We report a case of diffuse unilateral subacute neuroretinitis in a young boy with no clinical visualization of nematode. The diagnosis was made based on clinical findings and detection of Toxocara immunoglobulin G by Western blot test. An 11-year-old Malay boy presented with progressive blurring of vision in the left eye for a duration of 1 year. It was associated with intermittent floaters. Visual acuity in the left eye was 6/45 and improved to 6/24 with pinhole. There was positive relative afferent pupillary defect, impaired color vision, and presence of red desaturation in the left eye. There were occasional cells in the anterior chamber with no conjunctiva injection. Posterior segment examination revealed mild-to-moderate vitritis and generalized pigmentary changes of the retina with attenuated vessels. The optic disk was slightly hyperemic with mild edema. There was presence of multiple, focal, gray-white subretinal lesions at the inferior part of the retina. Full blood picture results showed eosinophilia with detection of Toxocara immunoglobulin G by Western blot test. Investigations for other infective causes and connective tissue diseases were negative. The diagnosis of diffuse unilateral subacute neuroretinitis secondary to Toxocara was made based on clinical findings and laboratory results. He was treated with oral albendazole 400 mg daily for 5 days and oral prednisolone 1 mg/kg with tapering doses over 6 weeks. At 1 month follow-up, the inflammation had reduced, and multiple, focal, gray-white subretinal lesions were resolved; however there was no improvement of vision.
Elektroretinogram paten (pERG) adalah pengrekodan respons retina terhadap stimulus paten yang dipancarkan bersilih ganti. Ia memberi maklumat mengenai integriti sel dalaman retina khasnya sel ganglion. Pengrekodan pERG dalam sesebuah makmal boleh dipengaruhi oleh beberapa faktor, maka piawai makmal perlu ada untuk memastikan bacaan pERG yang diperolehi boleh diulang dan dihasilkan semula. Objektif kajian ini ialah untuk menentusahkan faktor yang mungkin mempengaruhi pengukuran pERG untuk paiwaian Makmal Elektrofisiologi Jabatan Optometri, Fakulti Sains Kesihatan (FSK), Universiti Kebangsaan Malaysia (UKM). Kajian ini melibatkan 45 orang subjek yang berumur di antara 20 hingga 25 tahun yang dibahagikan kepada 3 kumpulan. Faktor yang dikaji adalah 1) kesan penggunaan anestetik Alcaine 0.5%, 2) variasi pengukuran pada waktu pagi dan petang dan 3) saiz dan bentuk target fiksasi yang berbeza terhadap bacaan pERG (amplitud dan tempoh pendam). Ujian-t berpasangan mendapati tiada perbezaan yang signifikan antara pengukuran sebelum dan selepas penggunaan Alcaine 0.5% bagi amplitud (p = 0.116) dan tempoh pendam
(p = 0.557). Pengukuran pada waktu pagi dan petang juga menunjukkan tiada perbezaan signifikan bagi amplitud (p = 0.864) dan tempoh pendam (p = 0.174). Untuk bentuk dan saiz target yang berbeza, didapati tiada perbezaan yang signifikan untuk parameter amplitud (p = 0.125) dan tempoh pendam (p = 0.404). Kesimpulannya, penggunaan Alcaine 0.5%, pengukuran pada waktu pagi dan petang dan target fiksasi yang berbeza tidak mempengaruhi bacaan pERG di Makmal Elektrofisiologi, FSK, UKM. Hasil kajian boleh diguna pakai untuk perbandingan dalam penyelidikan ataupun tujuan pendiagnosan penyakit retina di masa hadapan.
To compare the potential retinal toxicity of two commercially Brilliant blue G dyes (Brilliant Peel and Ocublue Plus) and Indocyanine green (ICG) at usual clinical concentration.
OBJECTIVE(S): To examine the effect of blood pressure (BP) on retinal vascular fractal dimension (Df), a measure of microvascular network complexity and density in a multiethnic cohort.
