Changes in Myopia and Aging Flashcards
At birth, the cornea’s diameter is….
10mm
90% of adult
Cornea grows to adult size at age….
3
Sclera grows to adult size at age….
10 - 12
Eyes should be emmetropic by age….
6 - 8
due to cornea and scleral growth
Aging Changes of Cornea
decrease in sensitivity increase light scatter flattens - against the rule stippling of Bowman's membrane thickening of Descemet's membrane
Corneal Arcus
bilateral ring of cholesterol and cholesterol esters in peripheral stroma; extends into Bowmans
if under age 40- hyperlipidemia
Integrins
form bridges from cell to cell or cell to extracellular matrix
aging causes reduction of adhesion molecules needed for intercellular junctions
Loss of Intracellular Junctions
breakdown of barrier function of corneal epithelium
Hudson-Stahli Line
iron deposits in epithelial cell cytoplasm
evident at lower lid margin
age 50-70
increased by hydroxychloroquine
Limbal Girdle of Vogt
degeneration of Bowman’s layer
yellow-white opacity at 3 and 9 positions
Changes in Descemet’s Membrane with Age
increases with thickness
Hassall- Henle bodies increase in periphery
Hassall- Henle Bodies
asymptomatic; small round peripheral indentations
from thickening of Descemet’s
appear as corneal guttata
can cause atypical arcus
Aging Changes to Corneal Endothelium
Decrease in cell density
more variation in size and shape
Krukenberg’s Spindle
pigment deposits on the posterior cornea with vertical orientation
Why does corneal sensitivity decrease with age?
loss of corneal nerves
