The document summarizes an experiment measuring pressure in goat eyes using an applanation tonometer. The experiment found that increasing vitreous pressure in the eye did not consistently increase or could decrease anterior chamber pressure, but increasing anterior chamber pressure did raise vitreous pressure. The conclusions were that anterior chamber pressure measurements do not correlate with vitreous pressure, vitreous pressure may be high even when anterior chamber pressure is normal, and glaucoma damage is caused by high vitreous pressure rather than anterior chamber pressure.

1. Tonopen applanation tonometer with small tip, ultrasound
verifies applanation.

2. Freshly enucleated goat’s eyes

3. Pressure checked on deep sclerectomy

4. drawbacks
1. Dead eye with inactive
metabolism
2. Test performed with eye out of
socket.
3. Deep sclerectomy depth was not
uniform in all eyes .

5. Instrument takes many measurements
and averages them.

6. Showing how pressure was changed

7. When vitreous pressure was increased anterior chamber
(ac)pressure did not increase or it even dropped. But when ac
pressure was increased, vitreous pressure went up hand in hand.
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8. conclusions
1. Anterior chamber (AC) pressure as is measured clinically
today does not corelate with vitreous pressure.AC
pressure values may be low or normalbut vitreous
pressure may be very high.
2. Glaucoma damage happens because of pressure effects
on the nerve head, namely the vitreous pressure.
3. The findings agree with a previous french study in its
findings, though pressure measurement method in the
french study was different.( acta ophthalmologica ,
Hernandez and Bolivar2010)
4. This may explain pathogenesis of low pressure glaucoma.
5. Instruments to measure vitreous pressure are
required.Surgeries /implants/drugs designed to
lower anterior chamber pressure may not help a
patient.