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Ocular Physiology > Lab Info > Flashcards

Lab Info Flashcards

1
Q

the ciliary muscle and iris sphincter are supplied by what nerve fibers from what ganglion?

A

parasympathetic nerve fibers from ciliary ganglion

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2
Q

the dilator muscle of the iris is supplied by what nerve fibers from what ganglion?

A

sympathetic nerve fibers from superior cervical ganglion

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3
Q

mydriatics have what affect on accommodative amplitude

A

decrease because pupil can’t constrict and you lose depth of focus

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4
Q

mydriatics have what affect on distance phoria

A

little to no change because of pinholes

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5
Q

mydriatics have what affect on near phoria

A

little to no change because pinholes and ciliary muscle not changed

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6
Q

mydriatics have what affect on NPC

A

no change or little receding change due to DOF

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7
Q

cycloplegics have what affect on accommodative amplitude

A

decreased

variation based on iris color

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8
Q

cycloplegics have what affect on distance phoria

A

no significant change because pinhole and no accommodation needed at distance

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9
Q

cycloplegics have what affect on near phoria

A

should go more eso- trying to accommodate more

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10
Q

cycloplegics have what affect on NPC

A

can’t see stimulus clear enough to fuse

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11
Q

how is AC/A ratio calculated

A

AC/A= (15-d+n) / 2.5
eso is + value
exo is - value

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12
Q

what test evaluates the quality of the tear film

A

TBUT

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13
Q

how can TBUT change with artificial tears and anesthetics?

A

stayed the same or increased- so lower TBUT because faster time (because increased evaporation rate)

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14
Q

what is evaluated with the Jones I and II tests?

A

drainage

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15
Q

tears running onto the cheek (epiphora) may be caused by:

A
  • hypersecretion

- insufficient drainage

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16
Q

where is the blockage if the Jones II test shows dye and saline in nose

A

blockage in sac/duct

{(this assumption 78% accurate)

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17
Q

where is the blockage if the Jones II test shows only saline in the nose

A

blockage in canaliculi or puncta (fluorescein didn’t reach sac)

18
Q

where is the blockage if the Jones II test shows nothing in the nose

A

complete obstruction of sac/duct

19
Q

Jones Test I is falsely positive (no dye discovered) in ___% of tests

A

22%

20
Q

the Schirmer I test measures the reflex and basic secretion of the ____ layer

A

aqueous

21
Q

norms for Schirmer I Test in 20s age group is

A

40-50 mm wetting

22
Q

what is considered a normal Schirmer test I values?

A

10 mm or more- normal and dry eye problem should not be based on aqueous production problems

23
Q

why is the basic secretion test used?

A

to isolate if defective secretion seen in Schirmer 1 is from the reflex lacrimal glands, accessory lacrimal glands, or both

24
Q

reduced tear volume causes what issues that the rose bengal tests for?

A

reduced tear volume causes a degeneration of corneal and conjunctival epithelium especially in the exposed interpalpebral aperture

25
Q

the diagnosis of keratoconjunctivitis sicca (aqueous deficient dry eye) is positive when:

A

a characteristic triangular stippled staining of the temporal and nasal bulbar conjunctiva (base towards limbus) in the interpalpebral area and punctate staining of the inferior 2/3 of the cornea is observed

26
Q

what does the ophthalmometer/ keratometer measure and compute?

A

determines the radius of curvature of the cornea, from which the dioptric power is computed

27
Q

how does the ophthalmomometer/ keratometer neutralize the measuring problem caused by minute eye movements?

A

the image of the mire is doubled and minified

28
Q

main assumptions of the ophthalmometer/ keratometer

A
  • spherical surfaces

- regular astigmatism

29
Q

how do you record findings on keratometry?

A

minus cylinder form with the axis of the weaker meridian

30
Q

is the cornea flatter or steeper in periphery?

A

steeper?

31
Q

the keratoscopic disc card is based on what imagery

A

they use the first Purkinje image formed by reflections from a small portion of the central corneal zone

32
Q

how would you use measurements from a photokeratoscopy image to record cylinder?

A

-long axis is the (-) cyl axis

33
Q

4 examples of how the sensitivity of the cornea is changed by local pathological processes

A
  1. chemical injuries
  2. corneal ulcers
  3. glaucoma
  4. herpetic keratitis
34
Q

average corneal diameter

A

11.5

35
Q

most important clinical factors in distinguishing different types of glaucoma

A
  • drainage angle
  • visual field changes
  • optic disc appearance
  • intraocular pressure
36
Q

the water drink test is for what type of glaucoma?

A

open angle

37
Q

water drink test resulting in an increase of ___ mmHg IOP is suggestive of open-angle glaucoma suspect

A

8 mmHg

38
Q

what conclusions can be made for an abnormal dark room prone provocative test?

A

8 mmHg increase in pre- to post-testing suggestive of narrow angle glaucoma

39
Q

mydriasis test results can suggest:

A

an increase of 8 mmHg in an hour suggested an angle-closure mechanism

40
Q

the pressure increment when changing from the seated to supine position averaged ___ mmHg

A
  1. 9 mmHg in normal eyes

3. 9 mmHg in glaucomatous eyes

41
Q

how does IOP change with corticosteroid use differ in normal versus open angle glaucoma patients?

A

5% of general population sustains an elevation in IOP

90% of pts with chronic open angle glaucoma sustained increased IOP

42
Q

a suggested theory on how the IOP increases in corticosteroid use is

A

mucopolysaccharides content of the trabecular meshwork might be altered with increased resistance to aqueous outflow

Ocular Physiology (8 decks)

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