A 67-year-old woman presents to the emergency department with increasing redness, pain, and decreasing vision of her right eye. Of note, she underwent uncomplicated cataract surgery in her right eye five days ago. The patient stated she was taking her post-operative drops as prescribed (an antibiotic and steroid combination eye drop every two hours). Over the past 12 hours she began to notice worsening ocular redness, discomfort, and rapid loss of vision.
On examination her visual acuity is counting fingers at 3 feet (right eye) and 20/40 (left eye). Her right pupil is not visualized but her left reacts to light normally. Intraocular pressures are 8 and 16 mmHg by Tonopen respectively. Slit lamp examination of the right eye demonstrates 3+ conjunctival injection, 2+ chemosis, trace central corneal edema with Seidel negative incisions (no leakage of intraocular fluid demonstrated after wetting a sterile fluorescein strip and painting the area across the wound). A 3 mm hypopyon with 4+ anterior chamber cell and an intraocular lens implant in the posterior chamber is noted in the right eye. Slit lamp examination of the left eye demonstratesa normal anterior eye exam, and a lens with 2+ nuclear sclerosis. The fundus was unable to be visualized in the right eye due to the presence of vitritis. Dilated fundus examination of the left eye is within normal limits. B-scan ultrasonography confirms the presence of vitritis (highly mobile echogenic spots within the vitreous cavity); the retina is attached.
The history and photograph are most consistent with which of the following:
Toxic Anterior Segment Syndrome (TASS)
TASS is a rare anterior segment reaction that may occur after surgery.1-3 It is caused by a moderate to severe sterile inflammatory reaction in response to contamination of instruments, bacterial toxins remaining after instrument sterilization, imbalanced solutions, medications, and preservatives. It may mimic acute endophthalmitis as it presents with a postoperative red eye, and anterior segment inflammation with or without hypopyon. However, itdiffers from endophthalmitisin that it tends to present earlier (within 12-48 hours after surgery), with diffuse limbus-to-limbus corneal edema, and it responds to topical steroids. When the diagnosis is in question, patients undergo frequent follow up or, patients are worked up and treated as infectious endophthalmitis until cultures from a vitreous tap come back negative.
Rebound iritis is a common condition that occurs following the taper of steroid drops after intraocular surgery.4 It is caused by topical steroid drops being tapered too quickly, or poor patient compliance with a steroid taper. Rebound iritis may mimic chronic endophthalmitis as it typically presents late in the post-operative course after 4–6 weeks, typically a few days after a topical steroid has been eliminated. Typically, the condition responds well to reinstituting a topical steroid, with clear instructions for the patient to undergo a slower taper. If a patient has difficulty being tapered off drops, or has a recurrent uveitis after intraocular surgery, the diagnosis of chronic endophthalmitis caused by an indolent bacterium such as Propionibacterium Acnes should be entertained. This entity is treated by injection of intraocular antibiotics, however in some cases the intraocular lens and capsular bag must be removed from the eye.
Retained lens material
Although typically cataract surgeries are performed without complication,at times some part of the lens may remain in the eye post-operatively. Remaining lens fragments may stay in the capsular bag, or fall into the vitreous if there is a tear in the capsular bag; the surgeon may elect to leave them in the eye if they are small enough, and treat with topical steroids; this is weighed against the risk of causing additional complications with another surgery. These retained lens fragments may or may not cause significant reduction in vision. Additional surgery may be indicated when visual symptoms interfere with daily activities. . When part of a cataract (or lens fragment) remains in the eye, a severe inflammatory reaction often occurs. This may cause increased intraocular pressure, anterior segment and corneal inflammation, as well as macular edema. In these cases, pars plana vitrectomy, or another surgical approach depending on the location of the retained fragment, may be indicated to remove the retained lens material. Careful history as well as visualization of the lens fragments can differentiate this from acute endophthalmitis.