7 - Cornea1

Question 1

Dellen

Answer 1

= DEHYDRATED STROMA

Area of cornea that wets poorly -> stromal dehydration + corneal thinning -> positive staining/pooling of fluoro

Seen adjacent to areas of elevation (e.g. pterygia)

Asymptomatic or complaints of FBS, other dry eye symp

Question 2

Exposure keratopathy

• pathophys
• signs/symp

Answer 2

= EYELID ISSUE

Abnormal or incomplete lid closure:

• CN7 issue: Bell’s (idiopathic), cerebrovascular accident, aneurysm, MS, HS/ZV, sarcoid
• orb.oculi issue: surgery causing ectropion, TED, floppy eyelid, #1 NOCTURNAL LAGOPHTHALMOS

Signs: vary from mild SPK (esp INFERIOR 1/3rd) to corneal ulceration, decr corneal sensitivity is common

Symp: redness/FBS/burning that’s WORSE IN THE MORNING

Question 3

Filamentary keratopathy

• who
• pathophys

Answer 3

Hx of multiple episodes, chornic symptoms of irritation and dryness

CHRONIC INFLAMMATION of cornea -> oc surf dz
#1 = keratoconj-itis sicca
-others: floppy eyelid, slk, corneal erosion, cls overwear, neurotrophic k

Question 4

Filamentary keratopathy

-signs/symp

Answer 4

Signs: filaments = mucus + degenerated epithelial cells

• remain attached to corneal surface
• range from 0.5 to 10mm
• early = comma-shaped, late = stringy
• will stain with fluoro

Symp: mild-severe FBS, photophobia, epiphora, blur, blepharospasm

Question 5

Superficial punctate keratitis

• pathophys
• signs/symp

Answer 5

Non-specific inflammation of corneal epithelium
-cls wear, corneal infxn, dry eye, blepharitis, etc.

Pinpoint defects in corneal epi - stains with fluoro
-localized, scattered, confluent (severe)
Asymptomatic; blur, irritation, fbs, photophobia, redness, tearing

Question 6

Thygeson’s superficial punctate keratopathy

• who
• pathophys

Answer 6

Rare, 2nd-3rd decade, hx of recurrent episodes, no sex predilection

UNKNOWN ETIOLOGY

• may be viral, autoimmune
• no known associated condns

Question 7

Thygeson’s superficial punctate keratopathy

-signs/symp

Answer 7

Signs: BILATERAL (90%), small, multiple, asymmetric GRAY-WHITE clusters of superficial INTRAEPITHELIAL raised CENTRAL corneal lesions (“crumb-like” opacities)

• acute attacks: last 1-2mo, light fluoro staining, exacerbations within 6-8wks
• remissions: no staining

Symp: FBS, photophobia, tearing, OCCASIONAL BLURRED VISION
-overall, eye is relatively quiet (no ac rxn, conj injection)

Question 8

3 condns to think of when see intraepithelial corneal defects

Answer 8

Thygeson’s
Herpes
Meesman’s

Question 9

Neurotropic keratopathy

• who
• pathophys

Answer 9

Past surgical procedures, cls wear, systemic dz, meds

Damage to sensory supply anywhere from trigeminal nucleus to corneal nerve endings -> CN V1 neuropathy -> decr corneal sensitivity + decline in corneal regeneration/wound healing

Question 10

Neurotropic keratopathy

-common causes

Answer 10

Directly affecting V1: HSV, HZV, DM, LASIK
-also RCEs/dystrophies, medications (timolol, betaxolol, diclofenac sodium)

Damage to CN 7 -> impaired reflex tearing -> chronic damage to ocular surf + disruption to V1

Question 11

Neurotropic keratopathy

-signs/symp

Answer 11

Signs: decr corneal sensitivity

• early: SPK, perilimbal injection
• late: sterile inferior oval ulcer (-) signs of inflammation

Symp: redness, tearing, decr vision, fbs, swollen eyelids
-CORNEAL FINDINGS»_space;> SYMPTOMS INDICATE

Question 12

Recurrent corneal erosion

-pathophys

Answer 12

POOR HEMIDESMOSOME ATTACHMENTS to underlying basement membrane
2 scenarios: past abrasian (trauma), dystrophy (EBMD)
-incr risk if abrasion results from organic etiology (fingernail, stick)

Question 13

Recurrent corneal erosion

-signs/symp

Answer 13

Signs: abrasion of varied size that stains with fluoro

Symp: recurrent, ACUTE PAIN WORSE IN MORNING UPON WAKENING, lacrimation, photophobia, blur

Question 14

Thermal/UV keratopathy

• who
• pathophys

Answer 14

Prolonged skin exposure, welding, skiing/mountaineer, sunlamps

Epithelium + Bowmans absorb <300nm (UVC)
Excessive UVC absorption -> hyperactivation of K+ channels -> loss of intracellular K+ -> cell death

Question 15

Thermal/UV keratopathy

-signs/symp

Answer 15

Signs: confluent SPK - stains with fluoro

Symp: pain, photophobia, blur
-WORSE 6-12hrs AFTER INCIDENT

Question 16

Dry eye disease

• definition
• who is most likely to have it

Answer 16

Multifactorial dz of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to ocular surface

Older, menopausal women

Question 17

Dry eye disease causes

-medications

Answer 17

Anticholinergic (anti-PNS) effects:

• STop ACH
• anti-histamines/psychotics/depressants/anxiety
• muscle relaxant (cyclobenzaprine)
• ipratropium (via muscarinic blockade)

Other: isotretinoin, BBs, contraceptives, HRT, ADHD, diuretics

Question 18

Dry eye disease causes

• sytemic diseases
• environmental factors

Answer 18

Big 4: TED, RA, Sjogren’s, Lupus

Fans, dusty environ, low humidity

Question 19

Dry eye disease

-signs/symp

Answer 19

Signs:

