Tuberculous orbital apex syndromes.

AIMS: To describe the clinical and radiological features of orbital apex syndromes caused by presumed tuberculosis (TB). METHODS: A review of the discharge summaries of all patients seen in the Medical Eye Unit (MEU), St Thomas' Hospital between 1975 and 2006 identified seven patients with a diagnosis of orbital apex syndrome or optic neuropathy attributable to TB. Case notes and radiology were reviewed retrospectively for each patient. RESULTS: All of the patients were born outside the UK and were HIV-negative. Four presented during 2005-6. Six of the seven patients presented with a visual acuity (VA) of less than counting fingers (CF), but all achieved a VA of 6/9 or better after a median 3 weeks of treatment with antituberculous treatment and systemic corticosteroids. All patients had constitutional symptoms. Chest x ray and CSF were normal in each case, but MRI was abnormal in six. CONCLUSIONS: We report a recent cluster of tuberculous orbital apex syndromes, in the context of an increasing incidence of TB in the UK. The condition is difficult to diagnose, but the combination of high-dose corticosteroids and anti-TB medication was rapidly effective and achieved a good outcome in all cases.

Hypotension and anaemia--a blinding combination.

We present a case of complete blindness following severe dengue haemorrhagic fever complicated by anaemia and a dialysis-related episode of profound hypotension. The clinical and radiological features indicated an optic neuropathy, most likely ischaemic in aetiology. The features of posterior ischaemic optic neuropathy and differential diagnosis are discussed.

Long-term recovery of the human corneal endothelium after toxic injury by benzalkonium chloride.

INTRODUCTION: The inadvertent intra-ocular administration of benzalkonium chloride-preserved hydroxypropyl methylcellulose during cataract surgery at another hospital in 1999 resulted in toxic corneal endothelial injury and profound postoperative corneal oedema as a result of endothelial decompensation. The long-term effect of this adverse event was assessed. METHODS: All 19 patients were invited to return for examination including corneal endothelial specular microscopy and pachymetry seven years after the incident. Results were compared with data from one year after the incident. RESULTS: Five patients attended for examination, one had received a penetrating keratoplasty and was, therefore, excluded. Ten patients had died and four had moved out of the region and were unable to attend. All four study patients were pain free and achieved 6/12 or better. Mean central corneal thickness reduced by 13% from 652.6 microm at one year to 563.4 microm. Mean central corneal endothelial cell density (n = 3) increased 28% from 663.7 cells/mm(2) at one year to 835.7 cells/mm(2) (p<0.05). CONCLUSIONS: After toxic injury, corneal endothelial function may have a remarkable capacity for recovery even after the first postoperative year. The rise in central endothelial cell density may represent cell migration from less affected areas or cellular proliferation. Should this unfortunate event recur, clinicians may expect continued recovery beyond one year.

Aqualase for cataract extraction.

PURPOSE: To report our experience of using Aqualase technology for cataract extraction. METHODS: In total, 33 patients (20 females; mean age 71.4 years) underwent cataract surgery using Aqualase through a 3.2-mm corneal incision. Grade of nucleus, nuclear removal technique, and intraoperative complications were noted. Clinical parameters from postoperative visits were collected. RESULTS: Aqualase is capable of removing cataracts up to nuclear sclerosis 2+ (out of 4) with relative ease. Nuclei graded 2+ or greater were technically more difficult and conversion to ultrasound phacoemulsification was required in one case. Two posterior capsule ruptures occurred: one during nucleus removal (contact with the tip while aspirating without Aqualase) and one unrelated to Aqualase during aspiration of cortex. Of 25 patients seen on the first postoperative day, 22 had a clear cornea. A total of 96% patients without preoperative comorbidity achieved 6/9 or better postoperatively. One patient had transient postoperative uveitis. CONCLUSIONS: Removal of softer cataracts with Aqualase has the theoretical advantage over phacoemulsification, by carrying less risk to the posterior capsule, since the handpiece has a smooth polymer tip that has no mechanical motion inside the eye. However, the tip should not be considered entirely capsule-friendly, as rupture is possible with the foot-pedal in position two (aspiration only). Although certain adjustments to the technique are required, the method is similar enough to phacoemulsification to ensure a brief learning curve. With increasingly firm cataracts, Aqualase becomes less effective and ultrasound phacoemulsification is still superior for such cases, in our experience.

