Asdfg Flashcards
1
Q
- What was the primary motivation for developing silicone-based contact lens (CL) materials?
- Reduced manufacturing costs
- 02 permeability
- Increased comfort
- Enhanced visual acuity
A
02 permeability
2
Q
- What characteristic of silicone hydrogel (SiHy) CLs makes them easier to handle than hydrogel CLs?
• Smaller size
• Higher water content
• Softer material
• Relative rigidity
A
• Relative rigidity
3
Q
- Why should an over-refraction be performed over a well-settled SiHy trial lens before ordering the final back vertex power (BVP)?
• To account for small prescription changes due to induced corneal alterations
• To test lens durability
• To ensure correct lens color
• To check for allergic reactions
A
• To account for small prescription changes due to induced corneal alterations
4
Q
- Which mode of wear is SiHy CLs suited for?
- Daily wear (DW)
- All of the above
- Continuous wear (CW)
- Extended wear (EW)
A
- All of the above
5
Q
- What type of surface charge do most
SiHy CLs have?
• Alternating positive and negative
• Highly negative
• Highly positive
• Little or no surface charge
A
• Little or no surface charge
6
Q
- Which SiHy CL material is known for having a charged surface due to plasma oxidation?
- Lotrafilcon A
- Senofilcon A
- Balafilcon A
- Comfilcon A
A
- Balafilcon A
7
Q
- According to the FDA materials grouping system, what group do most SiHy CLs belong to?
- Group 2: High water, Non-ionic
- Group 1 Low water, Non-ionic
- Group 4 High water, Ionic
- Group 3 Low water, Ionic
A
- Group 1 Low water, Non-ionic
8
Q
- What is the range of water content found in SiHy CLs?
- 24-75%
- 30-80%
- 24-50%
- 50-75%
A
- 24-75%
9
Q
- What is the range of oxygen permeability (Dk) for SiHy CLs?
• 60-120 barrer
• 70-130 barrer
• 55-100 barrer
• 55-140 barrer
A
• 55-140 barrer
10
Q
- What is the typical wetting angle range for SiHy CLs when measured with a sessile drop?
• 55-95
• 60-101
• 70-110
• 50-80
A
• 60-101
11
Q
- What is the typical wetting angle range for SiHy CLs when measured with a captive bubble?
• 40-55
• 20-35
• 27-45
A
• 27-45
12
Q
- What is the refractive index range for SiHy CLs?
•1.373 - 1.426
•1.360 - 1.410
• 1.350 - 1.400
• 1.380 - 1.430
A
•1.373 - 1.426
13
Q
- Which of the following is an indication for using scleral lenses?
• Greatly decentred pupils
• Mild astigmatism
• Low myopia
• Mild dry eye
A
• Greatly decentred pupils
14
Q
- What is a disadvantage of scleral lenses?
• Easy availability
• Low cost
• Long fitting time
• Quick fitting process
A
• Long fitting time
15
Q
- What type of scleral lens allows patients to experience the lens prior to fitting?
• Impression
• Preformed
• Custom toric lenses
• Disposable lenses
A
• Preformed
16
Q
- What is an advantage of preformed scleral lenses?
• They are more expensive
• They require more fitting time
• Precise lens specifications are known
• They have limited specifications
A
• Precise lens specifications are known
17
Q
- What should be present in the limbal zone of a properly fitted scleral lens?
• No air bubble
• Fenestration
• A tight seal
• Excessive clearance
A
• Fenestration
18
Q
- Which parameter affects both the static and dynamic fitting characteristics of a rigid lens?
• Lens age
• Refractive index
• Material color
• Lens diameter
A
• Lens diameter
19
Q
- Increasing the back optic zone diameter
(BOZD) of a rigid lens has what effect on apical clearance?
• Randomly changes apical clearance
• Increases apical clearance
• Decreases apical deeranee
• No effect on apical clearance
A
• Increases apical clearance
20
Q
- What happens to lens fit if the total diameter of a rigid lens is reduced?