• general: decr TBUT, incr tear osmolarity
• aqueous deficient: THIN TEAR MENISCUS/LAC LAKE/PRISM (<0.2mm), decr Schirmer + phenol red thread (<10mm in 15sec)
• evaporative: decr TBUT, poor expression/atrophy of meibomian gland
• other: conj hyperemia, tear film debris, staining with lissamine green (classically 3/9 o’clock)

Symp: burning, dryness, tearing, itching, blinking, photophobia, cls intolerance, fbs
-WORSE AT THE END OF THE DAY

Question 20

Dry eye disease
-interpretations of:
—Schirmer 1 + 2
—phenol red thread

Answer 20

S1 = WITHOUT ANESTHETIC = basal, reflex, emotional secr

• normal >10mm in 5 min
• abnorm <5mm in 5 min

S2 = WITH ANESTHETIC = ONLY BASAL (krause, wolfring) secr
-normal >5mm in 5 min

Phenol
-normal >10mm in 15sec

Question 21

Dry eye disease

-primary mechanisms (2)

Answer 21

Tear HYPEROSMOLARITY -> inflammatory cascade -> damages ocular surf + releases inflamm mediators into tears

• normal/avg: 308 mOSm/L
• dry eye is >308 OR >8 difference between eyes

TF INSTABILITY
-can be secondary to hyperosmolarity or disease process

Question 22

2 divisions of aqueous deficient dry eye

Answer 22

Sjogren’s

Non-sjogren’s

Question 23

Primary vs secondary sjogren’s

Answer 23

P: dry eye, dry mouth

S: TRIAD - dry eye, dry mouth, autoimmune CT dz

• RA, SLE, polyarteritis nodosa, wegener’s
• ACCOUNTS FOR 50% OF DRY EYE CASES!

Question 24

Non-sjogren’s aqueous deficient dry eye

Answer 24

Secondary to LACRIMAL GLAND DYSFUNCTION

Primary lac gland deficiency: #1 AGE-RELATED

Secondary lac gland deficiency: ABC

• attacked gland (sarcoid, lymphoma, aids, graft vs host)
• blocked gland duct (trachoma, pemphigoid, erythema multiforme, burns)
• cut nerves (cls wear*, diabetes, bells, drugs, neuro k, surgery)
• ~50% of cls wearers have dry eye symptoms

Question 25

Evaporative dry eye | -3 main causes

Answer 25

MGD Vit A deficiency Contact lens wear

Question 26

Evaporative dry eye | -intrinsic causes

Answer 26

``` Pathology in lid structure/dynamics #1 MGD Lid position disorders: ptosis, nocturnal lagophthalmos Low blink rate: intense concentration, computers, Parkinson’s -results in poor expression of meibum -> hyperkeratinize -> obstruction -> intraductal htn due to build-up -> duct dilation -> mg atrophy ```

Question 27

Evaporative dry eye | -extrinsic causes

Answer 27

Independent of lid pathology Oc surf dz: vit A deficiency (xerophthalmia), topical anesthetics/preservatives Contact lens wear

Question 28

All corneal ectasias can cause

Answer 28

Hydrops = splitting of Descemet’s

Question 29

List 3 corneal ectasias

Answer 29

Keratoconus Pellucid marginal degeneration Keratoglobus

Question 30

Keratoconus | -who

Answer 30

Usually sporadic 6-13% of cases are AD Commonly presents around puberty 53% have hx of atopy

Question 31

Keratoconus | -pathophys

Answer 31

Non-inflammatory, progressive, degenerative dz of unknown etiology Stromal collagen FIBRIL DISPLACEMENT due to loss of adhesion between fibrils -> corneal thinning + protrusion due to degeneration of fibrils by MMPs Assoc with eye rubbing, atopy, cls wear, ocular condns, systemic condns - ocular: allergic (vkc, akc, fes), connective tissue abnorm (fuchs, ppmd, granular, lattice), hereditary (aniridia, rp, lebers, rop, cone dystrophy) - systemic: TDOME (turners, downs, oi, marfans, ehlers)

Question 32

Keratoconus | -signs/symp

Answer 32

Signs: - early: fleischer’s ring (iron), scissors reflex, irregular mires, inferior topography steepening - late: vogt’s striae (vert lines in desc, disappear with pressure), muson’s sign, rizzuti’s sign (conical reflection on nasal cornea with temporal lighting), hydrops - 53% with mod-severe develop scarring Symp: progressive decr vision, photophobia, glare, monocular diplopia, ghost images -acute vision loss + pain if hydrops develops

Question 33

Keratoconus | -mild vs mod vs severe

Answer 33

Mild: <48D Mod: 48-54D Severe: >54D

Question 34

Pellucid marginal degeneration - who - pathophys

Answer 34

Early adulthood (20-40), no sex predilection Unknown etiology Thought that COLLAGEN ABNORMALITIES -> thin, weakened area with crescent-shaped inferior distribution IOP causes corneal protrusion right above area of thinning (NOT WITHIN area of thinning, as with keratoconus)

Question 35

Pellucid marginal degeneration | -signs/symp

Answer 35

No pain Bilateral, inferior corneal thinning: 4 to 8 o’clock, 1-2mm from limbus High ATR astig Topography: “kissing doves” or “crab claws”

Question 36

Keratoglobus - who - pathophys - signs

Answer 36

Congenital, AR (tho may be acquired from advanced k-con, trauma, exophthalmos) Assoc with Ehlers-Danlos, blue sclera, Leber’s congenital amaurosis Diffuse corneal thinning - concentrated in periphery Can result in acute corneal edema due to rupture in descemet’s