Abstract
Purpose: :
To present normative data of the outer photoreceptor layer (OPRL) thickness and to describe the change of the OPRL thickness in variable macular diseases, which were obtained by a simple modification of automated segmentation algorithm of spectral domain optical coherence tomography (SD OCT).
Methods: :
Forty one normal eyes from 24 healthy subjects (52.68±1.49 years) and 24 eyes from 20 patients (56.50 ± 3.60 years) who have variable macular diseases including closed macular hole (n=7), regressed central serous chorioretinopathy (n=5), dry type age related macular degeneration (n=8) and retinitis pigmentosa (n=4) were examined by 3D OCT-1000 (Topcon corp., Tokyo, Japan). Twelve-line rather than six-line radial scan (1024 axial scans/line) was done for measuring the OPRL thickness, a distance from inner segment/outer segment junction to outer margin of retinal pigment epithelium, which was enabled by utilizing the its own modifying menu of the automated segmentation algorithm. This maneuver also enabled us to produce both numeric and pseudo-color thickness and volume map of 9 subfield of macula instantly. We compated the OPRL measurements between normal eyes and the eyes wth macular disesases
Results: :
In healthy eye group, the mean OPRL thickness was 67.71±0.68 µm in central subfield and 61.98±0.67 µm in parafoveal area. The mean OPRL thickness measurement in central subfield was significantly thicker than each parafoveal subfields (p<0.05). However, in macular disease eye group, the mean OPRL thickness was 57.04±12.85 µm in central subfield and 55.65±12.06 µm in parafoveal area, which were significantly lower than healthy eye group. In addition, there was no statistical difference of the mean OPRL thickness measurements between foveal and parafoveal area.
Conclusions: :
The OPRL thickness is known as a strongly useful parameter of visual outcome. The OPRL thickness and volume maps could be obtained by simple modifying the automatic segmentation algorithm of Topcon 3D OCT. In some eyes with macular disease, the OPRL thickness measurements were significantly lower than normal eyes, which was most prominent in the central subfield area.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • photoreceptors • retina