Eccentric semilunar penetrating keratoplasty for peripheral corneal perforation following chemical eye injury: A case report

Abstract

BACKGROUND

Ocular surface chemical injury is a sight-threatening ophthalmic emergency. Even if adequately treated in the acute phase, it may lead to severe complications, including corneal perforation, resulting in irreversible visual loss. Although early irrigation is the mainstay of initial treatment, advanced ocular surface chemical injuries complicated by corneal perforation often require tectonic surgical intervention for globe preservation. However, in selected cases with localized defects, limited corneal grafting may be sufficient, reducing surgical trauma to otherwise healthy corneal tissue.

CASE SUMMARY

A 65-year-old female with no prior ophthalmic history presented to the ophthalmology emergency department one day after sustaining a chemical eye injury at her workplace. Despite immediate on-site irrigation with normal saline and a neutralizing solution, she reported foreign body sensation, ocular pain, and decreased visual acuity. Examination revealed corneal melting and perforation in the inferior quadrant, a flat anterior chamber with iris incarceration, oval pupil displacement toward the perforation site, and ocular hypotony. The patient was admitted to our hospital and underwent tectonic corneal transplantation, in the form of eccentric noncircular penetrating keratoplasty, with a semilunar donor graft fashioned using 11.0 mm and 10.0 mm trephines. The incarcerated iris was repositioned, and viscoelastic was injected to stabilize the anterior chamber. Postoperatively, globe integrity was successfully restored, with subsequent improvement in visual acuity and marked enhancement in ocular comfort.

CONCLUSION

The semilunar graft represents a viable tissue-sparing approach for managing peripheral corneal perforations in selected cases with preserved corneal tissue.

Key Words: Corneal perforation; Eccentric penetrating keratoplasty; Semilunar corneal graft; Tectonic keratoplasty; Chemical eye injury; Ocular surface chemical injury

Core Tip: Eccentric semilunar penetrating keratoplasty represents a viable tissue-sparing surgical option for managing acute peripheral corneal perforations secondary to chemical injury. This approach preserves the healthy central optical zone, minimizes antigenic load, and reduces the risk of immunologic rejection compared to total penetrating keratoplasty, while achieving the primary goal of globe salvage. However, the procedure presents significant technical challenges, including severe hypotony, anterior chamber collapse, and iris incarceration, requiring manual recipient bed preparation and viscoelastic-assisted chamber reformation. This emergency tectonic strategy preserves the central corneal architecture, maintaining the option for future optical keratoplasty if visual rehabilitation remains insufficient.

INTRODUCTION

Ocular surface chemical injury (OSCI) is a sight-threatening ophthalmic emergency that, even when adequately treated in the acute phase, may lead to severe complications, including corneal perforation and irreversible visual loss[1]. While immediate copious irrigation remains the cornerstone of initial management, advanced chemical injuries complicated by corneal perforation frequently necessitate urgent tectonic surgical intervention to preserve globe integrity and prevent further intraocular complications[2]. Traditional management of acute noninfectious corneal perforations typically involves large penetrating keratoplasty (PKP), which restores structural integrity and provides visual rehabilitation[3]. However, literature suggests that in selected cases with peripheral perforations, eccentric keratoplasty should be considered, as it may offer distinct advantages by preserving the central optical zone and reducing surgical invasiveness compared to total PKP[3].

Although eccentric PKP has been well-described for peripheral corneal pathologies such as peripheral degenerations, infectious keratitis, and traumatic scars[4-6]. Its application in the acute management of chemical injury-related perforations remains underreported in the literature. The technical demands of performing eccentric keratoplasty in eyes with significant hypotony, anterior chamber collapse, and compromised tissue integrity have likely limited its widespread adoption in acute emergency scenarios. We present the case of a 65-year-old female with corneal perforation secondary to workplace chemical injury who underwent successful emergency eccentric semilunar PKP. This case demonstrates the feasibility and efficacy of eccentric noncircular corneal grafting in acute perforations when the defect is localized and peripheral, thereby preserving healthy tissue and achieving favorable anatomical and functional outcomes.

CASE PRESENTATION

Chief complaints

Progressive visual deterioration, ocular pain, and foreign body sensation in the left eye following a chemical splash injury.

History of present illness

A 65-year-old female presented to the ophthalmology emergency department with a chemical injury to the left eye. Approximately 26 hours prior to presentation, she sustained a workplace chemical splash while working with various chemical reagents, including ethyl acetate, concentrated sodium chloride, sodium nitroprusside, and Trizma buffer. Immediately following the incident, she attempted irrigation with saline and a neutralizing solution. Despite initial first aid, she developed progressive visual deterioration, ocular pain, and foreign body sensation.

History of past illness

The patient had no prior ophthalmic history. Her medical history was significant for type 2 diabetes mellitus diagnosed 5 years prior, dyslipidemia, Hashimoto’s thyroiditis, and hypertension.

