Subthreshold Nanosecond Laser in Age-Related Macular Degeneration: Observational Extension Study of the LEAD Clinical Trial

CAMK2D and Complement Factor I-Involved Calcium/Calmodulin Signaling Modulates Sodium Iodate-Induced Mouse Retinal Degeneration

Purpose

To investigate the effect of Ca2+/calmodulin-dependent protein kinase II (CAMKII) δ subtypes (CAMK2D) on sodium iodate (NaIO3)-induced retinal degeneration in mice.

Methods

Bioinformatics analysis and Western blot experiments were used to screen the significantly differentially expressed genes in age-related macular degeneration (AMD) disease. CAMK2D knockdown and overexpression models were constructed by lentivirus (LV) infection of adult retinal pigment epithelial cell line-19 (ARPE-19) cells in vitro. Flow cytometry was used to detect ARPE-19 cell apoptosis induced by NaIO3. In vivo, CAMK2D knockdown and overexpression mouse models were generated by infecting mouse retinal pigment epithelium (RPE) with adeno-associated virus (AAV). Retinography, optical coherence tomography (OCT), and histological analysis (hematoxylin and eosin staining) were used to detect NaIO3-induced retinal structural changes in mice. Electroretinography (ERG) was used to detect NaIO3-induced retinal function changes in mice. TdT-mediated dUTP nick-end labeling (TUNEL) staining was used to detect the apoptosis of retinal cells induced by NaIO3. RNA sequencing (RNA-Seq) and bioinformatics analysis were used to screen for target genes affected by CAMK2D in CAMK2D-overexpressing ARPE-19 cells. And flow cytometry, OCT, and ERG were used to evaluate the regulatory effect of CAMK2D on target genes.

Results

Bioinformatics analysis found the expression of genes related to Ca2+ signal was significantly reduced in AMD patients. Western blot showed that in a mouse model of dry AMD induced by NaIO3, CAMK2D expression in RPE-Choroid tissue significantly lower than normal mice. In vitro, our results showed that overexpression of CAMK2D in ARPE-19 cells decreased apoptosis induced by NaIO3 and knockdown increased apoptosis. In vivo, CAMK2D overexpression in RPE cells can attenuate the retina degeneration induced by NaIO3 and CAMK2D knockdown aggravated degeneration. The bioinformatics analysis indicated that CAMK2D might affect AMD pathology through complement factor I (CFI). In vitro, knockdown of CFI in ARPE-19 cells increased apoptosis induced by NaIO3. In knockdown CFI ARPE-19 cells, overexpression of CAMK2D reduced the above apoptosis. In mice retina, CFI knockdown can aggravate the retina degeneration induced by NaIO3. In knockdown CFI mice, overexpression of CAMK2D in RPE can attenuate the above retina degeneration. Western blot confirmed that CAMK2D regulated the expression of CFI in mice.

Conclusions

CAMK2D can attenuate the retinal degeneration induced by NaIO3, which was achieved by regulating the CFI.

Detection sensitivity of fluorescence lifetime imaging ophthalmoscopy for laser-induced selective damage of retinal pigment epithelium

PURPOSE

To investigate the sensitivity of fluorescence lifetime imaging ophthalmoscopy (FLIO) to detect retinal laser spots by comparative analysis with other imaging modalities.

METHODS

A diode laser with a wavelength of 514 nm was applied with pulse durations of 5.2, 12, 20, and 50 µs. The laser pulse energy was increased so that the visibility of the laser spot by slit-lamp fundus examination (SL) under the irradiator's observation covers from the subvisible to visible range immediately after irradiation. The irradiated areas were then examined by fundus color photography (FC), optical coherence tomography (OCT), fundus autofluorescence (AF), FLIO, and fluorescein angiography (FA). The visibility of a total of over 2200 laser spots was evaluated by two independent researchers, and effective dose (ED) 50 laser pulse energy values were calculated for each imaging modality and compared.

RESULTS

Among examined modalities, FA showed the lowest mean of ED50 energy value and SL the highest, that is, they had the highest and lowest sensitivity to detect retinal pigment epithalium (RPE)-selective laser spots, respectively. FLIO also detected spots significantly more sensitively than SL at most laser pulse durations and was not significantly inferior to FA. AF was also often more sensitive than SL, but the difference was slightly less significant than FLIO.

