The role of anterior segment optical coherence tomography in the management of an intra-corneal foreign body

Association of Changes in Thickness of Limbal Epithelial and Stroma with Corneal Scars Detected by High-Resolution Anterior Segment Optic Coherence Tomography

AIM

To investigate the corneal central and limbal thickness in cornea scar patients using high-resolution anterior segment optical coherence tomography (AS-OCT) and to determine the changes in the limbal region due to the corneal scar. Also, to evaluate tear film parameters in scar patients.

METHODS

Thirty patients with central corneal scar and 30 control subjects. The control subjects were healthy individuals who came to our clinic for routine ophthalmological examination. They were enrolled in this matched case-control study. Central epithelial thickness (ET), stromal thickness (ST), limbal epithelial thickness (LET), and limbal stromal thickness (LST) were analyzed using high-resolution AS-OCT. For evaluation of the ocular surface, the following techniques were used: tear break-up time (BUT) employing standard sterile strips of fluorescein sodium, Schirmer test-I (SCH), and the Ocular Surface Disease Index (OSDI) Questionnaire.

RESULTS

The mean central ET of the patient group was 51.5 ± 12.4 µm, while the mean central ET of the control group was 59.2 ± 9.0 µm. There was a statistically significant difference between patients and controls (p = 0.008). The mean LST of the patients was 747.9 ± 115.7 µm, and the mean LST of the controls was 726.3 ± 79.7 µm. There was a statistically significant difference between patients and controls according to BUT (p = 0.009) and SCH (p = 0.04). However, there was no significant difference between OSDI results of patients and controls (p = 0.08).

CONCLUSION

Corneal monitoring with high-resolution AS-OCT is a simple, noninvasive, useful technique for corneal scar patients. Cornea scars cause decreased ET. This result could be associated with lower tear film parameters in scar patients. The scar length is associated with higher intraocular pressure (IOP) values. Decreased LET and increased LST were detected in scar patients.

Clinical Applications of Anterior Segment Optical Coherence Tomography: An Updated Review

Since its introduction, optical coherence tomography (OCT) has revolutionized the field of ophthalmology and has now become an indispensable, noninvasive tool in daily practice. Most ophthalmologists are familiar with its use in the assessment and monitoring of retinal and optic nerve diseases. However, it also has important applications in the assessment of anterior segment structures, including the cornea, conjunctiva, sclera, anterior chamber, and iris, and has the potential to transform the clinical examination of these structures. In this review, we aim to provide a comprehensive overview of the potential clinical utility of anterior segment OCT (AS-OCT) for a wide range of anterior segment pathologies, such as conjunctival neoplasia, pterygium, scleritis, keratoconus, corneal dystrophies, and infectious/noninfectious keratitis. In addition, the clinical applications of AS-OCT (including epithelial mapping) in preoperative planning and postoperative monitoring for corneal and refractive surgeries are discussed.

Anterior segment optical coherence tomography characteristics and management of a unique spectrum of foreign bodies in the cornea and anterior chamber

Purpose

To report anterior-segment optical coherence tomography (ASOCT) characteristics of different types of corneal and anterior chamber (AC) foreign bodies (FBs) and their usefulness in diagnosis and management.

Methods

This is a retrospective descriptive clinical study involving 11 eyes of 11 patients who presented at the outpatient department of a tertiary ophthalmic care center from January 2017 to January 2022. All patients had a diagnosed or suspected corneal FB. All participants underwent a comprehensive ophthalmological examination, followed by slit-lamp photography and ASOCT. FB removal was done where required by an external, internal, or combined approach.

Results

The mean age of patients was 28.2 (7-53) years. Ten were male, and one was female. Seven patients had a definitive positive history of injury; in one, there was a history suggestive of trauma, one had the post-operative complication of scleral buckling surgery, and two patients had a history of insect fall in the eyes. Three patients had acute, four had sub-acute, and four had chronic presentations. Descemet's membrane (DM) breach was suspected in three cases of deep FB, which was later confirmed on ASOCT. In two cases, DM was presumed to be intact clinically, but ASOCT showed an AC penetration. The FB was removed in seven patients, one via slit-lamp, one via an external approach, two via an internal approach, and three via a combined approach.

Conclusion

ASOCT facilitates non-invasive rapid imaging of ocular tissue at various depths, provides an accurate assessment of FB characteristics, and thereby serves as an additional tool in our armamentarium for diagnosis and management of deep corneal and AC FBs.

