post seg study guide
describe the d shaped mirror
60 degree angle Shows the AC angle
describe the appearance of congenital RPE hypertrophy
Benign Isolated, dark black/gray area of RPE hypertrophy Anywhere in the retina and variable in size Flat "Bear tracks" in the peripheral retina
describe pavingstone degeneration
Benign chorioretinal atrophy Appears as small, pale, yellow areas with surrounding RPE hyperplasia Can be one isolated area or it can coalesce to a large area Typically located between the equator and ora serrata (can extend into the ora if they coalesce)
describe the rectangular mirror
66 degree angle Shows retina between the equator and beginning of the ora serrata (peripheral retina)
describe the trapezoidal mirror
76 degree angle Shows retina between the posterior pole and equator (mid-peripheral retina)
how can you differentiate between RP and reticular degeneration?
Age: RP: 20's, Reticular: 60 and older Vision: RP: night blindness, VF loss, central vision decreased; Reticular: no change in vision but Diffuse spread in retina
what are the contraindications for gonio?
Allergies to drops used Significant corneal defects Eye infection Recent eye surgery Complicated trauma (acute)--Hyphema (blood in the AC), Corneal laceration, Globe perforation
what elements are part of the posterior pole?
Consists of the optic nerve, macula, and superior/inferior vascular arcades (those that travel temporally).
describe the appearance of bear tracks
Found unilaterally: typically benign Found bilaterally (or if irregularly shaped): often associated with Gardner syndrome Gardner syndrome: subtype of familial adenomatous polyposis; in people with Gardner syndrome, masses of non-cancerous tissue tend to form in many different organs, like the colon.
what are iris processes? what do they look like?
Iris process = thickened fibers that project from the iris root to the SS or higher Normal finding that can easily be seen in dark brown eyes □ Dark irides -- brown or yellowish processes □ Light irides -- gray or white processes Typically seen scattered 360 deg in angle Does not raise the iris out of position or interfere with trabecular outflow
describe the appearance of a halo nevus
Isolated, dark gray/black area of RPE hypertrophy Anywhere in the retina and variable in size Contains a depigmented area surrounding the lesion
which LGN layers receive inpot from the contalateral vs. ipsilateral eye?
Layers 1, 4, 6 = receive input from the contralateral eye's nasal hemi-retina Layers 2, 3, 5 = receive input from the ipsilateral eye's temporal hemi-retina
what are common OBJECTIVE symptoms of dry eye noted on the lids?
MGD = meibomian gland dysfunction (capped glands) Inflammation Telangiectasias -- common in acne rosacea- Small vessels on the eyelid margin "Notching" of lid margin -- indicative of longstanding blepharitis
what is the histo triad?
Maculopathy Punched out lesions or histo streaks in the retina Peripapillary Atrophy (PPA)
what is the schirmer basal tear secretion test? how is it performed/interpreted?
Measure: basal tear production Test length: 5 minutes, or until completely wet (perform as above with topical anesthetic in eye) Interpretation: <10 mm wet is suspicious
what is the schirmer I test? how is it performed/interpreted?
Measures: reflex and basal tear production Test length: 5 minutes, or until completely wet (with strip in palpebral conjunctiva) Interpretation: <10 mm wet is suspicious
what parts of the RNFL correspond to the quadrants of the visual field?
Nasal RNFL = temporal field Temporal RNFL = nasal field Superior RNFL = inferior field Inferior RNFL = superior field
what are peripheral anterior synechiae? what do they look like during gonio?
PAS = adhesion of the peripheral iris to the angle wall; very thick/wide fibers that extend from the iris root to the SS, TM, or SL Abnormal finding! Not always present 360 deg in angle Associated with closed angles and/or past or present inflammation "Tents" or lifts the iris out of position AND interferes with aqueous outflow
what does posterior embryotoxin look like during gonio?
PE = thickened Schwalbe's line (bold white line easily seen with slit-lamp and gonioscopy) Benign finding in about 20% of the population Most often associated with pathological findings of the iris and cornea, such as anterior chamber cleavage syndromes
what is the phenol red thread test? how is it performed/interpreted?
Place thread in lateral aspect of lower lid with patient in primary gaze Test length: 15 seconds Interpretation: <10 mm wet (turned pink) is suspicious for decreased production
describe bergmeister's papilla
Remnant of the embryonic hyaloid artery and its supportive glial sheath Not uncommon, particularly for patient's born prematurely Typically presents over the nasal portion of the optic nerve Often presents as coming toward the examiner
what are common OBJECTIVE symptoms of dry eye observed on the tear film?
