Abstract
Purpose: :
To determine whether the patterns of visual field damage between High Tension Glaucoma (HTG) and Normal Tension Glaucoma (NTG) are equivalent.
Methods: :
In this retrospective cross–sectional study fifty–one NTG and 57 HTG patients were recruited. For each recruited patient only one eye was randomly chosen. Glaucomatous patients had abnormal visual field and/or optic nerve head. They were classified as HTG or NTG on the basis of 24h intraocular pressure (IOP) measurements. The NTG subgroup had an IOP < 22mmHg without treatment throughout a diurnal tension curve, while HTG patients had an IOP > 21mmHg without treatment for at least three measurements. Patients' visual fields were analyzed by using Humphrey Field Analyzer (HFA), program 30–2, full threshold. The visual field sensitivity values and the pattern deviation map values of the 72 tested points were considered. Then a point–wise analysis and an area–analysis, based on the Glaucoma Hemifield test criteria were performed and a comparison between the two subgroups was made by Student’s t test.
Results: :
Between NTG and HTG, no significant difference was found point–wise for almost all the visual field points, except for two locations. One was under the blind spot and the other was in the inferior hemifield around the twenty degrees position. While when area–analysis was considered, three areas showed to have a different sensitivity between HTG and NTG.
Conclusions: :
These data suggested that there was no differences in the point–wise analysis between NTG and HTG, however when visual field areas were compared, superior nasal step and inferior and superior scotomata showed to be deeper in HTG than in NTG. No difference was found in the paracentral areas.
Keywords: visual fields • perimetry • intraocular pressure