Is Optical Coherence Tomography a Useful Tool to Objectively Detect Actual Posterior Vitreous Adhesion Status?

ROLE OF OPTICAL COHERENCE TOMOGRAPHY IN MANAGEMENT OF ACUTE POSTERIOR VITREOUS DETACHMENT AND ITS COMPLICATIONS

PURPOSE

Currently, no consensus exists on the role of optical coherence tomography (OCT) imaging in the setting of acute posterior vitreous detachment (PVD). The authors outline the clinical utility of OCT in the management of acute PVD and its complications.

METHODS

Literature review of OCT findings in association with acute PVD and report of illustrative cases.

RESULTS

Optical coherence tomography imaging in the setting of acute PVD can provide details of vitreoretinal interface that are difficult to appreciate on biomicroscopy alone including partial PVDs, focal vitreoretinal adhesions and traction, and subclinical macular changes. The presence of vitreous hyperreflective dots on OCT in the premacular space, especially if severe, is highly correlated with the presence of peripheral retinal breaks and development of epiretinal membrane. Advancements in OCT technology, including enhanced vitreous imaging OCT, swept-source OCT, wide-angle OCT, and widefield OCT, allow for increased resolution and expanded field of imaging of the vitreoretinal interface.

CONCLUSION

Optical coherence tomography imaging is an emerging standard of care in the setting of patients presenting with new flashes and floaters. The authors highlight the benefits of OCT imaging in patients with acute PVD, which includes recognition of the status of the vitreoretinal interface, assistance in identifying high-risk PVDs, and performance of risk assessment that predict future macular pathologic condition.

Optical Coherence Tomography Angiography Findings in Proliferative Diabetic Retinopathy

PURPOSE

To characterize preretinal neovascularizations (NV) and their corresponding branching routes in proliferative diabetic retinopathy (PDR) with optical coherence tomography angiography (OCTA) and compare the findings with fluorescein angiography (FA).

METHODS

In patients with PDR, angiograms were acquired with spectral-domain OCTA (CIRRUS 5000, OCTA AngioPlexTMCarl Zeiss Meditec, Inc.) and FA (Zeiss FF450PlusIR fundus camera or Spectralis HRA-OCT SLO, Heidelberg Engineering Inc.) and were consecutively evaluated. Neovascularization of the disc (NVD) and neovascularization elsewhere (NVE) were analyzed with 6 × 6 and 8 × 8 mm OCTA flow images and B-scans with flow registration. Segmentations of the vitreoretinal interface (VRI) and superficial retina were performed for analysis. Two independent investigators examined OCTA findings and compared them to corresponding FA.

RESULTS

Forty-two eyes of 30 patients with PDR were analyzed. A total of 76 NV with their corresponding proliferation routes were visualized and characterized, with 55 (72.4%) proliferating along the posterior hyaloid membrane (PHM), 14 (18.4%) along the epiretinal membrane, and 7 (9.2%) along the fibrovascular membrane. The posterior vitreous was partially detached in 37 of 42 eyes (88.1%), completely detached in 1 of 42 eyes (2.4%), and adherent in 1 of 42 eyes (2.4%). In 38 of 42 cases, OCTA was superior (n = 23) or equivalent (n = 15) to FA in detecting NV and provided a more detailed information of the neovascular vessels. In 4 of 42 study eyes, OCTA was inferior to FA.

CONCLUSIONS

OCTA is a useful tool to detect NV in PDR. In comparison to FA, OCTA has the advantages that it is noninvasive and the image capture takes only seconds. We were able to identify all NV and characterize their corresponding proliferation routes in the VRI, the superficial retina slab, or the B-scan with flow registration. Through evading the masking effect of dye leakage in FA, OCTA is capable of better visualization of NV. FA, however, remains essential for the detection of all NV, since OCTA supplies a smaller detection field. Additionally, we identified the PHM as the main proliferating route of diabetic NV (72.4%), marking it as an important structure for sprouting vessels in neoangiogenesis in PDR.

Swept Source Optical Coherence Tomography Compared to Ultrasound and Biomicroscopy for Diagnosis of Posterior Vitreous Detachment

Background

Biomicroscopy, B-scan ultrasound imaging, and SD-OCT are all modalities used to characterize a posterior vitreous detachment (PVD). Our objective is to assess the precision of the diagnosis of PVD by SS-OCT.

Methods

This prospective observational study examines ninety-five eyes of forty-nine patients with biomicroscopy, B-scan ultrasound, and SS-OCT for the presence or absence of a complete PVD. All SS-OCT images were reviewed by two retina specialists (RWSC, ZM). All three diagnostic methods were evaluated for agreement by Cohen’s kappa statistic.

