Development of a Low-Cost Scanning Laser Ophthalmoscope Using Semiconductor Laser Technology

Development of a Low-Cost Scanning Laser Ophthalmoscope Using Semiconductor Laser Technology

Hiroki Takizawa,¹ Hiroshi Kunikata,^1,2 Takeshi Yabana,¹ Masataka Sato,¹ Takahiro Ninomiya,¹ Neelam Kaushik,¹ Parmanand Sharma,¹ Noriko Himori,^1,3 Mitsuru Sugawara,⁴ Seiji Morino,⁴ Makoto Suzuki,⁴ Makoto Ishikawa¹ and Toru Nakazawa^1,2,5,6

¹Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
²Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
³Department of Aging Vision Healthcare, Tohoku University Graduate School of Biomedical Engineering, Sendai, Miyagi, Japan
⁴QD Laser Corporation, Kawasaki, Kanagawa, Japan
⁵Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
⁶Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan

In recent years, the use of scanning laser ophthalmoscopy (SLO) has emerged as a valuable tool in ophthalmic diagnostics. However, its widespread adoption has been prevented by substantial costs associated with existing devices. This study reports on the development of a low-cost SLO that is safe, requires no pupil dilation and no focus adjustment, and uses semiconductor laser technology for scanning. A prototype SLO equipped with red (638 nm) and infrared (IR; 795 nm) lasers was developed, and eyes with ocular diseases including glaucoma, branch retinal vein occlusion (BRVO), and diabetic retinopathy (DR) were examined using the SLO. We examined 53 patients (average age 62.0 ± 13.0 years; 93 eyes) with glaucoma (65 eyes), BRVO (11 eyes), and DR (17 eyes) using the low-cost SLO. Successful images were obtained from 83 eyes of 47 patients. The process was non-invasive, allowing for clear observation of the optic nerve head (ONH) and retinal vessels using both red and IR lasers. Furthermore, ophthalmological findings such as ONH cupping, macular edema, and retinal hemorrhage were detectable. Using a semiconductor laser, the prototype SLO successfully obtained high-quality images of ocular morphology and pathology without requiring pupil dilation and without focus adjustment. This low-cost SLO has the potential to enhance the accessibility of ophthalmic diagnostics, particularly in resource-limited settings, and contribute to the early detection and management of various ocular diseases.

Key words —— branch retinal vein occlusion; diabetic retinopathy; glaucoma; semiconductor laser; scanning laser ophthalmoscopy

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Tohoku J. Exp. Med., 2025 January, 265(1), 39-45.

Correspondence:Hiroshi Kunikata M.D., Ph.D., Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1, Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8574, Japan.

e-mail:drkunikata@gmail.com