Endothelial keratoplasty: Mild intervention to treat eye infection

Pre-descemet endothelial keratoplasty is one of the methods of endothelial keratoplasty (EK), a procedure that removes and transplants the affected layer of the cornea rather than transplanting the whole cornea.
Representative Image
Representative Image

KOCHI: At a young age of 29, Jishnu, from Kottayam in Kerala, was suffering from an infection in his cornea that could potentially lead to blindness. Though he underwent a therapeutic corneal transplantation earlier, it failed and affected his vision. When all hope seemed to fade away, his vision was saved through a one-day procedure - pre-descemet endothelial keratoplasty (PDEK).

"Jishnu, a fisherman, was suffering from a severe fungal infection in his right eye around one-and-a-half years ago. He had undergone therapeutic corneal transplantation (keratoplasty) to treat his severe corneal infection. However, due to the nature of the infection, the transplanted corneal tissue failed, greatly affecting his vision. We identified the diseased part of the cornea (endothelial layer, which is the innermost layer of the cornea) and replaced it with tissues harvested from a healthy cornea using PDEK," said Dr P Sanjana, consultant ophthalmologist at Agarwal's Eye Hospital in Kochi.

Minimally invasive

Pre-descemet endothelial keratoplasty is one of the methods of endothelial keratoplasty (EK), a procedure that removes and transplants the affected layer of the cornea rather than transplanting the whole cornea.

"Endothelial keratoplasty (EK) is a precise and less invasive corneal transplant surgery used to treat diseases affecting the endothelium, the cornea's innermost layer," according to Dr Ashwin Santosh Shetty, consultant in ophthalmology, Aster CMI Hospital, Bangalore.

"The endothelium keeps the cornea clear and healthy. When it's damaged, one can have blurred vision. EK surgery replaces only the diseased endothelium with healthy donor tissue," he said, adding that EK is preferred for conditions like Fuchs' endothelial corneal dystrophy, pseudophakic bullous keratopathy, and other endothelial diseases.

"EK is a newer procedure, where the affected layer of the cornea out of the six layers, is transplanted. In the conventional method of treatment, if any of these layers are damaged, we used to transplant the whole thickness of the cornea," said Dr Aneeta Jabbar, chief surgeon with the Cornea Unit at Little Flower Hospital in Angamaly, Ernakulam.

Only affected area replaced

Earlier, these conditions were treated by performing penetrating keratoplasty (PK), a procedure that replaces a diseased cornea with a healthy donor cornea. "The last two decades have seen some revolutionary changes in the field of corneal transplantation, and the present trend is to perform a component surgery of the cornea, whenever possible. This means replacing only the diseased part so that the risk of rejection is low. Endothelial keratoplasty is a procedure where only the back layer of the cornea is replaced. In corneal disease involving endothelium or the back layer of the cornea, EK has become the dominant way of transplantation at present," said Dr Anil Radhakrishnan, consultant in cornea and refractive surgery at Amrita Hospital in Kochi.

Dr Aneeta emphasised that endothelial keratoplasty is not a replacement for penetrating keratoplasty and is an advancement in the field, ensuring more specific treatment. "There are different EK techniques, each used to treat different conditions. The right method is opted depending on the condition of the patient, the expertise the centre has and the requirement. Also, there are automated and manual methods available in EK," she added.

"It is a day-care procedure that does not require hospital admission unless the patient has a serious health ailment. Within a few hours, the patient can leave the hospital, which makes it more convenient for the patients, as well as their family members," said Dr Anil, adding that the rest period after the procedure is also less.

Donor required

For performing endothelial keratoplasty, there are essentially two important requirements. "One is a highly trained specialised corneal surgeon, and the other is a healthy donor cornea. Fortunately, the number of trained cornea specialists, though it is low now, is gradually increasing. So there are more and more surgeons who are taking up specialised cornea training and can perform these surgeries now," said Dr Tushar Grover, associate consultant of ophthalmology at Sir Ganga Ram Hospital, Delhi, adding that as far as the corneas are concerned, there is always a shortage of donor corneas.

