Morphological and functional assessment of photoreceptors after macula-off retinal detachment with adaptive-optics optical coherence tomography (AO-OCT) and microperimetry

Abstract

Purpose : Limited information is available on morphological and functional regeneration of photoreceptors after retinal detachment (RD) surgery. This prospective, observational clinical study compared morphological and functional changes of cones between 6 weeks and 12 months after vitrectomy with gas for macula-off RD.

Methods : 10 eyes (5 RD, 5 healthy) of 5 patients (53-63yo) were examined with AO-OCT, spectral domain OCT (SD-OCT) and Nidek MP-1 microperimetry (MP) at 2.5° and 6.5° foveal eccentricity (ecc). Measurements were performed at week 6 (w6) and month 12 (m12) after surgery.
SD-OCT B-Scans and AO-OCT en face images were graded regarding irregularity and loss of photoreceptor signals from none to severely affected. Cone density was counted manually in AO-OCT images. MP with a custom grid was used to assess retinal function.
(Paired) T-Test, Spearman’s ρ, Mann-Whitney U and Χ² were used for statistics.

Results : At w6, the mean photoreceptor density (PD) at 2.5°ecc was 20.300/mm² in healthy fellow eyes (HE) and 5.470/mm² in RD (p<.001). At 6.5°ecc, PD was 16.170/mm² in HE and 9.860/mm² in RD (p<.001).
At m12, PD had not changed in HE compared to w6 and was 20.200/mm² at 2.5°ecc (p=.784) and 15.290/mm² at 6.5°ecc (p=.078). In RD, PD had increased significantly at 2.5°ecc to 8.520/mm² (p=.002) and at 6.5°ecc to 10.730/mm² (p=.003).
95.8% of AO-OCT images and 91.7% of SD-OCT B-Scans after RD showed irregular cone patterns (CP) with severe distortion in >66%. In HE, 95.8% of AO-OCT images and 100% of SD-OCT B-Scans showed regular CP. CP irregularity in SD-OCT was strongly associated with irregularity in AO-OCT (ρ=.781). Between w6 and m12, regularity of CP after RD improved in SD-OCT (p=.001) and AO-OCT (p<.001) images.
MP sensitivity in RD eyes (mdn=16; iqr=2) was lower (p<.001) than in HE (mdn=18; iqr=4) but showed only a weak correlation with PD (ρ=.354) or CP regularity (ρ=.371 to .394).

Conclusions : Cone density and morphology is significantly affected due to RD and remains abnormal even 12 months after surgery. Changes in cone patterns correlate well between AO- and SD-OCT.
AO-OCT is able to visualize and characterize cone alterations precisely and serves as an excellent tool to understand the pathophysiology of RD-induced photoreceptor damage.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

CP of IS/OS & cone tips (COST) in a 60yo patient after RD(OD) & in HE(OS) at w6 &m12