METHODS: A population-based study of 3876 Chinese, Malay and Indian participants in Singapore. Retinal Df was measured using a computer-based program from digital retinal photographs. Associations between retinal Df and mean arterial BP (MABP) in the whole cohort and in each racial group were analysed using linear regression analysis. Logistic regression was used to examine the association between retinal Df and hypertension status.
RESULTS: The mean retinal Df of the study population was 1.45 (standard deviation 0.03). After adjustment for age, sex, race, diabetes, BMI, cholesterol and creatinine levels, persons with smaller Df had higher MABP (mean difference MABP was 6.18 mmHg comparing lowest to highest Df quartiles, P<0.001). This was similar in Chinese, Malay and Indian persons [mean difference 6.40 (P<0.001), 4.72 (P=0.011) and 6.62 (P<0.001)mmHg, respectively]. Persons with smaller retinal Df were more likely to have uncontrolled treated or untreated hypertension [odds ratio 1.79 (P=0.003) and 2.60 (P=0.003), respectively, comparing lowest to highest Df quartiles] than those with no hypertension; this relationship was not seen comparing persons with controlled treated hypertension with no hypertension (odds ratio 1.01, P=0.972).
CONCLUSION: Hypertension was associated with a sparser retinal vascular network, which was similar across different racial/ethnic groups and most apparent in those with uncontrolled or untreated hypertension. These data suggest that microvascular remodelling can be quantified by measuring retinal vasculature.
The fractal dimension is a global measure of complexity and is useful for quantifying anatomical structures, including the retinal vascular network. A previous study found a linear declining trend with aging on the retinal vascular fractal dimension (DF); however, it was limited to the older population (49 years and older). This study aimed to investigate the possible models of the fractal dimension changes from young to old subjects (10-73 years). A total of 215 right-eye retinal samples, including those of 119 (55%) women and 96 (45%) men, were selected. The retinal vessels were segmented using computer-assisted software, and non-vessel fragments were deleted. The fractal dimension was measured based on the log-log plot of the number of grids versus the size. The retinal vascular DF was analyzed to determine changes with increasing age. Finally, the data were fitted to three polynomial models. All three models are statistically significant (Linear: R2 = 0.1270, 213 d.f., p
A 15-year-old boy presented with painless progressive blurring of vision in the right eye for 1 year in duration. His visual acuity in the right eye was hand movement. The right fundus showed presence of extensive subretinal exudates at the posterior pole and a retinal macrocyst at the temporal periphery. It was associated with exudative retinal detachment at the inferior periphery of the retina. Fundus angiography revealed telangiectatic retinal vessels at the superotemporal retina. Based on clinical and angiographic findings, a diagnosis of Coats disease was made. He was treated with retinal laser photocoagulation. There was resolution of the exudative retinal detachment, reduction of subretinal exudates, and regression of the retinal macrocyst with improvement of visual acuity to 1/60 post-laser therapy.
Fractal dimensions (FDs) are frequently used for summarizing the complexity of retinal vascular. However, previous techniques on this topic were not zone specific. A new methodology to measure FD of a specific zone in retinal images has been developed and tested as a marker for stroke prediction. Higuchi's fractal dimension was measured in circumferential direction (FDC) with respect to optic disk (OD), in three concentric regions between OD boundary and 1.5 OD diameter from its margin. The significance of its association with future episode of stroke event was tested using the Blue Mountain Eye Study (BMES) database and compared against spectrum fractal dimension (SFD) and box-counting (BC) dimension. Kruskal-Wallis analysis revealed FDC as a better predictor of stroke (H = 5.80, P = 0.016, α = 0.05) compared with SFD (H = 0.51, P = 0.475, α = 0.05) and BC (H = 0.41, P = 0.520, α = 0.05) with overall lower median value for the cases compared to the control group. This work has shown that there is a significant association between zone specific FDC of eye fundus images with future episode of stroke while this difference is not significant when other FD methods are employed.