Associations of major histocompatibility complex class I chain-related molecule polymorphisms with Behcet's disease in Caucasian patients.

HLA-B*51 is known to be associated with Behcet's disease (BD) in many ethnic groups. The pathogenic gene, however, may lie close to the HLA-B locus and therefore be in linkage disequilibrium with HLA-B*51. On the basis of the proximity of MIC genes to HLA-B, their expression pattern and their affinity for the activating NKG2D receptor on natural killer (NK) cells and gammadelta T cells, these molecules have been postulated as susceptibility factors in BD. DNA from 56 western European Caucasians with BD and 90 Caucasian controls were analysed by polymerase chain reaction using allele-specific primers for MICA and MICB alleles. An increased allele frequency of MICA*009 was found in the BD patient group (25.0%) when compared with the controls (7.2%). This was associated with a corresponding decrease in MICA*008 in the BD patients (36.6%) compared with the controls (46.7%), which was not significant. MICA*009 was strongly associated with the presence of HLA-B*51 in patients and controls. No significant difference in frequency of MICB alleles was found between patients and controls. Both HLA-B*51 and MICA*009 are strongly associated with BD in a pure Caucasian BD patient group, and the two alleles are in linkage disequilibrium. No MICB allele was found to associate significantly with the disease, an unexpected finding considering the close proximity of the MICA and MICB loci. Our results suggest that while MICB does not influence the development of BD, polymorphisms in MICA may be pathogenic, perhaps through the interaction with NK and gammadelta T cells.

Quality of life and visual function in patients with intermediate uveitis.

AIMS: To assess visual function, vision related quality of life (VR-QOL), and general health related quality of life (HR-QOL) in intermediate uveitis (IU). METHODS: VR-QOL and HR-QOL were evaluated in 42 patients with IU using the VCM1 and SF-36 questionnaires, respectively. LogMAR visual acuity (VA), Pelli-Robson contrast sensitivity (CS), Farnsworth-Munsell 100 hue colour vision (CV), and Estermann visual field (VF) were recorded monocularly and binocularly. RESULTS: Median (interquartile range) visual acuity (VA) and CS of 72 affected eyes were 0.1 (0.015-0.3) and 1.55 (1.35-1.65), respectively. 9.5% of patients had a VCM1 score of more than 2.0, indicating "more than a little" concern over vision. Worse eye VA (p=0.045) and CS (p=0.042) were predictive of a VCM1 score of more than 2.0 independently of age, sex, uveitis duration, laterality and activity, systemic uveitis therapy, and medical co-morbidity. The physical and mental component summary scores of the SF-36 were significantly worse in those who reported significant impairment of vision on the VCM1 than those who did not. CONCLUSIONS: The majority of patients with IU maintain good visual function and quality of life. VR-QOL impairment in IU correlates with vision in the worse eye and is associated with impaired HR-QOL.

Neural progenitor cells from postmortem adult human retina.

BACKGROUND: Given the presence of neural progenitor cells (NPC) in the retina of other species capable of differentiating into multiple neural components, the authors report the presence of NPC in the adult human retina. A resident population of NPC suggests that the retina may constitutively replace neurons, photoreceptors, and glia. METHODS: Adult human postmortem retinal explants and cell suspensions were used to generate cells in tissue culture that display the features of NPC. The phenotype of cells and differentiation into neurons was determined by immunocytochemistry. Dividing cells were labelled with 5-bromo-2-deoxyuridine (BrdU) and neurospheres were generated and passaged. RESULTS: Cells labelled with nestin, neurofilament M (NFM), rhodopsin, or glial fibrillary acidic protein (GFAP) grew out from explant cultures. BrdU labelling of these cells occurred only with basic fibroblast growth factor (FGF-2). Dissociated retina and pars plana generated primary neurospheres. From primary neurospheres, NPC were passaged to generate secondary neurospheres, neurons, photoreceptors, and glia. BrdU labelling identified dividing cells from neurospheres that differentiated to express NFM and rhodopsin. CONCLUSION: The adult human retina contains NPC and may have the potential to replace neurons and photoreceptors. This has implications for the pathogenesis and treatment of retinal disorders and degenerations, including glaucoma, and those disorders associated with retinal scarring.

