Iwan Sovani

A novel nonsense mutation in rhodopsin gene in two Indonesian families with autosomal recessive retinitis pigmentosa.

Purpose: To report a novel, identical nonsense mutation in the rhodopsin (RHO) gene in two Indonesian families with autosomal recessive retinitis pigmentosa (arRP). Methods: Mutation screening for the RHO gene was performed in 38 unrelated patients with retinitis pigmentosa (RP) by direct sequencing. Clinical features were also characterized, through complete ophthalmologic examination. Family members of RP patients testing positive for the RHO gene were subjected to genetic and clinical examination. To assess the founder effect in the two families, haplotype analysis also was performed. Results: A novel homozygous nonsense mutation was detected in two patients by a G to A transition at nucleotide position 482 in exon 2 of the RHO gene, resulting in substitution of a tryptophan-to-stop at codon 161 (c.482G>A, p.W161X). Examination of family members of these 2 patients showed that the affected members were homozygous and unaffected carriers were heterozygous for the p.W161X mutation. Haplotype analysis revealed that members of the two families carried the same disease-associated variants in markers (IVS1 RHO and D3S2322). No p.W161X mutations were detected in 45 normal Indonesian subjects, nor were any mutations detected in exons 1–5 of the RHO gene in the remaining 36 RP patients. Conclusion: We detected a novel, recessive nonsense mutation (p.W161X) in the RHO gene of two families through mutation screening of RHO in 38 Indonesian RP patients. Haplotype analysis suggested that p.W161X was the founder mutation.

Vessel enhancement algorithm in digital retinal fundus microaneurysms filter for nonproliferative diabetic retinopathy classification

Diabetic Retinopathy is one of a complication of diabetes which can cause blindness. There are two levels of diabetic retinopathy which are nonproliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR). The presence of microaneurysms in the eye is one of the early signs of diabetic retinopathy. Automated detection of microaneurysms in digital color fundus photographs is developed to help opthalmologist to detect the emergence of its early symptoms and determine the next action step for the patient. In this study we developed microaneurysms filter algorithm with the concept of vessel enhancement in order to extract the structure of microaneurysms in medical imagery, especially in the retinal image. Microaneurysms filter algorithm has been able to extract part of microaneurysms in the retinal image and detect pretty well. In addition, microaneurysms filters can also be developed to detect the next symptoms of diabetic retinopathy-hemorraghes (bleeding) that has features in common with microaneurysms which are larger and have irregular shape. Furthermore, the nonproliferative diabetic retinopathy (NPDR) classification system was developed based on the microaneurysms and hemorraghes detection. The system was tested against the patient data. Microanuerisyms detection results on DiaRetDB data has sensitivity value by 57,4% to ophthalmlogist 1, 35,37% for opthalmologist 2 and 62,68% for opthalmologist 3.

Low Vision Aid with Image to Text Converter to Enhance Magnified Text Image

Low vision is a condition when one has reduced vision even when using the best possible spectacle available. In Indonesia, the low vision people reach 2.2% of total populations. This impairments affect to theirs daily living. The most effective way to reduce the degree of handicap associated with visual impairment is to provide low vision devices as a part of a comprehensive low vision rehabilitative service. One of the low vision devices which widely used is closed circuit television system (CCTV). High quality CCTV is needed, yet it is also needs to be in reliable price. The purpose of this ongoing research is to design a low cost CCTV. By using a low pixel webcam, an optical character recognition program, and image processing system to adjust contrast, color, and line property, this design can meet the patient needs.

Automated Fluorescence as a System to Assist the Diagnosis of Retinal Blood Vessel Leakage

Leakage in retinal blood vessel may cause retinal edema which is a sign of diabetic retinopathy. Diabetic retinopathy is a severe and widely spread eye disease which can be regarded as manifestation of diabetes on the retina. So far the most effective diagnosis for this eye disease is early detection through FFA (Fluorescence Fundus Angiography) regular screening that can lead to successful laser treatments in preventing visual loss. FFA is a fundus photography technique which captures the flow/circulation of contrast agent (fluorescence) in retinal blood vessel. The problem arises since the fluorescence is a costly contrast agent and has some side effects to the patients. Some patients felt nauseous and lose their consciousness when the substance was injected to their body. To lower the risks of such screening, the Automated Fluorescence (AF) system is developed to detect the presence of leakage in retinal images obtained from fundus camera, without contrast agent injection (non-invasive).