Correlation of Vertical Cup Disc Ratio and Matrix FDT Mean Deviation in Primary Open Angle Glaucoma Patients

Nathaniel Godswill Inye,Pepple Godswill

doi:10.11648/j.ijovs.20210601.13

Abstract

Objectives: To evaluate the correlation between glaucomatous structural change using vertical-cup-disc ratio of the optic nerve head and functional loss measured by Frequency Doubling Technology perimetry. Materials and methods: It was a retrospective observational clinic-based study of 77 newly diagnosed Primary Open Angle Glaucoma (POAG) patients from a Private Eye clinic in a suburb of Port Harcourt city, Nigeria. They underwent clinical fundal examination with slit-lamp biomicroscope (Perkin’s slit-lamp) with 90D (Volk) lens; and Frequency Doubling Technology perimetry 24-2 threshold (Humphrey Matrix 800, 2011 Carl Zeiss Meditec, Dublin, California). The Vertical-cup-disc-ratio was assessed for each eye and the Mean deviation calculated for each eye. The relationship between VCDR and mean deviation was evaluated using Pearson’s correlation coefficient regression analysis. Result: There were 24 males (31.17%) and 53 females (68.83%). The mean age of the patients was 56.65 ± 14.33 years with a range of 37-78 years. The mean VCDR was 0.83±0.09 and 0.78±0.13 for the right and left eyes, respectively while mean FDT mean deviation was -13.99±9.33Db and -11.9.22Db for the right and left eyes, respectively. The VCDR significantly correlated with FDT mean deviation (Pearson Correlation Coefficient, r= -0.923, r2= 0.852, p-value=0.001 for the right eye; r= -0.915, r2=0.836, p-value=0.001 for the left eye. Conclusion: This study shows that at least 80% of VCDR correlated with the Mean deviation of matrix FDT amongst this cohort of POAG patients. it buttresses the fact that clinical evaluation of the optic nerve remains an indispensable tool in glaucoma diagnosis and can use to assess glaucoma severity in resource poor setting where visual field machine is not available.

Highlights

Glaucoma is a chronic, progressive optic neuropathy, characterized by atrophy of the optic nerve and loss of retinal ganglion cells, resulting in progressive vision loss and Primary open angle glaucoma (POAG) is the most common variant [1]
The aim of this study is to evaluate the correlation between the structural changes using clinical subjective measures of the Vertical Cup-Disc Ratio (VCDR) and functional changes using the Mean deviation on Matrix Frequency doubling Technology (FDT) perimetry in patients with Primary Open Angle Glaucoma (POAG)
It was a retrospective observational clinic-based study correlating the Mean deviation on Matrix FDT perimetry to the Vertical Cup Disc Ratio (VCDR) of newly diagnosed Primary Open Angle Glaucoma (POAG) patients managed in an Eye Unit of a private hospital Life forte Specialist Hospital in the suburb of Port Harcourt, Nigeria

Summary

Introduction

Progressive optic neuropathy, characterized by atrophy of the optic nerve and loss of retinal ganglion cells, resulting in progressive vision loss and Primary open angle glaucoma (POAG) is the most common variant [1]. In 2010, Quigley and Browman estimated that 44.7 million people worldwide suffered from primary open-angle glaucoma (POAG), and 4.5 million were blind, making POAG the most common type of glaucoma [2]. Primary Open Angle Glaucoma development is associated with loss of tissue in the neuro-retinal rim of the optic disc and a consequent increase in the size of the optic cup [4]. Diagnosis of POAG requires an assessment of intraocular pressure, Open- normal appearing anterior chamber angle, characteristics signs of optic disc damage and visual function loss on perimetry. Clinical assessment of an optic disc is still considered the gold standard in the diagnosis of POAG, though the inter-observer agreement is notoriously variable

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