Alain M. Bron

Falsely elevated intraocular pressure due to increased central corneal thickness

Abstract · Purpose: To evaluate whether ocular hypertensive subjects have a higher central corneal thickness than other individuals. · Methods: In this prospective study, 48 subjects with ocular hypertension, 63 patients with open-angle glaucoma, 56 nonglaucomatous patients with diabetes mellitus, and 106 control subjects were evaluated. Corneal thickness was measured by ultrasound pachymetry, and intraocular pressure was determined by Goldmann applanation tonometry. · Results: Central corneal thickness was significantly higher in the ocular hypertensive subjects, mean ±S.D., 592±39 µm, than in the patients with glaucoma (536±34 µm), the nonglaucomatous patients with diabetes mellitus (550±31 µm), and the normal subjects (545±33 µm), P<0.001. The three latter groups did not vary significantly in central corneal thickness, P>0.05. · Conclusion: In some individuals with increased transcorneal measurements of intraocular pressure, the cornea is thicker than in subjects with normal intraocular pressure readings or patients with glaucoma. It suggests that in ocular hypertensive subjects, corneal pachymetry should be performed to rule out an abnormally thick cornea as a reason for falsely high measurements of intraocular pressure.

Expression of Inflammatory Membrane Markers by Conjunctival Cells in Chronically Treated Patients with Glaucoma

PURPOSE Recent histologic studies of conjunctival tissues in patients who have had long-term treatment for glaucoma have shown in situ an abnormal infiltration by inflammatory cells. In this study, conjunctival inflammatory antigens were investigated in impression cytology specimens from patients who have been and those who have not been treated for glaucoma. METHODS This study included 107 eyes from 55 patients with primary open-angle glaucoma. Of these, 48 had received prolonged topical treatments, all containing benzalkonium chloride as a preservative. Seven glaucomatous eyes could be examined before any treatment. In addition, the authors examined 11 patients (21 eyes) receiving anticataract eye drops preserved with chlorhexidine and 15 normal untreated subjects (30 eyes). In all patients, immunocytochemistry was performed in impression cytology specimens, using two monoclonal antibodies against HLA-DR antigens and receptor to IgE CD23. RESULTS None of the untreated eyes showed reactivity for either monoclonal antibody. In contrast, HLA-DR expression by conjunctival cells was found in 43 of 88 treated eyes (mean percentage of reactive cells, 70% +/- 28%) and positive staining for receptor to IgE in 26 of 68 eyes (52% +/- 28% of conjunctival cells). Results were not related to a specific treatment or combination of anti-glaucoma drugs. However, the proportion of positive specimens (3/14 for both antigens) in the group receiving chlorhexidine-containing eye drops was significantly lower than that found in the patients with glaucoma. CONCLUSION This study showed abnormal expression of inflammatory markers without clinical inflammation at the level of conjunctival cells in repetitive contact with various anti-glaucomatous treatments and their common preservative, benzalkonium chloride. Failure in filtering glaucoma surgery was found to be related to prolonged medical treatment; therefore, a topical sensitization to preservatives and/or anti-glaucoma drugs has been hypothesized. An immunocytologic test thus could be useful for qualitative and quantitative investigation of drug-induced conjunctival inflammation and predict high-risk patients.

Clinical Assessment of Stereoscopic Optic Disc Photographs for Glaucoma: The European Optic Disc Assessment Trial

