angular gonioscopy with a Sussman or Zeiss lens (essential to evaluate the degree of opening or apposition of the iridocorneal angle); Slit lamp biomicroscopy (assessing microcystic corneal edema and anterior chamber depth); Ultrasonic corneal pachymetry to rule out pathological increase in corneal thickness due to stromal hydration.

Standard management

• Acetazolamide — 250 mg orally every 6 or 8 hours, or 500 mg intravenously in the context of an emergency due to acute glaucoma to drastically suppress the production of aqueous humor by the ciliary processes
• Pilocarpine — 2% eye drops, 1 drop administered serially into the conjunctival sac during the glaucoma attack to induce mechanical pupillary miosis and mechanically remove the peripheral iris from the trabecular angle
• Mannitol 20% (intravenous infusion of 1.5 to 2 g/kg to be administered over 45 minutes to osmotically dehydrate the vitreous and aqueous compartments).