Eye exams and sight test



Some optical stores offer sight tests, which often rely on automated machinery to generate a record from which to dispense glasses. However, the accuracy of a sight test is limited, and the sight test itself may also not be performed by a trained and licensed professional. 

Furthermore, these tests completely overlook many serious eye or health problems and diseases, as the eye itself is not examined during a sight test. Many serious conditions do not blur a person’s vision, or only do so once the disease is more advanced. Some of the eye and health conditions that cannot be detected through a sight test include: 

     • Glaucoma: a progressive eye disease affecting the optic nerve (a structure that connects the eye to the brain) and which can lead to permanent vision loss if not detected and treated
     • Diabetic retinopathy: a weakening or swelling of the tiny blood vessels in the retina, and sometimes the growth of new blood vessels. If diabetic retinopathy is left untreated, blindness can result
     • Tumors of the brain or eye (whether cancerous or benign)
     • High blood pressure, which can lead to stroke, heart attack, and other health problems
     • Retinal detachment: a condition where the retina partially or completely peels away from the back of the eye. Once it is detached, the retina stops working and light signals cannot get back to the brain to be processed. To the patient, some degree of vision loss occurs. Depending on the severity of the detachment, vision loss can be severe and permanent


What is a comprehensive eye exam?

An eye exam performed by an optometrist looks at the entire eye health and visual system, as well as your prescription. It is an important part of preventative health care: think of an eye exam as a physical for your eyes. Eye exams can detect eye diseases and disorders such as glaucoma, cataracts, retinal detachment, and macular degeneration.  It can also detect other health problems such as diabetes, high blood pressure and brain tumors. 

An optometrist may use automated computerized instruments to provide an estimate of the prescription prior to providing a more detailed refraction; however, they use their extensive training and experience, together with professional judgment, to direct the testing and interpret the results. Only on this basis can an accurate optical prescription be determined and customized to the patient’s visual needs. 

An eye exam includes: 

     • A case history, including past and present vision and medical issues, as well as a detailed family history.
     • An analysis of the patient’s visual needs at home, work, school and play
     • Measurement of the visual acuity (sharpness of vision) of each eye 
     • Binocular vision assessment: determining how well the eyes work together  
     • Diagnosis of the refractive status of the eye (focusing power of the eye)   
     • Eye health check: assessment of the internal and external health of the eye with specially designed instruments to uncover anything from a minor lid inflammation to a major retinal disease, or even a serious condition elsewhere in the body.
     • A neurological assessment of the visual system, including a review of the pupil reactions, eye muscle movement, and an assessment of the peripheral vision.

All of these tests are used in the final analysis to determine the appropriate prescription lenses to treat refractive and visual problems, to develop a program of eye training exercises, or to recommend medical or surgical treatment. Recommendations for future eye care can be made based on the history of eye health and the results of the examination.  The final analysis of the eye exam includes an optometrist’s professional knowledge, training, experience and judgment.


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