Optical Coherence Tomography (OCT): A Noble Diagnostic Biomedical Imaging Tool & my Tryst with it.

 

A fortnight ago, I had written about my right eye ailment and how it got aggravated due to a delayed diagnosis, which later turned out to be what is medically termed as ‘Anterior Uveitis’. Fortunately, the doctors could accurately diagnose my eye condition courtesy a biomedical engineering diagnostic tool – the Optical Coherence Tomography (OCT). Modern advancements in OCT and Raman spectroscopy hold great promise in providing new insights into the retina, which can serve ophthalmologists in saving many vision losses for their patients.

 

Uveitis is a serious eye condition characterized by inflammation of the uvea - middle layer of the eye, iris, ciliary body, and choroid. If left untreated, Uveitis can lead to disastrous consequences, a glimpse of which I had begun to experience with blurred vision and other complications. Uveitis can be classified based on the part of the uvea that is affected and, in my case, it was the Anterior uveitis (iritis): Inflammation of the front part of the uvea, including the iris and ciliary body. The technology that helped my Doctors - Dr. Jaydeep Walinjkar, Dr. Hitesh R Sharma, Dr Smit and my good friend Dr Natarajan - at the Aditya Jyot Hospital diagnose my symptoms - red eye, pain, light sensitivity, blurred vision - as Anterior Uveitis, was this noble biomedical diagnostic tool - OCT. I have accordingly been advised a proper regime of treatment for the Uveitis, which I am undergoing and hope to recover completely.

 

Now that I have been making the rounds to the Aditya Jyot hospital and my Doctor,  Dr Hitesh Sharma, and so also my good friend Doctor Natarajan - the man who founded the Aditya Jyot Hospital - have been very kind to discuss about my medical condition with me in some simple scientific terms, including showing me on screen OCT images and explaining how they are seen and interpreted, I am assured that by the time the six week Uveitis treatment regime - with the corticosteroids - are done with, my eye can come back to near normalcy - fingers crossed, they murmur. Having spent most of my professional career in science museums, I have learnt the skill of communicating complex science subjects in an easier to understand way with the public by interacting and learning the subject from experts. The challenge that I was facing with my eye provided me an opportunity on a platter to know more about Uveitis and how science and technology has helped its diagnosis. Therefore, I decided to use this opportunity to try and create an awareness about Uveitis and how early diagnosis can save patients from a possibility of permanent loss of vision and how technologies like the OCT help in early detection of such eye disorders. 

 

Doctors have helped me to understand the importance of OCT in early diagnosis by showing me and explaining the OCT images of my eye and how the data from these images can be interpreted for better understanding of the retina. OCT and such other medical diagnostic tools have resulted from harvesting the knowledge of science of nature that serves as an underpinning for development of any technology, including the medical tools that serve human society.

 

Just a couple of days ago the Times of India reported of a very high prevalence of conjunctivitis in Mumbai. In fact, I too was under the impression that I was affected with it. But then, it turned out to be something completely different and my experience has motivated me to appeal to all my friends and family that if you or any of your near and dear one’s experience symptoms such as eye redness, pain, light sensitivity, blurred vision etc. don’t neglect it as a conjunctivitis or some un harmful infection, it could be Uveitis or something else and therefore you must not delay in seeking professional medical advice as early as possible.

 Beginning in the late 1950s, but accelerating at an ever-faster pace thereafter, leading into the twenty first century, science and technology has dramatically transformed the landscape of modern medicine. The importance of S&T in modern medicine cannot be understated, more so when we  notice that before the World War a typical physician had a modest armamentarium as his toolkit in his arsenal, which included a thermometer, stethoscope, sphygmomanometer, and an occasional access to x-ray machines and electrocardiograph. These tools supplemented a limited cabinet of pharmaceuticals including sulfa drugs and negligible quantity of penicillin, which the Doctors had access to in the 1940s. 

 

There has been  a paradigm shift in the advancement of medical diagnostics, thereafter. After the World War, biological medical diagnostics research has witnessed unprecedented development with the efforts of many scientists and engineers who have helped in creating a new armamentarium of biophysics instruments- Electron Microscopes, Ultracentrifuges, Mass Spectrometers and new agents such as radioactive isotopes. A revolution in microelectronics and semiconductors initiated during the War together with the development of high computing devices, that can crunch elephantine data, have led the way to new fields of biomedical imaging such as Ultrasound, Computerized Tomography (CT), Positron Emission Tomography (PET) scanners,  Nuclear Magnetic Resonance Imaging, Magnetic Resonance Imaging (MRI) and the instrument which helped in diagnosing my eye problem,  ‘Optical Coherence Tomography (OCT). This essay will however, be confined to OCT.

