Subretinal drusenoid deposits as a biomarker of age-related macular degeneration progression via reduction of the choroidal vascularity index.

BACKGROUND/OBJECTIVES: This study aimed to analyse the role of the choroid in early age-related macular degeneration (AMD) by analysing choroidal vascularity index (CVI) in pure cohorts of patients with subretinal drusenoid deposits (SDD) or conventional drusen (CD). SUBJECTS/METHODS: This was an observational cross-sectional study. Comprehensive ophthalmologic examination and multimodal imaging including fundus photography, autofluorescence, near infrared reflectance, and spectral domain optical coherence tomography (SDOCT) was performed. CVI processing was performed on a foveal horizontal SDOCT scan with binarization using Image J Image software and calculated as the ratio between luminal area (LA) and total area (TA). RESULTS: Sixty-nine eyes of 69 participants were included; 23 eyes with SDD alone, 22 eyes with CD alone, and 24 control eyes of healthy age-matched subjects. CVI was significantly reduced in the SDD and CD group compared to controls (p = 0.0001). Post-hoc analysis revealed a significant reduction of CVI in the SDD versus the control group (p = 0.0002), in the CD versus the control group (p = 0.001), and in the SDD versus the CD group (p = 0.006). Covariance analysis showed a significant difference of LA (p = 0.033) but no significant difference of TA (p = 0.106) between the three groups. Direct comparison between CD and SDD showed a significant reduction of LA and TA in the SDD group. CONCLUSIONS: CVI may have prognostic implications in early AMD. SDD is a biomarker of AMD progression and the mechanism for this could be via reduction of the CVI.

Inner Retinal Layer Thickness Alterations in Early Age Related Macular Degeneration in Eyes with Subretinal Drusenoid Deposits or Conventional Drusen.

The purpose of this study was to evaluate central and parafoveal inner retinal layer thickness in patients with subretinal drusenoid deposits (SDD) or conventional drusen (CD). Participants underwent comprehensive ophthalmoscopic examination. Evidence of SDD or CD was evaluated with near infrared reflectance and spectral domain optical coherence tomography. Quantification of subfoveal lesions was made through a qualitative analysis of vertical and horizontal SD-OCT scans centered on the fovea. Inner retinal layer macular thickness measurements were obtained for central circles with 1, 3, and 5 mm diameter. Continuous variables were compared by the analysis of covariance (ANCOVA) with post-hoc Tukey HSD correction for multiple comparison analysis. Fifty-five patients were included in the study; 18 eyes with SDD alone, 19 eyes with CD alone, and 18 eyes of healthy age-matched subjects. Eight eyes with SDD (44%) and 13 eyes with CD (68%) had subfoveal lesions. There was significant reduction in the inner retinal layer thickness in the central 1mm area and in the superior 3 mm area in the SDD and CD group compared to controls. In conclusion the inner retinal layer is thinner in the central macula and in the superior parafovea in eyes.

Near-Infrared Reflectance Imaging in Retinal Diseases Affecting Young Patients.

Near-infrared reflectance (NIR) is a noninvasive, contactless, and rapid in vivo imaging technique for visualizing subretinal alterations in the photoreceptor layer, retinal pigment epithelium, and choroid. The present report describes the application of this imaging method in retinal and choroidal pathologies affecting young patients where scarce cooperation, poor fixation, and intense glare sensation can result in a challenging clinical examination. A literature search of the MEDLINE database was performed using the terms "near-infrared reflectance" and "spectral-domain optical coherence tomography." Articles were selected if they described the diagnostic use of NIR in children or young adults. Of 700 publications, 42 manuscripts published between 2005 and 2020 were inherent to children or young adults and were considered in this narrative literature review. The first disease category is the phakomatoses where NIR is essential in visualizing choroidal alterations recognized as cardinal biomarkers in neurofibromatosis type 1, microvascular retinal alterations, and retinal astrocytic hamartomas. Another diagnostic application is the accurate visualization of crystals of various nature, including the glistening crystals that characterize Bietti crystalline dystrophy. Acute macular neuropathy and paracentral acute middle maculopathy represent a further disease category with young adulthood onset where NIR is not only diagnostic but also essential to monitor disease progression. A further interesting clinical application is to facilitate the detection of laser-induced maculopathy where funduscopic examination can be normal or subnormal. In conclusion, NIR imaging has a noninterchangeable role in diagnosing certain retinal diseases, especially in children and young adults where there is scarce collaboration and a lack of evident clinical findings. Moreover, this technique can reveal unique retinal and choroidal biomarkers highly specific to rare conditions.

Cluster analysis of computerized visual field and optical coherence tomography-ganglion cell complex defects in high intraocular pressure patients or early stage glaucoma.

PURPOSE: The aim of the study is to evaluate the relationship between functional defects shown by cluster analysis of computerized visual field and anatomic defects from optical coherence tomography-ganglion cell complex examination in ocular hypertension or eyes affected by glaucoma. METHODS: 205 eyes affected by ocular hypertension (intraocular pressure > 22 mmHg) or early stage glaucoma were enrolled. The age of the patients ranged from 26 to 87 years (average: 61.83 ± 1.54 years). Computerized 30° visual field (Octopus G1x Dynamic strategy) and optical coherence tomography-ganglion cell complex (I-Vue Optovue) analyses were performed for each eye selected; 68 eyes were tested and retested from two to seven times for a total of 320 visual fields and 320 optical coherence tomography-ganglion cell complex examinations. The visual field was considered abnormal with a mean defect < -2 and loss variance > 6. The optical coherence tomography-ganglion cell complex was considered abnormal with a significant focal loss volume (p < 5%) and/or a significant thinning of total, superior, or inferior thickness (p < 5%). Four different groups of examinations were created according to the results of visual field and ganglion cell complex: normal visual field and normal ganglion cell complex (group 1), abnormal visual field and abnormal ganglion cell complex (group 2), normal visual field and abnormal ganglion cell complex (group 3), and abnormal visual field and normal ganglion cell complex (group 4). The cluster analysis of visual fields (EyeSuite software Interzeag CH) was performed only in the visual field of group 3, and the correlation between cluster values and topographical changes at optical coherence tomography-ganglion cell complex was analyzed. RESULTS: The results of the ganglion cell complex and visual field examinations matched 247 (77.19%) times. In 143 cases, the examinations belonged to group 1, in 104 to group 2, in 23 to group 3, and, finally, in 50 to group 4. The visual field cluster analysis performed on group 3 showed that the correlation between optical coherence tomography-ganglion cell complex and visual field cluster analysis defects was 100% (both the exams altered). In 72% of them, there was also a topographical correspondence between the visual field and optical coherence tomography-ganglion cell complex defects. CONCLUSION: In the early stages of glaucoma, the visual field cluster analysis seems to be useful to detect some focal defects that can be otherwise underestimated when globally considering the visual field. In group 3, where the conventional analysis of visual field was normal while the optical coherence tomography-ganglion cell complex exam was abnormal, the visual field cluster analysis showed a topographical correlation with optical coherence tomography-ganglion cell complex defects in more than 70% of the examinations performed. In addition, the patients with abnormal visual field and normal optical coherence tomography-ganglion cell complex were older than those with normal visual field and abnormal optical coherence tomography-ganglion cell complex (66.44 ± 3.51 vs 57.04 ± 5.96 years, p < 0.001 (0.0002)). These results confirm that the reliability of a visual field examination is subjective and decreases with age because of its difficulty and the personal compliance of the patient toward this examination.