• Tear exchange is reduced
• Lens movement increases
• The lit tightens
• The lens becomes easier to remove
A
• Lens movement increases
21
Q
- What must be compensated by -0.25 D for every 0.05 mm increase (flattening) in BOZR?
• Cons diameral
• Corneal curvature
• Lens thickness
• Tear lens power
A
• Tear lens power
22
Q
- What effect does a front surface design that increases upper lid interaction have on lens comfort?
• Randomly affects comfort
• No effect on comfort
• Increases comfort
• Decreases comfort
A
• Decreases comfort
23
Q
- For a patient with corneal astigmatism greater than 1.50 D, how should the BOZR be adjusted for each 0.50 D increase in astigmatism?
• Increases BOZR by 0.10mm
• Decreases BOZR by 0.05mm
• Increase BOZR by 0.10 mm
• Decrease BOZR by 0.05 mm : erase BOR by 0.50 mm
A
• Decreases BOZR by 0.05mm
24
Q
- What is the role of the back mid-periphery in a rigid lens design?
• Aligns with the flattening cornea
• Increases lens flexibility
• Decreases lens durability
• Improves aesthetic appearance
A
• Aligns with the flattening cornea
25
25. What is Orthokeratology primarily used for?
• Temporarily reduction of myopic correction by contact lenses
• Permanent correction of refractive errors
• Treatment of keratoconus
• Permanent reshaping of the cornea
• Temporarily reduction of myopic correction by contact lenses
26
26. Which type of contact lenses does
Orthokeratology employ?
• Soft contact lenses
• Daily disposable lenses
• Colored contact lenses
• Gas permeable (GP) reverse geometry lenses
• Gas permeable (GP) reverse geometry lenses
27
27. Which EOR is orthok mainly used to treat
• HYPEROPIA
• MYOPIA
• ASTIGMATISM
• PRESBYOPIA
• MYOPIA
28
28. What is one of the key benefits of Orthokeratology?
• Permanent elimination of refractive errors
• Instant vision improvement without adaptation
• Freedom from glasses during the day
• Suitable for everyone regardless of age
• Freedom from glasses during the day
29
29. What age is typically suitable for Orthokeratology?
• Older than 6 years
• Only seniors over 60 years
• Any age, including infants
• Only adults over 18 years
• Older than 6 years
30
30. Which of the following is NOT true about Orthokeratology?
• It uses specially designed contact lenses.
• It permanently reshapes the cornea.
• It requires commitment to ongoing treatment costs.
• It is a non-surgical technique.
• It permanently reshapes the cornea.
