Diagnostic value of culture results from aqueous tap versus vitreous tap in cases of bacterial endophthalmitis

OBJECTIVE

To investigate the concordance between aqueous and vitreous tap culture results among different types of bacterial endophthalmitis.

METHODS AND ANALYSIS

This retrospective cohort analysis included all cases diagnosed with endophthalmitis at Moorfields Eye Hospital between January 2008 and March 2020. Aqueous and vitreous samples obtained simultaneously at presentation. Samples were evaluated for sensitivity, specificity, negative and positive predictive values.

RESULTS

A total of 217 patients (217 eyes) were included in the study. Postsurgical endophthalmitis was the most common type of endophthalmitis and diagnosed in 35.9% of the cases. The rate of positive culture results was 32.2% from vitreous tap and 21.7% from aqueous tap. The culture yield through vitreous sampling was 15.7% when aqueous culture results were negative, and in 5.1%, the aqueous sample was positive when the vitreous tap results were negative. Considering the vitreous tap as the gold standard, aqueous sample culture results showed a statistically significant high specificity and positive predictive values in cases of postsurgical endophthalmitis, late-onset endophthalmitis associated with glaucoma procedures, postintravitreal injection and endophthalmitis associated with bacterial keratitis. Coagulase Negative Staphylococcus was the most common organism isolated from vitreous and aqueous samples.

CONCLUSIONS

Even though the sensitivity and specificity of aqueous tap are low, our results show that in a few cases it identified important organisms, otherwise missed by vitreous sampling alone. Culture of vitreous sample remains the gold standard for isolation of pathogen in bacterial endophthalmitis, but aqueous samples should also be obtained as an adjunct for the diagnosis.

Ocular toxoplasmosis: phenotype differences between toxoplasma IgM positive and IgM negative patients in a large cohort

PURPOSE

To investigate the differences in demographics and clinical characteristics of patients diagnosed with ocular toxoplasmosis according to their IgM status.

METHODS

Retrospective case note analysis was carried out on patients who tested positive for serum Toxoplasma gondii-specific IgM antibodies (IgM+) as well as a comparator group who tested negative for serum IgM (IgM-), but positive for serum IgG. Patient demographics and clinical features were compared between the two groups to evaluate for any significant differences.

RESULTS

One hundred and six patients were included in the study between March 2011 and June 2018, consisting of 37 in the IgM +group and 69 in the IgM- group. Patients in the IgM +group were significantly older (51.1 vs 34.1 years, p<0.0001), more likely to present with central macular lesions (32% vs 12%, p=0.012), and more likely to develop rhegmatogenous retinal detachment (11% vs 1%, p=0.049). In contrast, patients in the IgM- group were more likely present with pain (20% vs 3%, 0.017) and exhibit more severe inflammation of the anterior chamber and vitreous (p<0.05). Overall, retinal lesions were more likely to be superotemporal (55%) and superonasal (31%). Furthermore, age was associated with larger (p=0.003) and more peripheral lesions (p=0.007).

CONCLUSIONS

This study demonstrated significant differences in clinical characteristics of ocular toxoplasmosis according to serum IgM status. IgM+ patients were older, less likely to report pain, had lower levels of intraocular inflammation, but were more likely to have macular involvement. We also found age to be correlated with larger and more peripheral lesions.

Evaluation of fluocinolone acetonide 0.19 mg intravitreal implant in the management of birdshot retinochoroiditis

PURPOSE

To report treatment outcomes and efficacy of the fluocinolone acetonide 0.19 mg intravitreal implant (Iluvien) in controlling retinal and choroidal inflammation in 11 patients with birdshot retinochoroiditis.

METHODS

A single-centre, retrospective, interventional case series. The primary efficacy end point was improvement in vascular leakage on fluorescein angiography (FA), effect on cystoid macular oedema (CMO) and resolution of hypofluorescent lesions on indocyanine green angiography (ICGA); secondary measures were improvements on pattern and full-field electroretinogram (PERG; ERG) parameters. Safety outcome measures were intraocular elevation and cataractogenesis.

RESULTS

Fifteen eyes received Iluvien implant with an average follow-up of 31 months (range 12-36 months). Prior to the implant, 5 (33.3%) eyes had received dexamethasone intravitreal implant 0.7 mg (Ozurdex). FA showed evidence of vascular leakage in all eyes at baseline. Between month 6 and 12, FA showed that 73.4% of eyes had no leakage, this increased to 84.6% by month 24. Three eyes in our study had CMO at baseline. 6 months after Iluvien implant, all eyes achieved complete CMO resolution. One year after insertion of the implant, the characteristic hypofluorescent lesions on ICGA were unchanged in all cases. There was baseline ERG evidence indicating a high incidence of peripheral cone system dysfunction and most showed PERG evidence of macular dysfunction. Retinal function improved and macular function improved or was stable in the majority following treatment.

CONCLUSIONS

The results show the possible therapeutic effect of Iluvien in the management of Birdshot-related vascular leakage, CMO and retinal dysfunction. However, choroidal lesions seem to persist with no detectable response to treatment.

Peripheral Capillary Non-perfusion in Birdshot Retinochoroiditis: A Novel Finding on Ultra-widefield Fluorescein Angiography

Purpose: To report a novel peripheral finding in patients with Birdshot retinochoroiditis (BRC) using ultra-widefield fluorescein angiography (UWFFA). Methods: UWFFA images from 90 patients diagnosed with BRC were reviewed. All images were evaluated for the presence of peripheral retinal ischemic changes and ischemia-related complications. Findings: Thirty-six eyes of 24 patients showed features of peripheral ischemia, including 18 eyes with peripheral capillary non-perfusion (CNP), 5 eyes with teleangectasias, with or without microaneurysms, and 13 eyes with both teleangectasias and CNP. None of the 36 eyes with peripheral ischemic changes developed retinal neovascularization following the diagnosis of peripheral ischemia. Conclusions: Peripheral ischemia may present in eyes with chronic inflammation as seen in BRC but does not seem to progress to neovascular complications. This is likely to be more common than suspected and has now become evident following the advent of UWFFA. Abbreviations: HLA-A29: Human leukocyte antigen - A29; FFA: Fundus fluorescein angiography; OCT: Optical coherence tomography; ICGA: Indocyanine green angiography; UWF: Ultra-wide field; UWFFA: Ultra-wide field fluorescein angiography; CNP: Capillary non-perfusion.