Lazy eye is a common term for the condition amblyopia, a decrease in central vision due to abnormal visual stimulation of one or both eyes. Amblyopia is not related to an eye health condition and cannot be corrected with prescription lenses. The condition usually develops prior to age 6, and is often associated with crossed-eyes or a large … [Read more...]
How to Help Your Patient Get the Best Vision From a Magnifier Anyone working with low vision patients is familiar with the statement, “I have a drawer full of magnifiers and none of them work”. To help these patients, you have to understand three optical principles that apply to magnification: Translation of “x power” to … [Read more...]
The term, daltonism has its origin from British chemist and physicist, John Dalton (1766-1844) who is best known for his work as an early proponents of the Atomic Theory. It seems that John and his brother shared a common vision problem-they were red-green color deficient, which inspired Dalton to publish his first scientific paper, … [Read more...]
A scotoma (Greek for darkness) is an area of diminished or absent retinal sensitivity. It is most commonly referred to in visual field test interpretations. A defect in which no light is seen in the affected area is referred to as an absolute scotoma. If the test shows that the patient cannot view the dimmest light presented during testing, … [Read more...]
This is pretty cool- EyeTrain4You is now offering online interactive optican study flashcards. Over 700 of these cards are currently available with Rebecca Johnson planning on introducing more in the future. You can test a live demo on the site. Even though I am not an optician, I got 2 right!! There are 40 categories available from basic to … [Read more...]
Have you ever seen “stars before your eyes”? Seeing stars before the eyes does not only happen in cartoons. The experience of seeing light without light actually entering the eye is a medical phenomenon that has been discussed since the days of Isaac Newton. These lights are known as phosphenes (from the Greek phōs light + phainein to … [Read more...]
The Crowding Phenomenon is a term used to describe difficulty or inability to discriminate visual acuity chart letters when they are presented next to each other in a row. Although this phenomenon may be experienced by anyone, it is most often characteristic of patients with amblyopia. Amblyopia is a relatively common vision disorder that occurs … [Read more...]
According to the National Onion Association sulphuric compounds are released into the air from a cut onion, irritating the eye and causing it to tear. Their advice to reduce tearing: first chill the onions for 30 minutes and then cut off the top and peel the outer layers leaving the root end intact. (The root end has the highest concentration … [Read more...]
Contrary to what you might have heard on the playground as a kid, you do not close your eyes when you sneeze to keep them from rolling out of your head. The best explanation I could find came from an article in The Boston Globe: ''It is unclear, but scientists theorize that we close our eyes to protect them. We may be protecting our eyes from … [Read more...]
Just when you think that you have seen it all or heard it all. We close at 5:30. So, you all know the feeling when you have the patient or customer coming through the door at 5:20… This fellow comes in with the pair of glasses he picked up a few days ago and says he has been unable to wear them since he picked them up because, “When he … [Read more...]
Stereopsis refers to our ability to appreciate depth, or to distinguish the physical distance between objects. Without depth perception it is difficult to pour water into a glass from a pitcher, appreciate a 3D movie and parallel park a car. An Example: The Stereo Fly Test from Stereo Optical is used to evaluate both gross and fine stereo … [Read more...]
Have you ever heard of couching? The word causes me to see a visual image of my husband on Sunday afternoon during football season, but couching also has an ophthalmic connotation. It is the term used to describe an early cataract removal procedure in which a sharp instrument was inserted posterior to the limbus and with a downward movement the … [Read more...]
Technician Talk Color-Coded Caps: Help or Hindrance? In 1996 the Academy of Ophthalmology (AAO) published a Policy Statement endorsing the uniform use of a color-coding system for the caps and labels of topical ocular medications with an objective to help patients distinguish between various medications, thereby minimizing the risk of patients … [Read more...]
Can dogs see color? A study conducted at the University of California, Santa Barbara by Jay Neitz, tested the color vision of dogs. Neitz confirmed that dogs actually do see color, but many fewer colors than normal humans do. Test of color matching indicate that the dog retina contains two classes of cone photoreceptors with spectral peaks of … [Read more...]
Patients with cataracts often describe their vision as “foggy” or “like looking through a frosted window”. The term “cataract” is derived from the Latin, “cataracta” which means “waterfall” and the Greek” katarhaktes” which means "waterfall, broken water; swooping, rushing down”. In Latin, cataracta had the … [Read more...]
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