{'fraction_non_alphanumeric': 0.028052805280528052, 'fraction_numerical': 0.019251925192519254, 'mean_word_length': 5.25085910652921, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Retinal vessel tortuosity associated with central retinal vein occlusion: an optical coherence tomography study.

PURPOSE
We studied morphologic changes of the retinal vasculature in eyes with central retinal vein occlusion (CRVO) through the use of optical coherence tomography (OCT).


METHODS
Major retinal vessels in 35 eyes from 35 consecutive patients with acute CRVO were examined prospectively and longitudinally with sequential thin sectioning and circumpapillary scanning. Anteroposterior venous tortuosity associated with CRVO was quantified on longitudinal OCT images of a randomly selected major temporal vein. On OCT sections of a given vein, we identified the innermost and outermost points of the vessel wall. The degree of anteroposterior venous tortuosity was defined as the difference between the vertical distances from the retinal pigment epithelium to the center of the venous lumen at these two points.


RESULTS
The OCT images revealed that the major retinal veins traveled tortuously through the swollen neurosensory retina from the inner retinal surface to the retinal pigment epithelium. The degree of anteroposterior venous tortuosity was correlated with poor visual acuity (r = 0.457, P = 0.017), increased mean foveal thickness (r = 0.671, P < 0.001), and the height of foveal detachment (r = 0.414, P = 0.032). In 4 (11%) eyes, a localized retinal detachment was detected around the optic disc, which correlated with anteroposterior venous tortuosity. In 14 (40%) eyes, elongated major retinal veins disrupted the boundary between retinal vessels and parenchyma, which resulted in juxtavenous splitting of the neurosensory retina.


CONCLUSIONS
In eyes with CRVO, OCT can be used to visualize anteroposterior venous tortuosity and associated structural changes to the retinal parenchyma.