31
31. What type of astigmatism can Orthokeratology routinely treat?
● -2.00D with-the-rule astigmatism
• 1.50D orless with-the rule
astigmatism
• Any degree of against-the-rule astigmatism
• -3.00D against-the-rule astigmatism
● -1.50D or less with-the-rule astigmatism
32
32. What is a key requirement for a candidate considering Orthokeratology?
• Free of corneal pathology
• Below 6 years of age
• Must have hyperopia
• Unable to wear glasses
• Free of corneal pathology
33
33. What is the cylindrical refractive power limit for with-the-rule astigmatism in Orthokeratology candidates?
• -1.50D or less
• -0.75D or less
• -3.00D or less
•-2.00D or less
•-2.00D or less
34
34. What is a common characteristic of patients suitable for Orthokeratology?
• Must be older than 50 years
• Only need treatment once
• Have progressive myopia
• Have severe corneal pathologiea
• Have progressive myopia
35
35. Which of the following is a limitation of Orthokeratology?
• It is subject to individual variability
• It is subject to individual variability
• It permanently fixes refractive errors
• It is suitable for all astigmatism levels
• It is subject to individual variability
36
37. What is the maximum against-the-rule astigmatism that can be treated by Orthokeratology?
• -2.00D
• -3.00D
• -1.50D
• -0.75D
• -0.75D
37
38. Which of the following best describes the effect of Orthokeratology on the cornea?
• Thins the cornea
• Has no effect on the cornea
• Permanently reshapes the cornea
• Temporarily reshapes the cornea to reduce myopia
• Temporarily reshapes the cornea to reduce myopia
38
39. Who among the following would be the least suitable candidate for Orthokeratology?
• An adult with -0.50D WTR
astigmatism
• A 10-year-old child with progressive myopia
• A patient with significant corneal pathology
• A teenager with -1.00D myopia
• A patient with significant corneal pathology
39
40. When should Orthokeratology not be fitted?
• When the px has myopia
• When the px has hyperopia,
• When the patient has presbyopia
• When the cornea is distorted
• When the cornea is distorted
40
41. What should be treated before fitting Orthokeratology lenses if a patient has a habit of eye rubbing?
• Allergies and the habit itself
• Eye infections
• Hyperoia
• Myopia
• Allergies and the habit itself
41
42. Which of the following is a contraindication for Orthokeratology?
• Hyperopia
• Irregular corneal astigmatism
• Low myopia
• Regular corneal astigmatism
• Irregular corneal astigmatism
42
42. Which of the following is a contraindication for Orthokeratology?
Hyperopia
Irregular corneal astigmatism
Low myopia
Regular corneal astigmatism
Irregular corneal astigmatism
43
43. Which fitting method involves the use of a diagnostic trial set?
Virtual fitting
Empirical fitting
Theoretical fitting
Trial fitting
Trial fitting
44
44. In trial fitting, what is used to analyze the fit of the lens?
• Blood tests
• Visual acuity tests
Patient feedback
• Fluorescein pattern analysis and over-refraction
Fluorescein pattern analysis and over-refraction
45
45. What is the Jessen Factor commonly used in Orthokeratology lens design?
• -1.25D
-0.25D
-2.00D
-3.00D
-1.25D
46
46. The optic zone diameter of Orthokeratology lenses typically ranges between
8.0 mm to 10.0mm
5.0mm to 6.8mm
4.0mm to 5.00
6.8mm to 8.0mm
5.0mm to 6.8mm
47
47. The overall diameter of a reverse geometry Ortho-K lens is usually:
• Larger than the HVID
• Equal than the HVID
• 0.8mm to 1.2mm smaller than the
HVID
• Variable with no standard measurement
• 0.8mm to 1.2mm smaller than the
HVID
48
47. The overall diameter of a reverse geometry Ortho-K lens is usually:
• Larger than the HVID
• Equal to the HVID
• 0.8mm to 1.2mm smaller than the
HVID
• Variable with no standard measurement
• 0.8mm to 1.2mm smaller than the
HVID
49
48. What is the function of the tear film reservoir in Orthokeratology lenses?
To eliminate all astigmatism
To provide clearance for the amount of myopia being corrected
To store excess tears
To create a smoother fit
To provide clearance for the amount of myopia being corrected
50
49. The relief zone in some Ortho-K designs aims to:
Encourage epithelial cell proliferation
Provide additional comfort
Reduce overall lens diameter
Increase tear production
Encourage epithelial cell proliferation
51
50. What is the primary purpose of the alignment zone in Orthokeratology lenses?
To provide extra comfort
To store extra tears
To ensure proper centration
To enhance peripheral vision
To ensure proper centration
52
51. Which zone in a reverse geometry lens contributes most to proper lens centration?
Optic zone