Personal and family history

No relevant personal or family history was reported.

Physical examination

Distance visual acuity was 0.7 (Snellen 20/28) in the right eye and 0.2 (Snellen 20/100) in the left eye. Near visual acuity was 0.5 Snellen (Snellen 20/20 equivalent) in the right eye and 2.25 Snellen (Snellen 20/100 equivalent) in the left eye. Intraocular pressure measured by palpation was within normal limits in the right eye, with hypotony noted in the left eye. Slit-lamp examination of the left eye demonstrated conjunctival hyperemia, corneal melting extending to the limbal region, and perforation in the inferior quadrant, with a flat anterior chamber, iris incarceration at the perforation site, and an oval pupil displaced inferiorly toward the perforation site (Figure 1A). A hazy fundus view precluded detailed posterior segment examination.

Figure 1 Slit-lamp examination. A: Slit-lamp examination of the left eye at presentation demonstrating conjunctival hyperemia, corneal melting and perforation in the inferior quadrant, flat anterior chamber with iris incarceration, and oval pupil displacement toward the perforation site; B: Slit-lamp examination of the left eye at 10-month follow-up showing the inferiorly positioned semilunar graft with maintained central corneal clarity and peripheral neovascularization at the host-graft junction.

Laboratory examinations

No laboratory investigations were performed, as the clinical presentation warranted immediate surgical intervention for globe salvage without delay.

Imaging examinations

Ocular ultrasonography revealed shallow choroidal detachment extending circumferentially, sparing the temporal and superotemporal quadrants.

FINAL DIAGNOSIS

Corneal perforation secondary to OSCI.

TREATMENT

The patient underwent immediate emergency tectonic corneal transplantation in the form of eccentric semilunar PKP under analgo-sedation with peribulbar anesthesia. A donor graft was prepared using 11.0 mm and 10.0 mm manual trephines to define the curved borders, with the non-circular edges subsequently trimmed with corneal scissors to achieve the final semilunar shape. Due to significant hypotony in the recipient eye, the damaged corneal tissue in the inferior quadrant was marked with the same size trephines and removed using a 30-degree blade and corneal scissors to create a semilunar recipient bed. Excision was extended to macroscopically healthy stromal margins, as placement of sutures in chemically degraded, proteolytically softened tissue would prevent adequate wound tensioning and risk wound instability and aqueous leakage. The recipient bed dimensions were intentionally made slightly smaller than those of the donor corneal graft. Incarcerated iris tissue was carefully repositioned, and viscoelastic was injected to reform and stabilize the anterior chamber. The donor semilunar graft was secured with interrupted 10-0 nylon sutures, with cardinal sutures placed at the limbus at 4, 6, 8, and 12 o’clock positions at the host-graft junction. The viscoelastic was then irrigated from the anterior chamber. Seidel testing confirmed complete wound closure with no aqueous leakage. Peribulbar steroid and intracameral antibiotic were administered at the conclusion of the procedure.

OUTCOME AND FOLLOW-UP

The patient remained hospitalized for 7 days following surgery. Postoperative topical therapy consisted of ofloxacin 0.3% four times daily and loteprednol etabonate 0.5% three times daily. Due to elevated intraocular pressure in the early postoperative period, brimonidine 0.2% twice daily and a fixed combination of dorzolamide-timolol twice daily were added to the left eye. Systemic treatment consisted of oral methylprednisolone 20 mg daily, a proton pump inhibitor 20 mg daily, and ketoprofen 100 mg daily. At discharge, examination of the left eye revealed the semilunar graft positioned inferiorly, clear and well-secured with interrupted sutures. The anterior chamber was moderately deep with no cells or flare. A silicone hydrogel therapeutic contact lens was placed to protect the ocular surface and enhance patient comfort. Sutures were left unburied to allow selective removal as they loosened, as the transition between corneal and limbal tissue at the host-graft junction may result in uneven tension distribution and accelerated suture loosening compared to standard central keratoplasty. Nuclear-cortical cataract was noted at discharge, consistent with the patient’s age and diabetic history, with a moderate increase in lens opacity observed during follow-up.

Distance visual acuity in the left eye progressively improved from 0.09 uncorrected at the first postoperative visit to 0.4 uncorrected at the last follow-up visit, while near visual acuity remained stable at 0.5 with + 3.0 D correction. During follow-up, selective suture removal was performed for loose sutures, with well-tensioned sutures retained to maintain graft stability. The graft demonstrated sustained clarity centrally and superiorly with preserved structural integrity.

