Related Research Articles
Far-sightedness, also known as long-sightedness, hypermetropia, and hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred. This blur is due to incoming light being focused behind, instead of on, the retina due to insufficient accommodation by the lens. Minor hypermetropia in young patients is usually corrected by their accommodation, without any defects in vision. But, due to this accommodative effort for distant vision, people may complain of eye strain during prolonged reading. If the hypermetropia is high, there will be defective vision for both distance and near. People may also experience accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus. Newborns are almost invariably hypermetropic, but it gradually decreases as the newborn gets older.
LASIK or Lasik, commonly referred to as laser eye surgery or laser vision correction, is a type of refractive surgery for the correction of myopia, hyperopia, and an actual cure for astigmatism, since it is in the cornea. 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.
Eye surgery, also known as ophthalmic surgery or ocular surgery, is surgery performed on the eye or its adnexa. Eye surgery is part of ophthalmology and is performed by an ophthalmologist or eye surgeon. The eye is a fragile organ, and requires due care before, during, and after a surgical procedure to minimize or prevent further damage. An eye surgeon is responsible for selecting the appropriate surgical procedure for the patient, and for taking the necessary safety precautions. Mentions of eye surgery can be found in several ancient texts dating back as early as 1800 BC, with cataract treatment starting in the fifth century BC. It continues to be a widely practiced class of surgery, with various techniques having been developed for treating eye problems.
Radial keratotomy (RK) is a refractive surgical procedure to correct myopia (nearsightedness). It was developed in 1974 by Svyatoslav Fyodorov, a Russian ophthalmologist. It has been largely supplanted by newer, more accurate operations, such as photorefractive keratectomy, LASIK, Epi-LASIK and the phakic intraocular lens.
Refractive surgery is optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea (keratomileusis), lens implantation or lens replacement. The most common methods today use excimer lasers to reshape the curvature of the cornea. Refractive eye surgeries are used to treat common vision disorders such as myopia, hyperopia, presbyopia and astigmatism.
Phacoemulsification is a cataract surgery method in which the internal lens of the eye which has developed a cataract is emulsified with the tip of an ultrasonic handpiece and aspirated from the eye. Aspirated fluids are replaced with irrigation of balanced salt solution to maintain the volume of the anterior chamber during the procedure. This procedure minimises the incision size and reduces the recovery time and risk of surgery induced astigmatism.
An Intraocular lens (IOL) is a lens implanted in the eye usually as part of a treatment for cataracts or for correcting other vision problems such as short sightedness and long sightedness, a form of refractive surgery. If the natural lens is left in the eye, the IOL is known as phakic, otherwise it is a pseudophakic lens. Both kinds of IOLs are designed to provide the same light-focusing function as the natural crystalline lens. This can be an alternative to LASIK, but LASIK is not an alternative to an IOL for treatment of cataracts.
This is a partial list of human eye diseases and disorders.
A phakic intraocular lens (PIOL) is a special kind of intraocular lens that is implanted surgically into the eye to correct myopia (nearsightedness). It is called "phakic" because the eye's natural lens is left untouched. Intraocular lenses that are implanted into eyes after the eye's natural lens has been removed during cataract surgery are known as pseudophakic.
Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye that has developed a cataract, an opaque or cloudy area. The eye's natural lens is usually replaced with an artificial intraocular lens (IOL) implant.
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at night. Astigmatism often occurs at birth and can change or develop later in life. If it occurs in early life and is left untreated, it may result in amblyopia.
Epikeratophakia is a refractive surgical procedure in which a lamella of a donor cornea is transplanted onto the anterior surface of the patient's cornea. A lamellar disc from a donor cornea is placed over the de-epithelialized host cornea and sutured into a prepared groove on the host cornea. Indications include treatment of keratoconus, refractive errors like myopia and high hypermetropia including aphakia, which cannot be corrected with conservative methods.
Pellucid marginal degeneration (PMD) is a degenerative corneal condition, often confused with keratoconus. It typically presents with painless vision loss affecting both eyes. Rarely, it may cause acute vision loss with severe pain due to perforation of the cornea. It is typically characterized by a clear, bilateral thinning (ectasia) in the inferior and peripheral region of the cornea, although some cases affect only one eye. The cause of the disease remains unclear.
Blurred vision is an ocular symptom where vision becomes less precise and there is added difficulty to resolve fine details.
The eye, like any other optical system, suffers from a number of specific optical aberrations. The optical quality of the eye is limited by optical aberrations, diffraction and scatter. Correction of spherocylindrical refractive errors has been possible for nearly two centuries following Airy's development of methods to measure and correct ocular astigmatism. It has only recently become possible to measure the aberrations of the eye and with the advent of refractive surgery it might be possible to correct certain types of irregular astigmatism.
Iris-fixated intraocular lens is an intraocular lens that is implanted surgically into the eye and attached to the iris. Originally developed for aphakia, phakic versions have also been produced to correct myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. They are suited for correction of eyes where corneal refractive surgery is not applicable.
