An estimated 40.9 million US adults wear contact lenses, mostly for correction of refractive errors, though decorative-colored contact lenses are used.
The major types of lenses are rigid (gas-permeable) and soft. Rigid lenses, which need to be removed each day, are more durable and easier to care for than soft lenses but are more difficult to tolerate. Soft lenses are also usually removed every day but are also available for extended wear. Soft lenses are usually renewed every 2 weeks or monthly. Daily disposable soft lenses are available and can be renewed daily.
Contact lens care includes cleaning and sterilization whenever the lenses are to be reused and removal of protein deposits as required. Sterilization is usually by chemical methods. For individuals developing reactions to preservatives in contact lens solutions, preservative-free systems are available.
The major risk from contact lens wear is corneal infection, potentially a blinding condition. Such infections occur more often with soft lenses, particularly extended wear, for which there is at least a fivefold increase in risk of corneal infection compared with daily wear. Decorative contact lenses have a high prevalence of microbial contamination. Contact lens wearers should be made aware of the risks they face and ways to minimize them, such as avoiding overnight wear or use of lenses past their replacement date and maintaining meticulous lens hygiene, including not using tap water or saliva for lens cleaning. Contact lenses should be removed whenever there is ocular discomfort or redness.
et al. Status of the effectiveness of contact lens disinfectants in Malaysia against keratitis-causing pathogens. Exp Parasitol. 2017 Dec;183:187–93.
et al. Risk behaviors for contact lens-related eye infections among adults and adolescents—United States, 2016. MMWR Morb Mortal Wkly Rep. 2017 Aug 18;66(32):841–5.
et al. Identification of microorganisms isolated from counterfeit and unapproved decorative contact lenses. J Forensic Sci. 2018 Mar;63(2):635–9.
et al. Trends and associations in hospitalizations due to corneal ulcers in the United States, 2002–2012. Ophthalmic Epidemiol. 2016 Aug;23(4):257–63.
AA. JAMA patient page. Proper care of contact lenses. JAMA. 2015 Oct 13;314(14):1534.
et al. Risk factors and causative organisms in microbial keratitis in daily disposable contact lens wear. PLoS One. 2017 Aug 16;12(8):e0181343.
Various surgical techniques are available to reduce refractive errors, particularly nearsightedness. Laser corneal refractive surgery reshapes the middle layer (stroma) of the cornea with an excimer laser. Laser assisted in situ keratomileusis (LASIK), including wavefront or topography-guided LASIK and femtosecond laser assisted LASIK (IntraLASIK, FEMTO-Lasik); refractive lenticule extraction (ReLEx), including femtosecond lenticule extraction (FLEx) and small incision lenticule extraction (SMILE); the surface ablation techniques epithelial LASIK (Epi-LASIK), laser epithelial keratomileusis (also known as laser-assisted subepithelial keratectomy) (LASEK), and photorefractive keratectomy (PRK); and corneal inlay implantation for presbyopia differ according to how the stroma is accessed and treated. LASIK is most commonly performed because postoperative visual recovery is rapid and there is little postoperative discomfort, but it is contraindicated if the cornea is relatively thin. Approximately 16 million procedures have been performed worldwide with greater than 90% patient satisfaction after primary surgery. However, outcomes for individual cases are not completely predictable. It has been reported that repeated treatment is required in up to 15% of patients and serious complications occur in up to 5%. Other refractive surgery techniques are extraction of the clear crystalline lens with insertion of a single vision, multifocal, or accommodative intraocular lens as occurs after cataract extraction; insertion of an intraocular lens without removal of the crystalline lens (phakic intraocular lens); intrastromal corneal ring segments (INTACS); collagen cross-linking; laser thermal keratoplasty; and conductive keratoplasty (CK).
et al. Fifteen years follow-up of photorefractive keratectomy up to 10 D of myopia: outcomes and analysis of the refractive regression. Br J Ophthalmol. 2016 May;100(5):626–32.
et al. Laser-assisted subepithelial keratectomy (LASEK) versus laser-assisted in-situ keratomileusis (LASIK) for correcting myopia. Cochrane Database Syst Rev. 2017 Feb 15;2:CD011080.
et al. Corneal refractive procedures for the treatment of presbyopia. Open Ophthalmol J. 2017 Apr 27;11:59–75.
et al. Modern laser in situ keratomileusis outcomes. J Cataract Refract Surg. 2016 Aug;42(8):1224–34.
et al. Refractive eye surgery: helping patients make informed decisions about LASIK. Am Fam Physician. 2017 May 15;95(10):637–44.
C. Reduction of Rate of Progression of Nearsightedness
Topical atropine and pirenzepine, a selective muscarinic antagonist; rigid contact lens wear during sleep (orthokeratology); and various types of soft contact lenses and spectacles reduce the rate of progression of nearsightedness, but their long-term efficacy and safety are uncertain.