Abstract
Purpose: :
To assess the clinical application of multimodal imaging (MMI) using combined scanning laser ophthalmoscope, optical coherence tomography and micro-multifocal ERG (micro-mfERG).
Methods: :
An OCT/SLO scanner (OTI; Toronto, Canada) was modified to integrate an organic light emitting diode (OLED) display into the optics of the system. A high resolution micro-mfERG stimulus covering up to the central 24 degrees was projected onto the OLED display. During the 8 minute micro-mfERG recording time, OCT scanning was performed in both coronal (C-scan) and transverse (B-scan) planes in multiple locations to allow structural and functional information to be correlated for all the stimulated areas. Accurate patient fixation during the recordings was ensured by monitoring the SLO channel.50 patients with conditions affecting the macula (14 with a macular hole, 25 with age-related macular degeneration and 11 with other conditions) have been assessed using MMI and the structural and functional information obtained has been correlated. 12 patients with a macular hole and 15 patients with age-related macular degeneration (ARMD) have been re-assessed with MMI post-treatment and the structural and functional changes observed.
Results: :
MMI was well tolerated by all patients tested with good patient compliance observed in all recordings. Good correlation was observed between structural and functional alterations in most patients although in some cases functional abnormalities extended wider than structural alterations. In patients with a macular hole, pre-treatment MMI showed varying degrees of functional loss. Post-treatment MMI showed anatomical closure in all patients accompanied by improvements in micro-mfERG amplitudes but persistence of timing delays. In patients with ARMD there was generally good correspondence between the area of structural alterations and macular dysfunction. Most ARMD patients assessed post-treatment did not show significant functional improvements even though OCT confirmed improvements in macular structure. The patients with other conditions showed good correlation between the area of structural alterations and macular dysfunction.
Conclusions: :
MMI provides a means of simultaneously imaging the macular surface, substructure and function at multiple sites. It is well tolerated by patients and may help in improving our understanding of disease processes and in assessing the success of surgical or pharmacological interventions for various disorders affecting the macula.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • electroretinography: clinical • retina