Aravind Eye Hospitals

Coimbatore, India

Aravind Eye Hospitals

Coimbatore, India
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Karuppannasamy D.,PSG Institute of Medical science and Research | Venkatesan R.,Aravind Eye Hospitals | Thankappan L.,PSG Institute of Medical science and Research | Andavar R.,PSG Institute of Medical science and Research | Devisundaram S.,PSG Institute of Medical science and Research
Journal of Clinical and Diagnostic Research | Year: 2017

Introduction: Oxidative stress plays a central role in the pathogenesis of Diabetic Retinopathy (DR) and serum bilirubin has been shown to have antioxidant properties. Aim: To investigate the association between serum bilirubin concentration and DR in patients with Type 2 diabetes Mellitus (DM). Materials and Methods: This was a hospital based, crosssectional study where in 86 patients with Type 2 DM and 30 controls were recruited. The study was conducted at a tertiary care centre in South India between January 2014 and December 2014. The presence and the severity of DR were determined by fundus examination and grading of colour fundus photographs using the international clinical disease severity scale for diabetic retinopathy. Serum total, direct and indirect bilirubin levels were determined in all subjects and the association between bilirubin levels and severity of DR was studied. Results: Among the 86 diabetics, 24 had no retinopathy and 62 had diabetic retinopathy of varying grades. The mean total bilirubin level among diabetic subjects (0.52±0.17) and controls (0.51±0.19) were found to be similar. The mean total as well as direct bilirubin levels were found to be lower in patients with retinopathy as compared to no retinopathy group (p<0.001). The severity of DR was inversely proportional to the serum bilirubin levels (p=0.010). Serum total bilirubin was found to have a negative association with glycosylated haemoglobin and served as an independent determinant of diabetic retinopathy even after adjusting for risk factors known to be associated with DR (p=0.001). Conclusion: Low serum bilirubin levels are significantly associated with increased risk of diabetic retinopathy independent of classic risk factors. Serum bilirubin can serve as a useful biomarker in identifying patients at risk for developing proliferative diabetic retinopathy. © 2017, Journal of Clinical and Diagnostic Research. All rights reserved.


Bains S.,Aravind Eye Hospitals | Kim U.,Aravind Eye Hospitals | Shanti R.,Aravind Eye Hospitals
Indian Journal of Ophthalmology | Year: 2016

Primary orbital melanoma is rare and has varied initial presentation. A 28-year-old female presented with proptosis and decreased vision in the left eye. Computed tomography scan showed an orbital mass with contrast enhancement and calcification around the optic nerve leading to a diagnosis of meningioma. The patient chose to be on observation. Loss of vision with an increase in proptosis was seen at 6 months follow-up. On surgical exploration, a well-defined pigmented mass was seen encasing the optic nerve. Histopathological analysis revealed a malignant melanoma. Metastatic workup was negative. Left eye lid sparing exenteration was done. A high index of suspicion is necessary in a rapidly growing suspected optic nerve sheath meningioma and a differential diagnosis including orbital melanoma be considered. © 2017 Indian Journal of Ophthalmology.


Mehta J.S.,11 Third Hospital Avenue | Mehta J.S.,Singapore Eye Research Institute | Hemadevi B.,Aravind Medical Research Foundation | Vithana E.N.,Singapore Eye Research Institute | And 10 more authors.
Cornea | Year: 2010

Purpose: The purposes of this study were to describe the clinical characteristics of corneal patients with mutations in the SLC4A11 gene and to determine if these characteristics could be correlated with specific genetic mutations. Methods: A retrospective case series review was conducted. Baseline demographic data, including gender, age at diagnosis of congenital hereditary endothelial dystrophy, family history, and pedigree information, were obtained. Information from clinical examination, including intraocular pressure, ultrasonic pachymetry, best spectacle-corrected visual acuity, axial length, and slit-lamp biomicroscopic evaluation, including corneal diameter and fundus examination, were also documented from the notes. History of corneal surgery was also recorded. Hearing loss was assessed by audiometry. Genetic analysis was performed by polymerase chain reaction amplification and sequencing. Results: Seven patients were identified. Four of the seven had associated hearing loss; all of the patients had undergone or were awaiting penetrating keratoplasty to one or both eyes. No correlation could be reached between the ocular phenotype and the gene mutation in this small sample. Individuals with the same mutation had different degrees of hearing loss within their respective families. Conclusions: Corneal endothelial cells are more vulnerable to defects in the functional activity of SLC4A11 than cells of the striae vascularis of the inner ear. Both congenital hereditary endothelial dystrophy 2 and Harboyan syndrome have similar ocular phenotypes, ie, diffuse bilateral corneal edema present at birth or within the neonatal period; hence, audiometry must be performed to differentiate the two conditions. Copyright © 2010 by Lippincott Williams & Wilkins.