TBUT < 10 seconds Decreased production (test by looking at the height of the tear prism, Schirmer, phenol red) General quality -- debris, excessively oily Staining (Lissamine green, Rose Bengal, Fluress, etc.)
what is a kinetic visual field?
The subject is presented with moving stimuli, which are moved from an area of lesser sensitivity to an area of greater sensitivity (i.e. from a non-seeing to seeing area). For a particular stimulus, the kinetic VF determines the set of retinal locations (X,Y) at which that stimulus can be seen, creating an isopter. ◊ Examples: confrontation, Goldman perimetry bowl
how can you differentiate active toxo vs. histo?
Toxoplasmosis: will cause an anterior/posterior chamber inflammations--Large KPs, AC cells and flare, cells in the vitreous Histoplasmosis: will not cause an anterior/posterior chamber inflammation--No KPs, no AC cells and flare, no cells in the vitreous
what does a toxoplasmosis scar look like?
Typically presents as a yellow-white lesion with dark-pigmented borders Inactive toxoplasmosis: appears as any other chorioretinal (CR) scar Active toxoplasmosis: appears as a CR scar with a new adjacent yellow-white lesion
what's the protocol for assessing a choroidal nevus based on size?
Up to 2DD in size: document and follow 2DD to 5DD in size: may require special testing and careful F/U care Over 5DD in size: assume malignancy until proven otherwise
what are some absolute contraindications of puntal plugs?
poor tear film quality--indicates inflammatory dry eye Dacryocystitis Eye infection Silicone hypersensitivity--Many plugs are made of silicone
what is an FN error on a visual field test? what does a high FN error rate suggest?
(false negative) = an invalid negative test result (pt. sees but doesn't click) Here, the patient fails to respond to a known supra-threshold stimulus--this could indicate fatigue, inattentiveness, slow reaction time, or hysteria/malingering from the patient.
what is an FP error on a visual field test? what does a high FP error rate suggest?
(false positive) = an invalid positive test result (pt. clicks but doesn't see) Here, the patient responds to a known infra-threshold stimulus. High FP rate = "trigger happy"--this could indicate lack of understanding of the test, test anxiety, and/or guessing done by the patient.
target size/angular subtense of goldman 2 VF:
1 mm^2; 0.22 deg
what clock positions are you most likely to find vortex amullae?
1, 5, 7, 11
list the anterior chamber angle structures from posterior to anterior
1. ciliary body 2. scleral spur 3. trabecular meshwork 4. schwalbe's line
what is the mag and FOV of the 40D lens?
1.67X 69 deg
target size/angular subtense of goldman 1 VF:
1/4 mm^2; 0.11 deg
target size/angular subtense of goldman 4 VF:
16 mm^2; 0.86 deg
what is the mag and FOV of the panretinal 2.2 lens?
2.68X 56 deg
the total VF extends about ____ degrees; ______ degrees are shared, and the temporal _____ degrees are unshared
200; 120; 40
what clock positions are you likely to find the long posterior cilliary nerves? how do they divide the retina?
3+9 superior and inferior retina
what is the mag and FOV of the 20D lens?
3.13X 46 deg
target size/angular subtense of goldman 3 VF:
4 mm^2; 0.43 deg
what is the mag and FOV of the MP 5.5 lens?
5.5X 36 deg
what clock positions are you likely to find the short posterior cilliary nerves? how do they divide the retina?
6+12 nasal and temporal retina
the nasal VF extends ____ degrees, and the temporal VF extends ______ degrees.
60; 100
the superior VF extends ____ degrees, and the inferior VF extends ______ degrees.
60; 75
target size/angular subtense of goldman 5 VF:
64 mm^2; 1.72 deg
what is a static visual field?
Determines threshold stimulus by increasing/decreasing stimulus intensity (keeps target size constant!)
describe the safest way to remove the gonio lenses
Assume the mirror is suctioned on the eye (3 mirror only). Using the fleshy part of your finger, lift the lower lid, and press against the base of the mirror from the TEMPORAL side (you will have to switch hands). Push directly into the eye in order to break suction. As soon as the bubble appears, pull the mirror off. For the 4 mirror, there will be no suction. Simply remove the mirror.
what are the 2 kinds of punctal plugs?
Plugs can either be temporary (these are typically made of collagen and dissolve in about 7 days) or permanent (these are typically made of silicon and stay in the puncta until they are removed or spontaneously fall out).
where is the fovea located?
