|Year : 2021 | Volume
| Issue : 1 | Page : 83-86
Foreign body through the looking glass: Scheimpflug Imaging in inverse contrast
Prasanna Venkatesh Ramesh1, Shruthy Vaishali Ramesh2
1 Department of Glaucoma and Research, Mahathma Eye Hospital Private Limited, Tiruchirappalli, Tamil Nadu, India
2 Department of Cataract and Refractive Surgery, Mahathma Eye Hospital Private Limited, Tiruchirappalli, Tamil Nadu, India
|Date of Submission||15-Sep-2020|
|Date of Acceptance||01-Oct-2020|
|Date of Web Publication||19-Apr-2021|
Dr. Prasanna Venkatesh Ramesh
Mahathma Eye Hospital Private Limited, No.6, Seshapuram, Thennur, Trichy - 620 017, Tamil Nadu
Source of Support: None, Conflict of Interest: None
A 55-year-old male presented with foreign-body sensation in the left eye, with a history of hammering a chisel. On slit-lamp evaluation, two iron corneal foreign particles with rust ring were noted. The foreign bodies were removed with 26G hypodermic needle after instilling local anesthetic drops. The purpose of this manuscript was to provide a better understanding of the role of Scheimpflug imaging in objective evaluation of corneal epithelialization in such situations. Scheimpflug imaging along with anterior segment optical coherence tomography can be used to support diagnosis, objectively monitor the healing process (epithelialization) after removal, and reveal unexpected lesions, invisible on slit-lamp biomicroscopy.
Keywords: Anterior segment optical coherence tomography, foreign body, Scheimpflug imaging
|How to cite this article:|
Ramesh PV, Ramesh SV. Foreign body through the looking glass: Scheimpflug Imaging in inverse contrast. Kerala J Ophthalmol 2021;33:83-6
| Introduction|| |
Patients with corneal foreign bodies (FB) commonly present to emergency departments, urgent care centers, primary care providers, and eye care providers.[1-3] The cornea being the most richly innervated tissue in the body leads to multiple ocular symptoms such as pain, photophobia, decreased vision, copious tearing, blepharospasm, and conjunctival hyperemia, when a FB gets lodged in it. When objects are deeply embedded, corneal scarring or irregularities may occur, resulting in significant visual disruption.
In this report, the role of the Scheimpflug imaging system is highlighted in a situation where multiple FBs were lodged relatively deeper in the cornea. The application of the novel measuring tool, using the calipers of the Scheimpflug imaging system in inverse contrast, is highlighted for accurate mapping of the corneal healing process postremoval of the two relatively deep iron FBs with rust ring.
| Case Report|| |
A 55-year-old male presented with foreign-body sensation in the left eye with a history of hammering a chisel. On slit-lamp evaluation, two iron corneal foreign particles with rust ring [Figure 1] were noted in the cornea. As they appeared to be lodged relatively deep in the layers of cornea [Figure 2]a and [Figure 3]a], Seidel's test was done, and it was negative. Scheimpflug imaging [Figure 2]a and [Figure 3]a also confirmed that the lesion was only partial thickness and did not penetrate the deeper layers. The FBs were then dislodged, and the rust ring was completely removed with 26G hypodermic needle after instilling local anesthetic. After removing the FBs, a final evaluation with fluorescein sodium dye and cobalt blue light was performed with slit-lamp biomicroscopy for documenting the epithelial defect. Broad-spectrum topical antibiotics for 1 week were advised, and the corneal surface reepithelialization was monitored objectively, with Scheimpflug imaging system and anterior segment optical coherence tomography (AS-OCT). Objective revaluation of the cornea was done with Scheimpflug imaging system [Figure 2],[Figure 3],[Figure 4],[Figure 5],[Figure 6] in inverse contrast with the usage of calipers to assess the depth of the excavation and extent of the epithelial defect in a more precise manner, to monitor, evaluate, and understand the healing process. Scheimpflug imaging was done before the FB removal, immediately after the FB removal, and 24 h after the FB removal.
