Abstract
The objective of the present study was to evaluate changes in optic nerve head parameters, measured by confocal laser tomography, before and after trabeculectomy in order to identify outcome measures for the management of glaucoma. The optic nerve head of 22 eyes (22 patients) was analyzed by confocal laser tomography with the Heidelberg retinal tomogram (HRT) before and after trabeculectomy. The median time between the first HRT and surgery was 4.6 months (mean: 7.7 +/- 8.3) and the median time between surgery and the second HRT was 10.8 months (mean: 12.0 +/- 6.8). The patients were divided into two groups, i.e., those with the highest (group A) and lowest (group B) intraocular pressure (IOP) change after surgery. Differences in the 12 standard topographic parameters before and after surgery for each group were evaluated by the Wilcoxon signed rank test and the differences in these parameters between the two groups were compared by the Mann-Whitney rank sum test. Multiple regression analysis was used to evaluate the influence of the change in IOP (DeltaIOP and DeltaIOP%) and the changes in the other parameters. There were significant differences in the HRT measures before and after surgery in group A only for cup volume. In group B, no parameter was statistically different. The changes in group A were not significantly different than those in group B for any parameter (P > 0.004, Bonferroni correction for multiple comparisons). DeltaIOP and DeltaIOP% had a statistically significant effect on Delta cup disk area, Delta cup volume and Delta mean cup depth. Changes in cup shape size were influenced significantly only by DeltaIOP. Some optic disc parameters measured by HRT presented a significant improvement after filtering surgery, depending on the amount of IOP reduction. Long-term studies are needed to determine the usefulness of these findings as outcome measures in the management of glaucoma.
Highlights
The traditional outcome measure for adequacy of intraocular pressure (IOP) reduction with any medical or surgical intervention for glaucoma is the documentation of the stability or progression of optic neuropathy and visual field loss with time
An improvement in the appearance of the optic nerve head after reduction of IOP has been documented in children with glaucoma [10] and in adults [1,2,11]
Improvement of the optic disc has been reported in adults after both surgical and medical reduction of IOP and in a variety of glaucomas with different techniques used to measure the changes [12]
Summary
The traditional outcome measure for adequacy of intraocular pressure (IOP) reduction with any medical or surgical intervention for glaucoma is the documentation of the stability or progression of optic neuropathy and visual field loss with time. The obvious disadvantage of this strategy is that irreversible damage must occur before the inadequacy of the therapy is recognized. Most glaucomatous damage is irreversible, some optic nerve head and visual field improvement following IOP reduction have been reported. The improvement has been associated with the amount of pressure reduction [1,2,3]. Spaeth and associates [4,5] have suggested that improvement in the appearance of the optic disc and/or visual field is an important early indicator of the long-term adequacy of glaucoma management. With the advent of technologies to more precisely and quantitatively measure changes in optic disc topography, investigators are beginning to take a closer look at the influence of lowering the IOP on disc morphology [6,7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Brazilian Journal of Medical and Biological Research
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
