Preoperative duration of retinal detachment and subretinal immunoreactive endothelin-1: repercussion on logarithmic visual acuity

Baseline imaging characteristics and early structural changes in macula on rhegmatogenous retinal detachment

Animal models have demonstrated that structural changes affect the macula during peripheral rhegmatogenous retinal detachment. This study aimed to assess photoreceptors, retinal and choriocapillaris perfusion in non-macula involving rhegmatogenous retinal detachment by analyzing en-face images from structural OCTA segmented at the ellipsoid zone (EZ) level, calculating (1) "normalized" reflectivity as a surrogate biomarker of photoreceptor damage (2) perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) (3) perfusion density of choriocapillaris (PDCC). Twenty-one eyes affected by macula-on rhegmatogenous retinal detachment (RRD) were enrolled at the University "G. d'Annunzio", Chieti-Pescara. The fellow unaffected eye was used as control. The mean age at the onset of RRD was 60.09 ± 10.22 (range 34-83). Compared with fellow eyes, we found lower EZ "normalized" reflectivity in macula-on (0.42 ± 0.15 in fellow eyes and 0.31 ± 0.09 in macula on p = 0.004). The affected eye was also characterized by impaired perfusion in SCP (17.26 ± 3.34% in macula on and 20.56 ± 3.62% in the fellow eye p = 0.004) and CC (50.21 ± 6.20% in macula on the eye and 57.43 ± 6.20% in the fellow eye p = 0.004). Macula-on rhegmatogenous retinal detachment has subclinical changes in photoreceptors, SCP, and CC. Future longitudinal studies should evaluate if early changes could impact post-operative macular function.

Changes in Retinal Vessel and Retinal Layer Thickness After Vitrectomy in Retinal Detachment via Swept-Source OCT Angiography

Purpose

To compare postvitrectomy retinal and choroidal vessel density (VD) and retinal layer thickness between eyes with macula-off and macula-on rhegmatogenous retinal detachment (RRD) using swept-source optical coherence tomography (SS-OCT) and optical coherence tomography angiography (OCTA) and to identify OCTA factors associated with visual outcomes.

Methods

We retrospectively reviewed 31 eyes that underwent pars plana vitrectomy for primary RRD. Eyes with macula-off and macula-on RRD were compared with healthy fellow eyes. Both OCT and OCTA were performed 6 months after surgery, and the macula-off RRD group was divided into two subgroups according to the presence of an outer retinal defect. The correlations between postoperative best-corrected visual acuity (BCVA) at 6 months and SS-OCT and OCTA measurements were analyzed.

Results

Twenty eyes with macula-off RRD and 11 eyes with macula-on RRD were included. In the macula-off RRD group, the central retinal thickness was significantly decreased 6 months postoperatively compared with the fellow eyes (228.9 ± 29.7 µm and 253.6 ± 27.7 µm, P = 0.009). In the outer retinal defect group, the choriocapillaris plexus (CCP) VD was significantly decreased compared with the fellow eyes (56.4% ± 4.8% and 60.2% ± 4.0%, P = 0.026). In the macula-off RRD group, the postoperative BCVA at 6 months correlated significantly with the ratio of the center CCP VD of the detached eyes to that of the fellow eyes (R2 = 0.207, P = 0.025).

Conclusions

The CCP VD could be related to the anatomical restoration of the outer retinal layer in macula-off RRD. The CCP VD as determined by OCTA could be an indicator of the visual outcome after surgery in macula-off RRD.

Cytokine profiles of phakic and pseudophakic eyes with primary retinal detachment

PURPOSE

To compare the cytokine profiles of phakic (p) and pseudophakic (ps) eyes with primary rhegmatogenous retinal detachment (RD) to eyes with macular holes (MH) and to identify differences in the specific cytokine profiles.

METHODS

Aqueous humour (AH) and vitreous fluid (VF) were obtained from patients with primary RD without proliferative vitreoretinopathy undergoing vitrectomy. AH and VF of patients with macular holes (MH) served as controls. Forty-three different cytokines were quantified using multiplex cytokine analysis. Intergroup and intragroup comparisons were performed. To control for multiple comparisons, Holm's correction was applied.

