Mapping the visual field to the optic disc in normal tension glaucoma eyes

Purpose: To establish the anatomical relationship between visual field test points in the Humphrey 24-2 test pattern and regions of the optic nerve he ad (ONH) Design: Cross-sectional study. Participants: Glaucoma patients and suspects from the Normal Tension Glauco ma Clinic at Moorfields Eye Hospital. Methods: Sixty-nine retinal nerve fiber layer (RNFL) photographs with well- defined RNFL defects and/or prominent bundles were digitized, An appropriat ely scaled Humphrey 24-2 visual field grid and an ONH reference circle, div ided into 30 degrees sectors, were generated digitally, These were superimp osed onto the RNFL images. The relationship of visual field test points to the circumference of the ONH was estimated by noting the proximity of test points to RNFL defects and/or prominent bundles. The position of the ONH in relation to the fovea was also noted. Main Outcome Measures: The sector at the ONH corresponding to each visual f ield test point, the position of the ONH in relation to the fovea, and the effect of the latter on the former. Results: A median 22 (range, 4-58), of a possible 69, ONH positions were as signed to each visual field test point. The standard deviation of estimatio ns was 7.2 degrees. The position of the ONH was 15.5 degrees (standard devi ation 0.9 degrees) nasal and 1.9 degrees (standard deviation 1.0 degrees) a bove the fovea, The location of the ONH had a significant effect on the cor responding position at the ONH for 28 of 52 visual field test points. Conclusions: A clinically useful map that relates visual field test points to regions of the ONH has been produced. The map will aid clinical evaluati on of glaucoma patients and suspects, as well as form the basis for investi gations of the relationship between retinal light sensitivity and ONH struc ture. Ophthalmology 2000;107: 1809-1815 (C) 2000 by the American Academy of Ophthalmology.