Corneal collagen cross-linking (CXL) is the current gold standard to arrest the progression of keratoconus but its efficacy remains less predictable in thinner and steeper corneas. For such scenarios, a simple approach of transplanting Bowman layer and anterior stroma as Bowman-stromal inlay (BSI) in keratoconic patients as an intervention to cease progression of ectasia and increase the overall thickness of cornea is a new option.
S𝘁𝗲𝗽𝘀 𝗼𝗳 S𝘂𝗿𝗴𝗲𝗿𝘆 𝗜𝗻𝗰𝗹𝘂𝗱𝗲
1. Intrastromal pocket is created in patient's cornea using femtosecond laser
2. Inlay consisting of the Bowman's layer and anterior stroma is harvested from donor cornea using femtosecond laser
3. Implantation of inlay in recipient's intrastromal pocket using IOL injector
S𝘁𝗲𝗽 𝗜 – 𝗜𝗻𝗹𝗮𝘆 𝗽𝗿𝗲𝗽𝗮𝗿𝗮𝘁𝗶𝗼𝗻
- Donor corneal tissue is mounted on an artificial anterior chamber
- Alcohol assisted epithelial debridement is done to prevent epithelial ingrowth later
- The limbus is marked to ensure centration of graft
- Lamellar keratoplasty setting is used to harvest anterior lamellar graft - Bowman’s layer +anterior stroma
- Graft docking and centration is performed
- Donor cornea of desired thickness is cut from the top
- 360 edges of the lenticule are raised with LASIK flap lifter
S𝘁𝗲𝗽 𝗜𝗜 – 𝗥𝗲𝗰𝗶𝗽𝗶𝗲𝗻𝘁 𝗣𝗿𝗲𝗽𝗮𝗿𝗮𝘁𝗶𝗼𝗻 (𝗜𝗻𝘁𝗿𝗮𝘀𝘁𝗿𝗼𝗺𝗮𝗹 𝗽𝗼𝗰𝗸𝗲𝘁)
- Femtosecond laser is used with modified settings of LASIK flap software with minimal energy for side cut to create an intrastromal corneal pocket in the recipient’s cornea
- The patient and the inlay are both shifted to the main operating room
- The incision is made with a guarded knife
- Tunnel is opened up with appropriate dissectors
- Stromal pocket is opened up for smooth insertion of inlay
- Centre of the cornea is marked to ensure that the inlay is placed in the centre of visual axis
- Inlay is loaded into the IOL cartridge with Bowman's layer side up
- The tip of the injector is engaged in the canal
- Inlay is injected into the stromal pocket
- Inlay is unfolded with the help of 26G cannula and surface taps
- Inlay is centred around the pupil with the help of surface massage
- BCL is placed at the end of the surgery