Results

The inter-rater reliability between retina specialists reading the SS-OCT images was 97.9% (κ = 0.957). Agreement on PVD status between SS-OCT and biomicroscopy was 85.3% (κ = 0.711). Agreement between SS-OCT and B-scan ultrasound was 83.2% (κ = 0.667). Agreement between B-scan ultrasound and biomicroscopy was 87.4% (κ = 0.743).

Conclusion

For the diagnosis of complete PVD, SS-OCT allows for high accuracy and agreement between graders.

Effect of partial posterior vitreous detachment on spectral-domain optical coherence tomography retinal nerve fibre layer thickness measurements

Background/aims

To assess the effect of partial posterior vitreous detachment (pPVD) on spectral-domain optical coherence tomography (OCT) peripapillary retinal nerve fibre layer thickness (RNFL) measurements.

Methods

Spectral-domain OCT RNFL thickness measurements were obtained from 684 consecutive patients who were seen in the Massachusetts Eye and Ear Glaucoma Service. Of these patients, we compared RNFL thickness measurements between 101 eyes of 101 glaucoma suspects who met inclusion criteria (55 eyes with and 46 eyes without pPVD).

Results

Among all 684 patients, 253 (37%) had pPVD in at least one eye. Among a subset of 101 eyes of 101 glaucoma suspects, average RNFL thickness was greater in eyes with compared to eyes without pPVD (p=0.02). Measurements were significantly greater in the inferior (p=0.004) and superior quadrants (p=0.008), but not in the nasal (p=0.10) and temporal quadrants (p=0.25). The difference in average RNFL thickness remained significant (p=0.05) even when corrected for expected age-related decline in RNFL thickness.

Conclusion

Over a third of patients were found on peripapillary spectral-domain OCT to have a pPVD, which was associated with greater RNFL thickness measurements. Judicious clinical interpretation of this finding on spectral-domain OCT RNFL thickness scans should be factored into the assessment of glaucoma suspects.

Posterior vitreous detachment rate following intravitreal dexamethasone injection

AIM

To determine whether intravitreal dexamethasone (DEX) implant induces posterior vitreous detachment or not.

METHODS

We retrospectively reviewed 810 eyes of 405 patients who underwent intravitreal DEX implantation due to macular edema caused by diabetic and retinal venous occlusion in our clinic. The eyes having no injection were determined as the control group. The examination findings of the patients before the injection and 3mo after the injection and optical coherence tomography (OCT) images were scanned. The pre-injection OCT findings and OCT findings of the patients having no posterior vitreous detachment (PVD) and determined to have partial PVD were compared.

RESULTS

The separation in vitreoretinal adhesion and total PVD development of DEX-injected 56/208 (26.9%) eyes were statistically greater in comparison with the 12/129 (9.3%) eyes that had not been injected (P=0.001). PVD development was observed more in the patients that were younger, had larger macula thickness and lower visual acuity.

CONCLUSION

It can be stated that intravitreal DEX implant induces PVD development. Prospective, controlled studies are required in order to determine prognosis of vitreoretinal disease in PVD-developed patients and in non-PVD-developed patients.

[Morphology of the vitreoretinal interface in fellow eyes of patients with full thickness macular holes]

PURPOSE

We performed a retrospective, observational clinical study to evaluate the vitreoretinal interface (VRI) in fellow eyes of patients with full thickness macular holes (FTMH) based on spectral domain optical coherence tomography (SD-OCT) examinations.

METHODS

The VRI in fellow eyes of 38 patients with idiopathic FTMH, 6 of which had concomitant vitreomacular traction (VMT) and the VRI of 32 patients with FTMH with complete resolution of VMT were examined by SD-OCT for the presence of vitreomacular adhesion (VMA), VMT and the formation of FTMH, lamellar macular holes (LMH), macular pseudoholes (MPH) or epiretinal membranes (ERM). Patients underwent complete ophthalmic evaluation, including SD-OCT at baseline and follow-up visits. To classify the morphology of the VRI, we used the international vitreomacular traction study classification system by Duker et al. (Ophthalmology 2013), evaluating the baseline SD-OCT data for significant classification parameters, including size of VMA, macular thickness and volume and structural changes of retinal layers.

RESULTS

Of the 38 eyes with FTMH, 2 (5.3%) fellow eyes also showed evidence of FTMH, 5 (13.2%) had isolated VMT while 5 (13.2%) showed formation of ERM, of which 2 demonstrated MPH. In 5 patients (13.2%) showing evidence of VMA and 17 patients (44.7%) with an unremarkable VRI, 22 fellow eyes (57.9%) showed no pathological morphology. Altogether, 16 fellow eyes (42.1%) of patients with FTMH showed pathological changes of the vitreoretinal interface.

CONCLUSION

This high-resolution SD-OCT-based retrospective study showed that fellow eyes of patients with VMT or FTMH were at increased risk of demonstrating pathological changes in the morphology of the VRI.