Evaluating Depth and Width of Corneal Wounds Using Anterior Segment Optical Coherence Tomography After Foreign Body Removal

PURPOSE

To determine corneal foreign body (FB) location together with corneal wound depth and width by using anterior segment optical coherence tomography (AS-OCT) after uncomplicated FB removal.

METHOD

This prospective study was conducted with patients injured by a superficial metallic corneal FB. Under slit-lamp examination, after determining its location, the FB was removed with a 27-G needle. The depth and width of the corneal wound and the thinnest stromal thickness at the wound site were measured initially using AS-OCT. Measurements were repeated to assess the wound healing process at one week and at two months following FB removal.

RESULTS

Totally, 63 eyes of 63 patients were included in this study. The average age was 35.8 ± 11.0 years, and 96.8% of the patients were men. In terms of location of the FBs, 26 (41.3%) were in the central region, 21 (33.3%) were in the paracentral region, and 16 (25.4%) were in peripheral regions. The mean depth and width of the corneal wounds were 117.0 ± 42.5 µm and 332.9 ± 99.4 µm, respectively. The mean percentage of corneal wound depth was 18.9 ± 6.1%. In 20 patients who presented for follow-up, it was observed that the width of the wound increased and the thinnest stromal thickness at the wound site decreased over the two months.

CONCLUSION

The AS-OCT findings of the present study showed that the corneal FBs generally affected the anterior cornea with less than approximately 0.2 mm depth and 0.5 mm width. In addition, FBs were commonly located in the central and paracentral cornea.

Retrospective Evaluation of Corneal Foreign Bodies with Anterior Segment Optical Coherence Tomography

Objectives:

To assess the anterior segment optical coherence tomography (AS-OCT) findings of various types of corneal foreign bodies.

Materials and Methods:

The medical records of patients with corneal foreign body were retrospectively analyzed. Patients who underwent anterior segment photography and Spectralis AS-OCT (Heidelberg Engineering GmbH, Germany) imaging were included.

Results:

The AS-OCT findings of 22 eyes of 20 patients with corneal foreign body were reviewed. The mean age was 34.9±14.98 years (range, 15-71) with a female/male ratio of 4/16. The mean best corrected visual acuity at presentation was 0±0 LogMAR (range, 0-0). There were 18 metallic, 3 organic (chestnut burr), and 1 chemical clay foreign bodies. The metal materials demonstrated hyperreflectivity with a mirror effect. Chemical clay, which is an opaque material, had a hyperreflective appearance. Chestnut burr is an organic foreign body with a feather-like pattern and was not detected with AS-OCT.

Conclusion:

AS-OCT is a valuable non-invasive tool to define the characteristics of foreign bodies, as well as decide the proper treatment method and monitor patients with corneal foreign bodies.

Comparison of Different Types of Corneal Foreign Bodies Using Anterior Segment Optical Coherence Tomography: A Prospective Observational Study

PURPOSE

The present study highlighted the value of anterior segment optical coherence tomography (AS-OCT) for different types of corneal foreign bodies in humans.

METHODS

This study was a prospective observational study. The patients included were divided into two groups. If the patients were directly diagnosed based on eye injury history and slit-lamp examination, then they were assigned to Group A. Otherwise, the patients were assigned to Group B. We compared and described the characteristics of the corneal foreign body in both groups using AS-OCT.

RESULTS

From October 2017 to January 2020, 36 eyes of 36 patients (9 females and 27 males) with a mean age of 37.8 ± 11.7 years were included in the study. Patients in Group A were the majority and accounted for 72.2% (26/36). High signals on AS-OCT images were the main constituent and accounted for 92.3% (24/26) in Group A and 70.0% (7/10) in Group B. Most of the patients in Group A, 96.2% (25/26), had clear boundaries. A blurred boundary was observed in 70.0% (7/10) of the patients in Group B. The foreign bodies on AS-OCT images had key characteristics of a high signal followed by a central zone shadowing effect and a low signal followed by a marginal zone shadowing effect. Further, all of the lesions could be directly located in Group B, and 92.3% (24/26) of the patients in Group A did not have directly located lesions. Six representative cases are described in detail.

CONCLUSIONS

AS-OCT is a valuable tool in the diagnosis and management of corneal foreign bodies, especially for unusual corneal foreign body.

Femtosecond laser-assisted removal of an intracorneal chestnut, a case report

Background

To report a case of femtosecond laser-assisted removal of an intracorneal chestnut.

