This review aims to indicate that ophthalmology can utilize digitization technologies in the most sophisticated manner in medicine.
I. Digital analysis of irregular astigmatism
When I was a resident, corneal irregular astigmatism was evaluated qualitatively using the Plácido disc. I wondered why irregular astigmatism could not be digitized while spherical and cylinder components could be.
We introduced a mathematical method to decompose corneal topography data using Fourier harmonic analysis into spherical, cylindrical, asymmetric, and higher order irregular astigmatism components. A corneal topography system equipped with color-code mapping has enabled the understanding of corneal disease conditions and postoperative courses from a new viewpoint.
To further this approach, we made collaborative efforts to develop the wavefront analyzer to measure ocular aberrations by applying Zernike polynomials. With these new means, many novel research projects were carried out to quantitatively investigate the significance of higher-order ocular aberrations and their influence on visual functions and quality of vision of patients with various eye diseases.
II. Three-dimensional optical biopsy of anterior ocular tissues
For the detailed observation of anterior segment of the eye, modalities such as slit-lamp microscope and ultrasound diagnostic devices were not sufficient, and the observation area of conventionally used two-dimensional optical coherence tomography (OCT) was limited. We cooperated with the Faculty of Pure and Applied Sciences, University of Tsukuba to develop the world's first three-dimensional anterior segment OCT (AS-OCT), which allows non-invasive evaluation of intraocular structures. This technology received the Minister of Education, Culture, Sports, Science, and Technology Award and was registered as a new medical technology covered by the public healthcare insurance system 9 years after release on the market.
We developed new generation of OCT based on Jones-matrix algorithm, i.e., polarization sensitive OCT, and established a method that obtains qualitative information in vivo based on intra-tissue characteristics such as changes in collagen fibers. Our method has enabled the use of information that conventional modalities have failed to acquire when evaluating diseases and observing tissues.
III. Artificial intelligence (AI) in ophthalmology
Application of AI in the medical field is expanding. Ophthalmology utilizes a huge amount of digital data including images in daily practice and has high affinity with big data and AI technologies. The Japanese Ophthalmological Society has established two subsidiary organizations: the Japanese Society of Artificial Intelligence in Ophthalmology and the Japan Ocular Imaging Registry (JOI Registry). We closely cooperate with researchers from the National Institute of Informatics and industry (NII) personnel from the Japan Ophthalmic Instrument Associations to materialize our research and business plans. Such cooperation has facilitated infrastructure construction big data collection, and development of AI analysis algorithms. On another project, AI technology is applied to cataract surgery to enhance the safety of surgical procedures (to prevent medical malpractice), to improve the efficiency of surgical education, and to scientifically scrutinize the level of surgical skills.
IV. Image sharpening technology to improve ophthalmic images
Recently, a new technology in surveillance cameras has been introduced that digitally processes live images. Without the aid of AI or factitious plotting, this new technology can mathematically sharpen images by restoring original quality and resolution. We apply this method to improve ophthalmic images. An image sharpening system connected between an image input system and a monitor enables real-time image sharpening when performing dacryoendoscopy, endoscopic vitrectomy, and heads-up surgery with a delay of 0.004 seconds, resulting in smooth surgical manipulations. This technology can also be applied to still images, such as fundus pictures, angiography, and anterior segment photographs.
We need to make our utmost efforts to promote digital transformation in ophthalmology to brighten our profession's future.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 127: 257-296, 2023.