Non contact tonometer ppt

this slide is very and so easy to understand about non contact tonometre

1. NON CONTACT TONOMETER SATISH KUMAR B. Optm . 2 nd Year IGIMS PATNA

2. NON-CONTACT TONOMETER Mainly the tonometer is used as the pressure measurer of eyeball. It measures the IOP inside the eyeall . Non-Contact tonometer is a Part of Tonomerter by which we can measure the pressure of eyeball without contact of patient. The pressure is measured in mmhg .

3. HISTORY OF NCT Non Contact Tonometer was invented by Benard Grolaman (1972) of Reichert. It uses a rapid air pulse to applanate the cornea.

4. Principle of NCT A puff of air creats a constant force which momentraily deforms the cornea. It is difficult to determine the exact nature of corneal deformation, althrough it is potulated that the central cornea is flattened at the moment the pressure is measured.

5. Types of NCT Table mounted- Xpert NCT Hand held- Pulsair tonometer from keeler

6. Parts of NCT Alignment System Opto electronic applation monitoring system Pneumatic system

7. Aligment System Allows the operator to optically align the patients cornea in three dimensional-axial, vertical and lateral. In present models the air puff is automatically triggered when alignment criteria are satisfied

8. Monitoring System This consist of a transmitter, which directs A collimated beam of light at corneal vertex. A receiver and detector, which accepts only parallel and coxial rays, reflected form the cornea.

9. Pneuamtic System Generates a puff of air which is directed against the cornea. At the moment of centeral cornea is flattened the greatest numbers of reflected rays are received, which is recorded as the peak intensity of light detected.

10. The time interval for an average measurement is 1 to 3 ms (1/500th of the cardiac cycle) and is random with respect to the phase of the cardiac cycle, so that the ocular pulse becomes a significant variable and it cannot be averaged as with other tonometers . Glaucomatous eyes have significantly greater range of momentary fluctuations in IOP. It is recommended that more than 3 readings within 3 mm Hg range be taken and averaged as IOP.

11. Glaucomatous eyes have significantly greater range of momentary fluctuations in IOP. It is recommended that more than 3 readings within 3 mm Hg range be taken and averaged as IOP.

12. ERRORS IN NCT Corneal Opacity Hazy media High Astigmatism Low Visual Acuity

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