Anatomic-Functional Correlates in Lesions of Retinal Vein Occlusion

Deep Capillary Plexus as Biomarker of Peripheral Capillary Nonperfusion in Central Retinal Vein Occlusion

Purpose

To identify the vascular biomarkers of peripheral capillary nonperfusion in patients affected by naive central retinal vein occlusion (CRVO), and to analyze their changes over the follow-up.

Study Design

Consecutive prospective case series with a planned follow-up of 2 years.

Participants

Thirty-five patients affected by CRVO and 35 healthy gender- and age-matched subjects were enrolled in the study.

Methods

Ophthalmic examination included best corrected visual acuity (BCVA), ultrawidefield fluorescein angiography (UWFFA), OCT, and OCT angiography (OCTA).

Main Outcome Measures

Vessel density (VD) at the superficial capillary plexus and deep capillary plexus (DCP) were calculated on OCTA images. The ischemic index (ISI) was calculated on UWFFA.

Results

The mean baseline ISI was 37%, increasing to 40% at the end of the follow-up, whereas it was 4.9% in the patients' fellow eyes and 4.5% in the control group with no change over the follow-up. OCT angiography revealed VD reduction in the DCP, considering both 3 × 3 mm and 12 × 12 mm scans. The correlation analyses revealed that DCP VD was the only parameter showing a statistically significant correlation with the foveal avascular zone (FAZ) area, BCVA, and ISI.

Conclusions

Deep capillary plexus VD impairment is detectable in all CRVO cases, variably involving both the central retina (with enlarged FAZ) and the periphery (with VD reduction in the peripheral retina). The severity of DCP VD reduction has correlates with various clinical markers. Deep capillary plexus VD may represent a crucial biomarker to characterize CRVO, and further studies are necessary to identify the cutoff thresholds for the different clinical manifestations.

Intravitreal ranibizumab improves macular sensitivity in patients with central retinal vein occlusion and macula edema

Background

Patients with central retinal vein occlusion (CRVO) and macular edema often are treated by intravitreal ranibizumab injection (IRI). The role of changes in macular sensitivity in the positive effects of IRI on visual functions is unclear. Therefore, we assessed the relationship between macular sensitivity and improvement of visual functions.

Methods

We included 15 eyes of 15 patients with treatment-naïve CRVO and followed patients for 6 months after pro re nata IRI. IRI was repeated if the central macular thickness was greater than or equal to 300 µm. Microperimetry-3 was used to measure macular sensitivity within the central 1-mm, 3-mm, and 6-mm fields before and monthly for 6 months after IRI.

Results

IRI significantly improved mean macular sensitivity over time within the central 1-mm, 3-mm, and 6-mm fields (all P < 0.001). None of the fields showed significant differences in the change of mean macular sensitivity between patients with little improvement in best corrected visual acuity (BCVA; i.e., in patients with a change in logarithm of the minimum angle of resolution [logMAR] BCVA < 0.3) and those with marked improvement in BCVA (change in logMAR BCVA > 0.3). The mean macular sensitivity before IRI showed correlations with the improvement of macular sensitivity in every field.

Conclusion

These findings suggest that IRI improves macular sensitivity in patients with CRVO and macular edema independent of any improvement in BCVA and that macular sensitivity before treatment is associated with improvement of macular sensitivity after treatment.