LASIK or Lasik (Laser-Assisted in Situ Keratomileusis), commonly referred to as laser eye surgery, is a type of refractive surgery for the correction of myopia, hyperopia, and astigmatism. The LASIK surgery is performed by an ophthalmologist who uses a laser or microkeratome to reshape the eye’s cornea in order to improve visual acuity. For most patients, LASIK provides a permanent alternative to eyeglasses or contact lenses. Major side effects include halos, starbursts, night-driving problems, keratoconus (corneal ectasia), and eye dryness. Officially started in: On 20 June 1989, Gholam A.
Peyman was granted a US patent for LASIK What Are the Advantages of LASIK Eye Surgery? Around 90% of patients will have their desired vision after LASIK. An enhancement can further increase this number. LASIK is associated with very little pain. Vision is corrected nearly immediately or by the day after LASIK. No bandages or stitches are required after LASIK. Adjustments can be made years after LASIK to further correct vision. After having LASIK, most patients have a dramatic reduction in eyeglass or contact lens dependence and many patients no longer need them at all. Preoperative procedures: Contact lenses.
Patients wearing soft contact lenses are instructed to stop wearing them 5 to 21 days before surgery. Pre-operative examination and education In the USA, the FDA has approved LASIK for age 18 and over. [21] More importantly the patient’s eye prescription should be stable for at least one year prior to surgery. The patient may be examined with pupillary dilation and education given prior to the procedure. Before the surgery, the patient’s corneas are examined with a pachymeter to determine their thickness, and with a topographer, or corneal topography machine,[1] to measure their surface contour.
Using low-power lasers, a topographer creates a topographic map of the cornea. The procedure is contraindicated if the topographer finds difficulties such as keratoconus. How does LASIK work? During the LASIK procedure, a specially trained eye surgeon first creates a precise, thin hinged corneal flap using a microkeratome. The surgeon then pulls back the flap to expose the underlying corneal tissue, and then the excimer laser ablates (reshapes) the cornea in a unique pre-specified pattern for each patient. The flap is then gently repositioned onto the underlying cornea without sutures. Operative procedure:
Flap creation A soft corneal suction ring is applied to the eye, holding the eye in place. This step in the procedure can sometimes cause small blood vessels to burst, resulting in bleeding or subconjunctival hemorrhage into the white (sclera) of the eye, a harmless side effect that resolves within several weeks. Increased suction causes a transient dimming of vision in the treated eye. Once the eye is immobilized, the flap is created. This process is achieved with a mechanical microkeratome using a metal blade, or a femtosecond laser that creates a series of tiny closely arranged bubbles within the cornea.
[22] A hinge is left at one end of this flap. The flap is folded back, revealing the stroma, the middle section of the cornea. The process of lifting and folding back the flap can sometimes be uncomfortable. Laser remodelling The second step of the procedure uses an excimer laser (193 nm) to remodel the corneal stroma. The laser vaporizes the tissue in a finely controlled manner without damaging the adjacent stroma. No burning with heat or actual cutting is required to ablate the tissue. The layers of tissue removed are tens of micrometres thick.
Performing the laser ablation in the deeper corneal stroma provides for more rapid visual recovery and less pain than the earlier technique, photorefractive keratectomy (PRK). During the second step, the patient’s vision becomes blurry, once the flap is lifted. Repositioning of the flap After the laser has reshaped the stromal layer, the LASIK flap is carefully repositioned over the treatment area by the surgeon and checked for the presence of air bubbles, debris, and proper fit on the eye. The flap remains in position by natural adhesion until healing is completed. Postoperative care.
Patients are usually given a course of antibiotic and anti-inflammatory eye drops. These are continued in the weeks following surgery. Patients are told to rest and are given dark eyeglasses to protect their eyes from bright lights and occasionally protective goggles to prevent rubbing of the eyes when asleep and to reduce dry eyes. They also are required to moisturize the eyes with preservative-free tears and follow directions for prescription drops. Occasionally after the procedure a bandage contact lens is placed to aid the healing, and typically removed after 3-4 days.
Patients should be adequately informed by their surgeons of the importance of proper post-operative care to minimize the risk of complications Side effects: ·Surgery induced dry eyes ·Over-correction or under-correction. ·Vitamin D deficiency from sun sensitivity and hence avoidance. ·Fluctuation in Visual acuity. ·Halos and starbursts occur around bright lights at night. At night, the pupil may dilate to be larger than the flap leading to the edge of the flap or stromal changes causing visual distortion of light that does not occur during the day when the pupil is smaller.
The eyes can be examined for large pupils pre-operatively and the risk of this symptom assessed. ·Ghost images ·double vision ·Light sensitivity. ·Large pupils ·lid edge irritation Early post-operative complications Diffuse lamellar keratitis Diffuse lamellar keratitis (DLK) is an inflammatory process that involves an accumulation of white blood cells at the interface between the LASIK corneal flap and the underlying stroma. It is known colloquially as “sands of Sahara.
syndrome” because on slit lamp exam, the inflammatory infiltrate appears similar to waves of sand. The USAeyes organisation reports an incidence of 2. 3% after LASIK. [93][94] It is most commonly treated with steroid eye drops. Sometimes it is necessary for the eye surgeon to lift the flap and manually remove the accumulated cells. DLK has not been reported with photorefractive keratectomy due to the absence of flap creation. Infection The incidence of infection responsive to treatment has been estimated at 0. 4%.
[94] Keratoconus Keratoconus is a genetic condition that disposes the cornea to thinning after surgery. Although this condition is screened for in the preoperative examination, it is possible, in rare cases, (about 1 in 5,000)[citation needed] for the condition to appear later in life (the mid-40s). If this occurs, the patient may need rigid gas permeable contact lenses, Intrastromal Corneal Ring Segments (Intacs)[95] Corneal Collagen Crosslinking with Riboflavin[96] or a corneal transplant. Subconjunctival haemorrhage.
A report shows the incidence of subconjunctival hemorrhage has been estimated at 10. 5%. [9 Onset of presbyopia Myopic (nearsighted) people who are close to the age (mid- to late-forties) when they will require either reading glasses or bifocal eyeglasses may find that they still require reading glasses despite having undergone refractive LASIK surgery. Myopic people generally require reading glasses or bifocal eyeglasses at a later age than people who are emmetropic (those who see without eyeglasses), but this benefit may be lost if they undergo LASIK.