PURPOSE To determine the diagnostic accuracy of judging optic disc photographs for glaucoma by ophthalmologists. DESIGN Evaluation of diagnostic test and technology. PARTICIPANTS A total of 243 of 875 invited ophthalmologists in 11 European countries. METHODS We determined how well each participant classified 40 healthy eyes and 48 glaucomatous eyes with varying severity of the disease on stereoscopic slides. Duplicate slides were provided for determining intraobserver agreement. All eyes were also imaged with the GDx with variable corneal compensation (GDx-VCC) (Carl Zeiss Meditec AG, Jena, Germany) and the Heidelberg Retina Tomograph (HRT) I (Heidelberg Engineering GmbH, Heidelberg, Germany). Diagnostic accuracies of clinicians were compared with those of the best machine classifiers. MAIN OUTCOME MEASURES Accuracy of classification, expressed as sensitivity, specificity, and overall accuracy. Intraobserver agreement (kappa). RESULTS The overall diagnostic accuracy of ophthalmologists was 80.5% (standard deviation [SD], 6.8; range, 61.4%-94.3%). The machine classifiers outperformed most observers in diagnostic accuracy; the GDx-VCC nerve fiber indicator and the HRTs best classifier correctly classified 93.2% and 89.8% of eyes, respectively. The intraobserver agreement (kappa) varied between -0.13 and 1.0 and was on average good (0.7). CONCLUSIONS In general, ophthalmologists classify optic disc photographs moderately well for detecting glaucoma. There is, however, large variability in diagnostic accuracy among and agreement within clinicians. Common imaging devices outperform most clinicians in classifying optic discs. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

Increasing Prevalence of Myopia in Europe and the Impact of Education

Purpose To investigate whether myopia is becoming more common across Europe and explore whether increasing education levels, an important environmental risk factor for myopia, might explain any temporal trend. Design Meta-analysis of population-based, cross-sectional studies from the European Eye Epidemiology (E3) Consortium. Participants The E3 Consortium is a collaborative network of epidemiological studies of common eye diseases in adults across Europe. Refractive data were available for 61 946 participants from 15 population-based studies performed between 1990 and 2013; participants had a range of median ages from 44 to 78 years. Methods Noncycloplegic refraction, year of birth, and highest educational level achieved were obtained for all participants. Myopia was defined as a mean spherical equivalent ≤−0.75 diopters. A random-effects meta-analysis of age-specific myopia prevalence was performed, with sequential analyses stratified by year of birth and highest level of educational attainment. Main Outcome Measures Variation in age-specific myopia prevalence for differing years of birth and educational level. Results There was a significant cohort effect for increasing myopia prevalence across more recent birth decades; age-standardized myopia prevalence increased from 17.8% (95% confidence interval [CI], 17.6–18.1) to 23.5% (95% CI, 23.2–23.7) in those born between 1910 and 1939 compared with 1940 and 1979 (P = 0.03). Education was significantly associated with myopia; for those completing primary, secondary, and higher education, the age-standardized prevalences were 25.4% (CI, 25.0–25.8), 29.1% (CI, 28.8–29.5), and 36.6% (CI, 36.1–37.2), respectively. Although more recent birth cohorts were more educated, this did not fully explain the cohort effect. Compared with the reference risk of participants born in the 1920s with only primary education, higher education or being born in the 1960s doubled the myopia prevalence ratio–2.43 (CI, 1.26–4.17) and 2.62 (CI, 1.31–5.00), respectively—whereas individuals born in the 1960s and completing higher education had approximately 4 times the reference risk: a prevalence ratio of 3.76 (CI, 2.21–6.57). Conclusions Myopia is becoming more common in Europe; although education levels have increased and are associated with myopia, higher education seems to be an additive rather than explanatory factor. Increasing levels of myopia carry significant clinical and economic implications, with more people at risk of the sight-threatening complications associated with high myopia.

Measurement of inflammatory cytokines by multicytokine assay in tears of patients with glaucoma topically treated with chronic drugs

Aim: To investigate the ocular surface inflammatory response to chronic topical treatments in patients with glaucoma by measuring the cytokine level in tears using multiplex bead analysis. Methods: Tear samples were collected from 21 patients with glaucoma and 12 healthy volunteers. Tears were analysed for the presence of 17 cytokines: interleukin (IL)1β, IL2, IL4, IL5, IL6, IL7, IL8, IL10, IL12, IL13, IL17, granulocyte-colony stimulating factor, granulocyte-macrophage stimulating factor, interferon (INF)γ, monocyte chemotactic protein (MCP)1, macrophage inflammatory protein 1β and tumour necrosis factor (TNF)α. The cytokines in each sample of tears were measured using multiplex bead analysis with microspheres as solid support for immunoassays. Results: In the tears of treated patients, proinflammatory cytokines (IL1β, IL6, IL12, TNFα) were significantly increased compared with controls. T helper (Th)1 (INFγ, IL2) and Th2 (IL5, IL10, IL4) type cytokines were also significantly higher (p<0.05); however, the most marked increase was observed with Th1 cytokines. The expression of chemokine IL8 and MCP1 was also increased in the treated group. Conclusion: This study shows that pro-inflammatory cytokine secretion by conjunctival cells is increased in response to topical treatments for glaucoma. The characterisation of cytokines in tears was previously limited by the small volume attainable, a limitation that has been overcome by multiplex analysis.

