Skip Navigation
Wilmer Eye Institute
Print This Page
Share this page: More

Nearsightedness, Farsightedness and Astigmatism

Nearsightedness, Farsightedness and Astigmatism

Nearsightedness (myopia) is a very common condition in which the light coming into the eye is not focused properly onto the retina, making it difficult to see objects far away. The condition is usually caused by an elongation of the eyeball that occurs over time. Farsightedness (hyperopia) is the opposite of myopia, and is usually caused by shortening of the eyeball.

Astigmatism is an imperfection of the cornea preventing part of it from focusing light onto the retina. The result is a blurred area within an otherwise clear image. This problem may occur along with either myopia or hyperopia. These frequent conditions are termed "refractive errors."


The common method of measuring vision loss is the Snellen Test Chart, the familiar rows of increasingly smaller letters. Wilmer ophthalmologists also diagnose a decline in vision using refraction and retinoscopy and, when necessary, automated computerized devices.


Wilmer optometrists and ophthalmologists prescribe eyeglasses and contact lenses to compensate for most refractive errors. In addition, newer techniques actually change the curved shape of the cornea, causing it to focus light directly onto the retina, thus producing a clear image. The techniques performed at Wilmer include Automated Lamellar Keratectomy (ALK), Radial Keratotomy (RK), Excimer Laser Photo Refractive Keratectomy (PRK), and LASIK - a combination of ALK and excimer laser surgery currently undergoing investigation. Wilmer physicians participated in the development of the excimer laser, which they have used since 1990. With it, Wilmer physicians can remove a thin layer of the cornea to sculpt its shape to reduce or correct the refractive error. This new technique is approved for persons 18 years of age and older with specified types of nearsightedness.

In RK, the surgeon makes a series of incisions in the cornea, producing a spokelike pattern of cuts that flattens the tissue, causing light to be focused on the retina instead of in front of it. A 10-year, multicenter study of RK found that it safely and effectively reduces a person's dependence on eyeglasses or contact lenses.

> Treated by the Wilmer Optometry & Contact Lens ServiceLaser Vision Center, and
   Comprehensive Eye Service

Dr. Sheila West on the Link Between Smoking and Eye Disease in Women - 7/23/2014

Dr. Pradeep Ramulu and Colleagues Study Relationship Between Vision Loss and Work Status - 7/18/2014

Wilmer Resident Receives Lindstrom Research Grant - 7/11/2014

Four Wilmer Researchers Receive BrightFocus Foundation Awards - 7/10/2014

Dr. Michael Repka Part of Team Researching Telemedicine and ROP - 6/27/2014

Dr. M. Valeria Canto-Soler and Colleagues Featured on WBAL-TV - 6/24/2014

Dr. M. Valeria Canto-Soler and Colleagues Use Human Stem Cells to Create Light-Sensitive Retina in a Dish - 6/10/2014

Wilmer's Division of Ocular Immunology Announces "Living With Uveitis" Support Group - 6/10/2014

Dr. Neil Bressler to Speak on Diabetic Retinopathy at National Eye Health Summit and Webcast - 6/10/2014

Dr. Donald Zack Receives a Research to Prevent Blindness Nelson Trust Award for Retinitis Pigmentosa - 6/9/2014

Dr. Michael Boland Leads Study on Effectiveness of Automated Telecommunication-Based Reminders on Adherence to Glaucoma Medication Dosing - 6/4/2014

Dr. Christina Prescott Discusses Summer Eye Protection on Fox 45 News - 6/1/2014

Dr. Jonathan Song Discusses Treatment Options for Pediatric Cataracts - 5/23/2014

Johns Hopkins' Jordan Green Discusses His Work at Wilmer's Translational Tissue Engineering Center - 5/21/2014

Longtime Wilmer Employee Lillie Alston Honored by Hopkins - 5/19/2014

Dr. Richard Semba: Diets Rich in Antioxidant Resveratrol Fail to Reduce Deaths, Heart Disease or Cancer - 5/12/2014

Dr. Neil Miller Explains Eye Twitching in The Wall Street Journal - 5/12/2014

Dr. Hendrik Scholl Receives ARVO Award - 5/7/2014


Traveling for care?

blue suitcase

Whether crossing the country or the globe, we make it easy to access world-class care at Johns Hopkins.

U.S. 1-410-464-6713 (toll free)
International +1-410-614-6424



© The Johns Hopkins University, The Johns Hopkins Hospital, and Johns Hopkins Health System. All rights reserved.

Privacy Policy and Disclaimer