Ocular Conditions: Presbyopia Myopia Hyperopia Astigmatism
Myopia, or nearsightedness, is a refractive defect of the eye in which collimated light produces image focus in the front of the retina when accommodation is relaxed.
Those with myopia typically can see nearby objects clearly but distant objects appear blurred. The opposite defect of myopia is hyperopia or “far-sightedness” or “long-sightedness” – this is where the cornea is too lat or the eye is too short. Mainstream ophthalmologists and optometrists most commonly correct myopia through the use of corrective lenses, such as glasses or contact lenses. It may also be corrected by refractive surgery, such as LASIK or with Corneal Refractive Therapy (CRT).
Farsightedness, or hyperopia as it is medically termed, is a vision condition in which distant objects are usually seen clearly but close ones do not come into proper focus. Farsightedness occurs if your eyeball is too short or if the cornea has too little a curvature. This causes light entering your eye to focus incorrectly. Common signs of farsightedness include difficulty in concentrating and maintaining a clear focus on near objects, eye strain, fatigue and/or headaches after close work, aching or burning eyes and irritability or nervousness after sustained concentration. Hyperopia is usually present at much younger ages than myopia (nearsightedness) and is often easily overlooked in young children. Uncorrected hyperopia can be a cause of some poor academic performance and some behavior problems in children.
Astigmatism is a vision condition that occurs when the front surface of your eye, the cornea, is slightly irregular in shape. This irregular shape prevents light from focusing properly on the back of the eye, the retina. As a result, your vision may be blurred at all distances.
People with severe astigmatism will usually have blurred or distorted vision, while those with mild astigmatism may experience headaches, eyestrain, fatigue or blurred vision at certain distances. Almost all levels of astigmatism can be optically corrected with properly prescribed and fitted eyeglasses and/or contact lenses. Corneal modification, such as CRT or LASIK eye surgery may also be an effective treatment option for some patients