Philippe Gain

The outer limiting membrane (OLM) revisited: clinical implications

Purpose The outer limiting membrane (OLM) is considered to play a role in maintaining the structure of the retina through mechanical strength. However, the observation of junction proteins located at the OLM and its barrier permeability properties may suggest that the OLM may be part of the retinal barrier. Material and methods Normal and diabetic rat, monkey, and human retinas were used to analyze junction proteins at the OLM. Proteome analyses were performed using immunohistochemistry on sections and flat-mounted retinas and western blotting on protein extracts obtained from laser microdissection of the photoreceptor layers. Semi-thin and ultrastructure analyses were also reported. Results In the rat retina, in the subapical region zonula occludens-1 (ZO-1), junction adhesion molecule (JAM), an atypical protein kinase C, is present and the OLM shows dense labeling of occludin, JAM, and ZO-1. The presence of occludin has been confirmed using western blot analysis of the microdissected OLM region. In diabetic rats, occludin expression is decreased and glial cells junctions are dissociated. In the monkey retina, occludin, JAM, and ZO-1 are also found in the OLM. Junction proteins have a specific distribution around cone photoreceptors and Müller glia. Ultrastructural analyses suggest that structures like tight junctions may exist between retinal glial Müller cells and photoreceptors. Conclusions In the OLM, heterotypic junctions contain proteins from both adherent and tight junctions. Their structure suggests that tight junctions may exist in the OLM. Occludin is present in the OLM of the rat and monkey retina and it is decreased in diabetes. The OLM should be considered as part of the retinal barrier that can be disrupted in pathological conditions contributing to fluid accumulation in the macula.

Malignant glaucoma induced by a phakic posterior chamber intraocular lens for myopia

A 23-year-old woman with -14.00 diopters of myopia requested emmetropia for professional reasons. An ICM 130 V2 myopic phakic intraocular lens (IOL) (Staar Surgical AG) was implanted in the posterior chamber. Three days later, the patient developed malignant glaucoma. Pupillary block glaucoma and choroidal hemorrhage or effusion were ruled out. As maximum medical treatment failed, rapid secondary surgery was performed with sclerotomy, aspiration in the midvitreous cavity, and removal of the IOL. The follow-up was 43 months.

Lipid Composition of the Human Eye: Are Red Blood Cells a Good Mirror of Retinal and Optic Nerve Fatty Acids?

Background The assessment of blood lipids is very frequent in clinical research as it is assumed to reflect the lipid composition of peripheral tissues. Even well accepted such relationships have never been clearly established. This is particularly true in ophthalmology where the use of blood lipids has become very common following recent data linking lipid intake to ocular health and disease. In the present study, we wanted to determine in humans whether a lipidomic approach based on red blood cells could reveal associations between circulating and tissue lipid profiles. To check if the analytical sensitivity may be of importance in such analyses, we have used a double approach for lipidomics. Methodology and Principal Findings Red blood cells, retinas and optic nerves were collected from 9 human donors. The lipidomic analyses on tissues consisted in gas chromatography and liquid chromatography coupled to an electrospray ionization source-mass spectrometer (LC-ESI-MS). Gas chromatography did not reveal any relevant association between circulating and ocular fatty acids except for arachidonic acid whose circulating amounts were positively associated with its levels in the retina and in the optic nerve. In contrast, several significant associations emerged from LC-ESI-MS analyses. Particularly, lipid entities in red blood cells were positively or negatively associated with representative pools of retinal docosahexaenoic acid (DHA), retinal very-long chain polyunsaturated fatty acids (VLC-PUFA) or optic nerve plasmalogens. Conclusions and Significance LC-ESI-MS is more appropriate than gas chromatography for lipidomics on red blood cells, and further extrapolation to ocular lipids. The several individual lipid species we have identified are good candidates to represent circulating biomarkers of ocular lipids. However, further investigation is needed before considering them as indexes of disease risk and before using them in clinical studies on optic nerve neuropathies or retinal diseases displaying photoreceptors degeneration.

