Hyperopia

Overview

Hyperopia is a type of refractive error in which the point of focus is behind the retina because the cornea is too flatly curved, the axial length is too short, or both. In adults, both near and distant objects are blurred. Children and young adults with mild hyperopia may be able to see clearly because of their ability to accommodate.

Symptoms

The following symptoms can point to hyperopia:

  • Nearby objects may appear blurry
  • Eyestrain or discomfort
  • Headaches

Causes

In the normally refracted (emmetropic) eye, entering light rays are focused on the retina by the cornea and the lens, creating a sharp image that is transmitted to the brain. During accommodation, the ciliary muscles adjust lens shape to properly focus images. usually occurs when the axial length is too short due to abnormal shape of the eyeball. Instead of being focused precisely on the retina, light is focused behind the retina, resulting in a blurry appearance for nearby objects. Moreover, hyperopia may be due to the fact that the cornea is curved too steeply. Age-related hyperopia (presbyopia) is caused by a hardening of the lens.

Treatment

The goal of treatment is to compensate for the inability of your eyes to focus on nearby objects. Treatment options include wearing corrective eyeglasses or contact lenses, as well as undergoing refractive surgery.

Refractive surgery alters the curvature of the cornea to focus light more precisely on the retina. The goal of refractive surgery is to decrease dependence on eyeglasses or contact lenses.

The two most common refractive surgery procedures are femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) and Small Incision Lenticule Extraction (SMILE).

In Femto-LASIK, a surgeon separates a small flap of tissue from the cornea, using a femtosecond laser. The new profile of the cornea is created with a high-precision excimer laser so that light rays will be focused exactly on the retina. After changing the cornea surface, a flap of corneal tissue, which was separated in the first stage, is turned back. The flap is replaced without suturing. Because surface epithelium is not disrupted centrally, vision returns rapidly. Most people notice a significant improvement the next day.

In some cases, photorefractive keratectomy (PRK) is performed to correct hyperopia. In PRK, the corneal epithelium is removed and then the excimer laser is used to sculpt the anterior curvature of the corneal stromal bed. The epithelium typically takes 3 to 4 days to regenerate. PRK may be more suitable for patients with thin corneas or anterior basement membrane dystrophy.