**Acknowledgements**

None.

between the average measured thickness values for each section and the normal thickness values as a chart of change. Thanks to these software, changes that occur in the RNFL profile or the deterioration that occurs in the thickness over time can be detected at an early stage [50, 51].

There are 201 individuals registered in the normative database of this device, all of whom are Caucasian. Ages of these individuals range from 18 to 78, and 111 of them are male while 90 are female. The criteria for these people to be included in the database are naturally, their lack of a glaucoma history and the fact that they have normal intraocular pressure, visual field and

A new software called Posterior Pole Analysis is offered by the Heidelberg spectral OCT [33, 52]. Thickness of the entire posterior pole retina can be measured through this software. The posterior pole is scanned point by point, and the thickness asymmetry between the two eyes and the intraocular hemispheres are analyzed. Furthermore, the GCC loss is also assessed and findings for glaucoma at an early stage are analyzed through this software

OCT output for the analysis provides two basic maps. The first one is the map of hemisphere asymmetry while the second one is the map of RNFL thickness. The map of hemisphere asymmetry is in the form a grid where the average thicknesses of the upper and lower hemisphere are compared. Here, the squares that vertically have the same distance from the axe between the fovea and the optic disc are compared. While the squares in the upper half of the grid represent the differences between the RNFL thickness values in the superior and inferior regions, squares in the lower half represent the differences between the RNFL thickness values in the inferior and superior regions. If the difference between these values is zero or a positive value, the colored area looks white. If the area is dark gray or black, this refers to a local asymmetry

In the literature, there are several studies evaluating the diagnostic ability of abovementioned

Leung et al. reported that, in Spectralis, the global thickness parameter had the largest area under curve (AUC) in eyes with severe glaucoma [34]. Leite et al. reported that in Spectralis, superior quadrant RNFL followed by global RNFL, had the largest AUC and in Cirrus, global thickness was the parameter that has the largest AUC, with superior and inferior RNFL quadrants being the second and the third [54]. Park et al. and Leung et al. reported similar results with inferior, average and superior quadrant RNFL's having the best diagnostic performance

In their study, Leite et al. also showed that the diagnostic ability of all three devices for the nasal and temporal quadrants for glaucoma diagnosis was lower than the results received from the other quadrants [54]. This finding may be associated with the optic nerve damage

devices with some minor differences in the results [1, 2, 6, 10, 16–21, 23–41].

optic disc appearance. The results have been organized as a normative database.

**6.3. The normative database of Heidelberg spectra OCT**

**6.4. Posterior pole analysis**

168 OCT - Applications in Ophthalmology

in terms of RNFL thickness values.

for device Cirrus as Sehi et al. [29, 30, 34].

[53, 54].
