Refractive errors are the problems in focusing objects,either near or far-off distances. This is due to the abnormal size and curvature of the eye ball . This is quite a common problem.TYPES OF REFRACTIVE ERRORS1.Myopia or near-sightedness:Persons of Myopia have a blurred distant vision.Complaint of Hazy visionComplaint of headache, while doing near vison workConstant blinking of eyes as an effort to view the blackboardChillden viewing the T.V . at close distances in small roomsChildren finding difficulty to see blackboard and thus dull in studies2.Hypermetropia (Far-sightedness)Persons with Hypermetropia have difficulty in seeing both the distant and near objects. The condition can be overcome wearning convex lenses (Plus Power).3.AstigmatismIn a person with such a defect , a blurred distorted image falls on the retina at different angles. It results in strain for the person in viewing objects. This defect can be corrected by wearing cylindrical lenses, with axis of required degrees.4.PresbyoplaGenerally after the age of 40, a person may find it difficult to see near objects clearly. This is because the elasticity of the lens gradually decreases due to the age. Spectacles of requisite power can correct this defect . Bi-focal glasses with distance vision and near vision may be necessary in many cases.There are different types of bifocal lenses like kryptok, `D Base glasses and the transitional progressive glasses which almost guarantees 100% vision without distortion.