 

The importance of OCT as a marvel engineering technology for benefitting medical professional can be seen from the fact that the National Academy of Engineering (NAE), a premier American institution that provides engineering leadership to the nation for advancing the welfare and prosperity of the people has awarded a highly prestigious Fritz J. and Dolores H. Russ Prize (2017) for Biomedical Engineering to a group of scientists and engineers  - James G. Fujimoto, Adolf F. Fercher, Christoph K. Hitzenberger, David Huang, and Eric A. Swanson - for their contributions to the invention of the Optical Coherence Tomography (OCT). This $500,000 biennial prize - considered as prestigious as the Nobel Prize in the field of Biomedical engineering - recognises a bioengineering achievement that significantly improves human condition. The citation for the prize reads; “leveraging creative engineering to invent imaging technology essential for preventing blindness and treating vascular and other diseases." The recipients of this Prize “personify how engineering transforms the health and happiness of people across the globe," said NAE President C. D. Mote, Jr, while making this announcement. The creators of OCT  have dramatically improved the quality of life for people with diminished eyesight.

 

As the name suggests the OCT works on the principle of optics - interferometry, where a beam of light is split into two arms - a reference arm and a sample arm. In the sample arm, the light is directed towards the tissue being examined. Some of this light is reflected back, while some is scattered or absorbed by the tissue. The light that is reflected back from different depths within the tissue is then combined with the reference light in the interferometer. By comparing the time delay of the reflected light with the reference light, OCT creates a depth profile of the tissue being examined. This information is used to construct a detailed cross-sectional image of the internal structures, allowing doctors to visualize and diagnose various medical conditions non-invasively. OCT is majorly used in ophthalmology for retinal imaging and in other medical fields like cardiology and dermatology for examining various tissues and organs.

 

OCT has now grown to become one of the most widely used technologies for imaging the human eye and is an essential tool for the treatment of blinding diseases such as macular degeneration, glaucoma, and diabetic retinopathy. It has helped doctors in diagnosing millions of patients with eye disease at early treatable stages, before irreversible loss of vision can occur. Infrared light is used in OCT because of its relatively long wavelength, which allows it to penetrate the scattering medium. The concept of OCT was first introduced in the 1960s, but significant progress was made in the 1980s and 1990s when several researchers independently developed different OCT systems. 

 

The first two-dimensional picture of the fundus - inside, back surface of the eye made up of retina, macula, optic disc, fovea and blood vessels - of a human eye in vivo ( Latin word for ‘within the living’ ) was created by Adolf Friedrich Fercher, using white light interferometry. Fercher’s visionary ideas laid the basis for the development of OCT and the first in vitro OCT images were published by German and United States researchers in 1991. Fercher began his works in this field in late 1960s, while working for a private company. Post his graduation in physics, in 1968, Fercher had started working at Carl Zeiss, Germany, on optical testing, computer holography and holographic interferometry. In 1975, he became a professor at the University of Essen, Germany. Thereafter, he served as professor of medical physics and chair of the Department of Medical Physics, at the Medical School of the University of Vienna.  Fercher published his first paper on the biomedical applications of optics while he was still working for Carl Zeiss, by  calculating light scattering in a simplified model cell. He showed that the scattered signal oscillates as a function of scattering angle and that the oscillation length is related to particle diameter. It was during his time at the University of Vienna that Fercher and his colleagues worked on low partial coherence and white light interferometry for in vivo imaging of biological tissue. Their focus was on the human eye. Although the image quality of Fercher’s 2-D interferometric depth scans of the fundus was poor compared with modern standards, the retinal thickness and the excavation of the optic disc were visible.  His works created a spark for advances in this field of biomedical optics.

