Neuroprotective effect of epigallocatechin‐3‐gallate against N‐methyl‐D‐aspartate‐induced excitotoxicity in the adult rat retina

Purpose: Epigallocatechin‐3‐gallate (EGCG), the major polyphenol of green tea, has been suggested to reduce glutamate excitotoxicity. We therefore investigated the potentially protective effects of EGCG against N‐methyl‐d ‐aspartate (NMDA)‐induced excitotoxicity in the retina. Methods: Female Wistar rats (n = 171) were divided into a normal control group (n = 9); saline control group with intravitreal saline injections (n = 54); NMDA control group with an intravitreal NMDA injection and intraperitoneal saline injections (n = 54); and NMDA study group (n = 54) receiving an intravitreal NMDA injection plus intraperitoneal EGCG (25 mg/kg) injections. Starting at 2 days prior to the intravitreal NMDA injection, the intraperitoneal injections were performed daily for the whole study period. At 12 hr, 1, 2, 3 days, 1 and 2 weeks after the intravitreal NMDA injection, the animals were killed. We counted the neurons in the retinal ganglion cell layer (GCL) on histological sections, measured the thickness of Thy‐1 immunoreactivity and assessed the expression of Thy‐1 mRNA by real‐time polymerase chain reaction. Results: At all time‐points, GCL cell density, thickness of Thy‐1 immunoreactivity and expression of Thy‐1 mRNA were significantly (all p < 0.05) lower in the NMDA control group than in the NMDA study group, in which the parameters were significantly (all p < 0.05) lower than in the saline control group and the normal control group. In both groups with an intravitreal NMDA injection, GCL cell density, thickness of Thy‐1 immunoreactivity and expression of Thy‐1 mRNA decreased significantly with increasing follow‐up time. Conclusions: Intraperitoneal application of EGCG resulted in a significantly less marked NMDA‐associated loss of retinal ganglion cells.     

SARS‐CoV‐2 and COVID‐19 for the ophthalmologist

The COVID‐19 pandemic has had an unprecedented impact on ophthalmology. This review compiles general aspects of the novel coronavirus and COVID‐19, further dissects the most recent data on the role of the eye regarding disease transmission and manifestations, and summarizes preventive measures in the particular context of eye care.     

Cyclo‐oxygenase‐2 expression in photon‐radiated and non‐radiated uveal melanomas

Purpose: To determine and compare cyclo‐oxygenase‐2 (COX‐2) expression in photon‐radiated and non‐radiated malignant uveal melanomas and to analyse the correlation between COX‐2 expression and prognosis. Methods: Immunohistochemical staining for COX‐2 was performed on 21 uveal melanomas that were endoresected after prior stereotactic radiotherapy with photons and on 22 tumours that were treated by endoresection without prior radiotherapy. COX‐2 staining was further analysed in respect to cell type, maximal prominence, time interval between radiotherapy and surgery, apoptotic index (AI), proliferative index (PI) and the development of metastatic disease. Results: There was no difference in COX‐2 expression between radiated and non‐radiated melanomas (P > 0.15). COX‐2 staining correlated with neither the tumour prominence (P > 0.40) nor the AI or the PI (both P > 0.35). Tumours with high COX‐2 expression were significantly more likely to develop metastasis (P = 0.022). Conclusion: Radiotherapy with photons does not induce COX‐2 expression in malignant melanomas of the uvea. But high COX‐2 expression may be a marker for poor prognosis.     

Feasibility of multifocal intra‐ocular lens exchange and conversion to the bag‐in‐the‐lens implantation

