Work

GEODESIC LENGTH MORPHOMETRY: A simple method for quantifying severe degeneration laterally in rodent models of retinal photic injury

Year: 2026

Type: article

Abstract: Quantification of degeneration extent in curvilinear microscopic specimens, such as the retina, is challenging due to inherent geometric complexity. In the rodent retinal photic injury model, degeneration arc lengths are a critical, yet difficult-to-quantify parameter for assessing severity. We developed a novel, precise platform, termed “ Geodesic Length Morphometry ,” that quantifies the actual arc lengths of curvilinear structures using a precisely determined digital scale factor. In this methodology, defining a curved coordinate axis along the retinal contour enables precise numerical localization of any position and the measurement of dorsoventral arc lengths between any two points. This robust platform resulted in two analytical innovations. One is a new visualization method, termed “ Geodesic Equidistant-Projection Plot ,” which converts arc length data measured from curved anatomical imagery into a cumulative line chart, allowing for the direct visual comparison of actual degeneration arc length and location. The second is the definition of the “ Geodesic Index ” (0 ≤ x ≤ 1), which normalizes the degeneration arc length against the entire retinal arc length to enable an objective, size-independent comparison of extent of degeneration. The Geodesic Length Morphometry platform offers a robust standard for the quantitative analysis of curvilinear tissue arc length and serves as a versatile tool applicable to diverse biological and morphometric fields.

Source: MethodsX

DOI: 10.1016/j.mex.2026.104183

Authors: Kentaro Ohishi, Masafumi Ohtsubo, Akira Obana, Yoshihiro Hotta, Yu Nagashima, Shinsei Minoshima

Institutions: Hamamatsu University School of Medicine, Seirei Hamamatsu General Hospital, Shizuoka University

Language: English

Topic: Retinal Development and Disorders

Subfield: Ophthalmology

Field: Medicine

Domain: Health Sciences

Open Access status: gold

Estimated APC paid: $1,260

Funders: Japan Agency for Medical Research and Development, Ministry of Education, Culture, Sports, Science and Technology, Japan Society for the Promotion of Science