 

The next major development in this field came in the United States of America. In the late 1980s, a team of researchers, led by Dr. James Fujimoto at the Massachusetts Institute of Technology (MIT) and assisted by ophthalmologists Joel Schuman, David Huang, and Carmen Puliafito, worked on this concept by using low-coherence interferometry for the measurement of corneal thickness. Unfortunately, they had limited success and therefore the group decided to test its potential in retinal imaging. This decision proved  to be providential and in 1991, leading to a widely acclaimed publication by Huang and others on the very first retinal OCT images of an ex-vivo human eye. Dr Huang named this new diagnostic technique ‘optical coherence tomography.’ Soon thereafter, the first commercially available OCT device was launched by Humphrey Instruments in 1996.

 

One of the earliest OCT systems was time-domain based OCT (TD-OCT), which used a low-coherence interferometer to measure the echo time delay of backscattered light from tissues. However, TD-OCT had limitations in terms of speed and resolution and therefore it gave way to a Spectral-Domain OCT (SD-OCT). In the early 2000s, the advent of SD-OCT dramatically improved imaging capabilities. SD-OCT employs a spectrometer to measure the entire spectrum of backscattered light simultaneously, allowing for faster acquisition rates and higher resolution. This technological leap significantly enhanced the utility of OCT in ophthalmology, enabling more detailed visualization of retinal layers and facilitating the diagnosis of various retinal pathologies. Another significant advancement in OCT technology was the development of Swept-Source OCT (SS-OCT), which uses a tunable laser as a light source. SS-OCT offers superior imaging penetration, making it especially valuable for imaging deeper structures such as the choroid. Additionally, the integration of OCT with angiography techniques has enabled the visualization of blood flow in retinal vessels, enhancing diagnostic capabilities for vascular conditions.

 

The future for the OCT would be facilitated by added functionality of biochemical analysis, which can be provided by Raman scattering. This could provide critical molecular signatures for clinicians and researchers to understand the intricacies of the problems at the cellular level. OCT microscope for ex-vivo imaging combined with Raman spectroscopy will be capable of collecting morphological and molecular information about a sample simultaneously. Raman spectroscopy - spectroscopic method based on inelastic scattering of photons - allows the intrinsic biochemical composition of a sample to be identified.  Although there are challenges in the development of this dual-mode instrument and so also certain limitations for future in-vivo retinal imaging using such a dual mode instrument, however, looking at the pace with which science and technology develops the future seems to be brighter. The combination of OCT and Raman spectroscopy could provide new insights into the retina helping shed light into the lives of darkness that many people lead due to blindness and vision loss.

 

May the benefits of science and technology continue to benefit society.

Jai. Vigyan.

 

India - West Indies Test Series Begins today: Nostalgic account of the ‘Coming of Age’, two back-to-back 1971 Test series victories for India against West Indies and England.

After losing the ICC World Test championship (2021-23 cycle) to the deserving champion team, Australia, at the Oval, in the one-off test, India takes on the West Indies today to kick start their 2023-25 World Test Championship cycle, with a two-test series and three ODIs to be played in West Indies.

 Although the West Indies team have gone down the hill from their once mighty pivotal position in the cricketing arena, where they had ruled the world of cricket with back-to-back championship victories in the ICC Prudential World Cups in the inaugural championship in 1975 and 1979, historically speaking the India West Indies cricket series has always been of great importance for us. India, which was considered as a minnow’s team in the world of Cricket, came of the ages by winning the five-test series against the West Indies in 1971, which they followed it up by registering an emphatic historic series victory against the invincible England by defeating them on their home soil. 

 The impact of the back-to-back series wins by the Indian cricket team on foreign soil was so profound that it prompted the Films Division to produce their first ever full-length documentary film on Cricket under the title ‘Victory Story’. This outstanding black and white documentary film - nearly two hours duration - was directed by the veteran journalist Raju Bharatan. The Victory Story, produced in 1974, chronicled the first-ever maiden test series victory of the Indian cricket team over England during the tour of 1971. 

The Victory Story (1974), the first full-length cricket documentary for Films Division, which chronicled the first-ever maiden series victory of the Indian cricket team over England during the tour of 1971 and ran to packed houses across the country on its release. 

Films Division was one of the institutions that was created by Pandit Nehru in 1948 with a task to lead the development, production and distribution of documentary films on socially significant subjects with an objective of nation building, integration, and development that Nehru felt was necessary for the newly independent and democratic Republic of India. True to its objectives, the Films Division produced some of the best documentary films, particularly in the first three to four decades, and one of them was the Victory Story documentary. This film, directed by Raju Bharatan - a veteran journalist and a prolific writer on Indian cricket and Bollywood films - ran to packed houses across the country on its release. Its success had prompted me to use this film prominently as a part of the ‘Cricket Connects: India - England’, exhibition, which I had the honour to curate and present at the Lord’s stadium, Nehru Centre, London and in two other venues in Birmingham and Edinburgh in England in 2017. 

