YTU MKT Seminerleri-13Tüm Duyurular

Seminer #13,  09 March  2018 Friday, 11:00–12:00,

Place: A 310

Presentation Title: Engineering solutions to two medical problems on ophthalmology

Speaker: Dr. Onurcan Sahin

Summary: In this seminar two practical solutions to two ophthalmic problems, are going to be described. The first project is “Design and control of a visual servomechanism for automating corneal cross-linking treatment on keratoconus patients”. A novel mechatronic system designed for automated corneal cross-linking (CCL) treatment in keratoconus patients is introduced. Keratoconus is a serious illness that if not treated may cause serious distortion of vision. Currently, the CCL operation, which is the most promising treatment of this disease, is performed manually. The automated system developed is the first of its kind to automate the treatment with visual feedback, and it aims to increase the efficiency in treatment and to eliminate any potential side effects and risks of the treatment. To track the eye of the patient, the system consists of a camera, an image processing algorithm developed on OpenCV sharp, a planar servomechanism system consisting of various mechanical and electronic components, and a PIC microcontroller that contains digital PID controllers. The proposed system and the algorithms are designed and simulated in Matlab, and then the system is manufactured and various experiments with an eye pattern and animal eyes are performed. The results are shown and discussed.

The second project is “Fast optical measurement of intraocular straylight”. Light scattering in the human eye can deteriorate image quality and limit visual performance especially at the presence of a glare source. Optical measurement of straylight in the human eye is a challenging task where issues related to various inherent artifacts must be addressed. We report on a novel instrument based on the principle of double-pass optical integration that has been adapted for fast measurements suitable for a clinical setting. The instrument utilizes a light source formed by an array of green light emitting diodes that is projected onto the ocular fundus. The source has two concentric parts, a disk (field angle 0-3 degrees) and an annulus (3 - 8 degrees) that are modulated at different frequencies. A silicon photomultiplier receives the light reflected from the central part of the fundus and the Fourier transform of the signal reveals the contribution of each part of the source. Their relative amplitude is used to quantify light scattering by means of the straylight parameter. The instrument was initially validated using known diffusers. Straylight in a cohort of cataract patients was measured. The optically measured straylight parameter was correlated to the clinical cataract grade as well to the psychophysically estimated value. The measurement method, utilizing rotational symmetry and coding filed angles with different frequencies eliminates the need for a high- performance camera and allows fast measurements.


  • Born May 2, 1985, in Nigde Turkey.
  • Bachelor of science degree from physics engineering department, Istanbul Technical University 2004-2008.
  • Master of science degree from Department of Mechanical Engineering, System Dynamics and Control, Istanbul Technical University 2008-2011.
  • Accepted European Union ITN 7 Marie Curie program called Opal 2011-2014.
  • Doctor of philosophy degree from School of Medicine, institute of vision and optic at University of Crete 2012-2018.
  • Research and development manager in Dunyagoz hospital group 2015-Present.