At the 10-month follow-up, slit-lamp examination revealed mild superficial conjunctival irritation. The central and superior cornea maintained transparency, while the inferior graft showed slight haze, particularly in the temporal portion. Peripheral neovascularization was observed inferiorly at the host-graft junction. A peripheral anterior synechia was noted at the border between host and donor tissue in the pupil border area. The anterior chamber remained moderately deep and clear, with the pupil displaced inferiorly toward the iridocorneal synechia (Figure 1B and Figure 2). Systemic methylprednisolone was tapered gradually.

Figure 2 Anterior segment optical coherence tomography global scan at 10-month follow-up demonstrating graft integrity with well-apposed host-graft interface and maintained anterior chamber depth, alongside corneal topography map revealing irregular astigmatism induced by the semilunar graft.

DISCUSSION

This case demonstrates the feasibility of emergency eccentric noncircular PKP for acute corneal perforation secondary to chemical injury. The decision to preserve healthy central and superior corneal tissue was driven by the localized nature of the chemical damage confined to the palpebral aperture zone. Total PKP would have required a limbus-to-limbus graft exceeding 11.0 mm, carrying a higher rejection risk due to proximity to limbal vasculature. The eccentric approach minimized surgical trauma, reduced antigenic load, and preserved the native optical zone.

The procedure presented significant technical challenges inherent to the emergency setting. Persistent severe hypotony with complete anterior chamber collapse and iris incarceration at the perforation site excluded standard surgical techniques. Viscoelastic injection was essential to reposition the iris and reform the anterior chamber, enabling safe tissue manipulation. The preparation of the semilunar donor graft required modification of standard trephination techniques, as circular punches could not be directly applied. Similarly, recipient bed preparation in a hypotonic eye necessitated manual marking with trephines followed by careful excision with a 30-degree blade and corneal scissors. Suture placement was particularly challenging due to ongoing hypotony, iris prolapse, and the need to pass sutures through tissues of markedly different consistency at the limbal junction while maintaining appropriate tension to avoid distorting the host cornea. These technical demands likely explain the limited adoption of noncircular PKP in acute perforation scenarios.

Eccentric PKP has been well-documented in the literature for a variety of peripheral corneal pathologies. Published reports describe its application in peripheral corneal degenerations such as Mooren’s ulcer, Terrien’s marginal degeneration, peripheral ulcerative keratitis, and pellucid marginal degeneration, where noncircular grafts provide tectonic support while preserving healthy central tissue[5,7]. Small-diameter eccentric penetrating grafts have been successfully employed for localized perforations of infectious, autoimmune, or traumatic etiology, including fungal infections, rheumatoid melts, and post-surgical wound necrosis[4,6]. These grafts are positioned away from the visual axis and secured with sutures, achieving globe restoration and preserving healthy corneal tissue. In emergency situations with limited availability of fresh donor tissue, glycerin-cryopreserved grafts have also been utilized successfully[6]. Traumatic peripheral corneal scars and wound separation have similarly been managed with eccentric noncircular full-thickness grafts that spare the visual axis[4,8]. In the presented case, although the graft margins were positioned outside the pupillary zone, they remained partially within the optical zone. Current literature recommends a minimum distance of 3 mm between the corneal center and the graft edge to minimize the risk of visually significant complications[9]. Encroachment on the optical zone may result in corneal scarring and structural irregularities, which can directly compromise visual acuity and limit the refractive outcomes of the procedure[10].

Eccentric keratoplasty advantages include preservation of healthy tissue, reduced risk of immunologic rejection, and faster visual rehabilitation compared to total PKP[4]. However, the application of noncircular grafting specifically in the acute management of chemical injury-related perforations remains underreported. This case contributes to the limited evidence demonstrating that eccentric noncircular PKP can achieve structural stabilization and functional visual rehabilitation in emergency settings when the perforation is localized and peripheral, provided the surgeon possesses the technical expertise to navigate the challenges of operating in a hypotonic, unstable eye. The primary objective of this procedure was tectonic restoration of globe integrity rather than immediate optical rehabilitation. If visual outcomes become unsatisfactory, the patient remains a candidate for secondary optical PKP. The strategy of emergency structural repair followed by elective optical reconstruction may represent a viable alternative in managing acute localized perforations, balancing the urgency of anatomical restoration with the preservation of future therapeutic options.

CONCLUSION

This case demonstrates that emergency eccentric semilunar PKP is a feasible and effective approach for managing acute corneal perforation secondary to chemical injury when the defect is localized and peripheral. By preserving healthy central corneal tissue, this technique minimizes surgical trauma, reduces antigenic load, and maintains the native optical zone while achieving the primary goal of globe salvage. Although technically demanding due to hypotony, anterior chamber collapse, and tissue compromise, noncircular keratoplasty can be successfully performed by an experienced surgeon in OSCI. The favorable anatomical and functional outcomes observed in this patient support the consideration of tissue-sparing approaches in emergency corneal surgery, expanding the therapeutic options for managing acute corneal perforations.