Cornea and Cornea Topography

With Bausch and Lomb

Orbscan IIz

5 Layers of Cornea Epithelium Bowman’s Membrane Stroma Descemet’s Membrane Endothelium

Epithelium Provides Protection Provides a smooth surface so that

nutrients and oxygen can transfer to the cornea.

A lot of nerve endings

Bowman’s Membrane Composed of strong collagen tissue Helps to maintain the cornea’s shape Helps anchors down the epithelium

Stroma Contains mostly of water and protein The alignment of collagen fibers help

the cornea retain its clarity.

Descemet’s Membrane Filters out infections and disease Helps with the stroma in maintaining

the rigid shape of the cornea

Endothelium Helps pumps fluid out of the Stroma

Corneal Topography 3D view of Cornea Aids in diagnosis various cornea

conditions and disease Used in Laser Refractive Surgeries

K Readings Measures is Diopters K< 41D is consider flat K>46D is consider Steep K>41 but <46 is consider average Important in determining LASIK K readings are also used in IOL

Master to calculate IOL’s

Anterior Map

Posterior Map

Keratometric Map

Regular Astigmatism

Irregular Astigmatism

Pachemetry Map

Normal Topography

Abnormal Topography

Abnormal Topography

Keratoconus Abnormal Cornea condition where the cornea

protrudes out more; Instead of a Dome like Figure, it becomes like a cone

Distorts and reduces vision Usually bilaterally but asymmetrical Usually Myopic with large amounts of Irregular

astigmatism No corneal refractive surgeries can be done As the cornea steepens, the cornea pachemtry

gets thinner

Keratoconus cont…

3D Anterior Map of KC

3D Posterior Map of KC

How to take Topographies Have the patient sit at a comfortable

level Inform the patient on what test you

are doing Try to have a good tear film Let the patient know they cannot

move doing this test

Demonstration of Topography

How to take Pachs with Ultrasound

Always have pt look at a fixation point

Carefully touch the central cornea with tip

Try not to indent the cornea Always get a consistent reading

Demonstration of US Pachs

Keep in your head Consistency is the answer Knowing what is normal and

abnormal Good tear film Being comfortable with the machine

will make the patient more comfortable with you

When in doubt always ask