Purpose: Our purpose was to evaluate the surgical outcome after intra‐ocular lens exchange in patients who presented impairing visual complaints after primary multifocal intra‐ocular lens (MIOL) implantation. In particular, the study was undertaken to look at the number of eyes that could be equipped with the bag‐in‐the‐lens (BIL) IOL after MIOL exchange. Methods: This series consisted of 30 eyes of 21 consecutive patients scheduled for MIOL exchange. In 15 out of the 30 eyes, IOL misalignment was measured on slit lamp anterior segment photo’s after defining the mathematical centres of the IOL optic, pupil and limbus. Results: Diffractive MIOL was more frequently explanted (25; 83%) when compared with refractive MIOL (4; 13%) and progressive optic IOL (1; 4%). In 21 out of the 30 eyes (70%) a bag‐in‐the‐lens could be implanted. In 7 out of the 30 eyes (23%), the capsule was not considered sufficiently stable to accommodate an IOL. An iris‐fixated IOL or a sulcus‐fixated IOL was then implanted. In 2 out of the 30 eyes (6%) the remaining capsular bag could accommodate a traditional lens‐in‐the‐bag only. Eyes that underwent Nd:YAG laser capsulotomy prior to the MIOL exchange needed anterior vitrectomy peroperatively (11 eyes; 37%). Visual acuity improved postoperatively in 13 out of the 30 eyes and remained stable in 17 out of the 30 eyes. Conclusions: Since the BIL technique requires a very well‐preserved capsular bag for the purpose of the IOL implantation, the success rate of BIL implantation after MIOL is a good indicator to evaluate the degree of difficulty to exchange MIOL.     

Anti‐aquaporin‐4 antibody‐positive optic neuritis

Purpose: It has recently been reported that the anti‐aquaporin‐4 antibody (AQP4‐Ab) can be a specific marker of neuromyelitis optica. We present three cases of optic neuritis (ON) where the patients tested positive for AQP4‐Ab, but showed no neurological signs. Methods: Sera were obtained from 32 Japanese patients with ON and no other neurological abnormalities (mean age 46 ± 20 years). AQP4‐Ab was detected by indirect immunofluorescence staining using human‐AQP4‐transfected HEK 293 cells. Results: AQP4‐Ab was positive in three female patients (aged 9, 64 and 82 years). Their illness was characterized by bilateral severe optic nerve involvement, insufficient visual recovery, and autoimmune abnormalities (such as positive antinuclear antibody). Two of these patients experienced recurrent episodes of ON. In at least two episodes, the intracranial portion of the optic nerve showed significant inflammation on magnetic resonance imaging. Conclusions: These cases indicate that some ON patients have an immunological pathogenesis similar to that seen in neuromyelitis optica. In addition, examination for AQP4‐Ab positivity in the initial phase of ON is important in predicting the prognosis, including the possibility of the development of transverse myelitis.     

Increased serum total antioxidant status and decreased urinary 8‐hydroxy‐2′‐deoxyguanosine levels in patients with normal‐tension glaucoma

Acta Ophthalmol. 2010: 88: e259–e264

Abstract.

Purpose: To investigate the amount of systemic oxidative stress‐related DNA damage and serum total antioxidant status of patients with normal‐tension glaucoma compared with healthy controls. Methods: Forty‐three patients with normal‐tension glaucoma selected from 60 consecutive newly diagnosed patients with primary open‐angle glaucoma were enrolled. Each patient’s intraocular pressure (IOP) was measured seven times over a 24‐hour period. Those whose highest IOP was over 21 mmHg were excluded. Forty control subjects were recruited. The serum total antioxidant status was assessed colorimetrically by its ability to reduce the generation of the radical cation ABTS (2,2‐azinobis‐3‐ethylbenzthiazoline sulphonate). The urinary 8‐hydroxy‐2′‐deoxyguanosine was measured as a marker of oxidative DNA damage and normalized to creatinine. The results were compared between healthy subjects and patients with normal‐tension glaucoma. Results: The control and normal‐tension glaucoma groups did now show significant differences for age, gender, serum fructosamine, cholesterol and triglyceride levels; systolic and diastolic blood pressure, body mass index; and prevalence of hypertension. The serum total antioxidant status was significantly higher (p = 0.01) and the urinary 8‐hydroxy‐2′‐deoxyguanosine/creatinine level significantly lower (p = 0.03) in the patients with normal‐tension glaucoma compared with the controls. Even after we adjusted the data for independent variables, the incidence of normal‐tension glaucoma was significantly correlated with high serum total antioxidant levels (p = 0.03; odds ratio, 1.007; 95% confidence interval, 1.001–1.013) and low urinary 8‐hydroxy‐2′‐deoxyguanosine/creatinine (p = 0.02; odds ratio 0.76; 95% confidence interval, 0.61–0.96). Conclusions: Increased serum total antioxidant and decreased 8‐hydroxy‐2′‐deoxyguanosine may reflect compensatory alterations in response to increased systemic oxidative stress in patients with normal‐tension glaucoma.     

