【Toshiaki Goseki (Strabismus Specialist)】Pioneering the Field of Diplopia Through Inquiring Spirit and a Sense of Mission—Driven by Dedication to Patients and Japanese Ophthalmology
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Dr. Toshiaki Goseki graduated from the Kitasato University School of Medicine in 2001 and earned his PhD in Medicine from the same institution in 2007. After serving as a lecturer at Kitasato University and later as Director of Ophthalmology at Kitasato University Medical Center, he completed two research fellowships at the Stein Eye Institute at the University of California, Los Angeles (UCLA), deepening his clinical and academic focus in strabismus and diplopia. Throughout his career as a specialist in strabismus and neuro-ophthalmology, he was appointed Director of Ophthalmology at the International University of Health and Welfare (IUHW) Atami Hospital in 2020, and Professor in the Department of Ophthalmology at the IUHW School of Medicine in 2024.
Areas of Expertise: Strabismus, Diplopia (Double Vision)
【Background】Guided by My Grandmother's Words: The Path to Medicine
Could you tell us about your background and what led you to medicine?
I was born in Ryogoku, in Tokyo’s Sumida Ward. I did not come from a family of doctors—my father ran a construction company, and my mother handled the office administration there. I also have a younger brother who works as a first-class registered architect. Among our relatives, my cousin, who is six years older than me, works as a cardiologist, and his presence may have had some influence on me.
When my grandmother was still young, she suffered a cerebral infarction (stroke) that left her with lasting aftereffects. She often used to tell her grandchildren that she wanted us to become doctors. In the end, two of us actually did. She was a strong woman, very much the matriarch of the family. Looking back, it felt almost like an order.
I remember writing in an elementary school essay collection that I wanted to become a scientist or an academic. Leaning toward the sciences came naturally to me, and as I prepared for college entrance exams, I realized that medical school was particularly challenging to get into. That was when it clicked: "Ah, this is what my grandmother was talking about!" Looking up to my cousin, who had already become a physician, I set my sights on a career in medicine.
【Specialty】An Encounter with a Mentor, and the Journey into Strabismus and Diplopia Care
What led you to choose ophthalmology as your specialty?
During my medical school years, I felt that handling fields where clinicians regularly face matters of life and death would be emotionally challenging for me. On the other hand, I had a strong interest in medicine that focused on restoring and improving physical function. When I graduated from medical school, the current mandatory residency system—where trainees rotate through multiple clinical departments—was not yet in place; graduates typically entered a specific department right after graduation. Choosing a specialty relied heavily on the atmosphere and impressions gained during clinical clerkships, and I found myself debating between orthopedic surgery, otolaryngology (ENT), and ophthalmology. At that time, Dr. Kimiya Shimizu (Professor at the IUHW Center for Clinical Medicine and Professor Emeritus at Kitasato University), who was then the Professor and Chair of Ophthalmology, made a profound impression on me. He was an exceptionally skilled surgeon with a commanding presence. Seeing him in action was the deciding factor that led me into ophthalmology.
Initially, I aspired to become an ophthalmologist like Dr. Shimizu. As I worked alongside him, I was continually inspired by his remarkable surgical skills, while at the same time realizing that I wanted to carve out my own unique niche. That was when I encountered Dr. Hitoshi Ishikawa (Professor at the Kitasato University School of Allied Health Sciences). Dr. Ishikawa is a former President of the Neuro-Ophthalmology Society of Japan, and Kitasato University itself has a long and storied tradition in neuro-ophthalmology. Attracted by the depth of the field and the rare privilege of training under Dr. Ishikawa, I chose this path.
To me at the time, neuro-ophthalmology looked like a "blue ocean." While few physicians specialized in it, the need among patients was substantial. Many questions remained unanswered, and I saw both meaningful clinical purpose and immense potential in exploring them. Above all, having the opportunity to learn directly by Dr. Ishikawa’s side was an invaluable blessing.
