Optics Culminating Task: Laser Eye SurgeryBy: Robert LiaoIntroduction Laser eye surgery is a great way to correct vision and is an alternative to wearing glasses and can fix the vision of myopia, hyperopia and astigmatism. Laser eye surgery is quick as each eye only takes a few minutes when doing the procedure. The point of this surgery is to reshape the cornea as the cornea and the fluid behind it control how we see light. This is because the cornea and fluid focus the light that is going in our eyes. This light then goes through the pupil which controls the amount of light the eye takes in. Then, the lens and its muscles change how he see the image. The light then travels to the retina, but many people have the light create the image in front of or behind the retina. With laser eye surgery, surgeons burn away small amounts of tissue in order for our eyes to focus on the image. There are four very common types of eye surgery and they are laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), Laser Epithelial Keratomileusis (LASEK) and Epithelial Laser in Situ Keratomileusis (Epi-LASIK). A ophthalmologist will need to determine which type of eye surgery a person will need as they want the best procedure that suits their patient. After a procedure has been done, most patients tend to have 20/20 vision or even better. There is however, a 0.1% chance that there could be a minor complication, but most of these complications can be fixed.LASIK Laser Eye Surgery To start off, LASIK is the most common laser eye surgery of the four surgeries. Before the surgery starts, the surgeon puts gives the eye numbing eye drops to prevent discomfort during the surgery. Then, they use a lid speculum to keep the patient’s eyelids from blinking. It starts off by cutting a thin, circular flap from the cornea using either a laser or a blade. Then, according to LASIK.com, “Once the flap is created, the excimer laser is used to reshape the cornea, which corrects the refractive error.”(LASIK.com). In simple terms, it removes some tissue from the cornea. The excimer laser that is used is a UV or ultraviolet laser. For its medium, it uses different kinds of noble gases, such as halogen, in order to fulfill its duties to correct vision. However, nearsighted people and farsighted people have slightly different procedures. For nearsighted people, their cornea needs to be more flat while farsighted people need their cornea to be more steep. After the surgery is completed, the surgeon puts the flap back in its place, puts a few anesthetic drops on the eye and then the eye will heal naturally.PRK Laser Eye Surgery The second most common laser eye surgery is PRK. Many people prefer PRK as they do not cut off a flap from the cornea and PRK is better for people who have thin corneas. Before the surgery, the procedure is the same as LASIK as the surgeon numbs your eyes and puts a lid speculum around your eye. PRK starts off as the surgeon removes the outer layer of the epithelium or the cornea and is thrown away. Though, that outer layer can repair itself in just a few days. The surgeon then uses a excimer laser, the same one used in LASIK, and according to Brian Wachler, “used to precisely reshape the curvature of your cornea’s surface”(allaboutvision.com). After the surgery, an eye doctor puts a contact lens on the eye so it can help protect the eye while new cornea or epithelial cells grow. However, PRK takes longer than LASIK as it takes about four to five days to recover.LASEK Laser Eye Surgery LASEK is very similar to both PRK and LASIK. The procedure before the surgery is the same, but the surgeon starts off by putting alcohol onto the corneal epithelium for about 30 seconds. Then, the surgeon cuts of a very thin epithelial flap and moves it towards one side of the eye which makes it still attached. Then, the surgery is the same as before as the surgeon uses the excimer laser. After the surgery, the surgeon puts the epithelial flap is put back on the eye. Furthermore, the surgeon puts a contact lens that protects the patient’s eye and the procedure is done. For the first few days, people have reported mild discomfort, but is does get better. However, it is not as popular as it may take weeks and even months in order for the eyes to heal.Epi-LASIK Epi-LASIK is very similar to LASIK as it creates a small flap from the underlying corneal layer. The same process is then used from LASIK. After, the surgeon will put a contact lens to help protect the eye as the flap that was cut was very small compared to the LASIK surgery. However, the main difference between LASIK and Epi-LASIK is that Epi-LASEK takes three to six months in order for it the eyes to reach the final result which makes this surgery the least most common laser eye surgery.