Nestin positive cells in adult human retina and in epiretinal membranes.

BACKGROUND/AIM: Nestin is an intermediate filament marker for neural progenitor cells. The authors aimed to identify nestin positive cells in adult human retina and within surgically removed epiretinal membranes. METHODS: Adult human retina and epiretinal membranes were studied. Tissue was fixed and processed for semithin sections or whole mount preparations for immunohistochemical detection of nestin and glial fibrillary acidic protein (GFAP) expression. RESULTS: Nestin positive cells are most prominent at the ora serrata, possess fibrillary processes, small amounts of perinuclear cytoplasm, and are arranged radially within or superficially on the retina. In the posterior retina, speckled cytoplasmic nestin staining is seen around the nuclei of neurons. In the peripapillary retina most of the cells in the retinal ganglion cell layer are nestin positive. These cells appear to represent nestin positive neurons. Speckled cells are also seen in the myelinated portion of the optic nerve. In epiretinal membranes patches of elongated nestin positive cells were found. These cells were also positive for GFAP. CONCLUSIONS: Some neurons and glia in the adult human retina are nestin positive. Their pattern in anterior retina suggests an analogy with the ciliary marginal zone found in many other species. The role of these cells in pathological responses to retinal disease is suggested by the presence of large numbers of ectopic nestin positive cells in epiretinal membranes. The authors hypothesise that nestin positive cells represent a population of progenitor cells from normal adult human retina that differentiate to make up retinal scar tissue.

The pathology and pathogenesis of retinal vasculitis.

Retinal vasculitis is a rare, but potentially blinding intraocular inflammatory condition with diverse aetiology. Although commonly idiopathic, it has a strong association with systemic inflammatory diseases known to involve other areas of the central nervous system, most notably Behcet's disease, sarcoidosis, systemic lupus erythematosis and multiple sclerosis. This article describes the clinicopathologic features of retinal vasculitis and its visually damaging sequelae, reviewing available human histopathologic studies and work with experimental models to discuss the pathogenesis and immunopathology. Evidence indicates that noninfective retinal vasculitis is an autoimmune condition that may be induced by antecedent infection with microbes cross-reacting with putative autoantigens, influenced by genetic susceptibility of both HLA associations and cytokine polymorphisms. The growing understanding of the cellular mechanisms involved in the effector immune response is already providing a rationale for more specific therapeutic approaches.

Pulsatile ocular blood flow: the effect of the Valsalva manoeuvre in open angle and normal tension glaucoma: a case report and prospective study.

AIM: A case of severe normal tension glaucoma is reported in a trumpet player, along with a study investigating the association between glaucoma and raised intrathoracic pressure, using measurements of pulsatile ocular blood flow (POBF). METHODS: Three patient groups were studied; normals (n = 34), untreated primary open angle glaucoma (POAG) (n = 20), and untreated normal tension glaucoma (NTG) (n = 22), with a total of 76 patients who underwent measurements of POBF using the OBF pneumotonometer at rest and while forcibly exhaling through a mouthpiece connected to a mercury manometer (30 mm Hg) (Valsalva manoeuvre). RESULTS: POBF fell during Valsalva in all groups with the greatest predictor being the resting value of POBF. There was no evidence of significant differences in the mean change in POBF occurring during the Valsalva manoeuvre for the three groups studied before or after adjusting for the sex, the resting POBF, and the resting IOP of the patients (p = 0.294 and p = 0.542, respectively). However, statistically significant associations were found between the change in POBF and sex (p = 0.049), resting POBF (p<0.0001) and resting IOP (p = 0.032). Males had a greater drop, on average, in POBF during Valsalva manoeuvre than females after adjusting for the other factors. Additionally, there was a significant difference in the mean change in IOP during Valsalva for the three groups (p = 0.002), with the difference occurring between the normal and POAG groups (p<0.005). The POAG group had, on average, a drop in IOP during Valsalva, while the other two groups had an increase in IOP. Also noted was a significant difference in the distributions of the risk factors among the three groups (p = 0.002). CONCLUSIONS: This study demonstrates no difference between groups with respect to resting or Valsalva POBF, but does demonstrate a possible trend with respect to IOP, with a drop in IOP occurring during Valsalva in the POAG group. There is, however, much variability in the data left unexplained by our models. Thus, unfortunately, we cannot advise our trumpet player whether his NTG is directly related to his trumpet playing.