Dr. Ishikawa’s expertise centered on the pupil and the optic nerve. While studying neuro-ophthalmology under his guidance, I deliberately avoided overlapping our subspecialties, wanting instead to build a domain of my own. That focus led me to diplopia. Caring for patients with double vision offers the intellectual challenge of carefully identifying the underlying cause, combined with the surgical option of strabismus surgery to restore visual alignment and comfort when indicated. The ability to accompany patients through the entire continuum—from diagnosis all the way to treatment—offered a deep sense of fulfillment, and that is why I chose to make this my specialty.
【Sagging Eye Syndrome】A Condition Once Virtually Unknown in Japan: How the Frustration of "Not Knowing" Drove Me to Take Action
In neuro-ophthalmology, finding the cause often feels like investigative work—almost like being a detective. You run tests, identify the condition, and dig deeper. I found great clinical meaning in this process of investigating functional disorders.
Yet, in diplopia care, there were many instances where—acting like a detective—we simply could not identify the "culprit." As I continued my research and clinical study, I encountered what would become my core specialty: sagging eye syndrome.
Is sagging eye syndrome a rare condition?
Sagging eye syndrome was first proposed in 2008 by Dr. Joseph Louis Demer and his colleagues at the University of California, Los Angeles (UCLA). Even around 2013, roughly five years after it was introduced, the condition remained virtually unknown in Japan, as far as I was aware. That was precisely why I became eager to explore it further.
Then, in 2014, the meeting of the International Strabismological Association (ISA) was held in Kyoto, and I learned that Dr. Demer would be giving a lecture on sagging eye syndrome. I felt immediately that I could not miss this opportunity. I attended the meeting and approached Dr. Demer in person, telling him in broken English that I wanted to come study under him.
That took remarkable initiative.
By that point, I had accumulated clinical experience and had become reasonably proficient in strabismus surgery. When it came to diplopia, I even felt confident enough to consider myself perhaps the best at Kitasato University. Above all, it was immensely frustrating whenever I encountered cases where, no matter how hard I studied, I still could not determine the cause or reach a diagnosis. Looking back, that frustration was what drove me to take action.
Even when the underlying cause remains unknown, some patients do improve. Still, I found myself questioning whether leaving things at that was acceptable, or whether their condition might recur. I came to feel strongly that leaving room for ambiguity was irresponsible, and that approaching these cases with anything less than thorough dedication would be a disservice to our patients.
【Challenges in the Field】Strabismus Affects Roughly 4% of the Population, Yet Specialists and Accurate Diagnoses Are Limited
Having few peers in this subspecialty might also mean, from the perspective of the field as a whole, that there is a shortage of specialists.
That is exactly the point. As physicians, our duty is to help patients and contribute to society. Even if someone were to "dominate the market" from a business perspective, that solves nothing. The number of patients in need continues to rise.
That is why I actively pass on my techniques. Since moving to IUHW Atami Hospital in 2020, I have consistently welcomed clinical fellows. Moving forward, I want to dedicate my energy to training younger physicians and expanding the pool of clinicians capable of managing strabismus and diplopia.
Patients with strabismus account for roughly 4% of the general population. While not all of them require intervention, when you consider that glaucoma affects about 7% of the population, strabismus is clearly a major condition as well. With glaucoma, any general ophthalmology clinic can prescribe medicated eye drops, but that is not the case for strabismus. Receiving an accurate diagnosis is difficult in itself, and I believe that—compared to other ocular conditions—far fewer patients actually receive appropriate treatment.
【Patient Concerns】Beyond the Risk of Injury and Accidents: The Psychosocial Impact of Strabismus
Strabismus presents two distinct challenges. The first is functional: seeing double. Patients lose accurate depth perception and struggle to judge steps or uneven surfaces, which significantly raises the risk of missteps, falls, and injuries. The second is aesthetic. When ocular misalignment becomes noticeable, it takes a heavy toll on a patient’s psychosocial quality of life (QOL).
Patients often wonder, "What are people thinking when they look at my eyes?" They find themselves unable to make eye contact during conversations, and some slip into depression. For children, it can disrupt school life and lead to bullying. In short, it directly impacts their psychological well-being.