Eubacterial PCR for bacterial detection and identification in 100 acute postcataract surgery endophthalmitis.

PURPOSE To evaluate eubacterial PCR compared with conventional cultures for detection and identification of bacterial agents in ocular samples from patients with acute postcataract endophthalmitis. METHODS Broad-range eubacterial PCR amplification was used, followed by direct DNA sequencing in ocular samples (aqueous humor, vitreous samples from tap or vitrectomy) from 100 consecutive patients presenting with acute postcataract endophthalmitis. Bacterial cultures were performed on the same ocular samples by using traditional methods (brain-heart infusion broth). RESULTS At the time of admission, the detection rate was not significantly different between cultures and PCR (38.2% for cultures versus 34.6% for PCR in aqueous humor samples; 54% versus 57% in vitreous from a vitreous tap). In contrast, in the vitreous obtained from vitrectomy, after intravitreous injection of antibiotics, PCR detected bacteria in 70% of the cases, compared with 9% in cultures. By combining PCR and cultures, bacterial identification was obtained in 47% of aqueous humor samples at admission, in 68% of vitreous samples from a vitreous tap at admission, and in 72% of vitreous samples from pars plana vitrectomy. Gram-positive bacteria predominated (94.3%). The concordance between cultures and PCR was 100%. The contamination rate was 2%. CONCLUSIONS Cultures and eubacterial PCR are complementary techniques for bacterial identification in eyes with acute postcataract endophthalmitis. PCR technique was needed for identification of the involved microbial pathogen in 25% of all the cases. Eubacterial PCR is more effective than cultures in detecting bacteria in vitreous samples from patients with previous intravitreous administration of antibiotics.

Comparison of Face-Down and Seated Position After Idiopathic Macular Hole Surgery: A Randomized Clinical Trial

PURPOSE To compare two therapeutic modalities on anatomic and functional results after idiopathic macular hole (MH) surgery: seated vs face-down position. DESIGN Multicenter, prospective, randomized trial. METHODS SETTING University Hospital Dijon and University Hospital Nancy. PATIENTS One hundred and forty-four patients (150 eyes) were enrolled and randomly separated into two groups for postoperative position: for the 72 eyes in the P0 group and the 78 eyes in the P1 group, the patients were asked to keep the seated (P0 group) and the face-down position (P1 group) after the idiopathic MH surgery. INTERVENTION All patients underwent a complete vitrectomy with a fluid-air exchange and an intraocular gas tamponade. After the surgery, patients were asked to keep one of the two randomly chosen positions for five days. MAIN OUTCOME MEASURES Best-corrected visual acuity (VA), fundus examination, and macular optical coherence tomography were performed before and six months after surgery. RESULTS The overall anatomic success rate was 92.7%. The idiopathic MH sealed in 63 of 72 P0 eyes (87.5%) and 76 of 78 P1 eyes (97.4%) (P = .027). The mean VA increased from 0.86 to 0.61 logMAR (0.88 to 0.61 in P0 and 0.84 to 0.60 in P1). However, in a post hoc analysis based on the size of the idiopathic MH, the success rate in idiopathic MHs smaller than 400 microm was not influenced by the postoperative position (P = .47). CONCLUSIONS A face-down postoperative position is highly recommended in holes larger than 400 microm. The size of the idiopathic MH seems to be an important factor affecting outcome.

