Abstract
Purpose: :
Our recent data (ARVO, 2004) suggests that, compared to those with thicker corneas, glaucoma and ocular hypertensive patients with thin corneas had larger reductions in optic nerve head (ONH) cup depth and smaller improvements in neuroretinal rim blood flow when undergoing a sustained IOP reduction. Now we asked whether these ONH changes correlated with long term visual field stability.
Methods: :
26 glaucoma and pre–perimetric glaucoma patients had Heidelberg retina tomography and scanning laser Doppler flowmetry (SLDF software v3.3) of the ONH before and 2–6 months following sustained therapeutically indicated IOP reduction. Peripheral vasospasticity was measured with finger Doppler during cold water immersion. Ultrasound pachymetry was performed. Visual field stability was monitored over the following 4.2+/– 1.0 years using modified Hodapp–Anderson–Parrish criteria.
Results: :
8 patients progressed, 16 were stable , 2 were indeterminate (these were excluded from analysis). At initial IOP reduction, patients that eventually progressed had 89+/– 144 µm mean shallowing of cup depth vs. 1+/– 50 µm in the stable group (p=0.029), and were more vasospastic (minimum finger flow 4.1+/–2.3 tpu vs. 10.3+/–8.2 tpu, p=0.017). Progressing patients had insignificantly thinner corneas (546 +/–50µm vs 569 +/–59µm, p=0.4) and had insignificantly smaller initial increases in neuroretinal rim blood flow than stable patients (32 +/–96 au vs. 70+/– 119 au, p=0.44). Both progressing and stable groups had the same initial IOP reduction and the progressing group had slightly lower IOPs during follow–up.
Conclusions: :
Greater movement of the base of the cup, interpreted as a sign of a more compliant lamina cribrosa, appears to be linked to an increased risk of progressive glaucoma. Vasospasticity also appears to be linked to an increased risk of progression in this pilot series.
Keywords: lamina cribrosa • optic disc • optic flow