Original Article

The Measurements of Ocular Pulse Amplitude in Patients with Primary Open Angle Glaucoma and Ocular Hypertension Using Pascal Dynamic Contour Tonometer - Original Article

  • Özcan Ocakoğlu
  • Didar Uçar

Received Date: 11.04.2007 Accepted Date: 15.10.2007 Turk J Ophthalmol 2008;38(3):198-203


Ocular pulse amplitude (OPA) is the difference between the intraocular pressures (IOP) during systolic and diastolic phases. OPA depends on the fluctuations of ocular perfusion and IOP's valu-es. The changes of OPA may preclude the damage on optic nerve. In current study, OPA was determined using Pascal dynamic contour tonometer (DCT) in primer open angle glaucoma (POAG) and ocular hypertension (OHT) eyes and these values were compared with healthy control group. In other hand, the relationship between OPA and central corneal thickness (CCT), age and IOP parameters was investigated.

Materials and Method:

Our study included totally 154 patients (108 POAG, 46 OHT patients) and 54 healthy age-matched persons as control. No eyes had been operated before, no patient had serious oph-thalmic and systemic illness and no patient used systemic medication. In Humphrey visual field analyser central 30-2 threshold test, mean deviation (MD) were >8 db and <15 db in POAG eyes and <3 db in OHT eyes. C/D ratio were >0,5 and <0,7 in POAG eyes and <0,3 in OHT eyes. In healthy group, MD and C/D values were within normal limits. IOPs and OPA values of all three groups were measured simulta-neously using Pascal DCT. In other hands, CCT was determined with ultrasonographic pachymeter. As OPA value, the mean of three measurements of only "Quality 1" was accepted. Mean IOP and OPA values of three groups were compared with unpaired t test. Statistically significant limit was accepted p<0,05. The Pearson correlation analysis was used to investigate the relationship between OPA and age, CCT and IOP. Correlation coefficient was accepted as r>0,25 and statistically significance as p<0,05.


IOP values using Pascal DCT were 17,9+2,7 mmHg, 17,8+3,2 mmHg, 15,7+2,2 mmHg in POAG, OHT and control eyes, respectively. There was no difference with IOP values in POAG and OHT eyes (p>0,05). In control group, mean IOP values were lower than other two groups (p<0,05). OPA values were determined as 3,35+1,1 mmHg in eyes with POAG, 3,54+1,3 mmHg in eyes with OHT and 2,71± 0,9 mmHg in control eyes. OPA values in OHT eyes were statistically higher than both POAG and control eyes (p<0,05). There were no correlation between OPA and CCT (correlation coefficient rt= 0,11, p> 0,05) and age (r2=0,06,p>0,05). We found a weak correlation between OPA and IOP (correlation coefficient r3= 0,28, p<0,05).


OPA is a reflection of ocular blood flow and an indirect value of choroidal perfusion. OPA does not affected by CCT and age, but IOP changes may affect OPA minimally. In current study, OPA in OHT patients are higher than in POAG and healthy control eyes. The ireased OPA values may be a defence mechanism that increases choroidal blood flow in OHT patients to protect retina ganglion cells against the press bounded ischemia. The hypothesis needs further study.

Keywords: Glaucoma, Ocular Hypertension, Ocular Pulse Amplitude, Pascal Dynamic Contour Tonometer

Full Text (Turkish)