The term refraction means to bend light. Your optometrist will use several methods to bend or change the direction of light coming from a distant object, to focus accurately on the retina by introducing different lenses before your eyes. When this is achieved, vision will be clearest. This results in the prescription for your spectacles or contact lenses. Refraction can only be accurate if the letter chart is at least 6 meters or 20 feet away from the patient. Any shorter, and the accuracy drops. To save space, most practitioners will use a mirror to double the distance.
What is Diabetic Retinopathy? Diabetic retinopathy is the leading cause of blindness in the world. If you are suffering from diabetes, it is important that your blood sugar level is controlled. You should also have a dilated eye exam by an ophthalmologist at least once a year.
Visual Field Analysis
Visual Field testing is an important diagnostic tool in the assessment of the eye’s visual fields. A normal visual field as measured from the central fixation point is 90 degrees temporally, 50 degrees nasally, 50 degrees superiorly and 60 degrees inferiorly. Many eye conditions can cause a narrowing of the field of vision, examples are Retinitis Pigmentosa, Glaucoma, etc. Other conditions for example Macular degeneration will only affect central vision. Even space occupying lesions, for example tumors in the brain may cause abnormal patterns in the visual fields.
Optical Coherence Tomography
Optical Coherence Tomography Analysis is much like Ultra-Sound, except that it uses light instead of sound. This instrument is able to make 3-dimensional images of the Retina. The layers that make up the retina are easily visualized, the location of any abnormalities within the retina can then be identified. Eye conditions, for example Central Serous Retinopathy, Glaucoma may be diagnosed and monitored.
Cerium Precision Tinted Lenses
Have you ever looked at a pattern for example on a carpet and the pattern seems to be doing strange things like vibrating or seems to be moving. To some, Lines of text on a page can produce a similar illusion. . Patients describe he text as moving, lines going through the text,. reading is more comfortable in low light,. Even headaches have been reported. This results in slow readers as the illusion is distracting. This is call perceptual distortion.
Glaucoma presents in many forms. Most common are open and closed angle Glaucoma. Intraocular Pressure (IOP) in excess of 21mmhg, is a sign that requires close monitoring. Observation of the optic nerves is a must during any eye examination as low IOP can also result in Glaucoma.