The fovea is located 15 deg (3.5 mm) temporal of the edge of the disc and 6 deg (1 mm) inferior to the center of the blind spot . The fovea is 15 deg temporal and 6 deg inferior to the optic disk.
what is one relative contraindication of punctal plugs?
Entropian
what is part of the standard of care for patients with a known or suspected visual field loss?
Threshold visual field Determines the retinal threshold in each tested retinal location
after performing the jones II test, you see greenish irrigant in the basin. No reflux around the cannula or upper punctum was observed. what does this mean?
If dye is retrieved in the basin with no reflux, a partial nasolacrimal duct obstruction is suggested since dye can be irrigated through under nonphysiologic conditions.
after performing the jones II test, you see clear irrigant in the basin. No reflux around the cannula or upper punctum was observed. what does this mean?
If the irrigant retrieved is clear, no dye reached the lacrimal sac, and a punctal or canalicular obstruction is suspected.
after performing the jones II test, you do not see irrigant in the basin, and reflux was observed around the cannula. What does this mean?
If there is reflux around the irrigating cannula, the obstruction is likely at the level of the common canaliculus.
after performing the jones II test, you do not see irrigant in the basin, and reflux was observed around the punctum. What does this mean?
If there is reflux from the upper punctum, there is an obstruction at or below the sac.
what type of lens is used for direct gonioscopy? why is it not preferred?
Koeppe lens: high plus contact lens (50D) that allows 360 degrees of visualization of the angle--patient needs to be supine to obtain a 360 view
what are punctal plugs for?
Punctal plugs are used to decrease the outflow of tears through the lacrimal drainage system. They are typically inserted in the lower puncta, but can also be inserted into the upper puncta also.
the temporal retinal vessels that are part of the arcades supply?
These supply oxygen and nutrients to the inner 1/3 of the retina.
when would you perform indentation gonioscopy?
Used to distinguish between an angle closed by pupillary block (which can potentially be opened with peripheral iridotomy laser surgery) and an angle closed by peripheral anterior synechiae (impossible to open) in narrow angles.
describe average angle depth of each quadrant of the anterior chamber
Widest = inferior angle Narrowest = superior angle Temporal angle is more narrow than the nasal angle □ Basically, widest to smallest = inferior, nasal, temporal, superior The normal difference in the depth of angle between quadrants is only half structure.
define relative VF defect
a condition of less than normal sensitivity This is a defect in which the measured sensitivity at a location (X,Y) changes with change in the size and/or intensity of the stimulus (i.e. the person may see the stimulus if it is large or intense enough).
the vortex ampulla divide the retina how?
anatomically divide the mid-peripheral retina (posterior) from the far- peripheral retina (anterior).
what is the physiological blind spot?
area of no vision corresponding to the ONH which lacks photoreceptors □ Represented graphically by a bottomless pit with steep borders
what is the Jones II test? how is it performed?
assesses nasolacrimal drainage under nonphysiologic conditions. 1. remaining fluorescein is flushed from the conjunctival sac 2. Clear, sterile irrigation fluid (balance salt solution, saline) is placed in a 3-mL syringe with a lacrimal irrigation cannula. The cannula is inserted through the inferior punctum and canaliculus. Irrigation occurs with the patient's head held over a white basin.
what is the Jones I test for? how is it performed?
assesses nasolacrimal drainage under physiologic conditions. 1. Fluorescein 2% is placed in the tear meniscus. 2. A cotton tip applicator is then placed under the anterior half of the inferior turbinate (in the nose). 3. After 5 minutes, the applicator is removed. results: If dye is present, there is at least some flow of tears through the lacrimal system (positive result). If no dye is present, a functional obstruction of the lacrimal drainage apparatus is suggested. However, up to one-third of patients with unobstructed lacrimal systems may have a false- negative result.
homonymous "pie on the floor" defects are caused by lesions in?
baum's loop-parietal lobe
define absolute VF defect
defect in which no stimulus is perceived at a given location This is a defect in which the measured sensitivity at a location (X,Y) does NOT change with a change in the size and/or intensity of the stimulus (i.e. no matter how large or intense the stimulus is, the person will not see it).
how do inclined mirrors on indirect gonio lenses help obtain a better view?
eliminates internal corneal reflection of light that can degrade the images obtained and can also be done on an upright patient.
which dye do you use to measure TBUT?
fluress (fluorescein)
how do you perform/interpret the TBUT test?