Porkumaran K.,Coimbatore Institute of Technology | Shah P.K.,Aravind Eye Hospitals | Narendran V.,Aravind Eye Hospitals
Research Journal of Applied Sciences, Engineering and Technology | Year: 2014

The Retinopathy of Prematurity (ROP) is an ocular pathological disorder of the retinal blood vessels in premature infants and low birth weight infants. It is essential that those caring for premature infants should know who is at risk of ROP and their severity stage. It is also important that when screening must begin and how often these infants need to be examined otherwise the progression lead most severe stage and can cause blindness. The contrast stretching method has been utilized to enhance the ROP color image. Then an automatic method Isotropic Un-decimated Wavelet Transform (IUWT) has been proposed to extract the abnormal retinal blood vessel and measure its width and tortuosity. The ridge formation of this pathological disorder has also been obtained by the IUWT. The quantitative measurements of mean diameter, standard deviation, tortuosity, length of retinal blood vessel and ridge have been considered and computed the exact severity stage of ROP. The effectiveness of the proposed method has been verified through machine vision techniques and the results obtained are encouraged by experts. Automatic ROP screening system comprises several advantages, like a substantial time reduction of ophthalmologists in diagnosis, a non ophthalmologist can provide stage of ROP, improving the sensitivity of the test and a better accuracy in diagnosis. © Maxwell Scientific Organization, 2014.


Prabakar S.,Coimbatore Institute of Technology | Porkumaran K.,Coimbatore Institute of Technology | Shah P.K.,Aravind Eye Hospitals | Narendran V.,Aravind Eye Hospitals
European Journal of Scientific Research | Year: 2011

In this paper, an automatic method is proposed to detect various stages of Retinopathy of prematurity (ROP) in premature infants and low birth weight infants. It is essential that those caring for premature infants should know who is at risk of ROP, when screening must begin and how often these infants need to be examined otherwise it can cause blindness. So, ROP detection is necessary for both screening the pathology and progression measurement. Computerizing this task, which is currently executed manually, would bring more subjectivity and reproducibility. The proposed image processing algorithms for predicting the presence and stages of ROP are histogram equalization methods, feature extraction, measuring curvature by changes in intensity and template matching. The retinal vessels are segmented using simple and standard 2-D Gaussian Matched Filter. Segmented vessels are thinned, smoothened and filtered based on local intensity of the vessels. The effectiveness of the proposed method has been verified through machine vision techniques and the results obtained are encouraged by experts. Automatic ROP staging system comprises several advantages, like a substantial time reduction of ophthalmologists in diagnosis, a non ophthalmologist can provide stage of ROP, improving the sensitivity of the test and a better accuracy in diagnosis. © EuroJournals Publishing, Inc. 2011.


Kannan N.B.,Aravind Eye Hospitals | Adenuga O.O.,Aravind Eye Hospitals | Rajan R.P.,Aravind Eye Hospitals | Ramasamy K.,Aravind Eye Hospitals
Journal of Ophthalmology | Year: 2016

Purpose. Ocular siderosis (OS) is a sight threatening complication of retained iron-containing Intraocular Foreign Body (IOFB). Successful localization of the IOFB and timely removal are crucial to its management. The purpose of this study was to review the presentation, management, and outcome of OS at our institution. Methods. A retrospective case series of eyes with OS that underwent IOFB removal from January 2009 to March 2015 at our institution. Results. OS was seen in 9 eyes of 9 patients during the study period. There were 8 males and 1 female with an age range of 31.6 years. An IOFB was in all the eyes. The most common features of siderosis were cataract and pigmentary retinopathy seen in 6 (67%) and 4 (44%) eyes, respectively. Electroretinogram (ERG) readings were reduced in the 9 eyes. The IOFB was removed by pars plana vitrectomy in all the cases with improvement in ERG amplitudes occurring postoperatively in 7 (78%) eyes. Conclusion. A retained iron-containing IOFB can manifest itself after several years with features of OS. A careful clinical and radiologic evaluation is imperative in patients with history suggestive of penetrating ocular injury to rule out retained or occult IOFB and thus prevent this catastrophic condition. © 2016 Naresh B. Kannan et al.


