Prosthetics e-lectures

Question 1

procedure where the entire eyeball is removed

Answer 1

enucleation

Question 2

procedure with removal of eyeball’s contents and leaving the scleral shell intact, EOMs may still be attached

Answer 2

Evisceration

Question 3

procedure with removal of all orbital contents including eyeball, extra ocular muscles, fat and connective tissues where sometimes the eyelid is removed as well and the maxilla (upper jawbone and cheek)

Answer 3

Exenteration

Question 4

it is hard to differentiate with these two types of post-surgical eyes?

Answer 4

enucleation with implant vs. evisceration (without implant)

Question 5

enucleation without implant appears as

Answer 5

an empty socket

Question 6

when do you use a scleral shell or prosthetic scleral shell?

Answer 6

Phthisis bulbi: ocular end stage disease

atrophy, shrinkage, and disorganization of the eye ball and intraocular contents

Question 7

prosthetic eyes are made of a curved disc of plastic with a min center thickness of

Answer 7

2mm

Question 8

what are some ways to help tell if a prosthetic is a right or left side?

Answer 8

• nasal edge is more pointy
• superior trochlear curve
• steeper superior F2 curve
• flatter inferior F2 curve

Question 9

a shell eye is a curved disc of plastic with a center thickness of

Answer 9

less than 2mm

Question 10

a shell eye is designed to cover:

Answer 10

an intact eye or shallow socket

it may have open pupil for light perception

Question 11

reasons to get implant vs. no implant

Answer 11

• implant: allows for smaller ocular prosthetic

- no implant: fewer complications

Question 12

reasons to get solid vs. porous implants

Answer 12

solid: fewer complications

porous (integrated implants): better motility, allows fibrovascular growth

Question 13

what are two orbital implant complications?

Answer 13

• migration: (movement of implant laterally or vertically)

- extrusion: (implant boring out of conjunctival surface)

Question 14

is occlusion necessary in a routine eye exam on a prosthetic patient?

Answer 14

no

Question 15

what are some things to check for in gross evaluation of prosthetic eye

Answer 15

• binocular eye alignment
• vertical palpebral fissure size and symmetry
• iris diameter and color symmetry
• pupil diameter (habitual eye, bright and dim)
• sclera color (white, vessels)

Question 16

how often should a prosthetic be replaced?

Answer 16

5-7 years

Question 17

what are some prosthetic specific examination components?

Answer 17

• eyelids: symmetry and vertical palpebral fissure height
• iris: natural iris color, HVID, Nevus
• cornea: opacity, arcus, etc.
• pupil size: dim, moderate, and bright illumination
• strabismus

Question 18

prosthetic eye fitting: step 1

Answer 18

• determine ideal white or clear shape
• examine overall socket shape (foveal, triangular, other)
• diagnostic fitting vs. injection molding

Question 19

prosthetic eye fitting: step 2a

Answer 19

finalize overall shape, comfort, fit, (-) rotation

Question 20

prosthetic eye fitting: step 2b

Answer 20

prosthetic scleral shell

• gross evaluation: adequate tear exchange, excessive blanching, bubbles are acceptable, excessive edge lift
• biomicroscopy: ocular surface staining

Question 21

prosthetic eye fitting: step 3

Answer 21

determine color and shape

color match iris and sclera, iris position and size, pupil size

Question 22

prosthetic eye fitting: step 4

Answer 22

dispense, follow ups (2-4 weeks for initial shape, six month for polish, and annual examination)

Question 23

what are some common prosthetic complications?

Answer 23

• blepharitis
• conjunctivitis
• incomplete eyelid closure
• natural iris and scleral color changes

Question 24

problem with scleral shells (acrylic)

Answer 24

made of plastic (PMMA), but could not wear for extended periods of time due to no tear exchange

Question 25

pros and cons to introduction of corneal PMMA contact lenses

Answer 25

smaller design allowed for tear exchange and O2 transmissibility via movement, but movement would cause shifting of iris print

Question 26

examples of when to use of specialty contact lenses for non-functioning eyes

Answer 26

-opacified cornea -iris atrophy -white pupil -corneal scar etc.

Question 27

examples of when to use of specialty contact lenses for functioning eyes

Answer 27

-iris atrophy (large pupil) -strabismus -corneal scar (not in visual axis) etc.

Question 28

definition of "iris occlusion"

Answer 28

iris pigment on the lens. pupil is clear/open

Question 29

definition of "pupil occlusion"

Answer 29

black pupil at the center of the lens. no vision

Question 30

definition of "iris and pupil occlusion"

Answer 30

iris pigment on the lens and black pupil at the center of the lens

Question 31

tinted SCL (A)

Answer 31

- uniform color, no iris details | - translucent

Question 32

printed SCL (B)

Answer 32

- ready-made or stock lens - manufactured, some iris details - opaque

Question 33

hand-painted SCL (C)

Answer 33

- made to order, custom iris details | - opaque

Question 34

what are some characteristics of tinted lenses?

Answer 34

- homogenous - translucent - unlimited base curve, power, diameters, iris and pupil diameters - best for matching dark eyes

Question 35

what are some other uses for tinted lenses?

Answer 35

- red/green color deficiencies - achromatopsia - low vision patients

Question 36

what are some characteristics of printed lenses?

Answer 36

- iris details - complete occlusion possible - limited BC, power diameters, and iris/pupil diameters - best for matching all eyes - replicable - fitting set available

Question 37

what are some characteristics of hand painted lens characteristics?

Answer 37

- iris, pupil, scleral details - complete occlusion - unlimited BC, PWR, diameters, iris and pupil diameters - best for matching all eyes

Question 38

you should only use clear care for what type of lens

Answer 38

hand painted lenses

Question 39

what are some ocular disfigurements patients may want to conceal

Answer 39

- iris abnormality: coloboma, scar, irregularity - corneal abnormality: scar, band keratopathy - pupil abnormality: white pupil

Question 40

what are some reasons patients may want to improve visual function with prosthetic lenses?

Answer 40

- iris abnormality: traumatic iris atrophy, aniridia | - symptoms: glare

Question 41

reasons for an iris occluding (open pupil) lens:

Answer 41

- albinism: lacking iris color - aniridia: lacking an iris - coloboma: iris opening (usually inferior) - iris atrophy/ fixed dilated pupils: abnormal pupil function

Question 42

reason for pupil occlusion (with or without iris details)

Answer 42

- ambylopia: patching of the good eye - diplopia: binocular double image which cannot be suppressed or fused - leukocoria: white pupil, usually from posterior ocular scar tissue - corneal abnormalities: corneal scar, band keratopathy - strabismus: occluding one eye - achromatopsia: patients with rod-cone dystrophy - color vision difficulties: red magenta lens