CONCLUSION

Considering its high sensitivity in detecting laser spots and previously reported potential of indicating local wound healing and metabolic changes around laser spots, FLIO may be useful as a non-invasive monitoring tool during and after minimally invasive retinal laser treatment.

Advancements in Imaging and Therapeutic Options for Dry Age-Related Macular Degeneration and Geographic Atrophy

Age-related macular degeneration (AMD) is a leading cause of vision loss in the elderly, with dry AMD (d-AMD) leading to geographic atrophy (GA) and significant visual impairment. Multimodal imaging plays a crucial role in d-AMD diagnosis and management, allowing for detailed classification of patient phenotypes and aiding in treatment planning and prognosis determination. Treatment approaches for d-AMD have recently witnessed profound change with the development of specific drugs targeting the complement cascade, with the first anticomplement agents recently approved for GA treatment. Additionally, emerging strategies such as gene therapy and laser treatments may offer potential benefits, though further research is needed to fully establish their efficacy. However, the lack of effective therapies capable of restoring damaged retinal cells remains a major challenge. In the future, genetic treatments aimed at preventing the progression of d-AMD may emerge as a powerful approach. Currently, however, their development is still in the early stages.

Choroidal signal hypertransmission on optical coherence tomography imaging: Association with development of geographic atrophy in age-related macular degeneration

BACKGROUND

To examine the association between large choroidal signal hypertransmission ≥250 μm (LHyperT) on optical coherence tomography (OCT) with the risk of developing geographic atrophy (GA) and compare this risk with those associated with nascent geographic atrophy (nGA).

METHODS

Two hundred and eighty eyes from 140 participants with bilateral large drusen and without late age-related macular degeneration (AMD) or nGA at baseline underwent OCT imaging and colour fundus photography (CFP) at 6-monthly intervals up to 5 years. OCT scans were graded for the presence of LHyperT and nGA, and CFPs were graded for the presence of GA.

RESULTS

The five-year incidence of LHyperT and nGA were 37% and 27% respectively (p = 0.003), and the two-year probability of their progression to GA were 17% and 40%, respectively (p = 0.002). LHyperT and nGA explained 81% and 91% of the variance in the time to develop GA, respectively (p = 0.032), and they were both associated with a significantly higher rate of GA development compared to eyes without these lesions (adjusted hazard ratio = 110.8 and 183.2, respectively; p < 0.001 for both).

CONCLUSIONS

LHyperT and nGA were both high-risk features for GA development, but the latter showed a higher rate of GA progression and explained a significantly greater proportion of the variance in the time to develop GA. As such, nGA may be a more robust surrogate endpoint than LHyperT for the conventional clinical endpoint of CFP-defined GA for intervention trials in the early stages of AMD.

Reticular Pseudodrusen: Interreader Agreement of Evaluation on OCT Imaging in Age-Related Macular Degeneration

Purpose

To determine the interreader agreement for reticular pseudodrusen (RPD) assessment on combined infrared reflectance (IR) and OCT imaging in the early stages of age-related macular degeneration across a range of different criteria to define their presence.

Design

Interreader agreement study.

Participants

Twelve readers from 6 reading centers.

Methods

All readers evaluated 100 eyes from individuals with bilateral large drusen for the following: (1) the presence of RPD across a range of different criteria and (2) the number of Stage 2 or 3 RPD lesions (from 0 to ≥ 5 lesions) on an entire OCT volume scan and on a selected OCT B-scan. Supportive information was available from the corresponding IR image.

Main Outcome Measures

Interreader agreement, as assessed by Gwet's first-order agreement coefficient (AC₁).