RESULTS

VF and AH samples of 71 eyes with RD (pRD N = 38; psRD N = 33) and 26 eyes with MH were included. Cytokine levels in psRD and pRD were similar (none with >10-fold difference). The levels of 39 of 43 cytokines in the VF were significantly higher in eyes with RD than in those with MH (>10-fold: CXLC5, CCL26, CCL1, IL-6, CXCL11, CCL7, CCL13, MIG/CXCL9, CCL19 and TGF-β1). In the AH, 23 of 43 cytokines were significantly higher compared to MH (>10-fold: CXCL5, IL-4, IL-6, IL-8/CXCL8 and CCL7).

CONCLUSION

A complex, but nonspecific cytokine environmental response seems to initiate immunological and profibrotic processes following RD. Relevant differences in the cytokine profiles of eyes with pRD and psRD were not identified, whereas cytokine differences between AH and VF in RD could be explained by upregulation in the vitreous, a higher turn around in the anterior chamber, or differences in inflammatory cascades in both compartments.

Pathophysiology of proliferative vitreoretinopathy in retinal detachment

Because proliferative vitreoretinopathy cannot be effectively treated, its prevention is indispensable for the success of surgery for retinal detachment. The elaboration of preventive and therapeutic strategies depends upon the identification of patients who are genetically predisposed to develop the disease, as well as upon an understanding of the biological process involved and the role of local factors, such as the status of the uveovascular barrier. Detachment of the retina or vitreous activates glia to release cytokines and ATP, which not only protect the neuroretina but also promote inflammation, retinal ischemia, cell proliferation, and tissue remodeling. The vitreal microenvironment favors cellular de-differentiation and proliferation of cells with nonspecific nutritional requirements. This may render a pharmacological inhibition of their growth difficult without causing damage to the pharmacologically vulnerable neuroretina. Moreover, reattachment of the retina relies upon the local induction of a controlled wound-healing response involving macrophages and proliferating glia. Hence, the functional outcome of proliferative vitreoretinopathy will be determined by the equilibrium established between protective and destructive repair mechanisms, which will be influenced by the location and the degree of damage to the photoreceptor cells that is induced by peri-retinal gliosis.

Modelling postoperative visual acuity with and without proliferative vitreoretinopathy associated with primary rhegmatogenous retinal detachment

PURPOSE

To find models that will explain the variability in postoperative visual acuity (VA) (logarithmic: logMAR) associated with unilateral primary rhegmatogenous retinal detachment (RD).

METHODS

This was a prospective clinical cohort study of 33 patients with proliferative vitreoretinopathy (PVR: PVR<C3) and 33 without PVR, all of whom were candidates for scleral buckling (SB) surgery. Central retinal artery (CRA) Doppler sonography parameters (peak systolic, end diastolic velocities and resistibility index) and intraocular pressure (IOP) were measured before SB. Immunoreactive endothelin-1 (IR-ET-1) levels in both plasma and subretinal fluid (SRF) were measured using a radioimmunoassay. Visual outcomes were analysed by stepwise multivariate linear regression. The preoperative parameters used in the analysis included RD duration, IOP, logMAR VA, CRA parameters, preoperative plasma levels and intraoperative levels of IR-ET-1 in the SRF.

RESULTS

The models for 8-month-postoperative logMAR VA demonstrated a predictive power higher than 85%. The values of the 8-month-postoperative logMAR VA were as follows: (a) in No PVR= -0.151+0.06 preoperative duration (days), with a predictive power of 85.3%; (b) in PVR= -1.071+0.06 SRF IR-ET-1 (pg/ml)+0.459 preoperative logMAR VA explaining 89.9% of the variability in the postoperative logMAR VA.

CONCLUSIONS

The duration of RD and the levels of IR-ET-1 in the SRF appear to be the best explanatory variables in the models for 8-month-postoperative logMAR VA variability in RD patients. RD surgery should be performed as soon as possible to best preserve VA.