L10 Corneal Ectasia

common hallmark of corneal ectasias is that the cornea is ______

thinning

with corneal ectasias, is the condition bilateral or unilateral

bilateral

with corneal ectasias, is the condition symmetrical or asymmetrical

asymmetrical

in corneal ectasias, is there normally inflammation? yes or no

no, its non inflammatory

what is associated with corneal ectasias normally? (4)

obesity, sleep apnea, down syndrome, atopic disease

_____ is the bilateral, asymmetric, noninflammatory progressive corneal steepening and eventual corneal thinning

keratoconus

keratoconus typically effects the ___ to the ____ of the cornea

inferior, center

keratoconus usually onsets during _____ and varies its rate of progression lasting until 30s-___

puberty, 40s

does keratoconus affect one gender more than the other? yes or no

no

keratoconus has higher rates in ___/___ countries/area

asia/Middle East

keratoconus

keratoconus pathology begins with the combination of (3)

genetic, biochemical, and environment

keratoconus pathology begins with the combination of genetic, biochemical, and environment process. this gives rise to the alterations of enzyme levels causing stromal degradation leading to ____ ___. in addition to this, there is an increase levels of degradative lysosomal enzymes and decreased levels of inhibitor proteolytic enzyme

stromal thinning

during the keratoconus pathologenesis and after thinning of the stroma, next is the increased ______ of stromal keratocytes. due to this there is decreased collagen and extracellular matrix production thus leading to reduced _____ ____

apoptosis, stromal mass

keratoconus has a strona assoication with ____ ____ which is the mechanical epithelial truama. this trauma leads to wound healing and then keratocyte apoptosis

eye rubbing

its theorized that keratoconus has _____-_____ pattern of inheritance aka incomplete penetrance

autosomal - inheritance

keratoconus systemic associations are (6)

sleep apnea, asthma, down syndrome, Ehlers Danlos, osteogenesis imperfecta and marfans

Keratoncus ocular associations are (7)

VKC

floppy eyelid syndrome

leber congenital amaurosis

retinitis pigmentosa

retinopathy of prematurity

Fuchs dystrophy

posterior polymorphous dystrophy

1. corneal steepening

2. thinning of corneal apex

3. scarring at level of bowmans level

4. vogt striae

5. fleishers ring

6. munsons ring

7. rizuttis sign

8. charleux sign

9. scissoring reflex

are all signs of

keratoconus

what are tow machines that can diagnose keratoconus

topography and tomography

while diagnosing keratoconus, Rabinowitz criteria is used, which is ? (5)

K > +47.20D

I-S dioptric asymmetric > +1.20D

KISA% > 60%

Astigmatism >1.5D, Irregular astigmatism

pachymetry/asymmetrx index <105

what other criteria is considered while diagnosing keratoconus (3)

1. abnormal posterior elevation

2. abnormal corneal thickness distribution

3. clinical evidence of non inflammatory corneal thinning

keratoconus penatcam measures :

belin ambrosia enhanced ectasia display (BAD)

what is BAD total deviation value (BAD_D)

integrates anterior elevation, posterior elevation and pachymetry measurements relative to best fit spheres

a 22 year old patient comes in and their VA are not reaching 20/20 and you see signs of what could look like keratoconus before coming to that diagnosis, what are other differentials that it could be

pellucid marginal corneal degeneration

keratoglobus

contact lens induced corneal warpage

protrusion/thinning following ulceration

________ ____ _____ is described as one eye with bsence of clinical signs/topographic abnormalities and the other with KCN. in addition its important to consider prior to refractive sx

forme fruste kcn

____ ___ is described as one eye with topographic signs of keratoconus without slit lamp findings and the fellow eye is with KCN

subclinical KCN

1. steepening of anterior corneal surface

2. steepening of posterior corneal surface

3. thinning and/or increase in rate of corneal thickness change from periphery to thinnest point

this describes the progression of ______

keratoconus

the development of keratoconus can cause (4)

progressive myopia

irregular astigmatism

corneal scarring

corneal hydrops

there are several tx options for keratoconus such as (7)

spectacles

CL- spherical, custom, toric

RGP

special lens: hybrid, piggy back, slerals

surgery- PKP or DALK

INTAC corneal ring segment

_____ is full thickness transplant whereas _____ keeps the endothelium only but everything is else is from a donor.

PKP, DALK

DALK keep the patient's original endothelium this _____ chances of rejection because not foreign

decreases

___ _____ ____ halt or slows the progression of keratoconus

corneal cross linking

__ ____ ___ is the polymerization of stroma using riboflaviin and UVA

corneal cross linking

which version of corneal cross linking is FDA approved

epi off

for corneal cross linking what is the Dresden procol? (3)

removal of central epithelium

topical application of riboflavin

irradation with UVA (370nm) for 30 mins

who and when is corneal cross linking for

children at the onset of progression

corneal cross linking can result in complications such as (5)

stromal edema and haze

scarring

infectious keratitis (IK)

diffuse lamellar keratitis (DLK)

sterile infiltrates

what are contraindications of corneal cross linking (9)

corneal thickness <400um

preop K > 58D (too steep)

>35 yrs

history of herpes

concurrent infection

severe corneal scarring

history of poor wound healing

ocular surface disease

autoimmune disorder

a 40 year old patient comes to u with hx corneal scars and herpetic infection. you diagnose her with keratoconus. after a few visits she explains she wants to do corneal cross linking. you tell her she is not a good candidate. why did you say no?

she is older than 35, hx of herpes and corneal scars.

