Abstract
Purpose: :
To determine the relationships among the visual acuity (VA), macular retinal sensitivity (MRS), presence of a photoreceptor inner segment and outer segment (IS/OS) junction, and external limiting membrane (ELM) in the spectral-domain optical coherence tomographic (SD-OCT) images of patients with retinitis pigmentosa (RP).
Methods: :
Eighty-three eyes of 45 patients with typical RP were studied. The VA (logMAR units), MRS by microperimetry (MP1), and the SD-OCT images of the macula were examined. The lengths of the IS/OS junction and ELM were measured.
Results: :
An intact IS/OS junction was detected in 54 eyes (65%) and the ELM in 49 eyes (58%). The IS/OS junction and the ELM were not visible in the fovea of 29 eyes. There was a significant high correlation between the lengths of the IS/OS junction and the ELM (r =0.87, P<0.001). The mean length of the ELM (1.17 mm) was significantly shorter than that of the IS/OS line (2.04 mm; P<0.001). There were moderate but significant negative correlations between the VA and the ELM length (r=-0.55), and between the VA and the IS/OS junction length (r=-0.61; P<0.001). There were significant strong correlations between MRS and ELM length (r=0.83), and between the MRS and IS/OS length(r=0.92; P<0.001).
Conclusions: :
The length of the ELM was significantly shorter than that of the IS/OS junction, and the VA can be good despite the absence of an ELM. These results suggest that the breakdown of the ELM developed earlier than that of the IS/OS junction and also before the reduction of the MRS.
Keywords: imaging/image analysis: clinical • retinal degenerations: hereditary • photoreceptors: visual performance