Purpose:
To investigate changes in lamina cribrosa compliance in relation to the presence or absence of peripapillary atrophy (PPA) following therapeutic reduction of intraocular pressure (IOP) in patients with open-angle glaucoma (OAG) and ocular hypertension (OHT). Lamina cribrosa compliance was determined by the tendency of the base of the optic nerve head to move in response to changes in IOP.
Methods:
A total of 78 patients with OAG or OHT underwent scanning laser topographic measurements of the optic nerve head using the Heidelberg Retinal Tomograph (HRT) before and after at least 20% therapeutic IOP reduction and a minimum of 4 weeks follow-up. Based on the presence of at least 250 microns of temporal PPA (zone beta) measured on HRT images, patients were assigned to either a PPA group (n=39) or a NOR group (n=39). Lamina cribrosa compliance was estimated by the change in mean and maximum cup depth, which indicates displacement of the base of the cup relative to the retinal surface following sustained IOP reduction. Such changes were then assessed in both OAG and OHT subgroups. Statistical analysis was performed on both groups using two-tailed student’s t test.
Results:
Following a similar % of IOP reduction (37% in the PPA group, and 34% in the NOR group, p=0.21), changes in mean and maximum cup depth were not significantly different between both study groups (p=0.098 for mean cup depth and 0.085 for maximum cup depth). Further subgroup analysis revealed a significant change in mean and maximum cup depth within the OAG patients (p=0.007 and 0.025 respectively) but not in OHT patients (p=0.529 and 0.651 respectively).
Conclusions:
Presence of PPA was associated with greater lamina cribrosa compliance in OAG patients but not in OHT patients. This points to a possible role of lamina cribrosa compliance in the development and progression of glaucomatous optic neuropathy.
Keywords: lamina cribrosa • intraocular pressure • imaging/image analysis: clinical