Refractive Surgery

PRK (Photrefractive Keratectomy)

The epithelium, the cornea’s outermost layer, is removed carefully, and then the Excimer laser (wavelength 193 nm) is used to reshape the corneal surface, so adjusting the eye’s refractive power. The epithelium is very thin (50 microns) and often grows back within 3 days, which is why it is recommended to use a contact lens for a few days to aid in the eye’s healing.

LASIK (Flap Based Procedure)

A corneal flap (100-120 microns in thickness) is created in the epithelium, a layer of tissue just below the cornea’s surface, in this common surgery. There are two ways to make this flap.

• Microkeratome: Microkertome aided LASIK, also known as BLADE LASIK, uses a small, specialised blade to precisely cut the flap.
• Femtosecond laser (wavelength 1053nm): This is a unique type of laser that can make a flap exactly where you want it to be in terms of depth; it’s extremely different from the Excimer laser we discussed earlier and hence requires its own delivery system. Femtosecond laser in situ keratomileusis is also known as FEMTO- LASIK.

In either case, the flap is lifted after its creation, and the residual bed is given an Excimer laser treatment (same laser used in PRK). Following the surgery, the corneal flap is replaced on the corneal bed and the patient is sent home with medicine.

Refractive Lenticule Extraction – ReLEX SMILE / FLEX

The Femtosecond laser is all that is needed for this cutting-edge refractive surgery (same laser as described in FEMTO -LASIK). The eye’s refractive error can be fixed by implanting a lenticule (of a specific size and thickness) into the cornea. The lenticule is then removed in two different ways.

• Through a 4-5mm incision -this is called Femtosecond Lenticule Extraction (FLEX).
• Through a very small 2mm incision – this is known as Small Incision Lenticule Extraction (SMILE) 

The cornea’s shape is changed and the refractive error is corrected when this lenticule is removed. This procedure is often referred as as “blade-less” or “flap-less” refractive surgery because it does not include the use of an Excimer laser or a Microkeratome blade.

Lens Based surgeries

Lens based surgeries involve ‘in the eye -intraocular’ procedures to correct the spectacle power. It can be further divided as:

Implantable Collamer Lens (ICL)

To correct nearsightedness, surgeons insert a small, clear plastic implantable contact lens in front of the eye’s native crystalline lens. In contrast to conventional disposable contact lenses, ICLs are constructed from a biocompatible substance called collamer (combination of collagen and polymer).

Refractive lens exchange

In refractive lens exchange, the eye’s crystalline lens is surgically removed and replaced with a properly powered artificial intraocular lens (IOL). Because Ultrasonic energy (Phacoemulsification) is used to remove the eye’s natural lens, cataract surgery will become obsolete as a treatment option. ROBOTIC – Refractive Lens Exchange refers to a refractive lens exchange method in which a femtosecond laser platform is employed to aid in the process.

In addition to lubricants, protective eyewear, and antibiotic-steroid eye drop combinations, all patients undergoing refractive surgery also receive. Patients must be thoroughly examined on postoperative days 1, 3, 7, and 14, and thereafter on a consistent basis.