Conjunctiva ppt includes anatomy, physiology and age related changes in the eye,

1. Review of Basics
CONJUNCTIVA

2. Introduction
• The conjunctiva is a mucous membrane consisting of loose, vascular connective tissue.
• It is transparent.
• Its transparency is less than that of the cornea when observed with a slit-lamp.
• Is loose, to allow free and independent movement of the globe.
• Is thinnest over the underlying Tenon's capsule.

3. Parts of conjunctiva
• The conjunctiva can be divided into three
sections that are continuous with one
another:
• (1) the tissue lining the eyelids is the
palpebral conjunctiva, or tarsal
conjunctiva;
• (2) the bulbar conjunctiva covers the
sclera; and
• (3) the conjunctival fornix is the cul-de-
sac connecting palpebral and bulbar
sections

4. Cul-de-sac
Its continuous with
• the lining of the globe beyond the cornea the upper and
lower fornices
• the innermost layer of the upper and lower eyelids
•
• the skin at the lid margin
• the corneal epithelium at the limbus
• the nasal mucosa at the lacrimal puncta
• The cul-de-sac normally holds 7µl of tear fluid but has the
capacity to accommodate fluid up to 30 µl
Whitnall & Ehlers, 1965

5. Layers of conjunctiva
Microscopically conjunctiva consists of three layers- epithelium, adenoid layer, and a fibrous layer.

6. Conjunctival
Epithelium
Conjunctiva Number of layers Cells in the layers
Marginal 5 layered non-
stratified
squamous epithelium
Superficial layer:
cells
Middle three layers:
cells
Deepest layer:
Tarsal 2 layers of Stratified
epithelium
Superficial layer:
Deepest layer: cuboidal
Fornix and bulbar 3 layers of Stratified,
epithelium
Superficial layer:
Middle layer: polyhedral
Deepest layer: Cuboidal
Limbal 10 layers of stratified
epithelium
Superficial layer:
Middle layer: polygonal
Basal- cubical
Other than squamous epithelial cells
• Goblet cells- 10-20 µm in size, arise from
basal layer, secretes mucin
• Langerhans cell- dendritic immune cells
AKA Birbeck granule
• Melanocytes – secretes melanin

7. Substantia propria
or conjunctival
submucosa
• It consists of a superficial lymphoid layer and a deeper
fibrous layer
• This tissue has enormous anti-infectious potential.
Numerous mast cells (6000/mm3), lymphocytes,
plasma cells, and neutrophils are normally present in
this layer
• Lymphoid layer – CALT(Conjunctiva Associated
Lymphoid Tissue) consists of T & B lymphocytes
• Mast cells- Mast cells are granulocytic cell-like
basophils.coated with IgE antibody. The contents of the
mast cell act like mediators of allergic reactions.

8. Fibrous layer
• This layer contains the vessels and nerves of conjunctiva and aqueous secreting glands
• Protects deeper layers
Accessory lacrimal glands like glands of Krause & Wolfring are situated in this layer

9. Blood supply

10. Nerve supply

12. Age related changes in conjunctiva
Pinguecula
Definition
Harmless grayish yellow thickening of the conjunctival
epithelium in the palpebral fissure.
Epidemiology: Pinguecula are the most frequently observed
conjunctival changes.
Etiology: The harmless thickening of the conjunctiva is due
to hyaline degeneration of the subepithelial collagen tissue.
Advanced age and exposure to sun, wind, and dust foster the
occurrence of the disorder.
Symptoms: Pinguecula does not cause any symptoms.
Diagnostic considerations: Inspection will reveal grayish
yellow thickening at 3 o’clock and 9 o’clock on the limbus.
The base of the triangular thickening (often located medially)
will be parallel to the limbus of the cornea; the tip will be
directed toward the angle of the eye
Differential diagnosis: A pinguecula is an unequivocal
finding.
Treatment: No treatment is necessary. Only in cosmetic
considerations

13. Pterygium
Definition Triangular fold of conjunctiva that usually grows from the medial portion of the palpebral fissure toward the cornea.
Epidemiology: Pterygium is especially prevalent in southern countries due to increased exposure to intense sunlight.
Etiology: Histologically, a pterygium is identical to a pinguecula. However, it differs in that it can grow on to the cornea; also this encroachment
is thought to be a preventive measure to save the cornea, the gray head of the pterygium will grow gradually toward the center of the cornea.
This progression is presumably the result of a disorder of Bowman’s layer of the cornea, which pro-vides the necessary growth substrate for the
pterygium.
Symptoms and diagnostic considerations: A pterygium only produces symptoms when its head threatens the center of the cornea and with it
the visual axis. Tensile forces acting on the cornea can cause severe corneal astigmatism. A steadily advancing pterygium that includes scarred
conjunctival tissue can also gradually impair ocular motility; the patient will then experience double vision in abduction.
Differential diagnosis: A pterygium is an unequivocal finding.
Treatment: Treatment is only necessary when the pterygium produces the symptoms discussed above. Surgical removal is indicated in such
cases. The head and body of the pterygium are largely removed, and the sclera is left open at the site. The cornea is then smoothed with a
diamond reamer or an excimer laser (a special laser that operates in the ultraviolet range at a wavelength of 193 nm).
• Conjunctival graft is also used to prevent recurrence.

14. General age related changes
In old age, changes to the eye may include the following:
• Yellowing or browning of the conjunctiva caused by many years of exposure to ultraviolet
light, wind, and dust
• Thinning of the conjunctiva
•Overall dryness or loss of lustre of mucosal membrane of conjunctiva

15. References:
• Shumway CL, Motlagh M, Wade M. Anatomy, Head and Neck, Eye Conjunctiva. [Updated 2022 Aug 30]. In:
StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
https://www.ncbi.nlm.nih.gov/books/NBK519502/
• Histological, immunohistochemical and clinical considerations on amniotic membrane transplant for ocular surface
reconstruction - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Microscopic-
aspect-of-bulbar-conjunctiva-stratified-squamous-epithelium-situated-on_fig1_319332604 [accessed 26 Apr, 2023]
• Knop E, Knop N. The role of eye-associated lymphoid tissue in corneal immune protection. J Anat. 2005
Mar;206(3):271-85. doi: 10.1111/j.1469-7580.2005.00394.x. PMID: 15733300; PMCID: PMC1571473.
• Adler’s physiology of the eye
• Clinical anatomy & physiology of the visual system, Lee Ann Remington