In August 2011 Oregon Health & Science University, Casey Eye Institute received a 3.9 million dollar NIH grant entitled “Guiding the treatment of anterior eye disease with optical coherence tomography.” Dr. David Huang, the principal investigator, and other investigators at the Center for Ophthalmic Optics & Lasers (www.coollab.net) will coordinate the multi-center technology development and clinical study efforts. There are four sub-awards in this project: 1) James Fujimoto, PhD, Massachusetts Institute of Technology (engineering site), 2) Douglas Koch, MD, Baylor School of Medicine Cullens Eye Institute, 3) Mark Terry, MD, Legacy Emmanuel Health Center, Devers Eye Institute and 4) Bibiana Jin Reiser, MD, Children's Hospital Los Angeles. This is the second 5 year award for this multiyear project which started in 2007 and ends in 2016. Below is an overview of the project.
Optical coherence tomography (OCT) is a cross-sectional and 3-dimensional (3-D) imaging technology with very fine spatial resolution (5 microns). This project develops the methods and software needed for high-precision OCT measurements of the eye to guide implant, laser and transplant surgeries in the front part of the eye. This NIH grant aims to accurately calculate intraocular lens power and improve outcomes of cataract surgery in eyes with previous laser vision correction and to improve the precision, safety and effectiveness in laser correction of cloudy or irregular corneas and laser-assisted corneal transplantation.
The project aims to develop and utilize a new generation of very high speed OCT (about 10 times faster than previous models, taking an image in as little as 2/1000 of a second). The extended range will enable new types of measurements to be done accurately.
The Specific Aims of the grant are as follows:
(1) To develop ultrahigh-speed OCT hardware and software for measuring optical surfaces of the anterior eye. Intrinsic eye movements effectively limit measurement of corneal shape by commercial OCT. This will be overcome by several approaches, including ultrahigh-speed OCT at 500 kHz, dual-beam OCT to simultaneously capture the shape of both the cornea and the lens, simultaneous capture of Placido-ring videokeratography and motion correction software. The goal is to provide reliable measurements on front and back surfaces of both the cornea and crystalline lens.
(2) To develop an OCT-based intraocular lens power formula. Currently, surgeons lack an accurate way to calculate the precise intraocular lens (IOL) power for cataract patients who have previously had laser vision correction. These patients may be left near- or far-sighted after cataract surgery. An OCT-based IOL formula, using measurements of both anterior and posterior corneal powers, can give surgeons more precise information that will significantly improve visual outcomes. The OCT-based IOL formula will be tested in a clinical trial.
(3) To develop OCT-guided excimer laser surface ablation. The excimer laser can remove cloudy layers from the front of the cornea and correct distorted shape due to keratoconus or transplant surgery. The group has developed 3-D OCT-based planning to optimally remove cloudiness due to corneal scars and stromal dystrophies. This method will be tested in a larger clinical trial. The method will be improved by adding 3-D OCT measurement of corneal shape (topography) to plan the correction of any shape distortion.
(4) To develop OCT-guided laser-assisted anterior and posterior lamellar keratoplasty. Most corneal diseases involve only the inner or outer layer of the cornea. Thus a partial thickness transplant can treat these diseases while avoiding the complications of full-thickness transplantations (rejection, irregular wound shape, etc). However, manual dissection of corneal layers is technically difficult and vision after surgery is limited by the rough interfaces. Therefore, OCT methods have been developed to guide the shaping and smoothing of donor and host corneas with a combination of an excimer laser to create smooth interfaces and a femtosecond laser to create tongue-in-groove edge fits. Pilot clinical trials of these techniques are proposed. The end goal is to develop surgeries that reliably improve the vision in patients with keratoconus, corneal dystrophies and deep scars.
OHSU investigators will work with collaborators at the Massachusetts Institute of Technology and Optovue, Inc. to develop the advanced OCT imaging technology. The clinical studies will be performed at Casey Eye Institute, Cullens Eye Institute, Devers Eye Institute, and Children’s Hospital Los Angeles. The ultimate goal is to improve the precision, visual outcome, and safety of anterior eye surgeries.