Aberrant epigenetic profiles are concomitant with a spectrum of developmental defects and diseases. Role of methylation is an increasingly accepted factor in the pathophysiology of diabetes and its associated complications. This study aims to examine the correlation between oxidative stress and methylation of β1, β2 and β3-adrenergic receptors and to analyze the differential variability in the expression of these genes under hyperglycemic conditions.
Retinopathy of prematurity (ROP) is a disorder describing an immature vascularisation
of a developing retina in low birth weight preterm infants. This condition potentially
leads to blindness. ROP developed as a response of hypoxia of the eye due to
incomplete development of the retinal vessels. ROP is commonly reported as
bilateral disease,a small percentage of infants have asymmetrical changes. We
report a case of long-term outcome of a asymmetry ROP changes with peripheral
retinal ablation in a single eye. This particular case demonstrates the possible longterm
outcome of unilaterally treated ROP which could either be due to the severity
of the disease itself or the treatment she received. It is important to highlight the
possibility of unequal development of the eye in asymmetrical presentation of ROP.
Steroid-induced ocular hypertension (SIOH) is associated with topical and systemic use of steroids. However, SIOH-associated anterior and posterior segment morphological changes in rats have not been described widely. Here we describe the pattern of intraocular pressure (IOP) changes, quantitative assessment of trabecular meshwork (TM) and retinal morphological changes and changes in retinal redox status in response to chronic dexamethasone treatment in rats. We also evaluated the responsiveness of steroid-pretreated rat eyes to 5 different classes of antiglaucoma drugs that act by different mechanisms. Up to 80% of dexamethasone treated animals achieved significant and sustained IOP elevation. TM thickness was significantly increased and number of TM cells was significantly reduced in SIOH rats compared to the vehicle-treated rats. Quantitative assessment of retinal morphology showed significantly reduced thickness of ganglion cell layer (GCL) and inner retina (IR) in SIOH rats compared to vehicle-treated rats. Estimation of retinal antioxidants including catalase, superoxide dismutase and glutathione showed significantly increased retinal oxidative stress in SIOH animals. Furthermore, steroid-treated eyes showed significant IOP lowering in response to treatment with 5 different drug classes. This indicated the ability of SIOH eyes to respond to drugs acting by different mechanisms. In conclusion, SIOH was associated with significant morphological changes in TM and retina and retinal redox status. Additionally, SIOH eyes also showed IOP lowering in response to drugs that act by different mechanisms of action. Hence, SIOH rats appear to be an inexpensive and noninvasive model for studying the experimental antiglaucoma drugs for IOP lowering and neuroprotective effects.
Age-related Macular Degeneration (AMD) is an irreversible and chronic medical condition characterized by drusen, Choroidal Neovascularization (CNV) and Geographic Atrophy (GA). AMD is one of the major causes of visual loss among elderly people. It is caused by the degeneration of cells in the macula which is responsible for central vision. AMD can be dry or wet type, however dry AMD is most common. It is classified into early, intermediate and late AMD. The early detection and treatment may help one to stop the progression of the disease. Automated AMD diagnosis may reduce the screening time of the clinicians. In this work, we have introduced LCP to characterize normal and AMD classes using fundus images. Linear Configuration Coefficients (CC) and Pattern Occurrence (PO) features are extracted from fundus images. These extracted features are ranked using p-value of the t-test and fed to various supervised classifiers viz. Decision Tree (DT), Nearest Neighbour (k-NN), Naive Bayes (NB), Probabilistic Neural Network (PNN) and Support Vector Machine (SVM) to classify normal and AMD classes. The performance of the system is evaluated using both private (Kasturba Medical Hospital, Manipal, India) and public domain datasets viz. Automated Retinal Image Analysis (ARIA) and STructured Analysis of the Retina (STARE) using ten-fold cross validation. The proposed approach yielded best performance with a highest average accuracy of 97.78%, sensitivity of 98.00% and specificity of 97.50% for STARE dataset using 22 significant features. Hence, this system can be used as an aiding tool to the clinicians during mass eye screening programs to diagnose AMD.
