Abstract
Purpose: :
Spectral domain (SD)-OCT is used for precise measurements of different retinal conditions. Besides the morphologic changes, functional alteration is of clinical interest. Recently a combination of a SD-OCT with the option of real time registration of the fixation has been developed. For the first time a SD-OCT was used to investigate the fundus controlled fixation of healthy eyes and eyes with retinal diseases.
Methods: :
28 eyes of 16 patients (aged 16 to 86 years) and 6 eyes of 3 probands (39 - 50 years) were examined with SD-OCT (Spectralis, Heidelberg Engineering, Germany). In addition, the fixation was documented over a time of 20 seconds with 12 images per second. The overlay of single fixation locations on OCT images allowed for the precise registration of the preferred retinal locus (PRL) and to calculate the stability of fixation as well as to visualize fixation behavior over time.
Results: :
The documentation of fixation was possible in all eyes examined without problems. The analysis of fixation points on the OCT images demonstrated a very stable fixation in all normals. In healthy eyes the 1.96fold standard deviation was 30±15µm horizontally and 10.5±2.9µm vertically. In many patients the PRL moved away from the foveal depression depending on the macular pathology. In the majority of our patients some upwards shift was observed, while stability of fixation was reduced with a corresponding variation of 200±234 and 161±191µm, respectively.
Conclusions: :
The new option to correlate the exact location of fixation with SD-OCT measurements allows to evaluate the center of the PRL with respect to deep retinal structures and especially to the foveal depression. The option of presenting various images onto the fundus allows to correlate morphology and fixation behavior and may be helpful in counseling patient with different macular diseases.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • macula/fovea • retina