Abstract
Purpose :
Endophthalmitis is a severe sight threatening infection resulting from the introduction of an infectious agent into the eye. We report the causative incidence, visual outcomes and positive predictive value (PPV) and negative predictive value (NPV) of aqueous humour (AH) samples compared to vitreous cultures.
Methods :
A retrospective observational study was conducted in which all cases with clinical diagnosis of endophthalmitis at our hospital between January 2000 and December 2014 were identified. The incidence of endophthalmitis was calculated for different causative epidemiological variables. Anterior chamber (AC) tap cultures and smears were correlated with vitreous tap samples. Visual outcomes 3 months following treatment were also studied. Two independent observers reviewed materials to confirm that cases met a standardized definition.
Results :
189 cases of endophthalmitis were recorded during the study period. Decreased visual acuity, intraocular inflammation, vitreous opacification, pain and conjunctival hyperemia were found in all patients. Postoperative cases and posterior to intravitreal injection endophthalmitis accounted for 73 and 32 eyes respectively. 83 cases were non-iatrogenic (26 secondary to corneal abscess, 43 with penetrating trauma, 11 cases due to endogenous endophthalmitis and 3 cases with filtering bleb infection). The sensitivity (82.3%) and specificity (57.89%) of aqueous cultures were higher than in other studies. Positive and negative predictive values were 45.0% and 88.8% respectively. Gram-stained smear findings, where sensitivity and specificity were less than 60%, had very poor positive and negative predictive values as compared to vitreous cultures. Median visual acuity at diagnosis was 1.89 and 1.66 logMar 3 months following intervention/treatment (p= <0.01)
Conclusions :
The AH culture and gram-stained smear is a poor tool in the determination of the etiology of infectious endophthalmitis. We report a poor concordance between vitreous and anterior chamber culture and smear findings. AH samples do not aid in predicting vitreous findings and should not substitute vitreous tap in infectious endophthalmitis.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.