The correlation between frequency doubling technology matrix mean deviation and peripapillary retinal nerve fiber thickness of newly diagnosed glaucoma patients

Abstract

Objective: To evaluate the relationship between glaucomatous structural damage assessed by RTVue SD-OCT and functional loss as measured by Frequency Doubling Technology (FDT) perimetry. Materials and methods: One hundred and forty eyes of 70 newly diagnosed glaucomatous patients irrespective of intraocular pressure level were recruited from a private Tertiary Eye hospital in Lagos Nigeria. All the eyes underwent testing with Avanti RTVue XR SD-OCT (Optovue Inc., Fremont CA USA) and Frequency Doubling Technology (FDT) 24-2 threshold (Humphrey Matrix 800, 2011 Carl Zeiss Meditec, Dublin, CA). The relationship between average peripapillary retinal nerve fiber layer (pRNFL) and mean deviation on the FDT Matrix perimetry was evaluated using Pearson’s correlation coefficient regression analysis. Results: A total of 30 males (42.86%) and 40 (57.14%) females with mean age of 56±14 years with a range of 33-77 years. There were 46 (65.71%) patients with Primary Open-Angle Glaucoma (POAG) and 24 (34.29%) with chronic Primary Angle Closure Glaucoma (PACG). The FDT mean deviation was -14.68±10.59 dB and -10.88 ±8.34 dB for the Right eye (RE) and Left eye (LE) respectively. The mean average pRNFL thickness was 82.26±18.56 and 91.37±15.32 for RE and LE respectively. The Mean deviation significantly correlated with the average peripapillary RNFL thickness (Pearson correlation coefficient, r= 0.88, r2 = 0.77, p-value 0.001 for RE and r= 0.851, r2= 0.72, p-value 0.001 for LE). Conclusion: In this cohort of glaucoma patients, at least 70% of average peripapillary retinal nerve layer thinning measured with RTVue SD-OCT was associated with correspondent visual field loss in glaucoma.