ABO advance study guide Questions with Correct Solutions Rated A+

When taking seg height measurements, which of the following situations could result in a parallax error? - Patient sitting/ dispenser standing erect Which of the following is not significant in identifying the problem of vertical imbalance? - Patient's age Which of the following elements is NOT critical when determining vertical imbalance? - Lens power in the 180 degree meridian A prism will displace the object being viewed towards its ________. - Apex A prism will bend light towards its _______. - Base When dealing with problems of vertical imbalance which is the critical meridian of total lens? - 90 Which of the following prescriptions would pose the greatest prismatic imbalance at a reading depth of 10mm? - OD +2.50 OS -0.25 +2.50 x 090 A plus lens moved downward from the primary position will result in: - Base down prismatic effect What is a hereditary pigmentary degeneration of the retina called which results in gradual loss of peripheral vision? - Retinitis pigmentosa What is ocular hypertension? - Elevation of pressure in the eye above the range considered with an detectable changes in vision or damage to the structure of the eye. or Eye pressure can be elevated and cause damage in some eyes, but no damage in others. Which of the following statements is false regarding corneal ulcers? Corneal ulcers can be ________. - of little concern Approximately what percentage of humans have some alterations in lens transparency after age 65? - 60% What type of cataract is a fully developed opacity of the lens with fluid generation and swelling of the lens volume? - Hypermature Which of the following statements is false regarding cataracts? - Cataracts will only form in the nucleus of the lens. ________ is the condition in which both eyes have equal refractive power. - Insometropia Irregular astigmatism occurs when the principal meridians are not uniform along a major meridian and not uniform along a meridian. They are found at some place other than 90 degree apart. Irregular astigmatism is commonly caused by trauma surgery, or corneal dystrophy. TRUE or FALSE - True In poor light, a person sees red light better than blue, which is why the ocular system tends to be more myopic, i.e. twilight myopia. TRUE or FALSE - True _______ are _____ cells that detect motion within a field. - Rods-Long The crystalline lens is the same size at birth as in an adult, however, it adds cell layers throughout life, packing them in which makes the crystalline lens harder and is one of the causes of presbyopia. TRUE or FALSE - False The triangular structure between the choroid and root of the iris, containing the ciliary epithelium, stroma, and ciliary muscle is the: - Ciliary body There are 5 layers of the cornea. They are: - From most anterior to posterior. Epithelium-Bowman's Layer- Stroma- Descemet membrane- Endothelium The refractive index of the cornea is: - 1.376 The most powerful refracting medium of the eyes optical system is the cornea. There are five layers of the cornea, each having a unique purpose and cell structure. One of the requirements of clear vision is that the cornea ________. - must remain transparent and must have regular cell structures of all layers. Polarized filters are made by stretching thin sheets of __________ in one meridian. - Polyvinyl alcohol Visible glare can be dangerous because it can not only wash out colors, but in some instances, can cause _________. - Photokeratitis Features and benefits of Trivex include __________. - Superior optics Impact Resistant Ultra-lightweight What is the index of refraction of Trivex? - 1.53 What is the index refraction of polycarbonate? - 1.59 What company introduced CR-39 lenses? - PPG industries __________ are generally inorganic materials (metals or minerals) that are vacuum deposited to add color on glass lenses to give a uniform density of color on the lenses. - Vacuum color coating Glare is of more concern to which wearer? - Cataract patients _______ is better than ______ for improving contrast? - Green-Gray _______ added to any color increases contrast. - Yellow Although this may be the most popular color for sun lenses, it is not recommended for patients with emerging cataracts. - Gray Given a high plus or high minus RX, which lens material would offer the best choice for uniform density in sun lenses? - CR-39 & Trivex A Characteristic of a dark tinted glass lens with an RX of +4.00 SPH would be _________. - Darker in the center and lighter on the edge If a person has exposure to sunlight at least 2 hours or more during the day, __________. - their ability to adapt to night vision is compromised if they don't protect their eyes from the sun exposure. Standard transmission is sun lenses should range between _________. - 15% to 30% The denser the tint in a lens, __________ - the less transmission of light through the lens. The absorption of light in lenses is classified by two variables. What are they? - Tint & lens transmission Aphakia - An absence of the crystalline lens of the eye (pseudophakia: having a false lens) Apex - Thinnest edge of a prism. Anterior - front cavity or compartment of the eye, located between the cornea and CHAMBER: crystalline lens contains the aqueous humor. Anisometropia - Condition in which the refractive error of one eye significantly differs from that of the other. OD -1.00 OS -2.25 or OD +1.00 OS +2.25 Aniseikonia - A condition in which the ocular image of an object as seen by one eye differs so much in size or shape from that seen by the other eye that the two images cannot be fused into a single impression. Unequal size of retinal images. Ametropia - A refractive error in which the eye, when in a state of rest, does not focus the image of an object upon the retina; includes "hyperopia, myopia, & astigmatism.