Quantifiable Correspondence of Onset of RAPD, Visual Field Defects and RNFL Loss in Glaucoma

Nova Southeastern University, Davie, Florida, USA

Objective. To establish further evidence supporting the relationship of a 0.6 log unit afferent pupillary defect (APD), quantifiable retinal nerve fiber layer thickness (RNFLT) and mean deviation (MD) loss in subjects who have converted to glaucoma. Background. Evidence based data suggest that at the point where subjects converted to glaucoma the RNFLT was 75.3 um, 83 um and 87.5 um for the mean, superior and inferior values respectively, relative to the HVF threshold db values. From the mean RNFL normative values this represented approximately 17 %, 27.8%, and 25.8% loss respectively. Relative to the MD the mean RNFLT loss was 76.7 um or 17% loss.The average RNFL thickness in subjects at the time of conversion to glaucomatous HVF was 75.0 or approximately 18% loss. Results. A 0.6 log unit RAPD correlates with approximately 17-25% RNFLT loss. From data extrapolation a MD of 7 db corresponds approximately to 75.3 um RNFLT loss in glaucoma subjects. A 0.6 log unit RAPD correlates with a MD of 6 db. Conclusion. Evidence based data suggest a quantifiable relationship between RAPD, average RNFL and MD loss when subjects converted to glaucoma. A lesser RNFL quantifiable loss may correspond to the MD and RAPD if ganglion cell count values and or RAPD determined by automated pupillometry is taken into account. Grant. N/A