Alignment zone
Secondary zone
Reverse zone
Alignment zone
53
52. The greatest amount of epithelial thinning occurs under which zone?
Optic zone
Alignment zone
Secondary zone
Reverse zone
Alignment zone
54
53. What is the typical width of the secondary zone in a reverse geometry lens?
0.2mm to 0.5mm
0.1mm to 0.3mm
0.5mm to 1.0mm
1.0mm to 2.0mm
0.5mm to 1.0mm
55
54. What is the main purpose of the secondary zone in a reverse geometry lens?
To enhance the visual acuity
To form a smooth transition between the alignment and peripheral zones
To provide additional lens stability
To increase tear production
To form a smooth transition between the alignment and peripheral zones
56
55. Which condition is a contraindication for Orthokeratology?
Myopia
Keratoconus
Astigmatism
Presbyopia
Keratoconus
57
56. What is the purpose of fluorescein pattern analysis in trial fitting?
To test patient comfort
To check for lens durability
To analyse tear production
To analyze lens fit
To analyze lens fit
58
57. What is the typical width range of the reverse zone in an Orthokeratology lens?
• 1.0mm to 1.5mm
• 0.5mm to 1.0mm
• 0.2mm to 0.4mm
• 15mm to 2.0mm
• 0.5mm to 1.0mm
59
58. The fit of which zone contributes most to proper lens centration in Orthokeratology lenses?
Alignment zone
Optic zone
Peripheral zone
Reverse zone
Alignment zone
60
59. What is the follow-up schedule after the first night of wearing Orthokeratology lenses?
The third night
After two weeks
The morning after
The seventh night
The morning after
61
60. How long after the third night should the next follow-up visit occur?
The third night
After two weeks
The morning after
The seventh night
The seventh night
62
61. When is the final follow-up visit in the initial schedule for Orthokeratology lens wearers?
After three months
After two weeks
After a month
After one week
After two weeks
63
62. The relief zone in Orthokeratology lenses, when present, typically has a width of
0.3mm to 0.5mm
0.1mm to 0.3mm
0.5mm to 0.7mm
0.7mm to 1.0mm
0.5mm to 0.7mm
64
63. Orthokeratology should be stopped immediately if there is:
No discomfort while wearing lenses
Improvement in vision
Any change in ocular condition in general
Reduced dependency on glasses
Any change in ocular condition in general
65
64. Which of the following is a reason to stop Orthokeratology immediately?
Ocular discharge
Less frequent blinking
Increased vision clarity
Better lens comfort
Ocular discharge
66
65. Decreased wearing comfort of Orthokeratology lenses suggests:
• The lenses should be stopped immediately
• The treatment is complete
• No action is required
• The lenses are perfect
• The lenses should be stopped immediately
67
66. If a patient experiences irritated eyes or pain while using Orthokeratology lenses, they should:
• Use lubricating drops and continue
• Adjust the lenses themselves
• Stop wearing them immediately
• Continue wearing them
• Stop wearing them immediately
68
67. Optimum movement for rigid gas permeable lenses is characterized by:
Minimal central clearance
Reduced edge clearance
Heavy mid peripheral contact zone
Excessive central touch zone
Minimal central clearance
69
68. Which of the following describes a loose fit for rigid gas permeable lenses?
Excessive central clearance
Excessive edge width and clearance
Minimal central clearance
Stable and centered movement
Excessive edge width and clearance
70
69. A tight static fit in rigid gas permeable lenses typically has:
Smooth and vertical movement
Excessive edge clearance
Heavy and mid peripheral contact zone
Optical edge width
Heavy and mid peripheral contact zone
71
70. What characterizes the movement of a tight fit dynamic rigid gas permeable lens?
Excessive edge clearance
Rocky and smooth vertical movement
Unstable and high riding
Decentered movement
Rocky and smooth vertical movement
72
71. The optimal edge with for rigid gas permeable lenses ensures:
Fast speed movement
Reduced wearing comfort
Excessive central clearance
Light mid peripheral contact zone
Light mid peripheral contact zone
73
72. Wearing RGP lenses should provide:
• Good visual acuity
• Discomfort
Short wearing time
• Poor visual acuity
• Good visual acuity
74
73. What is a key characteristic of RGP lenses?
They require daily replacement
• They are made of soft materials
They always cause ocular insult
They should provide comfort
They should provide comfort
75
74. When evaluating the static fitting of an
RGP lens, it is important to assess:
• Tear film evaporation rate
• Lid interaction with the lens
Lens material flexibility
Lens position in primary gaze
Lens position in primary gaze
