The images of disease-affected and normal eyes collected from high-resolution fundus (HRF) image database are analyzed, and the influence of ocular diseases on iris using a reliable fuzzy recognition scheme is proposed. Nearly 45 samples of iris images are acquired using Canon CR-1 fundus camera with a field of view of 45° when subjected to routine ophthalmology visits, and the samples of eye images include healthy eyes, eyes affected by glaucoma, cataract, and diabetic retinopathy. These images are then subjected to various image processing techniques like pre-processing for de-noising using blind de-convolution, wavelet-based feature extraction, principal component analysis (PCA) for dimension reductionality, followed by fuzzy c-means clustering inference scheme to categorize the normal and diseased eyes. It is inferred that the proposed method takes only two minutes with an accuracy, specificity, and sensitivity varying in the range of 94% to 98%, respectively.
TopIntroduction
The most accurate method for biometric authentication is iris recognition and is most impressive worldwide, which results in creation of the distinctive identification numbers for the people in India using ADHAAR (Dhooge & de Laey, 1989), or Canadian border control system CANPASS (Roizenblatt et al., 2004). Like any other organ in the human body, the eyes and iris may suffer from various diseases like cataract, acute glaucoma, posterior and anterior synechiae, retinal detachment, rubeosis iridis, corneal vascularization, corneal grafting, iris damage and atrophy and corneal ulcers, haze or opacities. The eye pathologies are separated into five groups based on the impact on iris recognition: 1) healthy without impact), 2) illness detected but still clear and unaffected iris unaffected 3) geometric distortion 4) distortion in iris tissue and 5) obstruction in iris tissue (Aslam et al., 2009; Borgen et al., 2009; Dhir et al., 2010; ISO/IEC 19794-6:2011, 2011; Monro et al., 2009; Rajendra Acharya, 2011; Yuan et al., 2007).
MIRLIN, VeriEye and OSIRIS are the three methods used for iris recognition which is used to find the difference in the average value of the comparison scores inferred between the healthy and disease affected eyes. The comparison scores generated for the disease infected eyes as compared with healthy eyes is not within the tolerable limit when these conventional schemes are used. Variation in the comparison score may mislead in false non-match rate (Budai et al., 2013; McConnon et al., 2012; Neurotechnology, 2012; Odstrcilik et al., 2013; Seyeddain et al., 2014; Smart Sensors Ltd, 2013).
The various ocular diseases were detected using the database. The symptoms and the effects of various ophthalmic disorders are discussed here. Cataract is the common ophthalmic disorder indentified worldwide. The effect of this disease includes blurring of the eye lens causing reduced vision, Figure 1A. This eye disease occurs due to thickening of cornea which prevents the light from entering the lens thereby inhibiting the vision (Aggarwal & Khare, 2015; Canadian Border Services Agency, 2015; Haleem et al., 2015; Sutra et al., 2013; Trokielewicz et al., 2014; Unique Identification Authority of India, n.d.).
Figure 1. (Courtesy Department of Ophthalmology of the Medical University of Warsaw). The second kind of eye disorder is acute glaucoma which causes reduction in the space between iris and cornea closing the boundary of the iris on the outer side, hindering the flow of aqueous humor through the trabecular mesh work leading to drastic increase in ocular pressure resulting in loss of vision as in Figure 1B. The third kind is called as Posterior and anterior synechiae which occurs when the iris is partly attached to the lens or to the cornea. This changes the shape of the pupil, with deviation in circular shape, as in Figure 1C and 1D.
Diabetic retinopathy in Figure 2(a), results due to insulin disorders causing diabetes. The blood vessels in the light sensitive region retina are affected. It is because of insufficient supply of oxygen leading to blindness. If this eye disorder is diagnosed at early stage proper treatment can be given preventing blindness. The two major types of retinopathy are non-proliferative and proliferative retinopathy. The less severe type is non-proliferative retinopathy which causes hemorrhage in the retina. This produces a leak in blood serum making the retina wet which leads to diminished vision. The severe type is Proliferative retinopathy which produces new fragile blood vessels on the retina. These vessels frequently bleed into the vitreous, the clear jelly in the center of the eyes causing visual problems. It is treated by laser surgery which will reduce the progression of diabetic retinopathy and at times will reverse visual loss causing permanent damage. If Diabetic retinopathy is identified at early stages a better control of blood sugar can be maintained by ensuring lifestyle modification, including abrupt weight loss, dietary changes and simple exercises (Fuadah, Setiawan, Mengko et al, 2015; Panse et al., 2015; Sachdeva & Singh, 2015; Veras, 2015).