Comparison of optical coherence tomography measurements according to computerized visual field in diagnosis and follow up of primary open angle glaucoma

Purpose: To evaluate the relationship between visual field indices and optical coherence tomography measurements in primary open-angle glaucoma (POAG) patients and to investigate the role of early detection of glaucomatous progression. Materials and Methods: 84 eyes of 72 patients who diagnosed with POAG that controlled with medical treatment at Dicle University Faculty of Medicine, Unit of Ophthalmology Glaucoma follow-up between January 2007 and June 2012 included to the study. Glaucoma staging was done according to the value of visual field (VF) MD. Patients MD value ?-6dB (early-stage glaucoma) patients inclueded in Group 1, MD value between -6dB and -12dB (middle-stage glaucoma) in Group 2 and MD value ?-12dB (advanced stage glaucoma) in Group 3. The relationship between Optical Coherens Tomografi (OCT) parameters recorded with the VF parameters were examined. In addition, patients in each group were compared between groups by calculating the average optic nevre head (ONH) and retinal nevre fiber layer (RNFL) thickness measured by OCT with the stage of glaucoma and the relationship between RNFL thickness value was examined. The first and last measurements of VF and OCT were compared. 2 dB increase in MD and 20 microns thinning in Avg Thickness have been accepted as a progression and OCT in VF progression rates were calculated. Results: There was a strong relationship between VF MD index and OCT Smax/Tavg, Imax/Tavg, Smax/Navg, Max-Min, Smax, Imax, Savg, Iavg, Avgthick, RA, RCSA, RV, CA, CV, CDHR, CDVR, CDAR parameters. Significant correlation between the parameters of VF PSD index and OCT and Smax / Imax, Max-Min, Smax, Imax, Savg, Iavg, Avgthick, DA, RA, RCSA, RV, CA, CV, CDHR, CDVR, CDAR were found statistically. Also there were statistically significant differences in RNFL thickness between sub-groups of POAG in our study. The average RNFL thickness decreased with increasing stage of glaucoma. To investigate the progression, first and last measurements of VF and OCT parameters were compared in all patients. VF and OCT progression was found in 25% and 29,6% of patients respectively. In 4,6% of patients OCT progression observed without VF progression. Conclusion: There was a strong correlation between indices of VF and OCT measurements. OCT RNFL thickness in the monitoring of early progression in glaucoma are promising in terms of providing follow-up of glaucoma because it detectes early signs before VF analysis. However, the protocol and the parameters which should be used in OCT, large population based, controlled studies with longer follow-up periods are needed.