Lens used to treat myopia is
Ans. b (Concave). (Ref. Parson, Diseases of Eye, 18th/pg.65)MYOPIA (SHORT SIGHTEDNESS)# Most common is axial myopia# Clinically simple myopia is most common# If refractive error is > -6D, called high myopia, in which axial length is usually > 26 mm.# Pathological or degerative myopia is characterized by progressive AP elongation of the scleral envelope associated with secondary ocular changes (pale tessellated or tigroid fundus, focal chorioretinal atrophy, Lacquer cracks, Lattice degeneration, Foster-Fuch's spots and staphyloma), maculopathy and Retinal detachment.# Treatment- Optical-Concave lenses- Surgicala) Radical keratotomyb) Keratophakiac) Keratomileusisd) LASIK (Laser assisted in-situ Keratomileusis)e) Fukala's operationf) Scleroplasty- Minus IOL- Excimer LASER (Photorefractive keratoplasty/PRK)- Indications for LASIK:a) Stable refractive errorb) Age > 21 yearsc) Unsatisfactory result of non-surgical treatment
Convex
Concave
Cylindrical
Any of the above
Errors of Refraction