Retinal nerve fiber layer, retinal pigment epithelium, and choroidal thickness in vitiligo patients

Choroidal vascularity index and choroidal thickness assessment in vitiligo

CLINICAL RELEVANCE

Vitiligo is a skin disease characterised by depigmentation and loss of melanocytes. Melanocyte loss may not be limited to the skin in vitiligo, and various abnormalities may occur in the choroid, which is dense in melanocytes.

BACKGROUND

To evaluate structural changes in the choroid by measuring choroidal thickness and vascularity index using optical coherence tomography in patients with vitiligo and comparing them to healthy subjects.

METHODS

This study included 168 participants: 84 with vitiligo (30 females, 54 males) and 84 controls (36 females, 48 males). Choroidal thickness and vascularity index were measured using the enhanced depth imaging mode in spectral-domain optical coherence tomography. The choroidal thickness was measured at the following five points; subfoveal (SF), 500 μm (NCT1) and 1000 μm (NCT2) nasal to the fovea; and 500 μm (TCT1) and 1000 μm (TCT2) temporal to the fovea. The choroidal vascularity index was calculated using the ImageJ software.

RESULTS

SF (p < 0.001), NCT1 (p < 0.001), NCT2 (p = 0.021), TCT1 (p = 0.001), and TCT2 (p < 0.006) choroidal thicknesses were significantly smaller in the vitiligo group than in the control group. Total choroidal (p < 0.001) and stromal (p < 0.001) areas were significantly smaller in the vitiligo group than in the control group. Choroidal vascularity indices were significantly higher in the vitiligo group than in the control group (p < 0.001). However, luminal areas did not differ significantly between groups (p = 0.935).

CONCLUSION

Patients with vitiligo should be regularly monitored for choroidal alterations and, if necessary, referred to an ophthalmologist.

Glaucoma Detection through a Novel Hyperspectral Imaging Band Selection and Vision Transformer Integration

Conventional diagnostic methods for glaucoma primarily rely on non-dynamic fundus images and often analyze features such as the optic cup-to-disc ratio and abnormalities in specific retinal locations like the macula and fovea. However, hyperspectral imaging techniques focus on detecting alterations in oxygen saturation within retinal vessels, offering a potentially more comprehensive approach to diagnosis. This study explores the diagnostic potential of hyperspectral imaging for glaucoma by introducing a novel hyperspectral imaging conversion technique. Digital fundus images are transformed into hyperspectral representations, allowing for a detailed analysis of spectral variations. Spectral regions exhibiting differences are identified through spectral analysis, and images are reconstructed from these specific regions. The Vision Transformer (ViT) algorithm is then employed for classification and comparison across selected spectral bands. Fundus images are used to identify differences in lesions, utilizing a dataset of 1291 images. This study evaluates the classification performance of models using various spectral bands, revealing that the 610-780 nm band outperforms others with an accuracy, precision, recall, F1-score, and AUC-ROC all approximately at 0.9007, indicating its superior effectiveness for the task. The RGB model also shows strong performance, while other bands exhibit lower recall and overall metrics. This research highlights the disparities between machine learning algorithms and traditional clinical approaches in fundus image analysis. The findings suggest that hyperspectral imaging, coupled with advanced computational techniques such as the ViT algorithm, could significantly enhance glaucoma diagnosis. This understanding offers insights into the potential transformation of glaucoma diagnostics through the integration of hyperspectral imaging and innovative computational methodologies.

Comparison of the effects of psoriasis and vitiligo on retina pigment epithelium thickness

PURPOSE

The purpose of the study was to compare Retinal Pigment Epithelium (RPE) thickness in patients with Psoriasis and Vitiligo.

MATERIALS AND METHODS

The right eyes of 67 Psoriasis and 65 Vitiligo patients and 71 healthy individuals were included in the study. The RPE thicknesses were analyzed with the Spectral Domain Optical Coherence Tomography after routine ophthalmological examinations (SD-OCT).

RESULTS

No statistically significant differences were detected when Psoriasis and Vitiligo patients were compared in terms of RPE levels (p= 0.033). When compared with the control group, no significant differences were found with Psoriasis patients, but a significant difference was detected with Vitiligo patients (p=0.515, p=0.001, respectively).

CONCLUSION

Although no changes were detected in RPE in Psoriasis, the decreased RPE thickness in Vitiligo may be an indicator of the effect of melanin loss on the posterior segment of the eye in Vitiligo. For this reason, measurement of RPE thickness with OCT can help in detecting the damage in Vitiligo patients.

Choroidal Thickness In Patients With Alopecia Areata: Is It A Sign For Poor Prognosis?

INTRODUCTION

Alopecia areata (AA) is an autoimmune disease which causes non-scarring type hair loss considered to target the pigmentary system. The hair follicle may not be the only site for involvement of the disease. Iris, the ciliary body, choroid and epithelium of the retinal pigment may also be affected. The aim of the present study was to compare retinal pigment epithelium (RPE) and choroidal thicknesses between patients with AA and healthy controls.

METHODS

The study included 44 patients with alopecia areata, and 44 healthy individuals with similar age and gender distribution. RPE and choroidal thickness measurements were performed through Spectral-domain optical coherence tomography (SD-OCT) (Heidelberg Spectralis® OCT).

RESULTS

There was not any significant difference between patients with AA and healthy individuals for RPE and choroidal thickness (P = 0.751, P = 0.725, respectively). However, the choroidal thickness (422 ± 79 μm) was significantly thinner in patients with poor prognostic criteria than other patients (371 ± 75 μm) (P = 0.039).

CONCLUSION

Monitoring of choroidal thicknesses through optic coherence tomography (OCT) may provide an insight for the disease prognosis in patients with AA.