Use of white light in vivo confocal microscopy for the detection of spatial changes in the corneal nerves in cases of early-stage Acanthamoeba keratitis with radial keratoneuritis

Abstract

Purpose: Radial keratoneuritis (RK) is a common feature of Acanthamoeba keratitis (AK). In vivo confocal microscopy (IVCM) is noninvasive and provides real-time images for the diagnosis of corneal diseases by allowing the visualization of corneal structures and morphologies of living organisms at the cellular level. Images of AK with RK obtained using commercial white light IVCM devices have not been frequently evaluated. In the present study, a white light IVCM device was used to evaluate the corneal findings and describe spatial changes in the corneal nerves at different depths in cases of early-stage AK with RK. Methods: In this retrospective, observational study, white light IVCM images focused on RK were evaluated for Acanthamoeba cysts/trophozoites, corneal deposits, and altered corneal nerves, with special emphasis on three-dimensional spatial changes in the corneal nerves at different depths. Results: Seventeen eyes of 17 patients exhibiting early-stage AK with RK were included in the study. Acanthamoeba cysts/trophozoites were observed in the corneal epithelium of 13 eyes and stroma of 7 eyes. Alterations in the corneal nerve morphology and density were observed from the basal epithelial layer to the stromal layer in 12 eyes. Acanthamoeba trophozoites were attached to the corneal stromal nerves in five eyes. Conclusion: These findings suggest that white light IVCM can identify consistent corneal findings, particularly spatial changes in the corneal nerves, in cases of early-stage AK with RK.

Comparing the results of manual and automated quantitative corneal neuroanalysing modules for beginners

“…The examinations were performed by an experienced technician following published protocols 11 , 40 – 42 . Briefly, topical anesthetic was applied to the corneal surface, and a viscous gel medium was then applied to the corneal surfaces 5 min later, which permitted a visual gel bridge between the sterile cap on the microscope objective lens and the surface of the central cornea.…”

Diagnosing and monitoring the characteristics of Acanthamoeba keratitis using slit scanning and laser scanning in vivo confocal microscopy

“…Four articles mentioned the size of signet signs around 5-20 μm. 24,29,42 Single file Single file arrangements of cysts were found in 21% of the studies (Figure 2d). They were described as single file arrangement or linear chains of round or ovoid hyper-reflective objects 24,25,34,43 or linear tracks.…”

“…Many of the authors described the double wall cyst as a hyper-reflective or high contrast round, ovoid structure or highly refractive body with a bilayered or double-walled appearance. 2,24,25,[29][30][31][32][33][34] Some authors described the double wall cyst shape as polygonal. [35][36][37] The size of the double wall cyst was measured consistently between 10 and 30 microns (μm) in every study.…”

“…They were described as round, oval, hyper-reflective, high contrast reflective particles and objects or refractile bodies. 2,[24][25][26]29,31,36,[38][39][40][41] Signet signs Signet rings were the third most commonly reported cyst type and appeared in 29% of the included studies (Figure 2c). Signet rings have been defined as having a hyper-reflective cyst wall or outer ring with a dark centre or less reflectivity inside the ring.…”

“…2,24,25,42,43,45 Four articles mentioned the size of target signs around 5-20 μm. 24,29,42 Binary One article reported the appearance of binary, round or ovoid hyper-reflective objects 24 (Figure 2g).…”