Which statement about periorbital cellulitis is true?

• A. It involves eyelid and surrounding soft tissues but does not involve the orbit.
• B. It has no risk of spreading to the orbit.
• C. It commonly causes immediate vision loss.
• D. It is treated with intravitreal antibiotics.

Answer: (A)

Periorbital (preseptal) cellulitis is an infection of the eyelid and the surrounding soft tissues that lie anterior to the orbital septum. The orbital septum is a boundary that keeps infection from entering the orbit itself. That’s why the hallmark of this condition is eyelid swelling, redness, and tenderness without involvement of the eye itself or its movements in the early stages. Vision is usually preserved because the globe and extraocular muscles aren’t affected initially.

The true statement reflects this distinction: the infection involves the eyelid and surrounding tissues but not the orbit. However, it can spread posteriorly across the orbital septum into the orbit, leading to orbital cellulitis, which can cause proptosis, painful eye movements, impaired extraocular movements, fever, and potential vision changes. This is why clinicians monitor for signs of orbital involvement and may pursue imaging if there are concerning features.

Intravitreal antibiotics are reserved for infections inside the globe, such as endophthalmitis, not for periorbital cellulitis. Treatment of periorbital cellulitis is systemic antibiotics, typically started intravenously in more serious cases, with transition to oral therapy as appropriate, and with attention to underlying causes like sinusitis.