Purpose To investigate photoreceptor degeneration in retinitis pigmentosa (RP) by quantitatively analysing optical intensity of ellipsoid zone (EZ) on optical coherence tomography (OCT). Methods We conducted OCT line scans of the horizontal meridian in 24 eyes of 24 RP patients and 30 eyes of 30 healthy controls and obtained longitudinal reflectance profiles using ImageJ at every 5 pixels. Relative optical intensity was calculated from dividing the peak of EZ by the mean of the whole retina. Results The optical intensity of EZ variation followed a similar pattern in all patients. It decreased with eccentricity and then vanished, regardless whether it was normal or reduced at the fovea. The mean relative optical intensity of EZ in RP patients was 0.69 ± 0.13 to that of control subjects at the location just before it disappeared. The relative optical intensity of EZ at fovea was significantly correlated with the best‐corrected visual acuity in patients (r = −0.617, p = 0.001). Conclusion The optical intensity of EZ detected by OCT can serve as a biomarker for early detection of photoreceptor degeneration in RP.

Purpose: Several parameters on optical coherence tomography (OCT) have been suggested as biomarkers for photoreceptor degeneration in retinitis pigmentosa (RP). This study is to investigate which OCT parameters can serve as the earliest biomarkers in RP. Methods: OCT line scans of the horizontal meridian were conducted in 22 eyes of 22 RP patients and 30 eyes of 30 healthy controls. Longitudinal re ectance pro les were obtained using ImageJ at every 5 pixels. The following parameters on OCT were quantitatively measured: 1) relative optical intensity (ROI) of ellipsoid zone (EZ) and interdigitation zone (IZ); 2) thickness of outer nuclear layer (ONLT), photoreceptor (PRT), inner segment (IST) and outer segment (OST). The variations of these parameters across different regions were analyzed.Results: From fovea to peripheral retina, all the OCT biomarkers declined before disappeared, except IST and IZ-ROI. There was no identi able declining zone for the IST and IZ-ROI between the normal and disappeared zones. The earliest biomarker was the shortening of OST and reduced IZ-ROI, followed by the shortening of PRT, EZ-ROI, then IST, and nally, ONLT. All these biomarkers had signi cant correlations with best-corrected visual acuity, except ONLT. Conclusion:In retinitis pigmentosa, EZ-ROI, IZ-ROI, PRT, OST, IST and ONLT are valuable biomarkers of photoreceptor degeneration. OST and IZ-ROI may serve as the earliest biomarkers.

Purpose: Several parameters on optical coherence tomography (OCT) have been suggested as biomarkers for photoreceptor degeneration in retinitis pigmentosa (RP). This study is to investigate which OCT parameters can serve as the earliest biomarkers in RP.Methods: OCT line scans of the horizontal meridian were conducted in 22 eyes of 22 RP patients and 30 eyes of 30 healthy controls. Longitudinal reflectance profiles were obtained using ImageJ at every 5 pixels. The following parameters on OCT were quantitatively measured: 1) relative optical intensity (ROI) of ellipsoid zone (EZ) and interdigitation zone (IZ); 2) thickness of outer nuclear layer (ONLT), photoreceptor (PRT), inner segment (IST) and outer segment (OST). The variations of these parameters across different regions were analyzed. Results: From fovea to peripheral retina, all the OCT biomarkers declined before disappeared, except IST and IZ-ROI. There was no identifiable declining zone for the IST and IZ-ROI between the normal and disappeared zones. The earliest biomarker was the shortening of OST and reduced IZ-ROI, followed by the shortening of PRT, EZ-ROI, then IST, and finally, ONLT. All these biomarkers had significant correlations with best-corrected visual acuity, except ONLT.Conclusion: In retinitis pigmentosa, EZ-ROI, IZ-ROI, PRT, OST, IST and ONLT are valuable biomarkers of photoreceptor degeneration. OST and IZ-ROI may serve as the earliest biomarkers.