Eye disorders are problems with visual acuity that can be corrected with the use of eye glasses or contact lenses. Not to be confused with eye diseases like cataracts and glaucoma, eye disorders happen when the eyes of a person have trouble focusing light rays through the cornea to the retina, which results to blurred vision. Refractive errors can be measured using an ophthalmic instrument called an autorefractor or a phoropter, from which data the optometrist or optician would give a prescription for corrective lenses that would allow the patient their best visual acuity. These types of ophthalmic equipment are found in most any modern optician’s clinic.
Common eye disorders include myopia or near-sightedness. People with myopia may have narrow eyeballs that make the light rays bouncing off from the object being viewed focused in front of the retina instead of onto it. This result to blurred images of objects that are far away from the receiver and a clearer view of objects that are near. Some types of myopia include simple myopia, which is the most common among those suffering near-sightedness. Degenerative myopia is a malignant kind of near-sightedness that progresses to visual impairment or blindness.
Another refractive error is hyperopia or far-sightedness, where distant objects are clearer than those that are closer to the receiver. Hyperopia is a condition that results from the fact that the eyeballs may be too short or the lenses not round enough and light rays focus behind the retina instead of on it.
If the cornea gets distorted into a football or doughnut shape instead of the original circle, light rays entering the eyes scatter as they are refracted. This condition is called astigmatism, and people suffering from this refractive disorder are unable to see fine details, whether close or far away.
A refractive disorder that is similar to hyperopia is presbyopia, which is actually a natural occurrence that occurs with old age. Starting when a person is about forty to fifty years of age, presbyopia is actually the weakening of the eye’s capacity to focus on near objects. People with myopia, however, rarely suffers from presbyopia.
To diagnose and measure a person’s refractive disorder, there are several ophthalmic equipment that can be used to see how light rays enter the eyes through the cornea. The auto refractor is commonly used to measure visual defect, along with a phoropter, where the optometrist or the optician would ask the patient to try on several lenses in order for them to know which one would be most comfortable and provide them with best corrected vision. Retinoscopes are sometimes used for more accurate measurements and even for the diagnosing of latent hyperopia. Astigmatism can be detected by using a keratometer or ophthalmometer, which measures the curvature of the cornea.
Once the refractive disorder of the patient is detected, they will be fitted for glasses or contact lenses that would focus light rays on the retina for a clear image of the object being viewed. Another method for correcting eye defects is refractive surgery or laser eye surgery like LASIK or PRK. Ocular surgery entails the use of a laser to reshape the cornea and give back best vision to the patient.
For near-sighted people, glasses with convex lenses could be worn to focus light on a closer range and give them best corrected vision. On the other hand, concave lenses are used to correct myopic vision. To fill out the eyeglass prescription given out by an optometrist, an optician uses a lensometer to measure the dioptric power of the lenses going to be used for the eyeglasses. The dioptric power of a lens is the measurement of the amount that a lens can converge or diverge light and an accurate measurement of it can be taken using a vertometer. This ophthalmic equipment can be used to choose the best lenses to correct the patient’s refractive disorder and the best way to mount it for prescription glasses.
Regular eye examinations are also recommended for people with eye disorders in order to monitor the refractive errors and manage possible progression.
