Sir,

The Pentacam Scheimpflug1 camera (Oculus Inc., Wetzlar, Germany) captures images from the anterior cornea to posterior lens capsule. There is a single report in literature of Scheimpflug imaging for localisation of intralenticular foreign body.2 We evaluate the role of Pentacam in penetrating eye injury with anterior segment foreign bodies (FBs) by image-acquisition technique.

Case report

Case 1: A 22–year-old male presented with BCVA of 20/200 OS after trauma while hammering chisel. Biomicroscopy showed a corneal entry wound at 0300 hours with corresponding iris hole and a metallic intralenticular foreign body at 0430 hours (Figure 1a). Enhanced imaging with Scheimpflug analysis (Figure 1b) revealed a highly reflective intralenticular foreign body (95 u) within the posterior subcapsular space, 1860 u away from the anterior capsule (Figure 1c).

Figure 1
figure 1

(a) Metallic ILFB in the left eye at 0430 hours with associated posterior subcapsular cataract. The corneal wound of entry and the iris hole can be seen at 0300 hours. (b) Single-scan Pentacam image of the left eye through segment 135–315o showing a highly reflective ILFB with a spike height of 95 u on lens densitometry scale. The overlying anterior capsule opacification produced a densitometry reading of 38.8 u. (c) Single-scan Pentacam image of the same eye as in Figure 1a showing the ILFB lying just within the posterior subcapsular space, 1860 u away from the anterior lens capsule. Note that the posterior capsule is intact.

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Case 2: A 23–year-old male presented with BCVA of 20/40 OD after penetrating trauma to the right eye while working on a lathe machine. Biomicroscopy revealed a metallic FB on the iris surface at 0230 hours (Figures 2a and b). Pentacam image highlighted the corneal wound of entry and the reflective FB (37 u) within the angle recess (Figure 2c). There was no underlying iris or lens damage.

Figure 2
figure 2

(a) Slit lamp photograph of the right eye showing a wedge-shaped metallic foreign body resting on the iris surface. The overlying self-sealed corneal wound of entry is evident. (b) Gonio-photograph of the same eye as in Figure 2a showing the metallic foreign body anchored in the angle recess with surrounding synechiae. (c) Single-scan Pentacam image of the right eye through segment 190–10o with the image axis passing through the base of the foreign body produces a spike height of 37 u on densitometry scale. The overlying corneal wound of entry is highlighted with a higher spike on densitometry scale. Note that there is no lenticular opacity.

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Comment

Precise localisation of retained intraocular foreign bodies is important in surgical decision making. The integrity of anterior and posterior capsule, zonules, and iris are the key factors in deciding management of anterior segment foreign bodies associated with or without cataract.3 Scheimpflug imaging in case 1 allowed precise localisation and relation of the FB to intact posterior capsule.

Pentacam also allowed imaging of the trapped FB in the angle with meridional localisation and highlighted absence of damage to underlying iris and lens in case 2. The off-centered image axis gave a lower densitometry reading.

Though ultrasound biomicroscopy (UBM)4 and anterior segment OCT5 afford precise diagnosis of occult anterior segment FBs, their depth of penetration is limited. In addition, UBM is semi-invasive. Pentacam provides instant high-resolution images through a non-contact method in imaging of anterior segment FBs in clear media, useful in the setting of trauma. Thus, Pentacam is a potential tool for imaging in anterior segment FBs.