Hyperopia or hypermetropia, commonly known as farsightedness or longsightedness, is an abnormal eye condition whereby there is better visual acuity for objects in the distance than nearby. This results when incoming light rays enter the eye and converge behind the retina to create a blurred object, instead of converging directly on the retina to create a focused object.
Depending on the severity of hyperopia, an individual may experience a great number of symptoms to none at all. In extreme cases, close up and distant vision is impaired, where all objects are blurry. Other times objects are only out of focus for nearby objects. Headaches, aching eyes, burning, and eyestrain are the most common symptoms, especially when looking at objects up close. Children do not usually experience many symptoms.
Light rays and light particles entering the eye are converged at a point posterior to the retina while accommodation is maintained in a state of relaxation. The magnitude of hyperopia is determined by the diopteric power of converging lenses required to advance the focal point of light onto the retinal plane.
Physiologic (Simple and Functional) hyperopia is much more common than pathologic hyperopia. Decreased axial length is the most common etiology for hyperopia. Overall prevalence of hyperopia is around 10%, approximately 14 million people, in the United States. Most full-term infants are mildly hyperopic. By age 6-9 months approximately 4-9% of infants are hyperopic and by age 12 months the prevalence is approximately 3.6%. Infants with moderate to high hyperopia (greater than +3.50D) are up to 13 times more likely to develop strabismus by age 4 if left uncorrected.