Marco Ruggeri, Ph.D.
Instrumentation and quantitative imaging technologies for diagnostic and surgical applications in ophthalmology, including corneal, cataract, glaucoma, pediatric and retinal diseases
Optical Imaging and Instrumentation, Optical Coherence Tomography, Ocular Biometry, Optics, Accommodation
Dr. Ruggeri’s research at the Ophthalmic Biophysics Center (OBC) includes the development of new ophthalmic imaging technologies, particularly based on Optical Coherence Tomography (OCT), for in vivo imaging and biometry of the whole human eye and for supporting corneal and retinal surgery and diagnosis of retinal diseases in pediatric population. Dr. Ruggeri works closely with clinicians to develop imaging technology and applications that can have a direct impact on patient eye care.
Whole eye OCT imaging
Optical Coherence Tomography (OCT) is a non-contact non-invasive optical imaging technique based on interferometry that enables cross-sectional observation of biological tissues almost at cellular level. Since its first application for imaging of the retina (Huang et al, 1991), OCT has become a standard of care for diagnostic ophthalmic imaging because of its ability to display ocular tissues at micrometer-resolution. The initial commercial OCT instrumentations were based on so-called Time-domain technology (TD-OCT), which featured relatively low scanning rates. Over the past decade, OCT has evolved rapidly from time-domain to frequency domain technology (FD-OCT) enabling increased scanning speed. Today, conventional FD-OCT systems are extensively used in clinical practice. However, their use has been limited to imaging of relatively thin ocular structures such as the cornea and the retina because of the short imaging depth affecting FD-OCT. In the past few years, an effort has been made by Dr. Ruggeri’s team to extend the axial range of FD-OCT implementations to the full eye length while preserving high resolution. To do so, a technology based on optical switching was conceived and published in 2012. A patent including the optical switching method for extending the OCT axial range was recently granted (US 8,425,037 B2). The extended depth OCT technology developed at Dr. Ruggeri’s lab enables dynamic imaging of the eye from the cornea to the retina including its internal structures in real-time (Figure 1). The imaging equipment is currently used for research and clinical application where long imaging range is required such as, for example, studying the mechanical changes of the crystalline lens and the anterior chamber during accommodation and with age. Whole eye biometry is another promising feature provided by this technology that has the potential of producing accurate intraocular lens power calculation prior to cataract surgery.
Dynamic OCT imaging of accommodation
This project is part of a broad program established at the OBC that has the long term goal of developing and evaluating strategies to restore accommodation and treat presbyopia. The development of procedures to restore accommodation such as accommodative intraocular lens implants and lens refilling techniques has created a need for imaging tool that can objectively evaluate the clinical efficacy of these procedures. A new custom made OCT system was recently developed by Dr. Ruggeri’s team to simultaneously quantify the dynamic optical and mechanical accommodative functions of the human eye. The instrumentation to study accommodation will help characterize the age-dependence of the optical and anatomical changes in the lens and in the ciliary muscle with accommodation and age. Early in 2014, this work was recognized at the world’s largest biomedical optics conference (BiOS conference of SPIE) with the Pascal Rol award for excellence in Ophthalmic Technology.
Intraoperative imaging for guiding ophthalmic surgeries
The objective of this project is to produce and disseminate OCT technology through commercial partnership that can be used intraoperatively for assisting surgeons during retinal and corneal surgeries maneuvers. The use of intraoperative OCT for assisting partial corneal transplants, or selective lamellar keratoplasty, is one of the surgical applications of OCT that is currently investigated by Dr. Ruggeri’s team at the OBC. Selective lamellar keratoplasty embrace several techniques which selectively replace the diseased layers of the cornea while leaving the healthy layers undisturbed. Selective lamellar keratoplasty have several advantages compared to conventional corneal transplant procedures and are undergoing rapid and widespread adoption with ongoing refinements in the surgical techniques and instrumentation. However, manual dissection of selected corneal layers is still technically challenging and time consuming and vision after surgery may be affected by non-optimal preparation and placement of the donor grafts. These challenges are, in part, due to lacking of a high magnification cross-sectional view of the surgical site during donor graft preparation and surgery. OCT is a promising cross-sectional imaging tool for providing a detailed view of the surgical site to the surgeon in real-time (Figure 3). Other intraoperative applications of OCT under investigation at Dr. Ruggeri’s lab concern image guided retinal surgery.
Imaging for diagnosis and management of pediatric ocular diseases
Examination of the retina in children is important to identify early developmental or disease processes and minimize the risk of permanently impaired vision and blindness. Detecting and treating developmental diseases of the retina affecting prematurely-born children require practitioners to perform retinal screening and treatment in the neonatal intensive care unit (NICU). The examination of eyes in young children with complex retinal diseases is often performed with the child under anesthesia in the operating room (OR) because of the child’s reduced level of cooperation. The standard imaging tool used in pediatric retinal examination is wide-field color fundus photography, which only displays the surface of the retina potentially missing important underlying details about the state of the disease. The ability of OCT to display localized defects in the retinal sub-surface could significantly complement the information produced by fundus photography during pediatric retinal examination and greatly aid in identifying early stages of pediatric retinal diseases. Dr. Ruggeri’s team is currently investigating new OCT technology for imaging the pediatric patient eye in short time that can be used in the OR and NICU for routine diagnosis and management of pediatric retinal diseases. Prototypes and commercially available portable OCT systems for pediatric imaging are also evaluated at OBC.
Small animal model of ocular diseases
In vivo evaluation of the structural changes of the eye of small animal models of ocular diseases enables monitoring the disease through its entire course in individual animal models, which is essential for providing a better understanding of the pathophysiology of the disease and monitoring the response to therapies. During his tenure at BPEI, Dr. Ruggeri has been instrumental in pioneering non-invasive FD-OCT technology dedicated to in vivo eye imaging of small model of ocular diseases. Dr. Ruggeri’s team at the OBC continues developing new OCT imaging and analytical tools to support basic scientists at BPEI in performing longitudinal studies involving small animal model of ocular diseases.