18 Feb Refractive eye surgery
Refractive Surgery is a surgical method of correction of the common problem of refractive errors.
What are refractive errors?
How well you see depends on how your cornea and lens (our main focusing system) focus light rays on the retina (the sensory layer of the eye).
The principle of refraction ie Light rays must bend to form a focused image on the retina helps us see. The sensory layer (retina) is the light-sensitive nerve that lines the back of the eye and interprets images into impulses from the light rays that are sent through the optic nerve to the brain.
Refractive errors are in short errors in this system of focusing of light, causing vision problems. Can be caused by a cornea that is not shaped perfectly or imperfect length of the eye ball. The cornea is the clear part at the front of the Which bends and focuses light waves.
Refractive errors cause light from an object not to be focused and thereby causes a blurred image. Refractive errors is a common problem and often can occur in otherwise healthy eyes!
There are 4 types of refractive errors:
Nearsightedness (myopia) – A vision disturbance where Close objects appear sharp But objects in the distance are blurred. Here often the eye is longer than normal from front to back Or the cornea is curved too much! Resultant Image is focussed in front of the retina instead of on it.
Farsightedness (hyperopia) – Vision disturbance which lets us see distant objects clearly But not the objects which are up close, that appear blurred. The eye is shorter than normal Or the cornea is too flat causing the Images to focus behind the retina rather than on it .
Astigmatism – Vision disturbance that cause Objects to appear blurred at any distance. Shape of the cornea (often) or lens or both are altered causing images formed to be blurred and not focused sharply on the retina.
Types of refractive surgeries available to correct these include :
- PRK (Photorefractive keratectomy)
- Epi Lasik or LASEK
- ICL (implantable collamer lens)
- CLE (clear lens extraction)
- FemtoSecond LASIK OR Bladeless LASIK
Lasik – or laser in-situ keratomileusis is the most popular type of refractive surgery done. It involves making a corneal flap with the help of a specialised device named microkeratome. This enables easy access to provide adequate laser time inorder to correct the refractive error. Its a painless and fast procedure with great results, Often instantly after the procedure is completed
Femtosecond LASIK OR BLADELESS LASIK – is a variant of LASIK in which no blade or microkeratome is used , rather that step is replaced by another kind of laser for better precision and better outcomes. This is the latest technology in refractive surgery and yields great results
PRK And EpiLASIK – these are FLAP LESS surface ablation procedures where laser is directly applied to the outermost surface of eye or cornea without the need of creating a flap. This makes the procedure a more stable and long term success, an ideal procedure for patients with adventurous or sporting aspirations!
ICL OR implantable collamer lens is a surgery of choice in cases where laser may not be beneficial. By placing a permanent lens (contact lens) before the natural lens, this is ideal for high myopes and high hypermetropes .
CLE OR CLEAR LENS EXTRACTION – is the procedure of choice in older adults who want to permanently get rid of their glasses and can often be a boon to even correct their presbyopia.
A Timeline of Laser Eye Surgery