EXTENT OF DIABETIC MACULAR EDEMA BY SCANNING LASER OPHTHALMOSCOPE IN THE RETROMODE AND ITS FUNCTIONAL CORRELATIONS

Retromode imaging in retinal diseases: A systematic review of the literature

Retromode scanning laser ophthalmoscopy imaging captures a pseudo-3-dimensional image of the ocular fundus. Retromode scanning laser ophthalmoscopy imaging was introduced first in 2008 using the Nidek F-10 scanning laser ophthalmoscope (F-10; Nidek Co., Gamagori, Japan). At that time, no major role was described for this imaging modality. The interest in retromode scanning laser ophthalmoscopy imaging is reemerging with the recent advent of the Mirante that combines scanning laser ophthalmoscopy and optical coherence tomography (Nidek Co., Gamagori, Japan) that can capture retromode images of the fundus. We summarize the findings and clinical implications of retromode imaging using the Nidek F-10 and the Mirante in retinal diseases with the aim of helping researchers direct their future studies.

Retromode Scanning Laser Ophthalmoscopy for Choroidal Nevi: A Preliminary Study

The purpose of the present study was to document pathological findings on retromode imaging in choroidal nevi and evaluate its diagnostic validity, using the confocal scanning laser ophthalmoscope Nidek Mirante (cSLO). A total of 41 choroidal nevi from 41 patients were included. All patients underwent multicolor fundus (mCF), infrared reflectance (IR), green fundus autofluorescence (FAF), dark-field (DF) and retromode (RM) imaging and optical coherence tomography (OCT) scans. We investigated retromode images to evaluate choroidal nevus features by comparing the results with those of mCF, IR, FAF, DF and OCT. In 100% of available images, retromode scanning laser ophthalmoscopy was able to detect choroidal nevi with a characteristic "hypo-retro-reflective" pattern, even the cases not visible on mCF, IR and FAF images. It also made it possible to delineate the margins of lesions with the highest rate of sharpness and accuracy among the imaging modalities examined. These findings seem to demonstrate how RM-SLO is an innovative diagnostic tool to detect and follow up choroidal nevi in a fast, reliable and non-invasive way.

Retromode Imaging in Age-Related Macular Degeneration

Background and Objectives: Retromode is a relatively new retinal-imaging technique that is based on the transillumination principle and is obtained with a scanning laser ophthalmoscope that uses light in the infrared spectrum. The laser light penetrates into the deep retinal layers and the choroid. Retromode images are captured with a laterally displaced aperture, and the detector captures only the scattered light. The result is a high-contrast pseudo-three-dimensional image. Age-related macular degeneration (AMD) is a disabling retinal disease. AMD is characterized in its early stage by small and intermediate drusen formation, while the signs of intermediate AMD are large drusen and/or pigmentary abnormalities. Late AMD has two forms, geographic atrophy, which is the advanced form of dry AMD, and wet AMD. Most of the lesions of AMD are located in the outer layers of the retina. This new imaging method can provide a glimpse of the deep retinal layers' topographic changes in a non-invasive, fast, and effective way that can match the other imaging tools available. Materials and Methods: The literature review was performed by searching the PubMed database using the following combination of keywords: retromode imaging and age-related macular degeneration. Relevant images similar to the ones in the literature were identified and used as models. Results: The purpose of this article is to highlight the utility of incorporating retromode imaging into the multimodal evaluation of the retina in patients with AMD and to gather and integrate these findings into a brief but comprehensive paper. Conclusions: Retromode imaging is a good screening, diagnosis, and monitoring tool for patients with AMD.

Characterization of Choroidal Nevi with Dark-Field Infrared Scanning Laser Ophthalmoscopy

PURPOSE

To compare dark-field (DF) scanning laser ophthalmoscopy (SLO) against en face OCT and color fundus photography (CFP) in imaging of choroidal nevi and determining lesion area and to describe the characteristics of choroidal nevi using DF SLO.

DESIGN

Prospective cohort study.

PARTICIPANTS

Multimodal imaging, including DF SLO, OCT, and CFP, was performed in 24 patients (24 eyes; 10 men and 14 women; mean age, 45.1±13.4 years) with choroidal nevi and 14 healthy age-matched volunteers (24 eyes).

METHODS

For each imaging method, the area under the receiver operating characteristic curve was constructed to evaluate the ability to identify choroidal nevi. Using DF SLO, each nevus was characterized according to the intensity of the shadow, clarity of the borders, and presence of additional pigmentation. The lesion area was measured by 2 graders for each imaging method. The intraclass correlation coefficient and intergrader correlation coefficient were calculated.

MAIN OUTCOME MEASURES

Agreement of DF SLO with CFP and en face OCT in visualization of choroidal nevi.

RESULTS

Dark-field SLO showed the highest area under the receiver operating characteristic curve, 1.0, compared with en face OCT and CFP, 0.9 (P = 0.04) and 0.88 (P = 0.025), respectively. Using DF SLO in 17 patients (70.8%) and 7 patients (29.2%), nevus demonstrated dense and partially transparent shadow, respectively. In 10 patients (41.7%) and 14 patients (58.3%), nevus demonstrated sharp and blurred borders, respectively. Additional pigmentation was found in 5 patients (20.8%). The agreement in the evaluation of the area of the nevus between DF SLO and en face OCT and between DF SLO and CFP for grader 1 was 0.89 and 0.95, respectively, and for grader 2 was 0.95 and 0.95, respectively. Weighted κ values in reproducibility analysis for DF SLO, en face OCT, and CFP were 0.8, 0.71, and 0.67, respectively.

CONCLUSIONS

Dark-field SLO demonstrated excellent potential for identifying choroidal nevi and was in full agreement with conventional methods in the evaluation of the area of choroidal nevi.

Retro-Mode Scanning Laser Ophthalmoscopy Planning for Navigated Macular Laser Photocoagulation in Macular Edema

Purpose. To compare treatment areas and navigated macular laser photocoagulation (MLP) plans suggested by retro-mode scanning laser ophthalmoscopy (RM-SLO) image versus optical coherence tomography (OCT) central retinal thickness map and treatment planning among retina specialists. Methods. Thirty-nine eyes with diabetic or branch retinal vein occlusion-related ME undergoing navigated MLP with navigated photocoagulator had OCT and RM-SLO taken. OCT map and RM-SLO image were imported to the photocoagulator and aligned onto the retina. Two retina specialists placed laser spot marks separately based on OCT and RM-SLO images in a random fashion. The spots placed by each physician were compared between OCT and RM-SLO and among physicians. The areas of retinal edema on OCT and RM-SLO of the same eye were also compared. Results. The average number of laser spots using RM-SLO and OCT template was 189.6 ± 77.4 and 136.6 ± 46.8, respectively, P = 0.003. The average area of edema on RM-SLO image was larger than that on OCT map (14.5 ± 3.9 mm² versus 10.3 ± 2.8 mm², P = 0.005) because of a larger scanning area. There was narrow variability in treatment planning among retina specialists for both RM-SLO (P = 0.13) and OCT (P = 0.19). Conclusion. The RM-SLO image superimposed onto the fundus of the same eye can be used to guide MLP with narrow variability in treatment planning among retina specialists. The treatment areas suggested by RM-SLO-guided MLP plans for ME were shown to be larger than those suggested by OCT-guided plans.