BACKGROUND: Hydroxychloroquine (HCQ) is widely used for long-term treatment of autoimmune diseases such as rheumatoid arthritis. However, its long-term use is known to be associated with visual changes due to retinal damage. Retinal damage associated with long-term HCQ therapy is preventable if the drug is discontinued early when the patients are still asymptomatic. In view of contrasting reports from previous studies, we investigated the association of prolonged HCQ therapy with retinal thickness in macular area.
METHODS: This study included 48 patients on long-term HCQ therapy and 38 healthy controls. All subjects underwent examination for corrected visual acuity, fundus photography, visual fields and SD-OCT for retinal thickness.
RESULTS: Visual acuity, visual fields, fundus photography and SD-OCT did not reveal changes consistent with diagnosis of established HCQ retinopathy in any of the subjects from HCQ group. Retinal thickness in central, parafoveal and perifoveal areas did not show significant differences between HCQ and control groups. However, we observed negative correlation between cumulative dose and retinal thickness in the parafoveal (p = 0.003) and perifoveal areas (p = 0.019) but not in the central area.
CONCLUSIONS: Correlation of cumulative dose with retinal thickness in parafoveal and perifoveal areas and not the central area is in accordance with the late appearance of HCQ-induced bull's eye retinopathy. Hence screening of asymptomatic patients using OCT seems to be of great importance for early detection of retinal changes.
KEYWORDS: Cumulative dose; OCT; hydroxychloroquine; retinal thickness
Neurodegenerative disease is defined as a deterioration of the nervous system in the intellectual and cognitive capabilities. Statistics show that more than 80-90 million individuals age 65 and above in 2050 may be affected by neurodegenerative conditions like Alzheimer's and Parkinson's disease. Studies have shown that out of 2000 different types of edible and/or medicinal mushrooms, only a few countable mushrooms have been selected until now for neurohealth activity. Hericium erinaceus is one of the well-established medicinal mushrooms for neuronal health. It has been documented for its regenerative capability in peripheral nerve. Another mushroom used as traditional medicine is Lignosus rhinocerotis, which has been used for various illnesses. It has been documented for its neurite outgrowth potential in PC12 cells. Based on the regenerative capabilities of both the mushrooms, priority was given to select them for our study. The aim of this study was to investigate the potential of H. erinaceus and L. rhinocerotis to stimulate neurite outgrowth in dissociated cells of brain, spinal cord, and retina from chick embryo when compared to brain derived neurotrophic factor (BDNF). Neurite outgrowth activity was confirmed by the immu-nofluorescence method in all tissue samples. Treatment with different concentrations of extracts resulted in neuronal differentiation and neuronal elongation. H. erinaceus extract at 50 µg/mL triggered neurite outgrowth at 20.47%, 22.47%, and 21.70% in brain, spinal cord, and retinal cells. L. rhinocerotis sclerotium extract at 50 µg/mL induced maximum neurite outgrowth of 20.77% and 24.73% in brain and spinal cord, whereas 20.77% of neurite outgrowth was observed in retinal cells at 25 µg/mL, respectively.
To investigate the safety and efficacy of subretinal injection of human Wharton's Jelly-derived mesenchymal stem cells (hWJ-MSCs) on retinal structure and function in Royal College of Surgeons (RCS) rats.
An 18-year-old Malay gentleman was noted to have profound bilateral blurred vision for one month duration, associated with loss of weight, appetite, low grade fever and abdominal distension. Visual acuity on presentation was 6/60 on the right, counting finger on the left with no afferent pupillary defect. Anterior segments were unremarkable. Vitreous cells were occasional bilaterally. Fundus revealed multiple choroidal and sub-retinal Roth spots with areas of pre-retinal and intra-retinal haemorrhages, involving the macula in the left eye. Vessels were dilated and tortuous in all quadrants of the right eye. Many areas of capillary fall out at peripheral retina were demonstrated in fundus fluorescein angiogram. Further systemic and laboratory review confirmed the diagnosis of CML and chemotherapy was initiated. Both eye ischaemic retinopathy secondary to CML was confirmed and scatter pan retinal photocoagulation was performed bilaterally. Good improvement in vision noted during subsequent follow up to 6/24 on the right, 6/60 on the left. High levels of suspicion and accurate early recognition of fundus changes are vital in these types of cases to ensure the institution of prompt treatment.
