Validating the Endophthalmitis Infectivity Measurement Algorithm (EIMA) Imaging tool

Endophthalmitis after cataract surgery is rare but a potentially blinding condition if not recognised and treated early.  The Endophthalmitis Vitrectomy Study (EVS)- guided current management strategies of acute endophthalmitis after cataract surgery are microbiological workup of undiluted vitreous, intravitreal antibiotics in all patients and vitrectomy in eyes with poor presenting vision. If required, the treatment is revised after the culture-susceptibility report is available, usually in three to five days. Two important criteria in decision-making are the culture positivity and the presenting vision. The clinical course and features of culture-negative endophthalmitis (other than the toxic anterior segment syndrome) are likely to have different severity of the symptoms and signs than the culture-positive ones. It is challenging to differentiate culture-positive endophthalmitis from culture-negative endophthalmitis from the presenting vision alone. Poor presenting vision could be due to media opacity, such as corneal edema and inflammatory exudates in the pupillary area. Like infection, inflammation plays an equally important role in endophthalmitis. The inflammatory cascade activated by specific toxic effects of the pathogen ultimately determines the final anatomical and functional outcome. Anticipation of infectivity based on the clinical clues at presentation could help the treating ophthalmologist choose an initial treatment close to the final treatment before the microbiology reports are available. We hypothesize that the presenting vision (a surrogate measure for severity of infection) and the presenting inflammation score (a surrogate measure for inflammation) together are likely to differentiate infectious from non-infectious endophthalmitis.

Using the clinical clues we have developed to quantify inflammation in acute post-cataract endophthalmitis. The Inflammation score (IS) is measured from the at-presentation clinical status of four ocular tissues: cornea (clarity and abscess), anterior chamber (flare/cell and fibrin/hypopyon), iris (blood vessels, exudates over iris), and vitreous (flare, and opacities). The scoring was done from 0 to 4 in each category, with an additional allowance for poor ocular tissue clarity. The IS has been earlier used and validated and is currently used in the Endophthalmitis Management Study (EMS, a prospective randomized clinical trial)

Using large retrospective data, we constructed the Endophthalmitis Infectivity Measurement Algorithm (EIMA) to identify and differentiate infective from non-infective post-cataract surgery acute endophthalmitis. We validated it with a set of prospective data.