By Abhishek Bhatia

New Delhi:

, also infamously known as the silent thief of sight, is a serious eye condition that can cause blindness. At any given time in a year, around 12 million people (aged 40 or older) are affected by the disease in some way or another in India, and of this, around 10 per cent lose their vision. Although there is no permanent fix for the disease at an advanced stage,

options are available if it is diagnosed early.

A series of

known as glaucoma harm the

. For clear vision, the optic nerve is essential as it transmits visual data from the eye to the brain.

in your eye is frequently associated with damage to the optic nerve. Yet, glaucoma can develop with normal eye pressure as well. Numerous glaucoma types show no symptoms at all. People might not notice a change in vision until the problem is advanced, since the effect is really gradual.

Apart from medications and eye drops, there are

treatment procedures (i.e.,

and iridotomy) and advanced operational room surgeries (including trabeculectomy, glaucoma drainage devices, and cataract surgery). All of these procedures have specific needs and are required as per the progression of the disease.

On the occasion of

, ETHealthworld spoke with multiple domain experts to understand the new technological breakthroughs for the effective management of disease and whether India, which is considered a less expensive destination for glaucoma treatment as compared to the western world, is marching forward with time in the innovation space.

For peripheral and central vision, each and every point stimulates rods and cones inside the retina, which exists all the way inside the eye. Rods are responsible for vision at low light levels, or scotopic vision. Cones, on the other hand, are in charge of vision under brighter light, or photopic vision. The entire structure, including the retina, is full of rods and cones in which specific points are connected to the brain via a nerve fiber, which, according to experts, is like a telephone cable. When anything is simulated, the image travels to the brain via these nerves.

Emphasisng that there may be one billion of these nerves and cones, Dr Sudipto Pakrasi, Chairman, Ophthalmology, Medanta, Gurugram, said, "Each of these is connected with individual nerves to the parts of the brain that help us see. What happens in glaucoma is that the nerve fibers are entering the optic nerve and turning to go to the nerve from the retina, and it is like a 90-degree turn. That’s where the damage happens in the optic nerve fiber layer, which leads to loss of vision without patients realising it because there are no symptoms."

Speaking about the

that have taken place in glaucoma treatment, Dr Shayana Bhumbla, Adjunct Consultant, Glaucoma Services, Ophthalmology, Dr Shroff Charity Eye Hospital, Delhi, said, "The most recent advancement has been the introduction of Minimally Invasive Glaucoma Surgeries (MIGS), iStent – where a small (360 x 240 μm) titanium stent is placed in the eye to drain fluid out of the eye and hence control IntraOcular Pressure (IOP). There are other angle-based surgeries like BANG (Bent ab interno needle goniectomy), GATT (Gonioscopy-Assisted Transluminal Trabeculotomy), KDB (Kahook Dual Blade), and Trabectome. Also, a new valveless glaucoma drainage device called Ahmed Clear Path (ACP) is starting to come up."

Dr Pakrasi spoke about drugs of different kinds that are at the investigational stage and being looked into by researchers. In some of these investigations, the potential of the derivatives of cannabis is explored in the treatment of glaucoma, and in some cases, the pressure in the eye has also been reduced.

"Different studies are being done as we speak to find out whether IOP can be reduced with the use of different kinds of cannabis." They will be able to assist people whose pressures are not being controlled," he added.

Experts suggest that there have been continuous advancements on all fronts of glaucoma diagnosis and treatment. Dr Siddharth Dikshit, Senior Glaucoma Consultant, L V Prasad Eye Institute, said that the pandemic forced the patients and the ophthalmologists to stay at home. Dr Dixit informed that this mandated the use of technology to measure the intraocular pressure (IOP), which plays a major role in glaucoma treatment.

"Some devices, such as the ICare HOME, allow patients to measure and report their IOP from home. There are hand-held devices that can help a patient test their visual fields. The findings from these home-based care devices give us some idea of the IOP of a patient. These devices are continuously being upgraded and improving in precision and accuracy, and hopefully they will soon become cheaper and more accessible to a larger population. Ultimately, the information has to be used by a health care provider to modify treatment," Dr Dikshit elaborated further.

Dr Harshwardhan Ghorpade, Cornea, Cataract, and Refractive Surgeon, Hiranandani Hospital, Vashi-A Fortis Network Hospital, said that the minimally invasive glaucoma surgery (MIGS) procedures have made glaucoma surgery possible for even general ophthalmologists. "Being a procedure dependent on the stent rather than a surgeon created port, it has become more reliable in terms of results. Optometrists are the first line of care for eye patients, and they must be trained in checking eye pressure, observing the optic nerve, performing investigations such as OCT scans and perimetry, and referring appropriate patients to Glaucoma specialists," he added.

An innovative LIGHT study was reportedly published in The Lancet in April 2019 by specialists. The study suggested that selective laser trabeculoplasty (SLT) should be thought of as a first-line treatment for many people with open-angle glaucoma (OAG), according to research conducted in Europe that involved many centers and observer-masked, randomised, controlled trials.

The LIGHT study has shown an economic benefit when you include the costs of visits, medications, and the costs borne by the medical system. "This should be replicated in our system," said Dr Dixit, adding that Selective Laser Trabeculoplasty (SLT) has been the standard of care in newly diagnosed early and moderate open angle glaucoma in the western world. "Patients who have been newly diagnosed to have open-angle glaucoma and have not used medications for any significant duration, should be offered SLT. The major limitation here has been the availability of the instrument that delivers this laser. Once more, I would like to stress that they may not be the best option for patients with advanced glaucoma or those who have used medications for a significant duration," he elaborated further.

Underscoring that SLT is definitely the way to avoid long-term use of drops and their side effects, Dr Ghorpade said, "Also, being a one-time procedure, it is cost effective. However, it also depends on how meticulously it has been done, how easily the equipment is available, and if the patient is willing to pay a high amount in one go or wishes to opt for a much cheaper and equally effective option like eye drops."

Dr Bhumbla believes SLT is a very safe treatment option for newly diagnosed OAG patients, and as per literature, patients who received SLT had fewer chances of requiring surgery compared to patients who received drops. She called SLT a good first-line treatment option for mild to moderate open angle glaucoma and ocular hypertension patients, saying, "The effect lasts for 2-3 years and it can also be repeated. The effect of SLT is equivalent to 1-2 IOP lowering drops."

Experts agreed that understanding surgical advancements in the care of the glaucoma patient is integral to clinical practice for the modern primary care optometrist. Most glaucoma patients are managed by a glaucoma specialist and optometrist together. As per medical practitioners, it is helpful for both the patient and doctor if the entire team is well versed with all the treatment options, including their merits and demerits. Optometrists are usually the first point of contact with the patient; they usually screen them and refer them to a glaucoma specialist. However, in most places, the gaps with the primary care optometrist learning to examine beyond refractive error and cataract still loom large.