Optical coherence tomography analysis of bilateral end-stage choroidal neovascularization where one eye is treated with photodynamic therapy

Fibrosis in age-related neovascular macular degeneration in the anti-VEGF era

The natural history of neovascular age-related macular degeneration (nAMD) leads to scarring and loss of vision. Since the advent of anti-VEGF therapies, which are very effective for controlling exudation, large disciform scars are rarely encountered in the clinic. However long term studies show that smaller and less severe fibrotic scars are not uncommon and develop over time despite optimal treatment. This means that additional mechanisms of action may be required to completely address this condition. To permit new treatments, a proper understanding of the clinical impact of fibrosis is required. This review is focused on clinical aspects of fibrosis and summarises recent data on biomarkers, prevalence, causes, consequences, and therapies, highlighting the most important and urgent topics to tackle in order to advance in the treatment of fibrosis.

Fibrosis in neovascular age-related macular degeneration: A review of definitions based on clinical imaging

Despite the success of antiangiogenic therapy in controlling exudation in neovascular age-related macular degeneration (nAMD), the involvement of the outer retina in fibrosis results in gradual vision loss over time. The development of drugs that prevent or ameliorate fibrosis in nAMD requires that it is accurately detected and quantified with reliable endpoints and identification of robust biomarkers. Achievement of such an aim is currently challenging due to the lack of a consensus definition of fibrosis in nAMD. As a first step towards the establishment of a clear definition of fibrosis, we provide an extensive overview of the imaging modalities and criteria used to characterize fibrosis in nAMD. We observed variety in the selection of individual and combinations of imaging modalities, and criteria for detection. We also observed heterogeneity in classification systems and severity scales for fibrosis. The most commonly used imaging modalities were color fundus photography, fluorescein angiography and optical coherence tomography (OCT). A multimodal approach was frequently utilized. Our review suggests that OCT offers a more detailed, objective and sensitive characterization than color fundus photography/fluorescein angiography. Thus, we recommend it as a primary modality for fibrosis evaluation. This review provides a basis for future discussions to reach a consensus definition using standardized terms based on a detailed characterization of fibrosis, its presence and evolution, and taking into consideration impact on visual function. Achieving this goal is of paramount importance for the development of antifibrotic therapies.

Computerized assessment of intraretinal and subretinal fluid regions in spectral-domain optical coherence tomography images of the retina

PURPOSE

To evaluate a new computerized segmentation technique for the quantification of intraretinal and subretinal fluid in spectral-domain optical coherence tomography (SD OCT) images of the retina.

DESIGN

Prospective, cross-sectional study.

METHODS

Thirty-seven B-scan images of 37 patients with exudative age-related macular degeneration were chosen randomly from SD OCT volume scans (1 per volume scan). All hyporeflective areas in the image first were segmented automatically as candidate regions by the program. Researchers who were masked to the candidate region information selected each fluid region from the original image using a single mouse click. The program then delineated the boundary of each region selected and calculated quantitative parameters, including total area of fluid regions if multiple regions were selected. The performance of our technique was validated by comparing the results with the measurements obtained from boundaries manually delineated by 2 masked observers. Time efficiency, agreement with manual delineation, and intraobserver and interobserver agreement of using the program were evaluated.

RESULTS

The proposed technique reduced the average processing time per image approximately 6-fold (15 seconds for computerized segmentation vs 90 seconds for manual delineation). There was good agreement between computerized segmentation and manual delineation measured by intraclass correlation coefficient (range, 0.897 to 0.979) and the Dice coefficient (range, 0.721 to 0.785). The proposed technique has excellent intraobserver and interobserver agreement (intraclass correlation coefficient range, 0.998 to 0.999; Dice coefficient range. 0.959 to 0.981).

CONCLUSIONS

This computerized segmentation method allows for accurate and fast quantification of fluid in retinal SD OCT images and could assist in monitoring disease progression and evaluating therapeutic intervention.

Effects of ranibizumab on exudative disciform scars

BACKGROUND AND OBJECTIVE

To evaluate the effect of intravitreal ranibizumab in patients with leaking disciform scars.

PATIENTS AND METHODS

In this retrospective case series, 31 eyes received one or two ranibizumab injections for treatment of choroidal neovascularization. Visual acuity, central retinal thickness, and macular volume were measured prior to injection and at 1-month follow-up.

RESULTS

After one injection (n = 31), mean optical coherence tomography (OCT) central foveal thickness decreased from 317 to 242 microm (P = .00016). Mean OCT macular volume decreased from 7.89 to 6.80 mm3 (P = .00019). After two injections (n = 12), mean OCT central foveal thickness decreased from 310 to 248 microm following the second injection (P = .04). Mean OCT macular volume decreased from 7.80 to 6.43 mm3 at 1-month follow-up after a second injection (P = .006). There was no significant change in visual acuity after injections.

CONCLUSION

In the short-term, ranibizumab decreases the leakage associated with choroidal neovascularization in chronic macular degeneration.