"The need for corneas is much higher than the supply, but the eye banking system in India has become quite robust over the years and is improving further. So, while there is the limitation of relatively few trained surgeons and the scarcity of corneas, a good number of endothelial keratoplasties are being performed," he said.

The technology has been gaining more popularity as patients are aware of options available. "The number of people who opt for the treatment has increased recently in the last 15 years, mainly due to the awareness among the public. Also, most of the major hospitals are now equipped to perform the procedure with trained professionals," said Dr Aneeta.

"The popularity of this procedure has been increasing gradually over the last few years as more and more corneal surgeons have been getting trained to perform endothelial keratoplasty, and because of this, the proportion of full thickness or penetrating keratoplasty has been reducing and the proportion of endothelial keratoplasty increasing," said Dr Tushar.

The cost of the procedure is slightly high compared to the traditional method. "This method requires dedicated equipment, technology and surgical expertise - the reason for increased expenses varying from Rs 50,000 to Rs 60,000, including the eye bank and procedure charges," added Dr Anil.

Lesser complications

Dr Sanjana also pointed out that doctors prefer endothelial keratoplasty as a safer option in conditions where only the functional layer of the cornea is damaged without significant scarring.

"The possibility of operative and long-term complications is also reduced, according to subject experts. In traditional surgery, there would be at least 16 stitches on the cornea, while it is limited to a few or none in EK," said Dr Anil.

“We have been doing the procedure since 2013 and the outcome is very good. The recovery is faster and the chance of rejection also is lesser. It can be done even in young patients,” said Dr S Soundari, regional head-clinical services, Dr Agarwal’s Eye Hospital.

More patients are opting for the treatment as they are confident about the safety and results. “Earlier, when we informed the patient about cornea transplant surgery, it used to scare them - as we have to transplant the whole cornea. Now, it is easier to convince them as it is only about transplanting the layer which is damaged. They are not scared to undergo the procedure," said Dr Aneeta.

Better utilisation of donor eyes

The utilisation rate of donor eyes has also increased with this treatment mode. "In some cases, we cannot use the whole eye for several reasons. But this method helps in improving the utilisation rate. One eye can be used in more patients," said Dr Sanjana.

Dr Aneeta added that the availability and utilisation of donor corneas have improved due to the increasing number of such component keratoplasty.

“The main hospital in Chennai does around 75-90 cases in a month. Other centres like Kerala, Maharashtra, Bengaluru, Hyderabad and Punjab put together performs around 25 cases in a month. Since awareness on eye donation is there, there is no shortage for donors. We regularly get eye donations, and we keep doing PDEK procedures,” added Dr Soundari.

Fewer sutures 

  • Endothelial keratoplasty procedures require fewer sutures than other keratoplasty procedures

  • The technique uses an air bubble to keep the donor cornea in position

  • To increase the chance of success, you’ll need to make sure you’re lying face up when you rest or sleep for the first few days after surgery

  • Lying face up helps the air bubble keep your transplanted corneal tissue in place

Types of endothelial keratoplasty

  •          Descemet's Stripping Endothelial Keratoplasty

  •          Descemet's Membrane Endothelial Keratoplasty

  •          Deep lamellar endothelial keratoplasty

  •          Descemet stripping automated endothelial keratoplasty

  •          Pre-Descemet endothelial keratoplasty

Advantages

  •          Fewer complications

  •          Improved clarity of vision

  •          Faster recovery time

  •          Minimally invasive and fewer sutures - avoids possibility of surgical complications

  •          Lower risk of rejection compared to traditional corneal transplants

  •          Day-care procedure

 (With inputs from Rishita Khanna @ Bengaluru, Ashish Srivastava @ New Delhi)

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