Abstract
Purpose:
To evaluate ganglion cell complex (GCC) and peripapillary retinal nerve fiber layer (RNFL) damage using Spectral Domain-Optical Coherence Tomography (SD-OCT), and the possible correlation with visual function in POAG with localized visual field defects.
Methods:
Cross sectional study on 30 POAG patients (30 eyes) 17 males,13 females (mean age 66.1±11.9 years) with moderate glaucomatous loss according to Hodapp classification and 30 normal subjects (30 eyes) 10 males, 20 females (mean age 62.2±9.6 years). Complete examination, SAP (Humphrey, 30-2 SITA standard), Cirrus SD-OCT imaging of peripapillary retina and macula were performed. GCC and RNFL thickness values in the retinal areas associated with hemifield localized perimetric defects were compared with corresponding undamaged areas. 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 GCC thickness and total mean RNFL thickness between POAG and control group was found (59.9±10.77μm vs 83.63±6.11μm; 61.23±10.78μm vs 93.06±8.01μm respectively). In POAG, GCC and RNFL thickness mean values from the retinal areas associated with localized visual field defects were significantly less than in the corresponding perimetrically undamaged areas (55.23±10.62μm vs 64.73±13.06μm: p=0.003; 56.55±9.84μm vs 64.55±12.11μm: p=0.007 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 (GCC thickness 64.73±13.06μm vs 83.23±7.05μm: p<0.001; RNFL thickness 64.55±12.11μm vs 92.5±8.03μm: p<0.001). Total mean GCC thickness had the stronger correlation with MD and PSD (r=0.38 p=0.03; r=-0.321 p=0.08 respectively).
Conclusions:
In POAG patients with moderate localized perimetric defects, the new SD-OCT GCC Analysis evaluation could be useful in monitoring the glaucomatous disease and seems to detect earlier than RNFL Analysis the structural damage in accordance with the fact that GCC loss is supposed to occur before that of the RNFL.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
531 ganglion cells •
610 nerve fiber layer