FOVEA PLANA ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: New Perspectives

PURPOSE

To report on the reliability of optical coherence tomography angiography (OCTA) to diagnose fovea plana.

METHODS

A retrospective, cross-sectional, case-control study included patients with foveal persistence of the inner retinal layers, confirmed by spectral domain OCT, and superficial capillary plexus (SCP) and deep capillary plexus foveal vascularization confirmed by OCTA. A healthy control group was selected. The best-corrected visual acuity was obtained. Spectral-domain OCT was used for measuring the outer nuclear layer thickness, and OCTA determined the foveal avascular zone, SCP, and deep capillary plexus vascular density.

RESULTS

Optical coherence tomography angiography reliability, based on all parameters, reached 97%, whereas based only on SCP vascular density 91%. The plana group (n = 57) differed significantly from the control group (n = 28) in terms of foveal avascular zone, SCP, and deep capillary plexus foveal vascular density (P < 0.005). Subjects with SCP foveal vascular density >30% or foveal avascular zone <0.1 mm2 had fovea plana. The best-corrected visual acuity of the plana group had no correlation with OCTA quantitative parameters (Pearson |r|<0.18, Spearman |r|<0.44).

CONCLUSION

Optical coherence tomography angiography has a high accuracy in diagnosing fovea plana, as its characteristics differ significantly from the normal population. The lack of correlation between the best-corrected visual acuity and OCTA parameters implies that reduced the best-corrected visual acuity is likely to result from coexistent diseases rather than from the foveal structure.

CHANGES IN VISUAL ACUITY AND PHOTORECEPTOR DENSITY USING ADAPTIVE OPTICS AFTER RETINAL DETACHMENT REPAIR

PURPOSE

To quantify changes in photoreceptor density using adaptive optics fundus camera in patients after retinal detachment (RD) and to correlate them with macular involvement and best-corrected visual acuity.

METHODS

At 1 and 3 months (M1 and M3) after vitrectomy, 194 patients underwent adaptive optics imagery in both eyes, at 5 locations, that we matched between time points using anatomical landmarks. Twenty-two patients (10 fovea-OFF [OFF] and 12 fovea-ON [ON]) had matched and analyzable adaptive optics images. We used analysis of variance for repeated measures.

RESULTS

Best-corrected visual acuity (logarithm of the minimum angle of resolution and Snellen equivalent [SE]) was significantly different between OFF and ON RDs at baseline: 2.0 (2.3-0.95) (SE: 20/2000) versus 0 (0.1-0) (SE: 20/20); at M1: 0.35 (0.5-0.1) (SE: 20/40) versus 0.05 (0-0.1) (SE: 20/25); and at M3: 0.25 (0.3-0.1) (SE: 20/32) versus 0 (0-0) (SE: 20/20). We observed that cone density was stable in fellow eyes between M1 and M3 (P = 0.67); decreased in treated eyes than in fellow eyes (P < 0.05); and increased postoperatively in the ON group (P = 0.02) but not in the OFF group (P = 0.97). Visual acuity and RD type were independently correlated with cone density (P = 0.004, P = 0.000).

CONCLUSION

Postoperative cone density was reduced in OFF RD, but also in the ON group, although the drop recovered during the 3-month follow-up. Cone density was significantly correlated with both visual acuity and type of RD at both time points.

Iron is neurotoxic in retinal detachment and transferrin confers neuroprotection

In retinal detachment (RD), photoreceptor death and permanent vision loss are caused by neurosensory retina separating from the retinal pigment epithelium because of subretinal fluid (SRF), and successful surgical reattachment is not predictive of total visual recovery. As retinal iron overload exacerbates cell death in retinal diseases, we assessed iron as a predictive marker and therapeutic target for RD. In the vitreous and SRF from patients with RD, we measured increased iron and transferrin (TF) saturation that is correlated with poor visual recovery. In ex vivo and in vivo RD models, iron induces immediate necrosis and delayed apoptosis. We demonstrate that TF decreases both apoptosis and necroptosis induced by RD, and using RNA sequencing, pathways mediating the neuroprotective effects of TF are identified. Since toxic iron accumulates in RD, we propose TF supplementation as an adjunctive therapy to surgery for improving the visual outcomes of patients with RD.

