Reduced ocular pulse amplitude in low tension glaucoma is independent of vasospasm

Abstract

Methods: OPA, using the Langham Ocular Blood Flow (OBF) System, applanation intraocular pressure (lOP), systemic blood pressure and heart rate were measured and vasospasm was determined by a fingernail capillary blood flow test.Results: OPA (mmHg) in the LTG patients with a vasospastic reaction (LTG-V, 1.4 ± 0.1, n = 17) was not significantly (p>0.09) different when compared with non-vasospastic LTG patients (LTG-NV, 1.5 ± 0.2, n = 15) but was significantly (p<O.OOl) reduced in LTG-V and LTG-NV patients when compared with matched healthy control subgroups (2.3 ± 0.2 and 2.4 ± 0.3, respectively). lOP (mmHg) in LTG-V (13.3 ± 0.4) and LTG-NV (13.2 ± 0.5) patient groups was not signifi cantly (p>0.05) different when compared with each other, but was significantly (p<0.05) lower when compared with matched coutrol subgroups (15.0 ± 0.3 and 15.2 ± 0.4, respectively). Haemodyuamic para meters were not significautly different from controls. Conclusion:The abnormality in choroidal perfusion indicated by a rednction in OPA in all LTG patients is unrelated to the presence or absence of vasospasm. Quigley et al. 5 did not find a reduction in the number of blood vessels in the optic nerve head region whereas Schwartz6 using fluorescein angiogra phy showed filling defects in this area in glaucoma tous subjects. These findings suggest a connection between LTG and vascular abnormalities.The present study was designed to evaluate a parameter of choroidal perfusion, the ocular pulse amplitude (OPA), in LTG patients with respect to vasospasm.

Choroidal expansion during the water drinking test

“…The OPA has been used in many studies as an indirect measure of the choroidal perfusion [6,[15][16][17]. Differences in IOP values during systole and diastole are used to calculate an index that estimates ocular blood supply, whereas about 70-80% of it is due to the choroidal flow [6].…”

Spectral content of the intraocular pressure pulse wave: glaucoma patients versus normal subjects

“…This IOP pulse wave has been used as a means of assessing the ocular vascular status in glaucoma patients. Numerous studies have demonstrated reduced IOP pulse amplitudes and reduced pulsatile ocular blood flow in glaucoma patients compared with control subjects [11,14,15,20,21,22,24].…”

Doppler-Sonographie bei Normaldruckglaukompatienten

“…Während Patienten mit primärem Offenwinkelglaukom ein chronisch-erhöhtes intraokulares Druckniveau aufweisen, gibt es Patienten, die ohne eine Erhöhung des IOD, sowohl funktionell als auch morphologisch, alle Symptome eines Glaukomschadens aufweisen [12]. Als Ursache dieses so genannten Normaldruckglaukoms (NDG) wird eine Störung der okulären Perfusion angenommen [26], da für Patienten mit NDG bekannt ist, dass diese signifikant häufiger an vaskulären Erkrankungen wie Migräne und Vasospasmen leiden [4,21].…”