instill fluorescein via strip or drop, observe patient's eye with bright blue light. have patient blink several times then hold their eye open until you notice breakup. ◊ Hyperfluorescence: more than normal dye has pooled, indicates depression ◊ Hypofluorescence: less than normal dye, indicates elevation
define isopter
locations in the visual field with identical retinal sensitivity (aka areas on the retina with equal sensitivity)
the more intense the VF stimulus, the (higher/lower) the dB amount
lower
you see an abnormality in the upper right quadrant of your 20D lens when the patient is looking straight ahead (posterior pole). Were is the abnormality actually located on the retina?
lower left
what transition is marked by the ora serrata?
marks the transition from photosensitive cells to non- photosensitive cells.
hononymous "pie in the sky" defects are caused by lesions in?
meyer's loop-temporal lobe
how do you express a stimulus intensity using the standard established with the Goldmann bowl perimeter
multiply the value of the number by the letter
homonymous hemianopia with macular sparing is due to lesions in the?
occipital lobe (visual cortex)
what is the most anterior retinal finding?
ora serrata
krukenberg spinde, transillumination defects, and sampaolesi's line are common signs of?
pigment dispersion syndrome
when may schlemm's canal fill with blood?
pressure on the globe or occlusion of the recipient veins in a sector of the conjunctiva and episclera
samaolesi's line, transillumination defects at the pupil margin, and frosting of lens zonules are common signs of?
pseudoexfoliation syndrome
why is it necessary to ask the patient to look up and away from the nose during punctal dilation?
so the cornea is not endangered
what does rose-bengal/lissamine green stain actually stick to?
stains dead or devitalized tissues
punctal plugs work best for what type of dry eye?
tear film quantity issues--good quality, but insufficient production or excessive drainage
the LGN is located in the ?
thalamus
define threshold stimulus
the minimum stimulus size and intensity combination which a subject can detect at a point
how can you differentiate a choroidal nevus from a retinal nevus?
use the red free filter: the choroidal nevus will NOT show up
when would you do a lacrimal dilation/irrigation
when a patient has epiphoria
what is an absolute contraindication to lacrimal dilation/irrigation
□ Acute dacryocystitis = infection of the lacrimal drainage system
color, location, and function of trabecular meshwork:
□ Color: gray to brown band Anterior TM = less pigmented Posterior TM = more pigmented Posterior TM = more pigmented □ Function: drainage of aqueous humor □ Schlemm's canal lies behind the posterior 2/3 of TM
color, location, and function of ciliary body:
□ Color: light gray to dark brown □ Location: most posterior structure, extending from the ora serrata to the scleral spur □ Width varies depending on the iris contour □ Function: aqueous humor production
color, location, and function of schwalbe's line:
□ Color: thin and glistening white band □ Location: most anterior structure □ Function: marks the end of Descemet's membrane; serves as the transition from cornea to sclera
color, location, and function of scleral spur:
□ Color: white or gray band □ Location: prominent band between the darker CB and TM □ Function: point of attachment between the sclera and ciliary muscles
what are the 2 possible "results" of lacrimal irrigation?
□ If it is open, the patient should taste the solution in the back of their throat. □ If it is closed, the solution regurgitates from the puncta. In this case, counsel on surgical treatment and refer.
what oral medications can be used during the acute phase of acute angle closure?
□ If no kidney issues, use Acetazolamide 500 mg. □ If there are kidney issues, use Methazolamide 100 mg.
how does indentation gonio work?
□ Indentation of the corneal apex with the goniolens allows for visualization of the angle structures by pushing the iris root away from the angle.
what ocular medications can be given during the acute phase of acute angle closure?
□ Pilocarpine 2% mechanically reduces angle obstruction via miosis. □ Beta-blocker (timilol maleate 0.5% if no cardiac issues) decreases aqueous production. □ Alpha-adrenergic agonist (Alphagan P [brimonidine tartrate 0.1%]) decreases aqueous production and increases uveo-scleral outflow.
what drops do we use to dilate prior to BIO?
□ T1 (Tropicamide 1%)--what we use in lab □ PE2.5 (Phenylephrine 2.5%)
when would you want to use a 4-mirror gonio lens
◊ Routine observations of the anterior chamber and posterior pole ◊ "Can I safely dilate this patient?"
when would you want to use a 3-mirror gonio lens
◊ Studying anatomy and identifying pathology in both the anterior chamber, posterior pole, and the retina For more in depth views