Retinal nerve fibre layer and macular thickness analysis with Fourier domain optical coherence tomography in subjects with a positive family history for primary open angle glaucoma

Aim To detect early structural changes of retinal nerve fibre layer (RNFL) and macular ganglion cell complex (GCC) in subjects with a positive family history for primary open angle glaucoma (POAG) using Fourier domain optical coherence tomography (FD-OCT) (RTVue-100). Methods This was a cross-sectional observational study. First and second degree relatives of POAG patients, healthy subjects, and subjects with preperimetric glaucoma (PPG) without a family history for glaucoma, were enrolled. All participants underwent complete ophthalmic examination, visual field test and FD-OCT (RTVue-100) imaging. Average RNFL and GCC thicknesses were measured and a pattern analysis was applied to the GCC map. Analysis of variance (ANOVA), least significant difference post-hoc test, and multiple ANOVA were used. Results The final analysis included 271 eyes divided into several groups: 163 eyes of first and second degree relatives (85 healthy, 40 with ocular hypertension and 38 with PPG); and 108 eyes of subjects without a positive family history (60 healthy and 48 PPG). RNFL and GCC thickness values of these five groups were statistically different (p<0.001). RNFL superior, GCC average, GCC superior, and GCC inferior were found to be significantly thinner and the global loss volume was higher in normal relatives than in healthy subjects without a positive family history of POAG (p=0.04, p=0.001, p=0.005, p=0.004, p=0.009). RNFL and GCC thicknesses obtained by dividing the family members by the degree of consanguinity showed statistically significant thinning in siblings of glaucomatous subjects than in offspring. Conclusions Our study shows that the eyes of subjects with a positive family history for POAG have significantly thinner RNFL and GCC than normal eyes and a more accurate follow-up has to be performed.