Joshi G.D.,Indian Institute of Technology Hyderabad | Sivaswamy J.,Indian Institute of Technology Hyderabad | Krishnadas S.R.,Aravind Eye Hospitals
IEEE Transactions on Medical Imaging | Year: 2011

Automatic retinal image analysis is emerging as an important screening tool for early detection of eye diseases. Glaucoma is one of the most common causes of blindness. The manual examination of optic disk (OD) is a standard procedure used for detecting glaucoma. In this paper, we present an automatic OD parameterization technique based on segmented OD and cup regions obtained from monocular retinal images. A novel OD segmentation method is proposed which integrates the local image information around each point of interest in multidimensional feature space to provide robustness against variations found in and around the OD region. We also propose a novel cup segmentation method which is based on anatomical evidence such as vessel bends at the cup boundary, considered relevant by glaucoma experts. Bends in a vessel are robustly detected using a region of support concept, which automatically selects the right scale for analysis. A multi-stage strategy is employed to derive a reliable subset of vessel bends called r-bends followed by a local spline fitting to derive the desired cup boundary. The method has been evaluated on 138 images comprising 33 normal and 105 glaucomatous images against three glaucoma experts. The obtained segmentation results show consistency in handling various geometric and photometric variations found across the dataset. The estimation error of the method for vertical cup-to-disk diameter ratio is 0.09/0.08 (mean/standard deviation) while for cup-to-disk area ratio it is 0.12/0.10. Overall, the obtained qualitative and quantitative results show effectiveness in both segmentation and subsequent OD parameterization for glaucoma assessment. © 2011 IEEE.


Joshi G.D.,Indian Institute of Technology Hyderabad | Gautam R.,Indian Institute of Technology Hyderabad | Sivaswamy J.,Indian Institute of Technology Hyderabad | Krishnadas S.R.,Aravind Eye Hospitals
ACM International Conference Proceeding Series | Year: 2010

We present a novel segmentation method to better capture the boundary of a non-homogeneous object such as the optic disk(OD), defined locally by two similar characteristic regions. Existing active contour models which utilise gradient information [12] or global region intensity [2] fail to localise aforementioned boundaries. We propose a region-based active contour model that uses local image information around each point of interest in multi-dimensional feature space. This model uses a local energy functional and level-set representation to achieve desired OD segmentation. The local energy functional defined on each image point provides sufficient information to determine a desired OD segmentation which is robust to the variations found in and around the OD region. This method has been evaluated against the segmentation provided by three medical experts on 138 retinal images. Both region and boundary-based assessment performed against two well established active contour models show strengths of the proposed method. © 2010 ACM.


Joshi G.D.,International Institute of Information Technology, Hyderabad | Sivaswamy J.,International Institute of Information Technology, Hyderabad | Krishnadas S.R.,Aravind Eye Hospitals
IEEE Transactions on Biomedical Engineering | Year: 2012

Accurate segmentation of the cup region from retinal images is needed to derive relevant measurements for glaucoma assessment. A novel, depth discontinuity (in the retinal surface)-based approach to estimate the cup boundary is proposed in this paper. The proposed approach shifts focus from the cup region used by existing approaches to cup boundary. The given set of images, acquired sequentially, are related via a relative motion model and the depth discontinuity at the cup boundary is determined from cues such as motion boundary and partial occlusion. The information encoded by these cues is used to approximate the cup boundary with a set of best-fitting circles. The final boundary is found by considering points on these circles at different sectors using a confidence measure. Four different kinds of data sets ranging from synthetic to real image pairs, covering different multiview scenarios, have been used to evaluate the proposed method. The proposed method was found to yield an error reduction of 16 for cup-to-disk vertical diameter ratio (CDR) and 13 for cup-to-disk area ratio (CAR) estimation, over an existing monocular image-based cup segmentation method. The error reduction increased to 33 in CDR and 18 in CAR with the addition of a third view (image) which indicates the potential of the proposed approach. © 1964-2012 IEEE.

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