Results

When evaluating an entire OCT volume scan, there was substantial interreader agreement for the presence of any RPD, any or ≥ 5 Stage 2 or 3 lesions, and ≥ 5 definite lesions on en face IR images corresponding to Stage 2 or 3 lesions (AC₁ = 0.60-0.72). On selected OCT B-scans, there was also moderate-to-substantial agreement for the presence of any RPD, any or ≥ 5 Stage 2 or 3 lesions (AC₁ = 0.58-0.65) and increasing levels of agreement with increasing RPD stage (AC₁ = 0.08, 0.56, 0.78, and 0.99 for the presence of any Stage 1, 2, 3, and 4 lesions, respectively). There was substantial agreement regarding the number of Stage 2 or 3 lesions on an entire OCT volume scan (AC₁ = 0.68), but only fair agreement for this evaluation on selected B-scans (AC₁ = 0.30).

Conclusions

There was generally substantial or near-substantial-but not near-perfect-agreement for assessing the presence of RPD on entire OCT volume scans or selected B-scans across a range of differing RPD criteria. These findings underscore how interreader variability would likely contribute to the variability of findings related to the clinical associations of RPD. The low levels of agreement for assessing RPD number on OCT B-scans underscore the likely challenges of quantifying RPD extent with manual grading.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Perspectives from clinical trials: is geographic atrophy one disease?

Geographic atrophy (GA) is currently an untreatable condition. Emerging evidence from recent clinical trials show that anti-complement therapy may be a successful treatment option. However, several trials in this therapy area have failed as well. This raises several questions. Firstly, does complement therapy work for all patients with GA? Secondly, is GA one disease? Can we assume that these failed clinical trials are due to ineffective interventions or are they due to flawed clinical trial designs, heterogeneity in GA progression rates or differences in study cohorts? In this article we try to answer these questions by providing an overview of the challenges of designing and interpreting outcomes of randomised controlled trials (RCTs) in GA. These include differing inclusion-exclusion criteria, heterogeneous progression rates of the disease, outcome choices and confounders.

Subretinal drusenoid deposits: An update

A wide spectrum of phenotypic manifestations characterizes age-related macular degeneration (AMD). Drusen is considered the hallmark of AMD and is located underneath the retinal pigment epithelium (RPE). In contrast, subretinal drusenoid deposits (SDDs), also known as reticular pseudodrusens, are located in the subretinal space, on top of the RPE. SDDs are poorly detected by clinical examination and color fundus photography. Multimodal imaging is required for their proper diagnosis. SDDs are topographically and functionally related to rods. SDDs cause a deep impairment in retinal sensitivity and dark adaptation. SDDs are dynamic structures that may grow, fuse with each other, or regress over time. An intermediate step in some eyes is the development of an acquired vitelliform lesion. The presence of SDD confers an eye a high risk for the development of late AMD. SDD leads to macular neovascularization, particularly type 3, geographic atrophy, and outer retinal atrophy.

Effect of subthreshold nanosecond laser on retinal structure and function in intermediate age-related macular degeneration

BACKGROUND

Subthreshold nanosecond laser (SNL) treatment has been studied as a potential intervention in intermediate age-related macular degeneration (iAMD). This study investigated the effect of 100 SNL treatment spots on retinal structure and function.

METHODS

A prospective single-arm interventional pilot study. SNL treatment was delivered as 100 spots around the retinal vascular arcades of the study eye (worst visual acuity) in a single session in subjects with iAMD. Multimodal retinal imaging and dark-adapted chromatic perimetry were performed at baseline and at 0.5, 3, 6 and 12 months post treatment. Post treatment changes in best corrected visual acuity (BCVA), retinal thickness, relative ellipsoid zone reflectivity (rEZR) and rod-mediated functional parameters were compared to baseline.

RESULTS

Twenty-one subjects with iAMD were recruited. SNL treatment was associated with an increase in retinal thickness (p = 0.008) and decrease in rEZR (p < 0.001) at 2 weeks post laser. Recovery of retinal thickness and rEZR was observed at the 3-month post laser visit. A gradual improvement in BCVA was observed after laser treatment. The mean change in BCVA between baseline and 12-month visit was +1.9 ± 3.3 letters for the SNL treated eyes, compared to -0.4 ± 3.0 letters for the fellow eyes (p = 0.027). Rod-mediated function improved at 3 months post laser (p < 0.001) and returned to the baseline levels at 12 months post treatment.

CONCLUSIONS

A single treatment with 100 SNL spots causes a short-term change in retinal structure and improvement in retinal function that are apparent at 3 months post treatment.