That is why it has been so rewarding to see children who, once surgery restored their ocular alignment, regained their confidence and returned to school. Even when the children do not say it in so many words, parents will often share with me, "They seem so much happier going to school these days."
【Vision & Philosophy】Striving for World-Class Standards in Strabismus and Diplopia Treatment
Recently, I examined a patient recovering from Miller Fisher syndrome. While the underlying syndrome itself resolved, the diplopia in lateral gaze (secondary eye position) persisted indefinitely.
Because their vision in the primary position (straight ahead) had unified, their previous ophthalmologist told them they were "cured." However, the patient remained frustrated that while things looked single straight ahead, everything still split in two when looking to the side. Seeking a second opinion, they came to see me.
Generally, diplopia in lateral gaze is not considered an indication for surgery, not only in Japan but worldwide. The concern is that attempting to correct double vision in eccentric gaze could compromise the already unified primary position. On the other hand, for some patients, persistent double vision in side gaze causes substantial impairment in daily life. In carefully selected cases—after rigorous evaluation to ensure primary alignment remains intact—I consider surgical intervention. I performed surgery on this patient as well. I have previously published a peer-reviewed paper on surgical approaches that improve lateral-gaze diplopia while preserving primary-position alignment, and I want clinicians and patients to know that this treatment option exists.
What motivates you to challenge what has traditionally been considered off-limits in clinical practice?
Earlier in my career, my primary motivation was likely the desire to establish my own distinct expertise within the subspecialty of diplopia. Over time, however, through clinical practice and research, nothing has brought me greater fulfillment than seeing that knowledge and surgical skill translate directly into tangible improvements in how patients see and live. I want to see strabismus and diplopia care advance as vital, respected domains within ophthalmology—on par with vitreoretinal care and glaucoma. That conviction is now my strongest driving force.
Through our daily clinical work and research, I see genuine potential to bring viable solutions to patients who were previously deemed untreatable. Rather than keeping these insights to ourselves, I want to share them through mentoring younger colleagues and engaging with peers both in Japan and internationally, elevating the standard of strabismus and diplopia care nationwide. Ultimately, my hope is to generate meaningful clinical evidence from Japan that benefits patients across Asia and around the world.
【About the Hospital】Surgery at IUHW Atami Hospital: Healing and Hot Springs at Partner Hotels
Does IUHW Atami Hospital accept international patients?
Yes, we welcome consultations and patients from abroad. The IUHW School of Medicine is located near Narita International Airport in Chiba Prefecture; whenever they receive inquiries related to strabismus or diplopia, those cases are coordinated directly with me.
We are actively expanding our framework for international patients. Through a medical stay partnership with the adjacent Hotel Resorpia Atami, we offer a seamless itinerary: patients are admitted on Monday, undergo surgery on Tuesday, and are discharged on Wednesday. They then spend three relaxing nights at the hotel, attend a follow-up consultation on Saturday, and can travel home shortly after.
Because strabismus surgery is an extraocular procedure that does not involve operating inside the eyeball itself, the risk of serious infection is exceptionally low. Patients can resume washing their face starting on the third postoperative day. Soaking in the hot springs (onsen) is also permissible, as long as the bathwater does not splash onto the face or into the eyes. I would be delighted if patients choose us as a destination where they can receive specialized surgical care while enjoying the restful, restorative comfort of Atami’s hot springs.
International University of Health and Welfare (IUHW) Atami Hospital
13-1 Higashikaigan-cho, Atami, Shizuoka, Japan
※Approximately an 8-minute walk from Atami Station (JR Tokaido Shinkansen / JR Tokaido Line)
Clinic Hours: Monday – Saturday: 9:00 AM – 1:00 PM / 2:00 PM – 5:00 PM (Closed: Sundays, National Holidays, and Year-End/New Year Holidays)
Reception Hours: 8:30 AM – 11:00 AM (Appointment Scheduling / Rescheduling: 2:00 PM – 4:30 PM)
