Refractive surgery: principles, techniques, and advances

Left uncorrected, refractive errors result from irregularities or imperfections in the shape of the cornea or
lens that make up the defects that can be corrected by surgery include: myopia, hyperopia, astigmatism, and
presbyopia. Surgical intervention for the removal or significant reduction of the need for glasses was gaining more
preference over them on a long-term basis. Refractive surgery then became more fashionable than glasses and
contact lenses since the late 1900s when laser and intraocular surgery became popular because it was much safer and
effective used in both procedures. One of the refractive surgery techniques, called Radial keratotomy (RK), came
about back in the 1970s, implying an alteration in corneal shape by means of radial corneal incisions.
Functionally, however, that method was accompanied by a problem with vision fluctuation and corneal wobbling.
The excimer laser technology had influenced eye surgery in the 1980s due to the accurate and effective surgical
procedures introduced; among those was photorefractive keratectomy (PRK) and laser-assisted in situ
keratomileusis (LASIK). The recent progress in femtosecond laser technology, as well as corneal inlays and IOL
implants, makes the surgical option wider; these, then, are enhanced by such diagnostic tools as corneal tomography
and optical coherence tomography (OCT) even further through personalized therapy approaches. Most common
refractive surgeries include PRK, LASIK, small incision lenticule extraction (SMILE), and implantable collamer
lenses (ICL).
Patients who are thin-corneal or LASIK candidates at risk for complications may have PRK benefit. This operation
takes longer to heal, while LASIK is the one that sees most surgery as it is characterized by short recovery and
higher patient satisfaction, but causes a dry eye and flap complication. SMILE minimally invasive surgery has been
proposed as a method with corneal biomechanics preserved and dry eye risk reduced, mostly in cases of myopia and
mild astigmatism. ICLs work best in the case of individuals with extreme levels of refractive errors and for patients
who are contraindicated for corneal surgery.
There are certain complications following refractive surgery, such as dry eye, glare, and corneal ectasia; although
refractive surgery is generally considered safe. Screening and surgical improvements, such as corneal cross-linking,
have a positive effect on the results. Refractive surgery in the future may incorporate advancements like gene
therapy, corneal inlays, and non-surgical options, with a circuitously approaching avenue of customization and
efficacy dependent on the patient