The thinner the cornea, the greater the cup shallowing

Patients with open-angle glaucoma and ocular hypertension with thinner corneas show significantly greater shallowing of the cup and smaller improvements of neuroretinal rim blood flow after intraocular pressure (IOP) reduction, according to a report in the November 2006 issue of Archives of Ophthalmology.

Mark Lesk, Ali Hafez and Denise Descovich from the University of Montreal and the Maisonneuve-Rosemont Hospital, Canada, selected 16 patient with open-angle glaucoma and 16 patients with ocular hypertension to undergo retinal tomography and scanning laser Doppler flowmetry. These were performed in one eye before at least two months after a mean 35% reduction in IOP.

The 16 patients with thinner corneas (518±32 µm) had greater reductions in mean cup depth than those 16 with thicker corneas (587±31 µm). These changes were not statistically different between the open-angle glaucoma and ocular hypertension patients. Smaller mean improvements in neuroretinal rim blood flow were seen in patients with thinner corneas than those with thicker corneas (35±80 versus 110±111 arbitrary units; p=0.04).

The authors of the study concluded that those with thinner corneas demonstrate greater shallowing of the cup, a surrogate marker for lamina cribosa development, and smaller improvements in neuroretinal rim blood flow after IOP reduction.