Case presentation

A chestnut was obliquely protruding to the stroma of cornea and it was localized at the paracentral region on the left eye of a 32-year-old man. The best-corrected visual acuity (BCVA, in decimal values) was 0.6 in the injured eye. The white ulcers with feathery edges or satellite infiltrates were not observed in the lesion, and the anterior chamber was deep and quiet. Anterior segment optical coherence tomography (AS-OCT) demonstrated that the original entry path of the foreign body had been sealed, spanning a thickness of approximate 152 μm. In view of location of the intraocular chestnut at the paracentral region, femtosecond laser was applied according to the procedures of IntraLase Enabled Keratoplasty (IEK) to create an anterior lamellar flap rapidly and precisely. The lamellar flap was easily separated with a flap lifter, and the chestnut was removed entirely using a pair of forceps. In 3 days after surgery, the patient complained of mild pain and blurred vision. These symptoms were relieved after treatment with the eyedrops. At three-month follow-up, the corneal wound was healed well, and the BCVA was greatly improved to 1.2 in the left eye. A dot-like haze was observed corresponding to the scar at the site of foreign body removal. No surgical induction of corneal astigmatism was found in the corneal topography.

Conclusions

Without induction of a visually significant scar and corneal astigmatism, the IEK procedure of femtosecond laser is of particular interest as it provides a unique method for removal of intracorneal foreign bodies impinging on the visual axis.

Optical Coherence Tomography Examination of the Anterior Segment in a Case of Corneal Perforation and Lens Trauma by Chestnut Burr

Chestnut burrs, the thorny encapsulation of chestnut fruit, can sometimes cause corneal injuries and ulceration, with poor prognoses. We report a case of corneal perforation and damaged anterior lens capsule due to a chestnut burr, using anterior segment optical coherence tomography (AS-OCT). A 67-year-old woman with a chestnut burr injury in her right eye was referred to our hospital. Her right best-corrected visual acuity (BCVA) was 0.8. Slit-lamp examination and AS-OCT showed perforation involving the endothelial layer at the center of the cornea. The iris and anterior lens capsule were damaged. Cell infiltration was observed around the wound. Bacterial examination showed gram-positive cocci but no fungi. The patient was diagnosed with a corneal perforation and bacterial keratitis. Levofloxacin 1.5% and cefmenoxime treatments were initiated and a soft contact lens was placed to seal the wound. On day 3, there was no improvement in the corneal cell infiltration, but AS-OCT suggested that the inner wound had closed. A culture test revealed the presence of Propionibacterium acnes, which was sensitive to both levofloxacin and cefmenoxime. Therefore, we continued the same antibiotic treatment. On day 26, the opacification and cell infiltration at the center of the cornea had improved. AS-OCT showed healing of the corneal wound with reduction in the central corneal thickness. Her BCVA improved to 1.0. AS-OCT was a valuable tool to noninvasively observe wound shape and detect the presence of any intracorneal foreign bodies.

Anterior segment optical coherence tomography and retained vegetal intraocular foreign body masquerading as chronic anterior uveitis

Background

The purpose of this single case report was to report the use of anterior segment optical coherence tomography for the diagnosis and management of a retained vegetal intraocular foreign body.

Results

A 23-year-old otherwise healthy male presented with a progressive vision loss in the right eye (RE). He reported a mild ocular trauma with a tree leaf 1 year ago followed by recurrent episodes of redness and pain in the RE that partially resolved after a self-medication with topical steroids. Visual acuity of the RE was limited to light perception. Slit-lamp examination of the RE showed an iris granuloma with overlying exudate and associated anterior chamber inflammatory reaction. Film X-rays, contact B-scan ultrasonography, and CT scan showed no abnormalities. Anterior segment optical coherence tomography revealed an enclaved iris foreign body. The foreign body was removed after a short course of local antibio-corticosteroid therapy. This was followed 2 months later by cataract surgery with intraocular lens implantation, with subsequent improvement of visual acuity to 20/40.

Conclusions

A missed intraocular foreign body can lead to sight-threatening complications. Anterior segment optical coherence tomography may be useful for detecting non-clinically evident intraocular foreign body involving the anterior segment masquerading as chronic anterior uveitis.

Ocular Emergencies: Red Eye

"Red eye" is used as a general term to describe irritated or bloodshot eyes. It is a recognizable sign of an acute/chronic, localized/systemic underlying inflammatory condition. Conjunctival injection is most commonly caused by dryness, allergy, visual fatigue, contact lens overwear, and local infections. In some instances, red eye can represent a true ocular emergency that should be treated by an ophthalmologist. A comprehensive assessment of red eye conditions is required to preserve the patients visual function. Severe ocular pain, significant photophobia, decreased vision, and history of ocular trauma are warning signs demanding immediate ophthalmological consultation.