Lec. 2 PT.1: Background and Basic concepts of Glaucoma

Discuss the purposes of aqueous humor

All of the above

What is the purpose of longitudinal fibers in ciliary body muscle?

1. It attaches to the ciliary body to the limbus 

2. It pulls the choroid backwards and opens the TM which helps aqueous outflow

What is the purpose of circular fibers in ciliary body?

1. Anterior & inner portions of the ciliary body

2. It relaxes the zonules which makes the lens thicker and then you accommodate

What is the purpose of radial fibers of ciliary body?

They connect longitudinal fibers and circular fibers 

Name the functional unit of ciliary body that is responsible for production of aqueous humor

Ciliary processes

What are the two layers of ciliary epithelium?

Pigmented & non-pigmented

what does aqueous humor have more than the blood?

Vitamin C & ascorbate

what does blood have more than the aqueous humor?

Protein and glucose

Which process is most responsible for aqueous humor formation?

Active process/secretion - works against the concentration gradient

What time of the day is aqueous humor production highest?

Morning (8am-noon)

What time of the day is aqueous humor production lowest?

Midnight (midnight-6am)

Name two enzymes responsible for aqueous humor production?

Carbonic anhydrase and Na/K ATPase

What intermediate compound is formed when CO2 combines with water by the aid of carbonic anhydrase?

Carbonic acid

In the process of formation of aqueous humor Carbonic acid splits into what?

Bicarbonate and hydrogen ions

Explain pathway of aqueous humor drainage though trabecular meshwork

TM —> inner wall of schlemm’s canal into its lumen —> collector channels —> aqueous veins —> and episcleral venous circulation

Explain the pathway of drainage of aqueous humor through uveoscleral pathway

Across iris root —> uveal meshwork —> and the anterior face of ciliary muscle —> through the connective tissue between the muscle bundles & the suprachoroidal space —> out through the sclera

Uveoscleral pathway activated by prostaglandin analogs take approximately how many weeks to show effect ?

2 weeks when you see effect; 4 weeks for maximum effect.

What percentage range of aqueous humor outflow is trabecular outflow?

70-95%

What percentage range of aqueous humor outflow is uveoscleral outflow?

5-30%

What is lamen explanation of pseudofacility?

When the outflow of aqueous humor doesn’t change (aka TM is the same), but production decreases.

What is pseudofacility?

As IOP increases, aqueous inflow by ultrafiltration is suppressed which slows down rise in IOP, but outflow is not changed

Where do you find thin astrocytes when considering astroglial support of NFL and blood vessels?

Temporally

Where do you find thick astrocytes when considering astroglial support of NFL and blood vessels?

Inferiorly 

What is the effect of age and IOP on level of hyaluronate?

Both decrease hyaluronate

How do you know if the lamina cribrosa pores are healthy?

Round in eyes with physiologic cupping

How do you recognize lamina cribrosa pores of glaucomatous patients?

Compressed pores 

At what age does size of optic nerve head reach 95% of adult dimensions?

Before age 1

In which patient are you likely to see reversibility of cupping?

Children in whom lamina cribrosa is not fully developed

If neuro-retinal rim decreases there is a concomitant increase in what?

Cupping

Pallor of ONH is likely due to what?

Optic neuropathies other than glaucoma

Nitric oxide is beneficial at lower concentrations because?

Vasodilator properties