Ocular diagnostic and therapeutic methods Flashcards
name the preliminary ocular examinations in a lightened room?
Pupil light reflex (PLR)
Dazzle reflex
Schirmer tear test (STT)
define the PLR?
the reflex construction of the pupil in response to light striking the retina is termed pupillary light reflex
what can be shown by the dazzle reflex?
the reflex is absent in the presence of severe retinal, optic nerve, optic chasm, optic tract, or facial nerve lesions
define the schirmer tear test (STT)?
semi quantitive measurement of tear production
what condition is the STT used to indicate?
KCS
what is the normal value for STT in cat?
0-3
what is the normal STT value for a dog?
15-25
what is the STT value of a dog with a highly advanced severe KCS disease?
<5
name the tests used to evaluate vision?
falling cotton test
obstacle test
manace reflex test
name the two main methods used for vital staining?
Fluorescein dye
Rose Bengal
what does staining with fluorescein dye indicate?
determines the quality of the PTF
why should staining with fluorescein dye always be conducted before topical administration of steroid therapy?
All red, inflamed, or painful eyes should be stained with fluorescein to diagnose or eliminate corneal ulcers from consideration
what colour does fluorescein turn If there are defects in the corneal epithelium?
bright green areas
how are superficial ulcers stained with fluorescein stain?
the stain adheres to only the ulcer floor and has distinct margins
how are deep corneal ulcers stained with fluorescein stain?
the deep stromal ulcers both the walls and floor of the ulcer stain and there may be some diffusion of fluorescein into the neighbouring stroma, producing less distinct margins
what is stained with Rose Bengal dye?
dead and (degenerated) devitalised cells, including those that have altered superficial mucin layer and mucus in brilliant red
when would you use Rose Bengal dye?
when there is suspicion for KCS
describe the tear film breaking up time (TFBUT)?
the tear film break up time (TFBUT) is an assessment of the stability of the precorneal tear film
TFBUT is considered a measurement of mucin quality and quantity
what dye is used for TFBUT?
fluorescein stain
describe why Seidel’s test is used?
a method of assessing the cornea for perforation
Fluorescein is applied without rinsing
evidence of leaking of aqueous can be seen with perforation
describe the Ones test (fluorescein passage)?
topical application of fluorescein dye and observation for its appearance at the nares confirms potency of the nasolacrimal duct
normal passage time for Jones test?
10 minutes
what is seen normally with the lens?
Purkinje’s images formed on the anterior and posterior lens capsule are bright, clear and regular; there is no opacity on the lens
name the instruments used to measurement of intraocular pressure?
Schøtz tonometer
tonopen
tonovet
what kind of tonometer is the Shiøtz tonometer?
indentation tonometry
what kind of tomometer is the tonopen?
applantation tonometer
what kind of tonometer is the tonovet?
rebound tonometry §
