H M Diwan Eye Foundation
58 Bankim Mukherjee Sarani
Kolkata 700053
Phone 6291540070
info@hmdef.org | www.hmdef.org

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Investigations at HMDEF

Optical coherence tomography (OCT) is a non-invasive imaging test. OCT uses interference of light waves to take cross-section pictures of your retina. With this test your ophthalmologist can see a cross-section of your retina – layer by layer and pin point exactly where your disease lies. To perform an OCT your pupils need to be dilated using drops and may cause blurred vision for a couple of hours. This is a completely non-contact test and takes about 5 – 10 minutes. OCT is used for the following:
  •  Retinal conditions – retinal edema, macular hole, vitreous traction, epi-retinal membrane (ERM)
  •  Glaucoma & optic nerve related conditions
  • Corneal & anterior segment lesions
Fundus photography is a non contact , non invasive investigative modality to image the back side of the eye, namely the retina. Photographs are used to document a retinal disease. It is also an useful tool for patient education. Fundus photography is commonly employed in retinal conditions like diabetic retinopathy, age related macular degeneration, and other retinal conditions. The process of taking a photograph is simple and takes around 5 minutes per eye ; ideally after putting dilating drops into eye.
Digital Fundus Flourescein Angiography ( DFA/FA) is a invasive test done to image the retinal vessels, similar to what happens in cardiac angiography. Various retinal conditions like diabetic retinopathy, age related macular degeneration, retinal vein occlusion may need this test. The test is done after dilating both eyes. Ideally the test is done with minimal 2 hours of fasting and the entire procedure takes around 30 minutes. Patients undergoing the test are instructed to drink lot of water after the test. A harmless effect seen after the test is yellowish green discoloration pf urine which may persist for 24 hours. The test is to be avoided in pregnant ladies and those with iodine allergy . Those with kidney disease and heart problems should have the test only after obtaining proper fitness from their primary physician.
Ultrasound B Scan (USG) – uses sound waves beyond the audible range (greater than 20 kHz, usually in the range of a few MHz) to get echoes from the tissues of the eye where light cannot reach. It is most commonly used in ophthalmology to study tissues in the posterior part of the eye in the presence of an opaque media like cataract. It gives a gross idea of the status of the retina and optic nerve. However, subtle pathology may be missed.
Pentacam – is a cornea modelling system and is used to diagnose and follow-up ectatic disorders of the cornea like keratoconus, keratoglobus, pellucid marginal degeneration etc. It is also used to measure the cornea before implantation of sophisticated IOLs like Toric and multi-focal. Pentacam uses blue light and Scheimpflug technique to photograph multiple high resolution photographs of the cornea and anterior chamber of the eye to reconstruct a highly accurate 3D model of these structures.