Visual outcome and prognostic factors after magnetic extraction of posterior segment foreign bodies in 40 cases

AIMS To evaluate the clinical features as well as the visual and anatomical outcome in eyes with magnetic posterior segment foreign bodies, to identify prognostic factors after removal using an electromagnet. METHODS The records of 40 patients with posterior segment foreign bodies were retrospectively reviewed for 6 years (1989–94). Post-traumatic cataracts and secondary retinal detachments were treated using conventional surgical techniques. Pars plana vitrectomy was used only for late complications. The mean follow up was 30 months (6–71). Clinical factors were studied using univariate analysis. RESULTS The most common findings before treatment of these 40 eyes were lens wound, hyphaema, vitreous haemorrhage, and retinal impairment. The foreign body was in the vitreous (85%) or minimally embedded in the retina (15%). Initial visual acuity was worse or equal to 20/40 in 70% of the cases. Subsequent to surgical treatment, a cataract was reported in 60% of the patients. Postoperative complications included retinal detachment (15%) and phthysis (5%). The prognosis was worse in cases with intraocular foreign body of largest diameter ⩾3 mm, an initial visual acuity less than 20/200, or the presence of post-traumatic retinal detachment. Presence of initial intravitreous haemorrhage, hyphaema, or intraocular tissue prolapse did not appear to affect the prognosis. CONCLUSION The long term visual acuity results indicated that wound repair associated with conventional magnet extraction in an emergency is a viable treatment for posterior segment magnetic foreign bodies in this selected group. At the time of diagnosis, size of foreign body (<3 mm) and initial visual acuity ⩾20/200 were predictors of good visual outcome after primary magnetic extraction.

Relationship between baseline clinical data and microbiologic spectrum in 100 patients with acute postcataract endophthalmitis.

Purpose: To correlate the initial ocular presentation with bacterial identification in 100 patients with acute postcataract endophthalmitis. Methods: This was a prospective multicenter study. Demographic data, medical history, and the initial eye examination data were recorded on a standardized form. The relationship between bacterial identification and clinical factors at baseline was studied using univariate and multivariate analyses. Results: One hundred patients were admitted to the hospital with a median delay of 6 days after cataract surgery. The main symptoms were loss of vision (94.9%) and pain (75.5%). Major clinical signs were hypopyon (72%), pupillary fibrin membrane (77.5%), and loss of fundus visibility (90%). Baseline factors significantly associated with microbiologic identification were as follows: diabetes mellitus, a shorter delay of onset, initial visual acuity limited to light perception, higher intraocular pressure, chemosis, pupillary fibrin membrane, loss of the red reflex, and reduced fundus visibility. As compared with other bacteria, the identification of Streptococcus species (n = 19) was more frequently associated with male gender, diabetes mellitus, initial visual acuity limited to light perception, and pain. The Staphylococcus aureus and Staphylococcus lugdunensis group (n = 14) differed from other coagulase-negative Staphylococcus groups (n = 33) in that those patients had greater hypopyon height. Conclusion: The baseline features of acute endophthalmitis after cataract surgery in the era of phacoemulsification are similar to those reported in the Endophthalmitis Vitrectomy Study 15 years ago and differ according to the bacterial species. The association between the clinical signs and the microbiologic identification suggests that initial characteristics other than visual acuity may be useful in identifying patients presumed to be infected with a virulent species.

Assessment of blepharospasm surgery using an improved disability scale: study of 138 patients.

Purpose: To assess a new scale for grading functional disability in a series of patients operated on for blepharospasm resistant to treatment by botulinum toxin (BT) injections. Methods: The bicentric study included 138 patients: 80 (58%) with essential blepharospasm; 46 (33%) with apraxia of eyelid opening; and 12 (9%) with intermediate forms. They had undergone orbicularis myectomy (92 cases, 67%), frontalis suspension (31 cases, 22%), or both (15 cases, 11%). Functional disability was assessed by using an original scale covering 6 daily life activities, each graded using 5 levels from 0 (no disability) to 4 (activity impossible). The score obtained was related to the total of activities actually performed to produce a functional disability score (FDS) from 0 to 100. Each patient’s FDS was prospectively determined, before surgery and 3 months after surgery (M3). In patients who, after surgery, required a further course of BT injections, the FDS was assessed immediately before the third injection. Results: The mean FDS fell significantly, from 78 ± 15 (standard deviation) before surgery to 45 ± 21 at M3 (p < 0.01%), whatever the clinical form of essential blepharospasm or surgical procedure. The mean postoperative FDS was significantly lower in the 62 patients (45%) weaned off BT than in the unweaned group, respectively (31 ± 17 versus 56 ± 18; p < 0.01). In the latter group, the mean FDS after BT reinjection (34 ± 19) fell to a level comparable with that of the weaned patients. Conclusions: This accurate, easy-to-use scale makes it possible to quantify in patients with blepharospasm functional improvement as the result of surgery and, where applicable, of BT reinjection.