Radiation retinopathy (RR) is a known complication after radiotherapy for Nasopharyngeal Carcinoma (NPC). This study aims to relate the relationship of RR and radiation dose in patients with NPC through assessment with clinical
funduscopy and fundus fluorescein angiogram (FFA). A cross sectional study was conducted on patients with NPC who had completed radiotherapy treatment in the Oncology Clinic, Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Eighty two eyes of 42 patients were examined and the prevalence of RR was found to be 35.4%. The severity of RR is strongly associated with the dose of radiation to the retina (Spearman correlation value=0.48; p<0.001). The common features of RR assessed by FFA were telangiectatic vessels (26.2%) and capillary non-perfusion (14.3%). Retinal neovasularization occurred in 10.7% of eyes. The level of visual deterioration correlated with the severity of RR with 26% of eyes experiencing a visual acuity of 6/18 or worse. More than one third of patients developed RR, with radiation maculopathy being the commonest cause for significant visual loss. FFA is a useful tool in detecting early signs of radiation retinopathy and maculopathy.
Keywords: nasopharyngeal carcinoma, fluorescein fundus angiography, retinopathy, radiotherapy
Study site: Oncology Clinic, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
The availability of molecular genetic testing for retinoblastoma (RB) in Malaysia has enabled patients with a heritable predisposition to the disease to be identified, which thus improves the clinical management of these patients and their families. In this paper, we presented our strategy for performing molecular genetic testing of the RB1 gene and the findings from our first 2 years of starting this service.
Steroid-induced hypertension and glaucoma is associated with increased extracellular meshwork (ECM) deposition in trabecular meshwork (TM). Previous studies have shown that single drop application of trans-resveratrol lowers IOP in steroid-induced ocular hypertensive (SIOH) rats. This IOP lowering is attributed to activation of adenosine A1 receptors, which may lead to increased matrix metalloproteinase (MMP)-2 activity. This study evaluated the effect of repeated topical application of trans-resveratrol for 21 days in SIOH animals on IOP, changes in MMP-2 level in aqueous humor, trabecular meshwork and retinal morphology and retinal redox status. We observed that treatment with trans-resveratrol results in significant and sustained IOP reduction in SIOH rats. This IOP reduction is associated with significantly higher aqueous humor total MMP-2 level; significantly reduced TM thickness and increased number of TM cells. Treatment with trans-resveratrol also significantly increased ganglion cell layer (GCL) thickness, the linear cell density in the GCL and inner retina thickness; and significantly reduced retinal oxidative stress compared to the SIOH vehicle-treated group. In conclusion, repeated dose topical application of trans-resveratrol produces sustained IOP lowering effect, which is associated with increased level of aqueous humor MMP-2, normalization of TM and retinal morphology and restoration of retinal redox status.
KEY POINTS: Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2. Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen. The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function. This model demonstrates that the resting tonus of the vessels is at the mid-point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a PETCO2 of 32-37 mmHg but being limited below this threshold. Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end-tidal partial pressure of oxygen (PETCO2) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content for all stages of hypoxia used in the present study but can no longer compensate below a PETCO2 of 32-37 mmHg. These vessels have a great vascular range of adjustment, increasing diameter (8.5% arteriolar and 21% total venous area) with hypoxia (40 mmHg P ETC O2; P < 0.001) and decreasing diameter (6.9% arteriolar and 23% total venous area) with hyperoxia (500 mmHg PETCO2; P < 0.001) to the same extent. This indicates that the resting tonus is near the mid-point of the adjustment ranges at resting PaO2 where sensitivity is maximum.