IOP

Question 1

what is the “magic number for IOP?

Answer 1

21. greater than this is at risk for glaucoma but does vary. this is just a standard.

Question 2

Refractive error has association with the amount of pressure in eye. T or F

Answer 2

False. It has no association.

Question 3

Everyone IOP goes up with age. T or F

Answer 3

True

Question 4

IOP depends on parents. T or F

Answer 4

True

Question 5

Females have greater IOP after 40 yrs, whereas males have it 20-40 yrs old. T or F

Answer 5

True

Question 6

when is IOP GREATEST? IN WHAT SEASON

Answer 6

WINTER

Question 7

name factors that affect IOP in short term?

Answer 7

1) Diurnal variations
2) Postural variations: Supine cause increase
3) Exercise: Decrease in IOP (if done properly)
4) Blinking and forceful closure causes increase
5) Activities causing Valsalver maneuver
6) Trying to exhale with mouth closed
7) Eye movements

Question 8

name long term affects of IOP?

Answer 8

genetics, age, gender, seasons, NOT REFRACTIVE EROR.

Question 9

NAME DRUGS THAT CAN HAVE AFFECT ON IOP?

Answer 9

Alcohol: decrease in IOP
Caffeine: cause slight increase
Tobacco: May cause transient increase in IOP
Heroin and Marijuana: decrease in IOP

Question 10

Food cannot have an affect on IOP. T or F

Answer 10

False.

Question 11

what does a pneumotonometer do?

Answer 11

Pneumotonometer= measure blood flow to eye IOP

Question 12

what is tonometry used to measure?

Answer 12

pressure in the eye

Question 13

W = P x A

Where
 W= external force
 A=Area
P pressure inside sphere
what law was this? for what?

Answer 13

Imbert- Fick Law for tonometry.

Question 14

what were the problems with Fick-Lambert’s Law working with the eye?

Answer 14

perfect sphere, dry, infinitely thin. The eye is none of this.

Question 15

what factors can affect IOP measurements?

Answer 15

1) Central corneal thickness
2) Corneal curvature
3) Age related changes to cornea
4) IOP effects on cornea
5) Biomechanical properties
6) Rigidity
7) Hydration
8) Elasticity

Question 16

Tissue and similarly the cornea are elastic or viscoelastic?

Answer 16

viscoelastic

Question 17

IN FLAT CORNEA= OVERESTIMATE PRESSURE (LARGER RADIUS OF CURVATURE)
STEEP CORNEA= UNDERESTIMATE PRESSURE (SMALLER RADIUS OF CURVATURE)
True or False

Answer 17

True

Question 18

IF CORNEA IS THIN= UNDER ESTIMATE PRESSURE
CORNEA IS THICK= OVERESTIMATE PRESSURE

NORMAL 520 MICRONS CORNEAL THICKNESS
True or False

Answer 18

True

Question 19

Thickness of the cornea dictates how much pressure is in eye. True or False

Answer 19

False

Question 20

the majority of blood flow to the eye comes from where?

Answer 20

the choroid

Question 21

Name types of telemetry? name some

Answer 21

Non invasive- temporary
CL’s
continuous applanation or indentation devices
Invasive- permanent 
Subconjunctival
anterior chamber implants
in AC
as IOL haptics
Scleral buckle 
scleral fixated sensor 
Posterior chamber implants –choroidal

Question 22

With each pulsate your eye changes shape. T or F

Answer 22

True

Question 23

what does telemetry measure?

Answer 23

IOP number of pulsates

Question 24

what is a new advancement in telemetry where we can measure a patient eye non-invasive 24/7 IOP?

Answer 24

wireless CL (contact lens)