|Figure 1: Slit-lamp examination revealing two iron foreign bodies with rust ring|
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|Figure 2: Scheimpflug imaging system. (a) Image taken before removal of the foreign bodies (red arrow). (b) Image taken postimmediate removal of the foreign bodies showing epithelial defects (red arrow). (c) Image taken 1-day postremoval of foreign bodies showing the resolving epithelial defects (red arrow)|
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|Figure 3: Scheimpflug imaging system in inverse color. (a) Image taken before removal of the foreign bodies (red arrow). (b) Image taken post immediate removal of the foreign bodies showing epithelial defects (red arrow). (c) Image taken 1-day post removal of foreign bodies showing the resolving epithelial defects (red arrow)|
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|Figure 4: Scheimpflug imaging with calipers measurement measuring the dimensions of the epithelial defect 0.74 mm and 0.83 mm, respectively, with measurements of the white backscattering artifacts (0.33 mm × 0.62 mm and 0.56 mm × 0.38 mm, respectively) from the iron foreign bodies such as foreign body 1 and foreign body 2 before removal|
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|Figure 5: Scheimpflug imaging with calipers measurement immediately after removal showing the extent of the abrasion with epithelial defect (1.01 mm and 0.45 mm from foreign body 1 and 1.04 mm and 0.49 mm from foreign body 2, respectively) with the absence of the white backscattering artifacts. The depth of the epithelial defect craters is 0.19 mm and 0.16 mm created by foreign body 1 and foreign body 2, respectively|
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|Figure 6: Scheimpflug imaging with calipers measurement taken after 24 h postremoval showing the reduction of the corneal abrasion and epithelial defect (0.94 and 0.46 mm from foreign body 1 and 0.96 mm and 0.48 mm, respectively). The depth of the epithelial defect craters is 0.18 mm and 0.16 mm created by foreign body 1 and foreign body 2, respectively|
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| Discussion|| |
Corneal FBs are the second most common type of ocular injury, comprising approximately 30.8% of ocular injuries. Scheimpflug imaging system along with AS-OCT [Figure 7] can be used to support diagnosis of it, monitor the healing process after removal, and reveal unexpected lesions, invisible on slit-lamp examination.,,,To our knowledge, the role of Scheimpflug imaging in objective monitoring of epithelialization postcorneal FB removal is not reported in literature. Scheimpflug imaging (Sirius, CSO, Italy) images the AS of the eye from the front of the cornea to the back of the lens in the coronal plane by capturing the slices through the anterior chamber with high resolution and provides objective documentation of the AS with good three-dimensional corneal assessment in a fast and accurate way.
|Figure 7: Anterior segment optical coherence tomography. (a and b) Image taken before removal of foreign bodies (foreign body 1 and foreign body 2) revealing both the foreign bodies embedded on the cornea with back shadowing in the deeper layers of the cornea (red arrows). (c and d) Image taken after immediate removal of foreign bodies showing epithelial defect with reduction of the back shadowing (red arrows). (e and f) Imaging taken 1 day after removal showing resolving epithelial defects with epithelialization (red arrows) with the absence of back shadowing|
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Usage of Scheimpflug imaging system calipers and inverse contrast for accurate mapping of epithelialization
Scheimpflug system in this patient reveals the foreign body and the epithelialization postremoval [Figure 2]. With the application of the inverse contrast [Figure 3], the FB, its artifacts, and the epithelialization were appreciated much better and were more distinct than the default picture. Hence, Scheimpflug analysis with calipers was done in the inverse contrast image and high magnification [Figure 4],[Figure 5],[Figure 6]. The dimension of the epithelial defect before removal [Figure 4] was 0.74 mm and 0.83 mm, respectively, with the measurements of the white backscattering artifacts (0.33 mm × 0.62 mm and 0.56 mm × 0.38 mm, respectively) from the iron FBs (FB1 and FB2). Scheimpflug imaging with caliper measurement taken immediately after removal [Figure 5] showed the extent of the abrasion with epithelial defect (1.01 mm and 0.45 mm from FB1 and 1.04 mm and 0.49 mm from FB2, respectively) with the absence of the white backscattering artifacts. Scheimpflug imaging with caliper measurement taken after 24 h postremoval [Figure 6] shows the reduction of the corneal abrasion and epithelial defect (0.94 and 0.46 mm from FB1 and 0.96 mm and 0.48 mm, respectively). The depth of the epithelial defect reduced from 0.19 mm to 0.18 mm in the crater created by FB1 and the depth of the epithelial defect remained 0.16 mm in the crater created by FB2 in the 24 h follow-up [Figure 5] and [Figure 6].
The nature and extent of the FB event may determine the course of healing. Small, superficial FB is easily removed with little or no risk of negative sequelae. FBs more deeply embedded, as in this scenario or located centrally, are likely to result in visually significant scarring. An iron foreign body will usually leave a rust embedded in the corneal stroma. Rust can cause inflammatory reaction and delay wound healing and additionally promote scarring with corneal irregularity. However, in our scenario, due to skillful dislodgment of the FB with complete rust removal, the reepithelialization process was almost complete within 24 h postremoval without inflammation [Figure 6].
Although one can argue that these lesions are seen regularly and are visible on the slit-lamp biomicroscopy, the role of Scheimpflug imaging to monitor the epithelialization postremoval in such lesions is warranted to understand the innate nature of corneal healing, which is not objectively possible on a slit lamp with fluorescein staining alone.
| Conclusion|| |
Our observation suggests that the calipers with Scheimpflug imaging in inverse contrast are available to quantitatively measure the dimensions of reepithelialization during wound healing, post-FB removal. Thus, we conclude that Scheimpflug imaging is an extremely helpful imaging tool in monitoring corneal health in relatively deep corneal FBs.
Declaration Of Consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patient understands that names and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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