'One-stop' cataract surgery: the Bristol Eye Hospital experience 1997-1999.

PURPOSE: To evaluate patient satisfaction with and effectiveness of the 'one-stop' cataract service at the Bristol Eye Hospital. METHODS: One hundred and ninety patients referred with a view to cataract surgery were selected to attend 24 'one-stop' clinics between February 1997 and August 1999. Patients had initial assessment in the morning with suitable cases undergoing surgery during the afternoon. Forty 'one-stop' patients and 40 patients undergoing traditional surgery (three separate visits: initial clinic, pre-assessment and surgery) were surveyed by a questionnaire to determine their satisfaction with the service. RESULTS: One hundred and fifty-six of 190 (82.1%) patients invited to one-stop clinics underwent surgery the same day. Questionnaires were returned by 72 patients (35 'one-stop' and 37 control patients). Twenty-eight (80%) 'one stop' patients were 'very satisfied' and 7 (20%) were 'satisfied' with the time allowed to decide upon undergoing surgery, compared with 21 (57%) and 16 (43%) respectively in the control group (p = 0.06, chi-square, not significant). Overall satisfaction with the service was similar between the groups, with 33 (94%) of 'one-stop' and 35 (95%) of control patients considering the service 'very good'. CONCLUSIONS: There is a high level of patient satisfaction with a 'one-stop' cataract service which reduces hospital attendance from three visits to one. Potential problems include wasted theatre space when there is a shortfall of suitable cases on the day.

Differential effects of dimethyl sulfoxide and sodium butyrate on alpha-fetoprotein, albumin, and transferrin production by rat hepatomas in culture.

Radioimmunoassay was used to determine alpha-fetoprotein (AFP), albumin, and transferrin production (ng/10(5) cells/24 h) by two cell lines (7777 and 8994) derived from chemically induced rat hepatomas. alpha-Fetoprotein production was high (2000 to 4400) in 7777, but was very low (0.2 to 0.4) in 8994. Albumin production varied from 0.4-0.8 (7777) to 14-26 (8994). Both lines produced substantial amounts of transferrin (180 to 240 by 7777 and 29 to 42 by 8994). Addition of dimethyl sulfoxide (DMSO, 1 to 4%) or sodium butyrate (BA, 0.5 to 2.0 mM) to the medium inhibited growth in both lines, but 8994 was more sensitive to these agents than 7777. Dimethyl sulfoxide treatment (2 to 4%) resulted in a dose-related decrease (less than 10% of control at 4% DMSO) in AFP, albumin, and transferrin production by 7777, but in 8994, DMSO (1 to 2%) resulted in an increase (up to sixfold) in albumin and transferrin production, without affecting AFP production. By contrast, BA (2 to 4 mM) stimulated the production of all three proteins in both lines, most notably that of albumin (up to sixfold) by 7777 and that of AFP (up to 20-fold) by 8994. It is concluded that both DMSO and BA can enhance the expression of differentiated functions of the hepatoma cell, and that DMSO at the same time can suppress the expression of an oncofetal function. However, neither DMSO nor BA is selective in its effects on specific genes (i.e., normal, adult vs. oncofetal genes), and it appears that their effects may be the result of a more general phenomenon, the expression of which may be related to the stage of differentiation of the cell.