Efficacy of Tocilizumab in Two Patients with anti-TNF-alpha Refractory Uveitis

Purpose: To report on two patients with refractory uveitis treated with tocilizumab; a new humanized monoclonal antibody against the interleukin-6 receptor (IL-6R). Design: Retrospective interventional case series. Methods: Both patients received a monthly infusion of tocilizumab 8 mg/kg; associated with corticosteroids. Outcome measures were visual acuity and central retinal thickness evaluated with optical coherence tomography. Results: An improvement in visual acuity and a decrease in macular edema were observed in these two patients. Conclusions: Tocilizumab seems to be a promising treatment in refractory uveitis. A prospective study is needed to evaluate the role of this new agent in the management of refractory uveitis.

Cholesterol-24S-hydroxylase (CYP46A1) Is Specifically Expressed in Neurons of the Neural Retina

Increasing biological findings argue for the importance of cholesterol-24S-hydroxylase (CYP46A1) in cholesterol homeostasis in cerebral structures. Based on the similarity between the brain and the neural retina, the aim of the current study was to evaluate the expression of CYP46A1 in the mammalian retina. RT-PCR analysis of CYP46A1 in bovine samples revealed the highest expression in the neural retina. The retinal pigment epithelium expressed CYP46A1 gene at a low level while the ciliary body showed no expression. Immunohistochemical evaluation of the posterior pole of rat retina showed that the protein is specifically expressed in neurons, whereas cone-rods photoreceptors were negative for CYP46A1 staining. The metabolite produced by CYP46A1, 24S-hydroxycholesterol, was almost exclusively found in neural retina, the concentration therein being more than 10-fold higher than in the retinal pigment epithelium or the ciliary body. The results of the current study are consistent with our primary hypothesis: the neural retina specifically expresses cholesterol-24S-hydroxylase, a metabolizing enzyme responsible for the removal of cholesterol in neurons. Based on the link between cholesterol-24S-hydroxylase, 24S-hydroxycholesterol, and neurologic disorders, CYP46A1 may be a valuable gene candidate for retinal pathologies like age-related macular degeneration or glaucomas, and 24S-hydroxycholesterol may be involved in the onset of the degenerative processes in these diseases.

Oxysterols Induced Inflammation and Oxidation in Primary Porcine Retinal Pigment Epithelial Cells

Purpose: Aging is associated with an accumulation of cholesterol esters in the Bruch membrane. Cholesterol esters are prone to undergo oxidation and generate oxysterols that have cytotoxic and proinflammatory properties. We investigated the effects of three oxysterols on mitochondrial dysfunctions, inflammation, and oxidative stress in primary cultures of porcine retinal pigment epithelial (RPE) cells. Methods: RPE cells were incubated with oxysterols (50 μ M of 24-hydroxycholesterol, 25-hydroxycholesterol, or 7-ketocholesterol) for 24 hr and 48 hr. Oxysterol content was determined in cells and in corresponding media by gas chromatography. Mitochondrial activity was measured by mitochondrial dehydrogenase activity. The intracellular formation of reactive oxygen species in RPE cells was detected by using the fluorescent probe DCFH-DA. IL-8 was assayed in the supernatants by ELISA, and the corresponding cellular transcripts were semiquantified by RT-PCR. Results: Analyses of the oxysterols content in the RPE cells and corresponding media suggested a high rate of cellular uptake, although some differences were observed between 7-ketocholesterol on the one hand and 24-hydroxycholesterol and 25-hydroxycholesterol on the other hand. All oxysterols induced slight mitochondrial dysfunctions but a significant 2- to 4-fold increase in reactive oxygen species (ROS) production compared with the control. They also enhanced IL-8 gene expression and IL-8 protein secretion in the following decreasing order: 25-hydroxycholesterol > 24-hydroxycholesterol > 7-ketocholesterol. Conclusions: We conclude that in confluent primary porcine RPE cells, 24-hydroxycholesterol, 25-hydroxycholesterol, and 7-ketocholesterol are potent inducers of oxidation and inflammation.