Hyperactivation of retina by light in mice leads to photoreceptor cell death mediated by VEGF and retinal pigment epithelium permeability

Light toxicity is suspected to enhance certain retinal degenerative processes such as age-related macular degeneration. Death of photoreceptors can be induced by their exposure to the visible light, and although cellular processes within photoreceptors have been characterized extensively, the role of the retinal pigment epithelium (RPE) in this model is less well understood. We demonstrate that exposition to intense light causes the immediate breakdown of the outer blood–retinal barrier (BRB). In a molecular level, we observed the slackening of adherens junctions tying up the RPE and massive leakage of albumin into the neural retina. Retinal pigment epithelial cells normally secrete vascular endothelial growth factor (VEGF) at their basolateral side; light damage in contrast leads to VEGF increase on the apical side – that is, in the neuroretina. Blocking VEGF, by means of lentiviral gene transfer to express an anti-VEGF antibody in RPE cells, inhibits outer BRB breakdown and retinal degeneration, as illustrated by functional, behavioral and morphometric analysis. Our data show that exposure to high levels of visible light induces hyperpermeability of the RPE, likely involving VEGF signaling. The resulting retinal edema contributes to irreversible damage to photoreceptors. These data suggest that anti-VEGF compounds are of therapeutic interest when the outer BRB is altered by retinal stresses.

Intravitreal ranibizumab (Lucentis) in the treatment of retinal angiomatous proliferation (RAP)

BACKGROUND

Retinal angiomatous proliferation (RAP) is a distinct variant of neovascular age-related macular degeneration (AMD). The aim of this study is to evaluate the functional and anatomic outcome after intravitreal ranibizumab (Lucentis) treatment in patients with RAP.

METHODS

Prospective study of consecutive patients with newly diagnosed or recurrent RAP treated with intravitreal ranibizumab at the Jules Gonin Eye Hospital between March 2006 and December 2007. Baseline and monthly follow-up visits included best-corrected visual acuity (BCVA), fundus exam and optical coherence tomography. Fluorescein and indocyanine green angiography were performed at baseline and repeated at least every 3 months.

RESULTS

Thirty-one eyes of 31 patients were treated with 0.5 mg of intravitreal ranibizumab for RAP between March 2006 and December 2007. The mean age of the patients was 82.6 years (SD:4.9). The mean number of intravitreal injections administered for each patient was 5 (SD: 2.4, range 3 to 12). The mean follow up was 13.4 months (SD: 3, range 10 to 22). The baseline mean logMAR BCVA was 0.72 (SD: 0.45) (decimal equivalent of 0.2). The mean logMAR BCVA was improved significantly (P < 0.0001) at the last follow-up to 0.45, SD: 0.3 (decimal equivalent 0.35). The visual acuity (VA) improved by a mean of 2.7 lines (SD 2.5). Mean baseline central macular thickness (CMT) was 376 microm, and decreased significantly to a mean of 224 microm (P < 0.001) at the last follow-up. Mean reduction of CMT was 152 microm (SD: 58). An average of 81.5% of the total visual improvement and 85% of the total CMT reduction occurred during the first post-operative month after one intravitreal injection of ranibizumab. During follow-up, an RPE tear occurred in one eye (3.2%) of the study group. No injection complications or systemic drug-related side-effects were noted during the follow-up period.

CONCLUSIONS

Intravitreal ranibizumab injections appeared to be an effective and safe treatment for RAP, resulting in visual gain and reduction in macular thickness. Further long-term studies to evaluate the efficacy of intravitreal ranibizumab in RAP are warranted.

[Effect of squatting on sub-foveal blood flow defect in pseudophakic eyes operated by cerclage]

ZIEL: To investigate the relationship between velocity (Velch), blood volume (Volch) and blood flow (Fch), and the mean ocular perfusion pressure (PPm) in the foveal region, and to determine how the regulatory capacity of the choroidal circulation is affected after an encircling buckle procedure.

METHODS

We investigated both pseudophakic eyes of 6 patients (age range 56-79 years) in a masked study. Subjects presenting eye diseases (glaucoma, uveitis, diabetic retinopathy) as well as systemic diseases were excluded from the study. All subjects had in one eye a successful management of retinal detachment with an encircling buckling; the second eye was considered as control. Measurements of Velch, Volch and Fch were obtained by Laser Doppler Flowmetry (LDF) at baseline and during isometric exercise (squatting).

RESULTS

In the operated eyes, Velch and Fch increased significantly (ANOVA, p < 0.05) during the PPm raise, which was not the case for Volch (ANOVA, p > 0.05). In the control eyes, all hemodynamic parameters remained unaffected by the PPm increase (ANOVA, p > 0.05). The response of Velch and Fch was significantly different (ANCOVA, p < 0.002) between operated and control eyes.

CONCLUSION

These results suggest that encircling buckle does affect subfoveal choroidal blood flow regulation, which may explain a possible macular dysfunction in the operated eyes.