Ophthalmic Optics Quiz - Physics Trivia

Veiling glare refers to the phenomenon where unwanted light scatters within an optical system, reducing the clarity and contrast of the image formed on the retina. This scattering of light can lead to a decrease in the resolution of the image, making it appear less sharp and defined. Therefore, the statement that veiling glare causes a reduction in image resolution and a decrease in contrast of the retinal image is true.

Scratches on the back surface will reduce impact resistance more than on the front. Front = 20% decrease, back = 80% decrease

Option 4: The test setups are different: High mass is a pointed 1 inche diameter projectile dropped from a height of 51.2 inches onto a frame mounted face up. High velocity test is a series of steel balls traveling at 150ft/sec directed at 20 points o the frame

If the reading level is below the OC (Optimal Challenge), then the state of being bored and unengaged (BU) and the state of being disinterested (BD) are induced. If the reading level is above the OC, then the state of being bored and unengaged (BU) and the state of being overwhelmed (BD) are induced.

The explanation for the given correct answer is that all lenses, except for certain types such as laminated glass, non-prescription lenses, and raised edge multifocal lenses, must be tested for impact resistance. These exceptions can be tested through statistical sampling from each production batch. Therefore, the statement "All lenses must be tested for impact resistance" is true.

Option 2: As the patient's add power increases, the near working distance DECREASES

Individuals with reduced capacity to withstand ocular trauma, prior surgeries, injuries, HIGH myopes

Lateral protection must be 10 mm behind the corneal vertex. This means that any protective equipment or devices should be positioned at a distance of 10 mm behind the corneal vertex in order to provide adequate protection to the eye. This is important to prevent any potential injuries or damage to the cornea and surrounding structures.

In multifocal lenses, a fused multifocal segment has a higher index of refraction than the distance carrier, contrary to the false statement that it's lower. Custom-made lenses with a small segment glued to the distance lens are known as cement lenses. In one-piece multifocal, the change in power is due to a difference in surface curvature, and the segment can be felt, whereas in fused multifocal, the segment is embedded and cannot be felt.

Lenses with indexes of refraction greater than crown glass bend light more, causing the lens clock to measure a smaller power than the true power, hence underestimating the true lens power. On the other hand, lenses with indexes of refraction less than crown glass bend light less, causing the lens clock to measure a larger power than the true power, hence overestimating the true lens power.

The linear field of fixation through a segment increases as the segment diameter and viewing distance increases because a larger segment diameter and greater viewing distance allow for a wider range of vision. On the other hand, the linear field of fixation decreases as the vertex distance increases because a greater vertex distance narrows the field of vision.

The statement "The image jump decreases the farther the segment OC is away from the top of the segment line" is false. Instead, image jump increases as the distance between the segment OC and the top of the segment line grows, leading to a more noticeable prismatic effect and image displacement. Image jump results from the prismatic effect at the line between the carrier lens and the segment, and differential displacement of light at the top of the segment creates an apparent scotoma. If the reading level is not coincident with the segment OC, image displacement occurs due to prismatic displacement.

Much of the light in the UV and IR regions of the spectrum that strikes the eye never reaches the retina. Instead it is absorbed by the cornea, aqueous humor, crystalline lens, or vitreous humor of the eye.

Option 5: That should be glasses

Glass is weakened more by scratching than CR-39. This means that when glass is scratched, it is more likely to experience a decrease in strength or durability compared to CR-39. This suggests that CR-39 is more resistant to scratches and therefore has a higher level of durability when it comes to scratching.

Option 1 - should read: AR coatings are a number of thin optical coatings applied to BOTH surfaces of the lens to reduce reflections

Option 3 and 4- refers to polarized lenses

It can only be done on crown glass

The "B" dimension is not a safety frame marking requirement. The other options listed, such as DBL (distance between lenses), manufacturer's identifying trademarks, "Z87" for 3.0mm thickness lenses - basic impact lenses, and "A" dimension, are all safety frame marking requirements. The "B" dimension is not mentioned as a requirement in the given options.

Option A: Basic impact = drop ball: 1 inch steel ball from a height of 50 inches, need to be minimum of 3.0mm thick
Option D: High impact lenses must be a minimum of 2.0mm thick

The optical performance of bifocals is not dependent on the overall lens thickness. The overall lens thickness refers to the physical thickness of the bifocal lens, which does not affect the optical performance of the lens. Optical performance is primarily determined by factors such as image jump at the seg top, image jump at the reading level, chromatic aberration, and total displacement at the reading level.

Glass photochromic lenses contain silver halide - when activated by UV, the silver halide breaks into silver and halogen.

According to our notes Dr. Y listed Photokeratitis and Pterygia as effects of UV absorption. Option B. Should read Increased temperature on tissue causes denaturation of proteins

Option A. The statement is true for glass BUT plastic may be tested in uncut-finished form Option C. That describes safety lenses, dress lenses have no minimum thickness requirement just the impact resistance requirements

Plastic photochromic lenses contain molecules like indoline spiro oxazine (ISN) that rupture and change structure upon activation by UV light, causing the lenses to darken. As the UV light diminishes, these lenses revert to their original state, increasing light transmittance. They are available in various colors, not just tint and gray.

According to ANSI Z80.3 standards, cosmetic sunglasses block at least 50% of both UV-B and UV-A rays, while general purpose sunglasses block at least 95% UV-B and 60% UV-A. Special purpose sunglasses should block at least 99% UV-B and up to 99% UV-A, making the pairing "Special Purpose: blocks at least 99% UV-B and 60% UV-A" incorrect.