Delayed post-operative endophthalmitis is a complication of modern cataract extraction and posterior chamber lens implantation. Propionibacterium acnes has been isolated in a few such cases but the majority are culture-negative, compounding surgical and medical management decisions. A method of detecting bacterial, and specifically P. acnes, DNA by the polymerase chain reaction (PCR) directed at 16S rDNA is reported. Nested PCR with universal eubacterial primers complimentary to regions of 16S rDNA conserved sequences detected 50 fg of bacterial DNA spike in normal vitreous. Nested PCR with P. acnes primers detected 10 fg of DNA. Vitreous samples from 29 patients undergoing vitrectomy for reasons unrelated to infection and 23 samples from 19 patients with delayed post-operative endophthalmitis were analysed. Four (14%) of 29 normal individuals and 17 (74%) of 23 delayed cases gave positive results with universal eubacterial primers. None of 29 and eight of 23 samples gave positive results with P. acnes primers. The 14% positive rate with universal primers in non-infected cases may limit their use in delayed post-operative endophthalmitis. PCR detection of bacterial DNA with specific primers from vitreous samples may prove a useful means of diagnosing delayed post-operative endophthalmitis and facilitating management decisions when conventional bacterial culture is negative.

No abstract

FHC and IAU are two forms of anterior uveitis which are localized to the eyes with no evidence of systemic involvement. However, FHC has distinct clinical features and differs from IAU in that the inflammation is low grade, steroid non-responsive, and has a less aggressive clinical course. To try to dissect the mechanism for this difference the phenotypes of the cells in the AH and blood (PB) and the cytokines present in the AH in patients with FHC and IAU were compared. Three-colour flow cytometry was performed on the cells isolated from the AH and PB. Percentage of cells bearing the following markers were determined: CD3, CD4, CD8, CD4/CD25, CD8/CD25, CD19 and CD14. The cytokines IL-4, IL-10, IL-12 and interferon-gamma (IFN-gamma) were assayed by ELISA. In both groups T cell numbers were higher in the AH than PB, although the distribution of T cell subsets in PB was similar. In the AH, CD8+ T cell numbers were higher in FHC than in IAU (P = 0.003), whilst CD4+ numbers were higher in IAU than FHC (P = 0.01). AH cytokine profiles were different in the two groups: IFN-gamma levels were higher and IL-12 levels lower in the FHC group than IAU (P = 0.02), whilst IL-10 levels tended to be higher in the FHC group (P = 0.5). We suggest that different local mechanisms governing the balance of T cell/cytokine-mediated inflammation in the anterior segment may underlie clinical differences such as chronicity and response to steroids in these disorders.

Aims: To examine the visual outcome and identify risk factors for postoperative uveitis, macular oedema and neodymium-doped yttrium aluminium garnet (Nd:YAG) capsulotomy after phacoemulsification and intraocular lens (IOL) implantation in patients with uveitis. Method: This is a retrospective review of the medical records of 101 eyes of 101 patients. One eye was randomly selected for inclusion in patients who had bilateral surgery. Patients with juvenile arthritis, keratouveitis and lymphoma-associated uveitis were excluded. Results: At the first postoperative and final visits, visual acuity was significantly better (p,0.001), and 64.4% and 71.3% of patients, respectively, had achieved >2 Snellen's lines of visual improvement. The cumulative probability of doubling of the visual angle was 52% over 6 years of follow-up, and this occurred at a higher rate in the presence of preoperative retinal or optic nerve lesions (HR (95% CI) 4.49 (1.41 to 14.29)). Within 3 months after operation, uveitis was more likely to develop in female patients (OR (95% CI) 6.21 (1.41 to 27.43)) and in the presence of significant intraoperative posterior synechiae (OR (95% CI) 8.43 (1.09 to 65.41)); macular oedema was more likely to develop in patients who developed postoperative uveitis (OR (95% CI) 7.45 (1.63 to 34.16)). Nd:YAG capsulotomy occurred at a higher rate in patients aged (55 years (HR (95% CI) 2.28 (1.06, 4.93)) and in those with hydrogel IOLs (HR (95% CI) 3.71 (1.04 to 13.20)), and occurred at a lower rate in patients who had prophylactic systemic corticosteroids (HR (95% CI) 0.25 (0.11 to 0.59)), with plate-haptic silicone IOLs (HR (95% CI) 0.23 (0.08 to 0.64)) and three-piece silicone IOLs (HR (95% CI) 0.19 (0.05 to 0.74)) in comparison to those with polymethylmethacrylate IOLs. Conclusion: Most patients with uveitis achieve improved visual acuity after phacoemulsification, but an increasing rate of visual loss is observed in those with pre-existent macular or optic nerve lesions. Identifying patients who are at risk of postoperative complications should help in patient counselling and to pre-empt these complications by using preoperative prophylactic corticosteroids, careful IOL selection and postoperative intensive corticosteroids.

