The influence of color vision deficiency on vessel visibility during colorectal endoscopic submucosal dissection and the potential advantage of red dichromatic imaging to achieve color vision barrier-free.

Objectives: Although color information is important in gastrointestinal endoscopy, there are limited studies on how endoscopic images are viewed by people with color vision deficiency. We aimed to investigate the differences in the visibility of blood vessels during endoscopic submucosal dissection (ESD) among people with different color vision characteristics and to examine the effect of red dichromatic imaging (RDI) on blood vessel visibility. Methods: Seventy-seven pairs of endoscopic images of white light imaging (WLI) and RDI of the same site were obtained during colorectal ESD. The original images were set as type C (WLI-C and RDI-C), a common color vision. These images were computationally converted to simulate images perceived by people with color vision deficiency protanope (Type P) or deutanope (Type D) and denoted as WLI-P and RDI-P or WLI-D and RDI-D. Blood vessels and background submucosa that needed to be identified during ESD were selected in each image, and the color differences between these two objects were measured using the color difference (ΔE 00) to assess the visibility of blood vessels. Results: ΔE 00 between a blood vessel and the submucosa was greater under RDI (RDI-C/P/D: 24.05 ± 0.64/22.85 ± 0.66/22.61 ± 0.64) than under WLI (WLI-C/P/D: 22.26 ± 0.60/5.19 ± 0.30/8.62 ± 0.42), regardless of color vision characteristics. This improvement was more pronounced in Type P and Type D and approached Type C in RDI. Conclusions: Color vision characteristics affect the visibility of blood vessels during ESD, and RDI improves blood vessel visibility regardless of color vision characteristics.

Meningeal carcinomatosis with decreased visual acuity: a case report.

Meningeal carcinomatosis is a condition in which cancer cells diffusely metastasize to the cerebral pia mater in the cerebrospinal membrane or cerebrospinal cavity. It causes a wide array of symptoms according to the site of metastasis. The prognosis is poor, especially in metastasis from solid tumors. This study reports a case of meningeal carcinomatosis caused by advanced gastric cancer, manifested by headache and vision loss. The patient was a 69-year-old man who underwent head computed tomography (CT) and magnetic resonance imaging (MRI) for persistent headaches. No abnormal findings were found; however, his vision declined, convulsions occurred, and cerebrospinal fluid (CSF) cytology showed poorly differentiated adenocarcinoma. Therefore, meningeal carcinomatosis was diagnosed. The patient died after receiving FOLFOX therapy to relieve symptoms and prolong his life. An autopsy showed no invasion of the optic nerve or surrounding tissues. As the frequency of complications of meningeal carcinomatosis in solid cancers is rare, it is crucial to actively suspect and make an early diagnosis.