Abstract
Purpose:
To evaluate the possible correlation between visual field (VF) localized defects in early POAG and ganglion cell inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) damage as measured by Spectral Domain-Optical Coherence Tomography (SD-OCT).
Methods:
Cross sectional study on 45 POAG patients (45 eyes) 22 males, 23 females (mean age 67.8±12.2 years) with early glaucomatous loss according to Hodapp classification and 45 normal subjects (45 eyes) 20 males, 25 females (mean age 60.6±9.9 years). Complete examination, SAP (Humphrey, 30-2 SITA standard), Cirrus SD-OCT imaging of peripapillary retina and macula were performed. GCIPL 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 GCIPL thickness and total mean RNFL thickness between POAG and control group was found (65.24±10.46μm vs 83.3±6.03μm; 67.53±9.75μm vs 92.68±8.02μm respectively). In POAG, GCIPL and RNFL thickness mean values from the retinal areas associated with localized VF defects were significantly less than in the corresponding VF undamaged areas (61.68±10.55μm vs 69.31±11.36μm: p=0.001; 56.61±8.57μm vs 63.91±10.46μm: p=0.000 respectively). Mean values of the same parameters in the VF undamaged retinal areas of POAG and in the corresponding sectors of control group were significantly different (GCIPL thickness 69.31±11.36μm vs 83.02±6.66μm: p<0.001; RNFL thickness 63.91±10.46μm vs 88.18±10.28μm: p<0.001). MD had the stronger correlation with total mean GCIPL thickness and total mean RNFL thickness (r=0.348 p=0.019; r=0.3 p=0.04 respectively). PSD showed only a mild correlation with total mean GCIPL thickness (r=-0.266 p=0.07).
Conclusions:
In our study, in POAG patients with early localized perimetric defects, GCIPL and RNFL were significantly correlated with VF parameters in hemiretinae either with or without VF loss: both SD-OCT parameters seem to be susceptible to glaucomatous injury even when the extent of the VF damage is mild and confined to the other hemifield and they could be useful in monitoring the glaucomatous disease.
Keywords: 531 ganglion cells •
550 imaging/image analysis: clinical •
610 nerve fiber layer