Purpose: To evaluate quantitatively retinal nerve fiber layer (RNFL) change in areas of normal-appearing visualfield in eyes with high-tension glaucoma (HTG) and hemifield defects using scanning laser polarimetry (GDx: Laser Diagnostic Technologies, San Diego, CA, USA).
Methods: Forty eyes from forty patients with HTG with supeior or inferior hemifield defects based on the Humphrey field analyzer (HFA) underwent RNFL thickness measurements. Twenty normal eyes from twenty subjects matched in age and refractive error were selected as a control group. The RNFL thickness was measured with a scanning laser polarimetry. Mean RNfL thickness was evaluated in four quadrants. supeior or inferior quadrant in the defined ring of scanning laser polarimetry corresponds with inferior or superior hemifield in HFA.
Result: The mean RNfL thickness in the unaffected quadrant ( the quadrant corresponding to the hemifield with apparently normal visual field based on HFA) in HTG group was significantly thinner than athe average RNFL thickness of the corresponding quadrant of control eyes. The RNfL thickness of the unaffected quadrant in the eyes with HTG was reduced and statistically similar to that of affected quadrant. Symmetry, calculated as the ratio of superior to inferior RNfL thickness showed no statistical difference between the study and control group.
Conclusion: Changes in RNFL are present in the normal-appearing hemifield in the eyes with HTG. The thickness of RNFL is reduced symmetracally in bothsuperior and inferior quadrants based on the GDx parameters.