Rates of Neuroretinal Rim and Peripapillary Atrophy Area Change: A Comparative Study of Glaucoma Patients and Normal Controls
Presented at: Association for Research in Vision and Ophthalmology Annual Meeting, May 2006, Fort Lauderdale, Florida.
Received 25 September 2008; received in revised form 31 October 2008; accepted 3 December 2008.
Objective
To compare the rates of global and sectoral neuroretinal rim area (NRA) and peripapillary atrophy area (PPAA) change in open-angle glaucoma patients and normal control subjects and to determine the relationship between rates of NRA and PPAA change.
Design
Prospective, longitudinal cohort study of cases and controls.
Participants and Controls
Ninety-four patients with open-angle glaucoma and 54 control subjects.
Methods
Patients and controls were imaged with confocal scanning laser tomography every 6 months. The NRA and PPAA in 1 eye were analyzed to determine the rate of change globally and in 12 30° sectors by regression analysis. Rates of global NRA and PPAA change were correlated. Sectors were ranked from 1 to 12 each according to the magnitude of NRA and PPAA change and were compared between patients and controls using rank-order correlation. Spatial concordance between rates of NRA and PPAA change was calculated as sector rank distance between correspondingly ranked sectors.
Main Outcome Measures
Rates of global and sectoral NRA and PPAA change.
Results
The mean (±standard deviation) follow-up was 8.6±2.9 years for patients and 7.1±3.6 years for controls. Globally, NRA declined more rapidly in patients compared with controls, expressed either in absolute units (medians, –5.33×10−3 mm2/year and −1.25×10−3 mm2/year, respectively; P = 0.006) or percentage of baseline NRA (medians, −0.42%/year and −0.07%/year, respectively; P = 0.001). The global rate of PPAA change was not significantly higher in patients compared with controls (12.66×10−3 mm2/year and 9.43×10−3 mm2/year, respectively; P = 0.173). Rates of global and sectoral NRA and PPAA change were correlated poorly in either group. There was a high correlation between ranked sectors of NRA change in patients and controls (P≤0.001), indicating similar patterns of NRA decline in patients and controls; however, this was not the case for rates of PPAA change.
Conclusions
These findings indicate an age-related regional susceptibility of the optic disc that may be accelerated in glaucoma. The poor relationship between rates of NRA and PPAA change suggests their temporal dynamics are uncoupled.
Financial Disclosure(s)
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Nova Scotia, Canada
Correspondence: Balwantray C. Chauhan, Department of Ophthalmology and Visual Sciences, Dalhousie University, 2nd Floor Centennial Building, 1278 Tower Road, Halifax, NS, Canada B3H 2Y9
Manuscript no. 2008-1158.
Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Supported by the Canadian Institutes of Health Research (grant no.: MOP11357 [BCC]), Ottawa, Ontario, Canada.
ABSTRACT