Today, as India takes on the West Indies at Windsor Park in Roseau, Dominica in their opening test of the two-test series, I am reminded of that historic 1971 five test series that India played and won against the mighty West Indies. This series served as the beginning of the story of the coming of ages in the colonial game for India, which they now proudly lead the world in its administration. The Indian team followed up its historic 1971 win against the West Indies with a maiden test series victory against England in England in the same year. I had used these two series victories in the Cricket exhibition - Cricket Connects: India England - under the title ‘Coming of Age’. Incidentally, The Eastern Eye Title had nominated the Cricket Connects: India England Cricket Relations exhibition for the Eastern Eye Arts, Culture and Theatre in the Eastern Eye Community Engagement Award category in England. 

Raju Bharatan, the Director of the film Victory Story, was a multi-talented journalist and prolific writer on Indian cricket and Bollywood films. The Victory Story (1974), the first full-length cricket documentary for Films Division, which chronicled the first-ever maiden series victory of the Indian cricket team over England during the tour of 1971 and ran to packed houses across the country on its release. 

Coming of Age: (1971

The watershed year for Indian Cricket) Ever since India’s debut in the test cricket at the Lord's, England, on 25 June 1932, for nearly forty years, India continued to be a weak team in comparison with other Test cricket teams, such as Australia and England. The year 1971 was a watershed year that remains etched in the annals of cricket history in India. It was in that year and under the new captain – Ajit Wadekar – India registered her first-ever away-series victories in the West Indies and England to inject a refreshing self-belief in the Indian cricket, hitherto unseen. The team backed up the two back-to-back series victories over seas with a series win against England in India a year later thus achieving a remarkable three series wins on the trot. 

The West Indies team of 1971 wasn’t their strongest side, yet it consisted of some of the most well-known names in international cricket. Roy Fredericks, Rohan Kanhai, Gary Sobers and Clive Lloyd formed the backbone of the West Indies team. India, too, had a number of veterans in their ranks like ML Jaisimha, Salim Durrani, Dilip Sardesai and EAS Prasanna. But the one player who would go on to make a monumental difference to the team India in the years to come was a 21-year-old collegian with no international experience. The youngster – Sunil Gavaskar – made the kind of debut that Test cricket has not seen till this day. The 5 Test series that India played against the West Indies in 1971 is now synonymous with Sunil Ganvaskar’s majestic batting and Sar Desai’s rock-like presence at the other end. 

India did not field Sunil Gavaskar in the first of the five Tests at Kingston, Jamaica due to injury. Indians made a remarkable beginning to the 5 Test series by enforcing a follow on to the West Indies in this Test, which shocked the conscience of West Indies captain Sobers. The Test though ended in a draw. 

The second Test was at Port of Spain, Trinidad and it marked the beginning of one of the greatest Test careers of Sunil Manohar Gavaskar. He walked out to open batting for India for the very first time after Bedi and Prasanna had bowled out the West Indies for 214. Gavaskar laid the foundation of the Indian innings scoring 65, which was strongly cemented by Sar Desai (112) and Solkar (55) leading to an Indian score of 357. India’s chances of winning a historical Test depended a lot on how quickly and cheaply they could get rid of the two left-handers – Clive Lloyd and Gary Sobers. 

Durani came into the party and bowled Sobers for duck and, followed it up with the wicket of Lloyd caught by Wadekar. Venkat then ran through the bottom half of the Windies with a five-wicket haul to restrict the home team to 261. With 124 needed for victory, Gavaskar led the run-chase with 67 not out helping India to achieve a historic win for the Indians. 

The next two Test matches at Guyana and Barbados ended in draws in which Gavaskar (116, 117*) Sardesai (150) and Sobers (108*, 178*) helped themselves with plenty of runs. The fifth and the final Test was played at Trinidad. Since it was the last Test of the series, it was to be a six-day match. India batted first and scored 360 on the back of Gavaskar’s 124 and Sardesai’s 75. West Indies, intent on winning the match to level the series, which India was leading 1-0, piled on 526 and it was India who had to save this match. Gavaskar then played the most crucial innings of the whole series. He scored a classy 220 out of India’s 427 that too with a severe toothache. West Indies set a target of 262 to win ended on 165 for eight at the end of the sixth day’s play and that meant India had won the five-match series 1-0. Gavaskar amassed a mammoth 774 runs in four Tests in this historic series. 