Phacolytic glaucoma (PG) is a form of glaucoma which is caused due to a leaking mature or immature cataract. Inflammatory glaucoma which occurs in phacolysis is a condition which is a result of the leakage of protein within the lens into the capsule of a mature or hyper mature cataract and involves a simple procedure to be cured that is referred to as cataract extraction.
Secondary glaucoma is a collection of progressive optic nerve disorders associated with a rise in intraocular pressure (IOP) which results in the loss of vision. In clinical settings, it is defined as the occurrence of IOP above 21 mmHg requiring the prescription of IOP-managing drugs. It can be broadly divided into two subtypes: secondary open-angle glaucoma and secondary angle-closure glaucoma, depending on the closure of the angle between the cornea and the iris. Principal causes of secondary glaucoma include optic nerve trauma or damage, eye disease, surgery, neovascularization, tumours and use of steroid and sulfa drugs. Risk factors for secondary glaucoma include uveitis, cataract surgery and also intraocular tumours. Common treatments are designed according to the type and the underlying causative condition, in addition to the consequent rise in IOP. These include drug therapy, the use of miotics, surgery or laser therapy.
Manual small incision cataract surgery (MSICS) is an evolution of extracapsular cataract extraction (ECCE); the lens is removed from the eye through a self-sealing scleral tunnel wound. A well-constructed scleral tunnel is held closed by internal pressure, is watertight, and does not require suturing. The wound is relatively smaller than that in ECCE but is still markedly larger than a phacoemulsification wound. Comparative trials of MSICS against phaco in dense cataracts have found no difference in outcomes but MSICS had shorter operating times and significantly lower costs. MSICS has become the method of choice in the developing world because it provides high-quality outcomes with less surgically induced astigmatism than ECCE, no suture-related problems, quick rehabilitation, and fewer post-operative visits. MSICS is easy and fast to learn for the surgeon, cost effective, simple, and applicable to almost all types of cataract.
Clear lens extraction (CLE), also known as refractive lensectomy or refractive lens exchange (RLE) is a surgical procedure in which clear lens of the human eye is removed. Unlike cataract surgery, where cloudy lens is removed to treat cataract, clear lens extraction is done to surgically correct refractive errors such as high myopia. It can also be done in hyperopic or presbyopic patients who wish to have a multifocal IOL implanted to avoid wearing glasses. It is also used as a treatment for diseases such as angle closure glaucoma.
References
- 1 2 3 4 5 6 7 8 Khurana, AK (2015). "Errors of refraction and accommodation". Comprehensive ophthalmology (6th ed.). Jaypee, The Health Sciences Publisher. pp. 37–38. ISBN 978-93-86056-59-7.
- ↑ Mary V Gibbens; R Goel; S E Smith (1989). "Effect of cataract extraction on the pupil response to mydriatics". British Journal of Ophthalmology. 73 (7): 563–565. doi:10.1136/bjo.73.7.563. PMC 1041802 . PMID 2757997.
- ↑ Alpar, John (1 April 1989). ""Present state of management of aphakia. Future of spectacles and contact lenses"". Indian Journal of Ophthalmology. 37 (2): 54–57. ISSN 0301-4738. PMID 2583777.
- ↑ "Congenital primary aphakia". rarediseases.info.nih.gov.
- ↑ R M Anderson (1983). "Visual perceptions and observations of an aphakic surgeon". Perceptual and Motor Skills. 57 (3_suppl): 1211–1218. doi:10.2466/pms.1983.57.3f.1211. PMID 6664798. S2CID 20005737.
- ↑ David Hambling (29 May 2002). "Let the light shine in". The Guardian.
- 1 2 Textbook of ophthalmology Vol 1. Agarwal, Sunita. New Delhi, India: Jaypee Bros. Medical Publishers. 2002. ISBN 978-81-7179-884-1. OCLC 49561947.
{{cite book}}: CS1 maint: others (link) - 1 2 3 Ramanjit, Sihota; Radhika, Tandon (2015). Parsons' diseases of the eye (22nd ed.). New Delhi, India: Elsevier. ISBN 978-81-312-3819-6. OCLC 905915528.
- ↑ Sowka, Joseph W. (November 2002). "Pupil block glaucoma from traumatic vitreous prolapse in a patient with posterior chamber lens implantation". Optometry (St. Louis, Mo.). 73 (11): 685–693. ISSN 1529-1839. PMID 12516797.
- ↑ Ophthalmology. Yanoff, Myron,, Duker, Jay S., 1958- (5th ed.). Edinburgh: Elsevier. 2019. ISBN 978-0-323-52821-4. OCLC 1051774434.
{{cite book}}: CS1 maint: others (link) - ↑ aphakia at Wiktionary https://en.wiktionary.org/wiki/aphakia
- ↑ aphakia. (n.d.) Farlex Partner Medical Dictionary. (2012). Retrieved April 13, 2016 from http://medical-dictionary.thefreedictionary.com/aphakia