Abstract
Purpose :
To study the influence of selective retina therapy (SRT) on the function of sensory retina after long-term follow-up by using electroretinography (ERG).
Methods :
Subjects consisted of 12 eyes of 12 patients (7 males and 5 females) treated with SRT for macular edema at Department of Ophthalmology of Osaka City University Hospital. Mean age was 68 years old (range 52-85). The causative diseases of macular edema were branch retinal vein occlusion with 7 eyes, central retinal vein occlusion with 1 eye and diabetic macular edema with 2 eyes. The average period from initial SRT to ERG measurement was 22 months (range 12 to 48 months). Best corrected visual acuity (BCVA) and central macular thickness (CMT) were measured before and after SRT. RETevalTM (LKC technologies) was used for ERG. Dark adapted (DA) flash electroretinograms were recorded with two flashes of 0.01cd/s/m2 (DA0.01) and 3.0cd/s/m2 (DA3.0). The implicit times and amplitudes of b-wave in DA0.01 (DA0.01b), a-wave and b-wave in DA3.0 (DA3.0a and DA3.0b), and oscillatory potential 1-3 (OP1-OP3) were compared between treated and fellow eyes.
Results :
The mean logMAR BCVA and CMT were significantly improved from 0.29 to 0.16 and 491 µm to 283 µm, respectively, at the latest follow-up time point (BCVA: P<0.01, CMT: P<0.01). There were no significance in the mean implicit times between treated and fellow eyes (110.0 ms and 114.0 ms for DA0.01b, 19.5 ms and 19.2 ms for DA3.0a, 53.0 ms and 52.0 ms for DA3.0b, 20.3 ms and 19.7 ms for OP1, 27.1 ms and 26.8 ms for OP2, and 34.1 ms and 33.9 ms for OP3, with P=0.31, 0.82, 0.46, 0.60, 0.81 and 0.88, respectively). Regarding mean amplitudes, there was a significant reduction of OP2 in treated eyes (8.6 µV) compared to the fellow eyes (12.8 µV, P=0.03). OP2 generally reflects the function of inner retina, to whose abnormality macular edema may strongly attribute. The other amplitudes did not show any significant differences between treated and fellow eyes (45.0 µV and 45.1 µV for DA0.01b, -40.0 µV and -39.0 µV for DA3.0a, 73.4 µV and 76.8 µV for DA3.0b, 9.7 µV and 11.8 µV for OP1, and 7.3 µV and 7.4 µV for OP3, with P=0.99, 0 .74, 0.46, 0.13, and 0.90, respectively). There was no difference in a-wave, which may generally suggest the function of outer retinal layer.
Conclusions :
ERG after long-term follow-up of SRT for macular edema showed no electrophysiological abnormality that might be caused by SRT.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.