Chennai: Corneal diseases are supposed to be the 4th most important cause for blindness worldwide after cataract, glaucoma and age-related macular degeneration. Corneal transplantation served as the golden procedure that restored the visual function when the visual impairment caused by corneal diseases became too severe.
While corneal surgery was the magical wand, which literally provided new eyes, it had its own limitations. According to a study published in JAMA Ophthalmology in 2016, there’s a huge demand and supply gap in the availability of corneas for the procedure with only one cornea available for 70 needed.
There have been a lot of efforts taken to encourage cornea donation as a part of the strategies to prevent and control blindness but it seems essential to also find alternative solutions for the same.
Also, cornea rejection occurs in about 20% of the cases. Graft failure can also occur at any time after the cornea has been transplanted, even years or decades later. These complications are the greatest barriers for the global corneal surgery market, which is expected to grow at a CAGR of 5.2% during forecasted period 2018-2023.
An alternative proposed in the market is a special type of contact lenses called Boston Scleral Lenses. A survey conducted by Boston Foundation for Sight in 2010 showed that 80% had significant success with BostonSight PROSE (prosthetic replacement of the ocular surface ecosystem) treatment. For many of the thousands of patients suffering from complex corneal disease, PROSE may be the ideal, and sometimes only, treatment capable of restoring visual function and reducing eye pain and light sensitivity.
Till date, the benefit was limited in India because of the high cost. L V Prasad Eye Institute (LVPEI) has a facility in Hyderabad that produces special type of contact lenses (Boston Scleral lenses) in collaboration with Boston Foundation for Sight, USA, with the goal of increasing access to specialized forms of contact lenses for the treatment of corneal problems, avoiding corneal transplantation in some cases. The new manufacturing facility is said to have been created to make it available to all sections of the society. This unit reached a milestone of 1,000 lenses in December 2018. This is the only facility outside of the US. Now the unit has received the government license to export these lenses outside the country.
According to Dr Ashutosh Richhariya, Associate Director of Engineering Group of Srujana Innovation Centre in LVPEI, the Centre has started manufacturing PROSE and Scleral lens in India. The cost has come down significantly but the bigger advantage is said to be of the turnaround time. Previously, it was usually one to three months, which has been brought down to three days. He says that making the Scleral lens available to all who need it is the agenda of this project and they are providing this to many more practices in India and abroad.
Srujana Innovation Centre has identified and partnered with numerous practitioners across India and is supplying them these customized lenses. In future, it is also going to cater to other countries in Asia and Africa and help people start research in contact lens design and improvise them.
Scleral lenses are commonly known for their use in patients with Stevens-Johnson syndrome, keratoconus, corneal grafts, chemical and thermal burn injuries, and ocular pemphigoid, among other uses. The increased spotlight on scleral lenses has led to their use in more number of patients with severe dry eyes due to Sjögren’s syndrome, autoimmune diseases, chronic graft-versus-host disease, post-LASIK dry eye, and irregular astigmatism.
BostonSight PROSE treatment uses custom designed and fabricated prosthetic devices to restore visual function, support healing, reduce symptoms and improve quality of life for patients suffering with complex corneal disease. PROSE treatment uses scleral lens prosthetic devices that are FDA approved for therapeutic indications.
While discussing various clinical aspects of this treatment, Dr Pravin Krishna Vaddavalli, Director of Tej Kohli Cornea Institute at LVPEI, Hyderabad, explains the intricacies about the device that it is a prosthetic device like a contact lens and does not involve any surgical procedure. Like a contact lens, it is worn on a daily basis during the day and removed before going to bed.
The big difference from a routine contact lens is that this device does not depend on the curvature of the cornea or the severity of the keratoconus to achieve excellent vision, since it does not sit on the cornea. Instead the PROSE device is supported on the white part of the eye called the sclera, which is much less sensitive than the cornea, thus making extended wear more comfortable and stable, according to Dr Vaddavalli.
Additionally with the advent of the PROSE device, a number of patients whose only recourse would have been corneal transplantation can now avoid this complex surgery.
Regarding the associated complications, Dr Vaddavalli says that since the PROSE device rests on the sclera, it is extremely stable and comfortable. As with other contact lenses, if the wearer sticks to the suggested regimen for wear and cleans the device adequately, complications are extremely rare. Dropping the device and breakage has been the most common issue but a care package that takes care of lens replacement within the first year allows patients greater confidence while using it. Since the procedure is non-surgical, there is no tedious learning curve for the practitioners necessary. This device, which has been revolutionary in the field of corneal diseases, is also hoped to make the lives of patients with keratoconus, dry eyes and similar conditions more comfortable in future.
by Usha Nandini
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