The ganglion cell complex as an useful tool in glaucoma assessment

Dana Dascalescu,Speranta Schmitzer,Miruna Burcel,Valeria Coviltir,Mihaela Constantin,Vasile Potop,Catalina Ionescu,Veronica Strehaianu,Catalina Corbu

doi:10.22336/rjo.2018.46

Abstract

Glaucoma is known as an optic neuropathy prone to progression that determines characteristic not only structural (loss of the ganglion cells as well as their axons) but also functional defects (visual field loss). Objective: To evaluate the possibility of applying ganglion cell complex analysis (GCC) in patients who associate ocular hypertension with tilted disc and marked peripapillary atrophy. Methods: In order to evaluate its components, GCC can be investigated using the Optical Coherence Tomography (OCT) revealing: ganglion cell layer (cells bodies), inner plexiform layer (dendrites and synapses), and nerve fiber layer (axons). Our study included 196 eyes divided into 3 groups: 52 diagnosed with primary open angle glaucoma (POAG), 63 with ocular hypertension (OH), and 81 healthy (normal) eyes (NE). All eyes were submitted to a complete ophthalmologic checkup that involved advanced optic nerve and GCC evaluation. Results: A positive statistically significant correlation was identified between the GCC thickness and the RNFL in all three categories taken into account: R=0,6, p<0,0001 for glaucoma group, R=0,66, p<0,0001 for OH group and R=0,46, p<0,0001 for normal group. Conclusions: GCC has been proved useful for the assessment of the retinal nerve fiber layer (RNFL) in eyes with OH that associate tilted disc or peripapillary atrophy where the optic disc edges might not be certainly determined by the OCT.

Highlights

Glaucoma is defined as an optic neuropathy that alters the ganglion cells and all their segments: dendrites, cell body, and axon [1]
All the patients were submitted to a complete ophthalmological examination that began with visual acuity testing, slit lamp examination of the anterior pole, corneal biomechanics investigation in order to establish IOPg, IOPcc, CH and CRF (Ocular Response Analyzer, Reichert, New York), intraocular pressure (IOP) measurements (Goldmann applanation tonometer), ultrasound pachymetry in order to measure central corneal thickness (CCT) (Alcon® OcuScan® RxP Ophthalmic Ultrasound System), gonioscopic examination (Goldmann lens with three mirrors), visual field analyses strategy 24-4 (Humphrey Field Analyzer II Carl Zeiss Meditec Inc, Dublin, California) and finished with fundus examination
Our study revealed that the peripapillary retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL)+internal plexiform layer (IPL)+nerve fiber layer (NFL) values in glaucomatous eyes are inferior to those in the ocular hypertension (OH) and healthy eyes

Summary

Introduction

Glaucoma is defined as an optic neuropathy that alters the ganglion cells and all their segments: dendrites, cell body, and axon [1]. Having an early diagnosis is decisive, but usually patients present to the ophthalmologist when their visual acuity starts to decrease and the visual field defect appears. When the visual field defect appears, we can only aim to keep the affection. In order to save visual function we need to recognize glaucoma prior to this stage and to initiate an early therapeutic plan [2,3]. Studies have shown that the visual field starts to be affected when about 40% of the axons are no longer functional [4]. The visual field loss appears only after the RNFL and retinal ganglion cell disturbance [2]. The RNFL defect represents one of the first signs that can be found in a patient [5]. In order to confirm our RNFL analysis, we tried to use the macular GCC scan to see if there is any consistency in the two types of scans

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Conclusion