NOCE Cheat Sheet 2026

The 30 highest-yield NOCE facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the ideal movement of a correctly fitted soft contact lens following a blink? → 0.5 to 1.0 mm of movement
2. Which of the following ophthalmic lens materials has the highest index of refraction, resulting in the thinnest lens for a given prescription? → High-Index Plastic (1.74)
3. When comparing two finished lenses of the exact same power and size, which material property is the primary determinant of the lens's final weight? → Specific gravity
4. Which of the following instruments is used to measure the curvature of the front or back surface of a spectacle lens? → Lens Clock (Geneva Gauge)
5. Which contact lens care concern has been associated with certain multipurpose solutions and silicone hydrogel lens materials? → Decreased surface wettability due to preservative interaction
6. Which multifocal contact lens design features alternating concentric rings of distance and near powers? → Concentric (annular) simultaneous vision design
7. Photochromic lenses darken when exposed to sunlight. What is the primary trigger for this change in modern plastic photochromic lenses? → Exposure to ultraviolet (UV) radiation
8. A patient reports seeing color fringes around objects, especially in their peripheral vision. This phenomenon is most likely caused by which lens aberration? → Chromatic Aberration
9. What is the recommended replacement schedule for daily disposable contact lenses? → Discard after each single use
10. What does 'limbal clearance' refer to in the context of contact lens fitting? → The space between the lens edge and the corneal limbus
11. A soft lens patient reports significant end-of-day dryness and discomfort. Which change would MOST likely improve comfort? → Switching to a silicone hydrogel lens material
12. What is the minimum oxygen transmissibility (Dk/t) recommended for daily wear soft contact lenses to prevent corneal hypoxia? → 24 × 10⁻⁹
13. In a myopic eye, parallel light rays from a distant object come to a focus: → in front of the retina
14. For a patient with a spectacle prescription of -2.50 -1.50 x 180, which contact lens type would provide BEST visual correction? → Toric soft contact lens
15. A patient wearing extended wear contact lenses presents with a red, painful eye and photophobia. What is the MOST critical first step? → Remove the lens immediately and refer for urgent medical evaluation
16. When instructing a new contact lens wearer on lens insertion, what is the correct sequence of steps? → Wash hands, verify lens orientation, then insert lens
17. In RGP contact lens fitting, a fluorescein pattern showing central touch (dark area centrally) with excessive edge lift indicates: → A flat lens fit
18. In the visual pathway, nerve fibers from the nasal retina of the left eye and the nasal retina of the right eye decussate (cross over) at which structure? → Optic Chiasm
19. When fitting a toric soft contact lens, which factor is MOST critical for achieving adequate visual correction? → Axis alignment and rotational stability
20. When initially selecting a base curve for a soft contact lens, which measurement is most commonly used as the starting point? → The average of both K readings
21. Which ocular structure is primarily responsible for the production of aqueous humor, the fluid that fills the anterior and posterior chambers? → Ciliary body
22. When fitting a patient for monovision contact lenses, which eye is conventionally corrected for distance vision? → The dominant eye
23. Slab-off prism is ground on a spectacle lens to correct for: → vertical imbalance at the reading level
24. A patient's spectacle prescription is -4.50 DS with a vertex distance of 12mm. What contact lens power would you expect to order? → -4.25 DS
25. Which lens parameter describes the peripheral edge design and tear exchange area of a rigid gas permeable contact lens? → Peripheral curve radius
26. Which instrument is considered the gold standard for accurately measuring a patient's interpupillary distance (PD)? → A pupilometer
27. Which of the following lens materials has the highest Abbe value, resulting in the least amount of chromatic aberration? → Crown Glass
28. During an RGP lens follow-up, a lens rides superiorly and shows temporal lag with each blink. What is the most likely cause? → The lens is fitted too flat
29. What is the primary purpose of sodium fluorescein dye when fitting RGP contact lenses? → To visualize the tear layer distribution beneath the lens
30. Which of the following layers of the cornea is a single cell thick and actively pumps fluid out of the stroma to maintain corneal transparency? → Endothelium