Macular and Peripapillary Structural Alterations in Patients With Open Angle Glaucoma

Abstract

Purpose:: To evaluate macular and peripapillary retinal nerve fiber layer (RNFL) structural damage using optical coherence tomography-OCT 3, and the possible correlation with visual function in POAG with localized visual field defects.

Methods:: Controlled prospective study on 30 POAG patients (30 eyes) 12 males,18 females (mean age 67.2±13.6 years) and 30 normal subjects (30 eyes) 8 males, 22 females (mean age 60.1±12.9 years). Complete examination, SAP (Humphrey, 30-2 SITA standard), OCT 3 imaging of peripapillary retina and macula were performed. Macular thickness, volume and RNFL thickness values in the retinal areas associated with hemifield localized perimetric defects were compared with corresponding undamaged areas. Paired Student t-test and Pearson’s correlation coefficient (r) between the considered parameters and MD-PSD were used for statistical analysis.

Results:: A significative difference (P<0.001) in total mean macular thickness, total mean macular volume and total mean RNFL thickness between POAG and control group was found (235.7±16.9µm vs 254.7±15.7µm; 6.37±0.4mm³ vs 6.9±0.4mm³; 70.8±17.6µm vs 99.8±9µm respectively). In POAG, macular thickness, volume and RNFL thickness mean values from the retinal areas associated with localized visual field defects were significantly less (P<0.001) than in the corresponding perimetrically undamaged areas (226.1±18.6µm vs 243.3±20.5µm; 1.48±0.1mm³ vs 1.6±0.1mm³; 70.3±23.2µm vs 96.9±24µm respectively). Mean values of the same parameters in the perimetrically undamaged retinal areas of POAG and in the corresponding sectors of control group were significantly different (macular thickness 243.3±20.5µm vs 258.7±16.3µm P=0.009; macular volume 1.6±0.1mm³ vs 1.71±0.1mm³ P=0.004; RNFL thickness 96.9±24µm vs 122.9±15.3µm P<0.001). Total mean RNFL thickness had the stronger correlation with MD and PSD (r=0.6 P<0.001; r=-0.5 P=0.006 respectively).

Conclusions:: In POAG patients with localized perimetric defects, not only RNFL thickness loss, but also corresponding alterations in macular thickness and volume were found. Evaluation of these last parameters could be useful in monitoring the glaucomatous disease.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer • visual fields