Latest news with #JacquesDaviel
The Hindu
23-06-2025
- Health
- The Hindu
The story of cataract surgeries: restoring sights to millions
June is observed globally as Cataract Awareness Month, drawing attention to the leading cause of blindness worldwide. Blindness is not just the loss of sight but also the loss of autonomy, income, and social mobility. Today, despite the world's population being around 8.2 billion, the prevalence of blindness has declined to less than 0.5% thanks to advances in surgical care. With roughly 30 million cataract surgeries performed globally each year, millions are prevented from going blind, making it one of the greatest public health success stories. Yet, cataracts still account for about 40% of all cases of existing blindness, indicating the need for accessibility and awareness. Also Read: Cataract patients getting younger: report The patho-anatomy of the lens The human lens is a transparent, biconvex marvel no larger than a shirt button that helps us read, walk, recognise faces, and interpret the world in fine detail. It is formed in the womb from the surface ectoderm and remains sealed from the rest of the body for life. Unlike most organs, it has no blood supply, receives no immune surveillance, and is nourished solely by surrounding fluids. This isolation ensures perfect clarity but leaves it vulnerable to accumulating damage over time, usually from the fifth decade onwards. However, damage can occur at any age. A cataract is not a disease in the usual sense; it is a mechanical opacity in an otherwise healthy eye. But this unique anatomical trait is also why no drug/drops, exercise, or diet can reverse it. The lens cannot regenerate or absorb medicine. Only surgery can cure cataracts by replacing the damaged lens. A cataract occurs when the crystalline lens, normally transparent, becomes cloudy due to age-related protein denaturation, oxidative stress, or metabolic dysfunction. This clouding scatters light and blocks it from reaching the retina, leading to gradual, painless vision loss. Evolution of surgical techniques In ancient India, Sushruta practised 'couching', where a sharp instrument was used to dislocate the opaque lens into the vitreous cavity, moving it out of the visual axis. Though vision improved slightly because light could now pass unobstructed, the absence of a focusing lens left patients with severe hyperopia (far-sightedness) and frequent complications like glaucoma or retinal detachment. For nearly 1,800 years, this anatomical limitation was a surgical dead end. True progress in cataract surgery only began in the past 250 years, when surgical precision, sterilisation, optics, and, later, biomedical materials like PMMA (polymethyl methacrylate) and foldable lenses converged. In 1747, Jacques Daviel revolutionised care with extracapsular extraction, removing the lens but preserving its capsule, allowing some focusing power. Later, intracapsular extraction removed the entire lens and capsule, but thick spectacles were needed to compensate. In 1949, Sir Harold Ridley implanted the first intraocular lens, inspired by pilots whose eyes tolerated acrylic shards without reaction. In 1967, Charles Kelman further revolutionised the field with phacoemulsification, using ultrasounds to dissolve and remove the lens through a tiny incision. Foldable lenses, topical anaesthesia, and femtosecond lasers soon followed, making cataract surgery one of the safest, shortest, and most effective surgeries ever devised. The business of blindness This unique lens anatomy gave rise to something no other speciality achieved: scalability. Because cataract surgery requires only a lens and no external anaesthesiologist support in most cases and involves localised, avascular tissue, it can be safely performed by a single surgeon in a clean environment, with minimal dependence on supporting departments. Even more, cataract surgery fits naturally into the economics of ageing. As India's life expectancy rises, so does the geriatric population, creating a steady demand. This independence, mass-producibility of artificial lenses and increased demand due to ageing created the ideal conditions for growth. The unique anatomy of the lens, along with the relatively short operating time needed and minimal resource requirements, has facilitated the rise of corporate and charitable eye care chains across India. India is a global leader in delivering affordable and high-volume eye care. Unlike cardiac or neurological surgeries, which involve high costs and unpredictable outcomes, cataract surgeries are affordable, completely curable, and high-yield. No other surgical speciality enjoys such autonomy. Most major surgeries require teams, general anaesthesia, and post-operation monitoring. In contrast, cataract surgery (in uncomplicated cases) is a ten-minute procedure that restores function completely. Over 70% of preventable blindness in India is due to cataracts—and over 16 million such surgeries were performed last year, many free or subsidised by the National Programme for Control of Blindness and Visual Impairment. The surgery is often performed under topical or local anaesthesia, with daycare discharge and return to routine life within 24 hours. The outcomes are extraordinary, and thus, cataract surgery is a statement of human progress. The human lens, though born as a delicate piece of our own body, is perhaps the only 'organ' that can be replaced not by a donation but by a factory-made crystal—folded like a petal, slipped into the eye, and left to bloom silently. Unlike hearts, lungs, and kidneys that beg for an immunological match and a donor's mercy, this lens knows no rejection and has no waiting list. It fits nearly every adult eye similarly, making it the most scalable 'transplant' known to medicine. And for a device that can be manufactured at a cost lower than a bucket biryani, its return—both in economic cost and the social dignity of restored sight—is extraordinary. (Dr. C. Aravinda is an academic and public health physician. The views expressed are personal. aravindaaiimsjr10@ Dr Sangeetha Raja is an ophthalmologist at Aravind Eye Hospital, Thanjavur, and the author of Mastering Uvea and Mastering Glaucoma for postgraduate ophthalmology students. sangeesara03@
Mint
01-06-2025
- Health
- Mint
HEALING SECRETS
Cataract surgery dates back to 800 BC, but it was risky and unsafe. In the 1700s, Jacques Daviel advanced the method, laying the groundwork for today's refined surgical treatments. Credit : PEXELS