___ ____ is sporadic, usually unilateral, non progressive condition in which the posterior corneal surface protrudes into the stroma

posterior keratoconus

what are the two types of posterior keratoconus

keratoconus posticus generalis

keratoconus posticus circumscriptus

posterior associations (c/w dysgenesis) includes (7)

aniridia

ectropion uvea

glaucoma

iris atrophy

anterior lenticonus

ectopia lentis

anterior lens opacities

posterior keratoconus is associated with systemic abnormalities such as (4)

cleft lip

webbed neck

defects in extremities

genitourinary abnormalities

from posterior keratoconus it can lead stromal ____

scarring

what are the two tx options for posterior keratoconus

PKP

does not require tx

___ ___ ___ is corneal thinning and protrusion in the inferior peripheral cornea

pellucid marginal degeneration

pellucid marginal degeneration is characterized by a protrusion _____ area of maximal thinning. There is thinning _-_mm inside the inferior limbus. In addition, horizontal oval band _mm radial, 6-8mm horizontal extent

ABOVE, 1-2, 2

t/f in pellucid marginal degeneration, there is usually a clear cornea without iron line. and regular ATR astigmatism leads to irregular astigmatism

true

pellucid marginal degeneration appears as ____ ____ or ____ ____ in topography and tomography

crab claw, kissing doves

pellucid marginal degeneration usually affects people in which age group

20s-50s

pellucid marginal degeneration can lead to

hydrops

what is tx for pellucid marginal degeneration (4)

spectacles

CL

large diameter RGP

large eccentric keratoplasty

____ is defined as bilateral ectactic disorder that is nonprogressive or minimally progressive

keratoglobus

____ _____ is characterized as limbus to limbus thinning with greatest in corneal periphery/midperiphery

globular corneal protrusion

keratoglobus

what are the two types of keratoglobus

congenital/juvenile

acquired adult

what are two types of congenital/juvenile keratoglobus?

Ehlers Danlos syndrome type VI

brittle corneal syndrome

t/f keratoglobus can be associated with blue sclera

true

is keratoglobus associated with atopy or downsyndrome? yes or no

no

after the development of keratoglobus what can form next (2)

hydrops

perforations

what are the 2 tx options for keratoglobus

protection from truama

PKP but could have poor outcome

is keratoconus bilateral or unilateral and asymmetric or symmetric

bilateral,asymmetric

during which age does keratoconus typically onset?

puberty

keratoconus usually has thinning in the ____ paracentral

inferior

keratoconus has protrusion which is thinnest at the ____

apex

pellucid marginal degeneration is bilateral or unilateral

bilateral

pellucid marginal degeneration onsets durings which years of life

20-40s

pellucid marginal degeneration has thinning at the ____ band 1-2 mm from limbuus

inferior

pellucid marginal degeneration has protrusion _____ to _____

superiorly, thinning

keratoglobus is bilateral or unilateral

bilateral

what is the age of onset for keratoglobus

birth

keratoglobus has thinning ____ but mostly peripherally

global

keratoglobus protrusion is _____

generalized

Posterior KCN is bilaterally or unilateral

unilateral

age of onset for posterior KCN ?

birth

posterior KCN has thinning? (2)

paracentral posterior or

global

posterior KCN has protrusion? yes or no

usually non

keratoconus

pellucid marginal degeneration

keratoglobus

posterior keratoconus

___ ____ ____ ____ ____ is thought to be due to distruption of biomechanical integrity of the cornea even years after

post-refractive surgery corneal ectasia

for refractive sx, FDA requires at least ____um of untouched tissue

250

someone wants to undergo refractive surgery but there are some risks factors that need to be considered such as (5)

abnormal preoperative corneal topography

>40% of tissue altered

low operative corneal thickness

high myopia

younger age

if someone undergoes post refractive surgery and they have corneal ectasia, what are the tx options ?

glasses and CL

possibly CXL (corneal crosslinking

& ICRS(intracorneal ring segment)

___ ____ ___ occurs when there is a break in decemets membrane with inward curling of the membrane

acute corneal hydrops

in acute corneal hydrops, there is stromal ____ due to aqueous entering the breaks as well as intrasomal clefts

edema

acute corneal hydrops commonly seen in patients with

down syndrome

a established patient with keratoconus enters complaining of redness, discomfort, and photophobia. in the slit lamp you notice there is edema and it is not transparent. you also note the patient has down syndrome. what is causing these symptoms?

acute corneal hydrops

acute corneal hydrops usually self resolved within _-_ monhs

2-4

after corneal hydrops corneal ____ could form

scarring

what is the management for acute corneal hydrops (1)

follow up every 1-4 weeks until resolved

what are the tx options for acute corneal hydrops (7)

bandage CL

topical cycloplegia

NaCI 5%

topical steroids

aquous suppressant

injection of gas

pkp

for acute corneal hydrops why is NaCI 5% an option

pulls water out

acute corneal hydrops

keratoglobus

pellucid marginal degeneration

keratoconus