Cup‐to‐disc ratios of Aboriginal and non‐Aboriginal youths

Background: The determination of the cup‐to‐disc ratio (C/D) is a standard procedure in an eye examination and is pivotal in the diagnosis of glaucoma. Determining the size of the C/D ratios of different races of young people may be helpful in determining the genetically predetermined differences between Aboriginal and non‐Aboriginal people. The aim of this study was to determine whether there is a statistically significant difference in the average C/D ratios of young Aboriginal and non‐Aboriginal people. Methods: The overall average C/D ratios of 104 subjects aged between five and 23 years were compared for two age‐matched groups by stereoscopic indirect ophthalmoscopy. Differences between the overall average C/D ratios of the two groups were assessed for significance using an unpaired Student’s t test. Results: While the range of C/D ratios within each group was the same (zero to 0.7), there was a statistical difference (p < 0.001) between the overall average C/D ratios of the Aboriginal (C/D = 0.295) and non‐Aboriginal (C/D = 0.159) groups. Conclusions: Results indicating a difference between the overall average C/D ratios between Aboriginal and non‐Aboriginal young people may have implications for initial assessments of glaucoma in patients of any age.     

Dry‐eye syndrome after allogeneic stem‐cell transplantation in children

Purpose: To report the prevalence of dry‐eye syndrome (DES) in children and young adults treated with allogeneic stem‐cell transplantation (SCT) during childhood; to relate DES to conditioning regimes, including total body irradiation (TBI) and chemotherapy, and to immunosuppressive drugs and graft‐versus‐host disease (GVHD). Methods: This cross‐sectional study included 60 children/young adults transplanted because of leukaemia, various haematological disorders and inborn errors of metabolism between 1986 and 2004, with a follow‐up time of 7.0 years (median, range 2–18). Clinical assessments, performed at a median age of 15.6 years (range 5.5–23.5), included an inquiry form on dry‐eye symptoms, corneal status including fluorescein staining, ‘break‐up time’ (BUT) and Schirmer test. Results: A total of 37 of 60 patients had DES defined as presence of corneal epithelial lesions with a pathological BUT and/or Schirmer test. Twenty‐nine had had staining <1–10% of the corneal surface while eight patients had staining ≥10–25% of the corneal surface. All 37 patients with objective signs of DES, graded and not graded, had significant associations to subjective symptoms of dry eyes including dry eyes, red eyes, ocular irritation, secretion and sensitivity to light. Frequent occasions (above median; n = 7) of high cyclosporine A trough levels above 250 ng/ml were associated significantly with DES (P = 0.002). However, there was no association between DES and conditioning with single‐dose (s‐TBI) or fractionated TBI (f‐TBI), busulfan or other chemotherapy. There were no associations between prolonged corticosteroid treatment or chronic GVHD and DES in the present study. DES was more common in patients with malignant diseases (P = 0.02). Malignant disease increased the risk of DES in girls but not in boys. Increased age at SCT increased the risk for DES in boys but not in girls (P = 0.02). Although severe keratitis occurred in three patients, nobody suffered corneal perforation. Conclusion: DES with epithelial punctata keratopathy was common in children/young adults treated with SCT and more common if the patients were exposed to repeated high trough levels of cyclosporine A; however, DES was not associated with irradiation, corticosteroids or GVHD in the present study. Patients with objective DES also had subjective symptoms of dry eyes, which facilitate diagnosis. Girls with malignant diseases and boys who underwent SCT at later ages seem to demand higher attention and more frequent check‐ups regarding DES. Patients with diagnosed severe DES needed frequent and continuous ophthalmological care to maintain treatment motivation.     

The short‐sighted perspective of long‐term eye health‐care

Eye health‐care in Australia encompasses patients with chronic disorders being referred to ophthalmologists for detailed assessment and subsequent management. An increasing case load and relative decrease in ophthalmologists predicted over the next few years portend of an upcoming bottleneck in care delivery. To improve the efficiency and effectiveness of patient care within a rapidly changing health system, we propose that minor adjustments to existing services could improve the proficiency of resources. Such changes will require service providers to rethink their positions and roles and actively collaborate with each other for improved patient outcomes.