Uveitis is a term which encompasses many clinical syndromes which would appear to be discrete entities. Both clinically and experimentally, the separation of uveitis affecting only the anterior segment from that affecting the posterior segment has a sound pathogenetic basis. However, clear distinctions among the various forms of endogenous posterior uveitis are more difficult to maintain in the light of evidence from experimental models of autoimmune uveitis (EAU). EAU can be induced by a variety of retinal antigens and each antigen has been shown to induce somewhat different forms of EAU, depending on such factors as dose of antigen, species and strains of animal model, and the type(s) of adjuvant used. However, within each model a similar spectrum of uveoretinal responses can be induced by each antigen suggesting that the pathogenetic mechanisms are probably similar also. In addition, if these models are analogous to human disease, then each clinical entity within this apparently heterogeneous group of clinical posterior uveitis syndromes may represent one aspect of a general organ-specific uveoretinal response to autoantigens.

Intermediate uveitis (IU) and Fuchs' heterochromic cyclitis (FHC) are two chronic ocular inflammatory disorders. They differ considerably in ocular morbidity, which is higher in IU. T cell lines were derived from the vitreous humour (VH) and peripheral blood (PB) of 10 patients with IU and four patients with FHC. There was a predominance of CD8+ in all the lines. However, there was a significantly higher percentage of CD4+ T cells in the T cell lines derived from VH of IU (32.0 +/- 8.6%) compared with FHC patients (19. 2 +/- 8.9%) (P = 0.04). The VH-derived T cell lines (VDTC) produced significantly higher levels of IL-2, interferon-gamma (IFN-gamma) and IL-10, but not IL-4, compared with PB-derived T cell lines (PBDTC) in both entities. There was significantly higher IL-2 production by VDTC from IU when compared with FHC patients (1810 +/- 220 pg/ml versus 518 +/- 94 pg/ml; P = 0.009), which could account for the more aggressive clinical features of this condition. In contrast IL-10 production was significantly higher by the VDTC from FHC compared with IU patients. The high IL-10 production by T cells infiltrating VH of FHC patients could down-regulate the inflammatory responses, thereby contributing to the benign clinical course seen in these patients. The accumulation of T cells with differing cytokine profiles in the VH suggests an important role for these cytokines in the pathogenesis of these chronic uveitides.

It was possible to measure cytokines titrated into normal AH specimens by CBA, and a greater number of cytokines were detected with increased sensitivity than with ELISA. Elevated IFN-gamma in active uveitis and decreased IL-5 in posterior uveitis suggest Th1 polarity is more marked, with greater uveal tract involvement. The increased IL-10 in the steroid treated group suggests glucocorticoid-induced IL-10 upregulation.

The clinicopathologic correlation of two patients with primary intraocular lymphoma is described, both of whom had a rare and unusual presentation of hypopyon uveitis. Sampling of aqueous fluid proved the cytopathologic diagnosis of B-cell lymphoma in the first patient. In the second patient an iris biopsy confirmed a T-cell lymphoma. The samples were examined using haematoxylin and eosin, and immunohistochemical stains. These patients were diagnosed with primary intraocular lymphoma on initial presentation with hypopyon uveitis. Secondary glaucoma was noted in the patient with T-cell lymphoma. Both cases appeared confined to the eye and initially responded favourably to aggressive chemotherapy and radiotherapy, but later went on to develop systemic involvement. Clinicians should be aware of this dramatic mode of presentation, which is unusual for ocular lymphoma.