Photoreceptor Impairment and Restoration on Optical Coherence Tomographic Image

Abstract

With recent development of spectral-domain optical coherence tomography (SD-OCT), the pathological changes of retina can be observed in much greater detail. SD-OCT clearly delineates three highly reflective lines in the outer retina, which are external limiting membrane (ELM), photoreceptor inner and outer segment (IS/OS) junction, and cone outer segment tips (COST) in order from inside. These lines can serve as hallmarks for the evaluation of photoreceptor condition. In retinitis pigmentosa (RP) leading to photoreceptor degeneration, the ELM, IS/OS, and COST lines are shortened with the progression of the disease. In addition, shortening of the ELM, IS/OS and COST lines is significantly associated with each other. The line length is longest in the ELM, followed by the IS/OS, and COST, suggesting that retinal layer becomes disorganized first at the COST, followed by the IS/OS and finally the ELM. This finding is consistent with the previous report that the earliest histopathological change in RP is a shortening of the photoreceptor outer segments. On the other hand, retinal layer becomes restored first at the ELM, followed by the IS/OS and finally the COST after macular hole surgery. There may be a directionality of photoreceptor impairment or restoration on optical coherence tomographic image.

Genetic rescue models refute nonautonomous rod cell death in retinitis pigmentosa

“…Under favorable conditions, rod and cone OSs are capable of regrowth-for example, following light-induced damage (15), retinal detachment (16), or macular hole surgery (17). However, the extent and time course of regrowth depend on the severity of the damage (15).…”

Optical Coherence Tomographic Analysis of Retina in Retinitis Pigmentosa Patients

“…One reason was that some eyes with relatively intact EZ lines had reduced mfERG amplitudes. It was the abnormality of the IZ line that led to reduced mfERG amplitudes, while the EZ line was intact in OCT images [34]. A second possibility was that the functional abnormality preceded the structural changes in RP eyes.…”

Associations between preoperative OCT parameters and visual outcome 3 months postoperatively in patients undergoing vitrectomy for idiopathic epiretinal membrane

“…A number of studies have directed particular attention towards central foveal thickness (CFT) [3,[8][9][10][11][12][13][14][15][16], and several studies have found a correlation between a reduced CFT and better postoperative visual acuity [3,14,16], while others have not [7,8,15]. Numerous studies have also found that an intact preoperative ellipsoid zone (previously known as the inner/outer segment junction line) [17] is significantly correlated with better postoperative visual acuity [6,7,[18][19][20][21].…”