A multicentre prospective study of post-traumatic endophthalmitis

Purpose:  Study the clinical and microbiological characteristics and the prognostic factors of post‐traumatic endophthalmitis.

Use of a pair of blood culture bottles for sterility testing of corneal organ culture media

AIMS To test the effectiveness and rapidity of a pair of blood culture bottles in the diagnosis of bacterial and fungal contamination of corneal organ culture media. METHODS 761 microbiological analyses of storage media (Inosol and Exosol, Opsia, Toulouse, France), sampled in all phases of the organ culture at 31°C of 410 consecutive corneas, were analysed. Each medium was inoculated in a pair of Bactec Plus Aerobic/F and Bactec Lytic/10 Anaerobic/F blood bottles and placed in a Bactec 9240 incubator for 14 days at 37°C and in a Sabouraud broth at 20°C. Changes in colour or turbidity of storage media were evaluated daily at the corneal bank. Recipients were screened post-graft for infectious signs. RESULTS Overall contamination rate was 2.4% (18/761). Contamination was detected in less than 1 day in 78% (14/18) and less than 2 days in 94% (17/18). Positivity of the microbiological controls of starting media preceded changes medium colour in 10 out of 14 cases. Bactec blood bottles allowed detection of bacteria as well as yeasts. CONCLUSION The use of a pair of Bactec blood culture bottles appears reliable for the rapid diagnosis of a wide range of microbiological contaminations of organ cultured corneas during banking.

Handheld Reflectance Confocal Microscopy for the Diagnosis of Conjunctival Tumors

PURPOSE To evaluate whether the handheld in vivo reflectance confocal microscopy that has been recently developed for the study of skin tumors is suitable for the diagnosis of conjunctival tumors. DESIGN Prospective study, observational case series. METHODS We prospectively evaluated the reflectance confocal microscopy features of 53 conjunctival lesions clinically suspicious for tumors of 46 patients referred to the University Hospital of Saint-Etienne (France) by using the handheld device. Twenty-three lesions were excised (3 nevi, 10 melanomas, 5 squamous cell carcinoma, 2 lymphomas, and 3 pinguecula/pterygium) while the other 30, presenting no reflectance confocal microscopy malignant features, were under follow-up for at least 1 year. Clinical reflectance confocal microscopy and histologic diagnosis were compared. RESULTS In vivo reflectance confocal microscopy diagnosis was in agreement with the histologic diagnosis in all cases and none of the lesions that were not excised show any clinical progression under follow-up. CONCLUSION In vivo reflectance confocal microscopy with a handheld dermatology-dedicated microscope can play a role in the noninvasive diagnosis of conjunctival lesions. Further studies should be performed to better define the diagnostic ability of this technique.

Correlation between clinical data and antibiotic resistance in coagulase-negative Staphylococcus species isolated from 68 patients with acute post-cataract endophthalmitis

Coagulase-negative staphylococci (CNS) cause the majority of post-cataract endophthalmitis, which can lead to anatomical and/or functional loss of the eye. This study reports the antibiotic susceptibilities of CNS isolates associated with acute post-cataract endophthalmitis cases and correlates antibiotic resistance with severity and outcome of infection in these patients. Clinical data (initial ocular examination, final prognosis, antibiotic treatment) and the antibiotic susceptibilities of the isolated CNS strains were obtained from 68 patients with post-surgical endophthalmitis recruited during a 7-year period by the FRench Institutional ENDophthalmitis Study (FRIENDS) group. The CNS strains displayed 100% susceptibility to vancomycin, 70% to fluoroquinolones, 83% to fosfomycin, 46% to imipenem and 18% to piperacillin. The most effective antibiotic combinations were fosfomycin plus a fluoroquinolone and imipenem plus a fluoroquinolone, which were considered adequate in 80% and 58% of patients, respectively. Methicillin resistance was significantly associated with older age (p 0.001), diabetes mellitus (p 0.004), absence of fundus visibility (p 0.06), and poor visual prognosis (p 0.03). Resistance to fluoroquinolones was significantly associated with absence of fundus visibility (p 0.05) and diabetes mellitus (p 0.02). This large prospective study demonstrates that methicillin resistance and, to a lesser extent, fluoroquinolone resistance in CNS strains causing postoperative endophthalmitis are both prevalent in France and associated with a poorer visual prognosis. These results emphasize the need for an effective surveillance of this antibiotic resistance and the development of new diagnostic tools for rapid detection for early optimization of antibiotic therapy in endophthalmitis patients.