Sub-threshold nanosecond laser (SNL) treatment in intermediate AMD (IAMD)

Two potentially distinct pathways to geographic atrophy in age-related macular degeneration characterized by quantitative fundus autofluorescence

BACKGROUND/AIMS

To demonstrate two distinct pathways to geographic atrophy (GA) that originate from soft drusen/ pigment epithelial detachments (PEDs) and subretinal drusenoid deposits (SDDs), respectively, and are characterized by their final quantitative autofluorescence (qAF) levels.

METHODS

23 eyes of 18 patients with GA underwent spectral-domain optical coherence tomography (SD-OCT) and qAF imaging on the qAF-ready Heidelberg Spectralis. 52 GA Regions-of-interest (ROIs), or clusters of adjacent lesions, were selected, and the ROIs were divided into groups by the dominant iAMD precursors on prior serial tracked SD-OCT scans. Mean qAF values and structural SD-OCT findings of groups were compared.

RESULTS

Group 1 lesions (soft drusen/PED precursors, 18/52) were isolated, with lower mean qAF (35.88 ± 12.75 units); group 3 lesions (SDD precursors, 12/52) were multilobular, with significantly higher mean qAF (71.62 ± 12.12 units, p < 0.05). Group 2 lesions, (mixed precursors, 22/52) had intermediate mean qAF (58.13 ± 67.92 units). Significantly greater prevalence of split RPE/ Bruch's membrane complex in SDD-associated GA, suggesting basal laminar deposit (BLamD), than in drusen-associated lesions was the major structural difference.

CONCLUSION

Quantitative autofluorescence (qAF) of GA lesions may reflect two distinct pathogenic pathways and structural outcomes, originating from soft drusen/PED and subretinal drusenoid deposits (SDDs), with the final qAF values lower or higher, respectively. Basal laminar deposit specifically in and adjacent to SDD-associated lesions may account for their greater autofluorescence. The potential importance of this paradigm is that it could direct, simplify and facilitate research on geographic atrophy by dividing the disease into two components that may be studied separately.

Effects of subthreshold nanosecond laser therapy in age-related macular degeneration using artificial intelligence (STAR-AI Study)

PURPOSE

To investigate changes in retinal thickness, drusen volume, and visual acuity following subthreshold nanosecond laser (SNL) treatment in patients with age-related macular degeneration (ARMD).

DESIGN

Retrospective chart review.

METHODS

Patients with intermediate ARMD treated with a single session of SNL (2RT®, Ellex R&D Pty Ltd, Adelaide, Australia) were included. Swept-source optical coherence tomography (OCT) imaging (Triton; Topcon Medical Systems, Tokyo, Japan) was performed within 6 months before and after SNL treatment. Retinal layers were segmented using the artificial intelligence-enabled Orion® software (Voxeleron LLC, San Francisco, USA). The macular region was analyzed according to the Early Treatment Diabetic Retinopathy Study map. Mean difference and standard deviation in baseline and post-treatment retinal layer thicknesses are reported.

RESULTS

37 eyes from 25 patients were included in this study (mean age 74.7±9.2 years). An average of 51±6 spots were applied around the macula of each study eye, with a mean spot power of 0.33±0.04mJ. Increases in total retinal thickness were observed within the outer temporal and inferior sectors (P<0.05). Within the annulus, there was an increase in thickness of the sub-retinal pigment epithelial (RPE) space [0.88±2.41μm, P = 0.03], defined between the RPE and Bruch's membrane. An increase in thickness of 1.13±2.55μm (P = 0.01) was also noted in the inferior sector of the photoreceptor complex, defined from the inner and outer segment junction to the RPE. Decreases in thickness were observed within the superior sector of the inner nuclear layer (INL) [-1.08±2.55μm, P = 0.01], and within the annulus of the outer nuclear layer (ONL) [-1.44±3.55μm, P = 0.02].

CONCLUSIONS

At 6 months post-SNL treatment, there were sectoral increases in OPL, photoreceptor complex, and sub-RPE space thicknesses and sectoral decreases in INL and ONL thicknesses. This pilot study demonstrates the utility of OCT combined with artificial intelligence-enabled software to track retinal changes that occur following SNL treatment in intermediate ARMD.

Subthreshold laser treatment for reticular pseudodrusen secondary to age-related macular degeneration

There is a lack of treatment aimed at the regression of reticular pseudodrusen (RPD) secondary to age-related macular degeneration (AMD). The aim of this prospective, pilot study is to evaluate the safety and short-term efficacy of subthreshold laser treatment (SLT) in patients affected by RPD secondary to dry AMD (dAMD). Twenty eyes of 20 patients (mean age 78.4 ± 6.8 years) with RPD secondary to dAMD were prospectively enrolled. All patients were treated in an extrafoveal area of 1.27 mm² using end-point management yellow subthreshold laser and followed for 3 months. Best-corrected visual acuity was 0.140 ± 0.09 LogMAR at the baseline and no changes were observed during the follow-up (p = 0.232). No significant worsening was disclosed before and after the treatment analyzing the macular sensitivity of the treated area (p = 0.152). No topical and/or systemic side effects were disclosed during the 3-month follow-up. The distribution among the RPD stages changed after the treatment (p < 0.001). In detail, in the treated area, we observed a significant increase in the number of Stage 1 RPD during the follow-up (p = 0.002), associated with a significant decrease of Stage 3 RPD (p = 0.020). Outer nuclear layer (ONL) thickness analysis showed a significant increase after the treatment associated with RPD regression (p = 0.001). End-point management SLT appears a safe treatment for RPD secondary to dAMD, showing short-term safety outcomes. Our results suggest that SLT could be effective in inducing a RPD regression in terms of RPD stage and ONL thickening.