The England series 

Ajit Wadekar, the successful captain had learnt captaincy from Tiger Pataudi who had helped the team in improving the attitude of the players and also in vastly getting better in fielding. The Indian Team could now aim to beat other teams away from home due to the new-found confidence from series win in the Caribbean. That confidence was further boosted when they followed it up with another series win in England later that year. 

The Indian team went to England - to play a 3 match Test series - 2 months after its tour to the West Indies in the same year 1971. The Test matches were played in July-August that year by which time the pitches tended to wear in England and support spin. The Indian spin quartet included Bedi, Chadrasekhar, Prasanna, and Venkatraghavan. 

The England team was in high spirits for they had just won the 7 Test Ashes series 2-0 against their arch rivals Australia. The England team, led by a thorough professional, Ray Illingworth, was clear favourites to win the series against India. The team also included BL D’Oliveria, a central figure in the ante apartheid and boycott of South Africa from International cricket. The Indians opened their England tour with the tour match against Middlesex at the Lords (23-25 June, 1971) which they won by 2 wickets. They however lost the next match to the Essex. They played 6 other tour matches four of which were won by the Indians and two were draw. The Indians went into the First Test, at the Lords (July 22-27) with full of confidence. 

India dominated the first Test of the series, which ended in a draw. Aided by three scores of fifty plus by Captain Wadekar, Vishwanath and Solkar the Indians were able to score 9 runs more than the England team in the first innings. England was bundled out for 194 in the second innings. Set to score 183 to win in the fourth innings India ended the last day with a score of 145 for 8 thus ending the first test in a draw. The Indian spin trio of Venkat, Chandra and Bedi had dominated the England team. 

This test also witnessed an untowardly incident. Sunil Gavaskar and Snow were involved in this incident when the mightily looking Snow collided with Sunny while Sunny was taking a quick run. Sunny went tumbling down due to the massive impact. Snow was unfortunately dropped for the next Test. The second Test was played at the Old Trafford, Manchester. England chose to bat first after winning the toss. Aided by captain’s century knock, England scored an imposing 386 runs. The Indians were bundled out for 212. Gavaskar and Solkar scored half centuries for the touring team. England declared their second innings at 245 for 3 with the opener Luckhurst scoring a century. The Indians, set to score a massive 420 runs for the win or bat out the remaining time for a draw, were aided by the rain and the match was called off when Indians were 65 for 3. 

With the series level at 0-0, both teams then met at the Oval in the final match. England who won the toss and elected to bat first was bowled out for 355. In reply, India made 284 runs as the hosts took a 71-run lead in the first innings. Chandrasekhar then spun magic with the ball picking up a match-winning 6-wicket haul to bundle out England for a paltry 101 in the second innings. Chandra finished with figures of 8 for 114 in the match. India chased down the target of 173 with four wickets in hand to record the historic series win at the Oval on 24th August, 1971. 

The scene of this historic victory at the Oval in London was ecstatic with scores of Indian fans thronging to the ground, where Ajit Wadekar’s team had beaten England by four wickets to end the hosts' run of 26 Test matches without defeat. Each member of India's XI was a hero during and after this magnificent win, but the one who really stood out was the legendary leg spinner Bhagwat Chandrasekhar, who had helped the team to the historic win. 

The three Indian spinners along with Prasanna took 197 of the 244 wickets to fall in the entire series thus dominating the bowling and paving the way for an era of spin that was to follow in India. The England team came to the subcontinent the following year (1972) and found the spin trio too hot to handle once again on the spin-friendly tracks in India. The visitors were handed a 2-1 defeat in the subsequent five-match series at home with Wadekar registering his third successive series win as captain of the Indian team. 

The year 1971 and the three successive series victories including two overseas for the Indians has helped the team come off ages and ever since the Indian team has continued to move up in the ranking, both in Test cricket and One-day Internationals. India now stands among the top ranking cricket nations and is one of the most talented cricket teams in the world and the roots for this success were sown by the teams that won three back to back series that started in West Indies in 1971.

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