Iris recognition in the presence of ocular disease

Iris recognition systems are among the most accurate of all biometric technologies with immense potential for use in worldwide security applications. This study examined the effect of eye pathology on iris recognition and in particular whether eye disease could cause iris recognition systems to fail. The experiment involved a prospective cohort of 54 patients with anterior segment eye disease who were seen at the acute referral unit of the Princess Alexandra Eye Pavilion in Edinburgh. Iris camera images were obtained from patients before treatment was commenced and again at follow-up appointments after treatment had been given. The principal outcome measure was that of mathematical difference in the iris recognition templates obtained from patients' eyes before and after treatment of the eye disease. Results showed that the performance of iris recognition was remarkably resilient to most ophthalmic disease states, including corneal oedema, iridotomies (laser puncture of iris) and conjunctivitis. Problems were, however, encountered in some patients with acute inflammation of the iris (iritis/anterior uveitis). The effects of a subject developing anterior uveitis may cause current recognition systems to fail. Those developing and deploying iris recognition should be aware of the potential problems that this could cause to this key biometric technology

An unusual case report of primary vitreoretinal lymphoma

Abstract Background Primary vitreoretinal lymphoma (PVRL) is a rare ocular condition and its diagnosis remains a challenge. The clinical presentation is variable and it can masquerade as chronic intermediate or posterior uveitis. We report an unusual case of primary central nervous system lymphoma (PCNSL) presenting as migrating retinal lesions with unique shapes. The diagnostic challenges are described and the clinical features of intraocular lymphoma are reviewed. Case presentation A 53 year-old gentleman presented with unilateral visual disturbance and a wide area of retinal whitening with sharp borders temporal to the macula, corresponding to hyper-reflective subretinal changes on optical coherence tomography (OCT). The lesion resolved spontaneously after 6 weeks but was replaced by multiple punctate sub-retinal and sub-retinal pigment epithelial lesions. The second eye was involved 4 months later and there were new areas of hyper-reflective changes in both eyes, which migrated nasally within a week, with no evidence of scarring in the previous sites. The diagnosis of diffuse B-cell lymphoma was made on brain biopsy when the patient subsequently presented with acute confusion and magnetic resonance imaging brain scan showed a frontal lesion. Following systemic chemotherapy, the sub-retinal changes resolved with complete restoration of retinal architecture and improvement in visual acuity. Conclusion We report an unusual case of PVRL presenting as migrating retinal lesions with unique shapes. PVRL is a great imitator and a high index of clinical suspicion is required in unexplained ocular lesions to prevent a delay in diagnosis