Corneal wound burn is an intraoperative complication that occurs during phacoemulsification (PEA). Commonly called phacoburn, it is caused by friction heat between the ultrasound tip and the surrounding irrigation sleeve. When the temperature of the collagen fibers in the corneoscleral tunnel reaches 60°C, thermal damage occurs within 1–3 seconds, leading to shrinkage and degeneration of the incision site and surrounding tissue 2).
Regarding incidence, a survey of 920,095 corneal surgeries performed in the United States and Canada from 2006 to 2009 reported 0.037% 4). Another study reported 75 wound burns out of 76,581 cases (0.98 per 1,000 cases), with 72% occurring during nucleus removal and 28% during initial groove creation 2). Considering unreported cases, the actual incidence may be higher 4).
In recent years, improvements in fluidics and advances in power modulation have reduced the frequency of wound burns, but it remains an important complication that has not been completely eliminated 2).
Corneal wound burn is an intraoperative complication, and the findings recognized by the surgeon are central.
Intraoperative findings:
Postoperative findings:
In the case by Mansour et al., 5 D of astigmatism was noted 8 hours postoperatively, but after placement of a Tenon’s capsule patch and suture removal, the astigmatism resolved and corrected visual acuity recovered to 20/25 1). In contrast, in the case by Ashena et al., persistent microleakage was observed even after 3 weeks, and could not be closed with conventional sutures and a bandage contact lens 3).
Insufficient Irrigation
Tip occlusion by viscoelastic material: High-viscosity viscoelastic (especially Healon5) can occlude the tip and impede cooling 4).
Irrigation bottle problems: Insufficient flow due to empty bottle or low bottle height.
Tubing kinking: Kinking or compression of the irrigation tubing causing cessation of flow.
Excessive ultrasound energy
High power, long duration: Especially common during emulsification of hard nuclei (grade 4 or higher)
Continuous mode: Continuous ultrasound increases the risk of wound burn by 3 times compared to pulse or burst mode2)
Ultrasound emission at the wound: US emission under low aspiration and low aspiration flow settings during nucleus occlusion
| Procedure | Risk | Reason |
|---|---|---|
| Divide and conquer | High | High dependence on US2) |
| Stop and chop | High | Long US usage time |
| Phaco chop | Low | Utilizes mechanical force4) |
In the study by Sorensen et al., an inverse correlation was found between the surgeon’s number of surgeries and the incidence of wound burn, with the incidence decreasing by 45% for each doubling of the number of surgeries 4). The phaco-chop technique had a significantly lower risk compared to the divide-and-conquer and stop-and-chop techniques 2)4).
The type of ophthalmic viscosurgical device (OVD) is also an important risk factor. Healon5 and Viscoat are associated with a higher incidence of wound burn, whereas HealonGV, despite its high viscosity, shows minimal temperature rise and a very low incidence. Not only the viscosity but also the heat generation characteristics of the OVD contribute to the risk 2).
Other reported risk factors include shallow anterior chamber 1)3), sleeve compression due to a small incision 1), deep-set eye 1), and the use of dispersive OVDs in Fuchs endothelial corneal dystrophy (risk of tip occlusion) 2).
Femtosecond laser is used for pre-fragmentation of the nucleus and capsulotomy, which may reduce the amount of ultrasound energy used during phacoemulsification. However, ultrasound is still needed for emulsification and aspiration of the nucleus, so the risk of wound burn is not completely eliminated. Proper irrigation management and device setup remain as important as in conventional phacoemulsification.
The diagnosis of corneal incision wound burn is primarily based on direct intraoperative observation.
Intraoperative warning signs:
Postoperative evaluation:
If a wound burn occurs, prioritize wound closure first. Induced astigmatism can be addressed later.
Tenon's capsule patch
Method: Harvest Tenon’s capsule from the inferior conjunctiva and place it over the dehisced wound. Fix with two radial 10-0 nylon sutures1)
Advantages: No rejection because it is autologous tissue. Fibroblasts promote wound healing. No additional cost1)
Outcome: In Mansour’s case, suture removal was possible at 10 days, achieving corrected visual acuity of 20/25 without astigmatism1)
Pericardial patch
Method: Suture a Tutoplast pericardium (multidirectional collagen matrix) onto the wound3)
Advantages: Absorbed in about 6 weeks, reducing irregular astigmatism after suture removal. Low risk of rejection3)
Indications: Useful for large dehiscences where conventional suturing or bandage contact lenses are ineffective3)
Corneal patch grafts and scleral patch grafts are also options. In the case by Giglio et al., a full-thickness corneal patch graft of 4 mm diameter was performed, eventually leading to penetrating keratoplasty (PK)2). Corrected visual acuity after PK was 20/322). Khodabakhsh et al. reported that among 4 cases of severe thermal burns, 3 underwent lamellar patch grafts and 1 underwent PK, with significant improvement in astigmatism in all cases2).
Other treatment options include conjunctival flaps (suitable for small to moderate wound gaps) 1), amniotic membrane transplantation, and cyanoacrylate adhesive, but a standardized treatment approach has not been established 2).
Immediately stop ultrasonic oscillation and irrigate the wound with balanced salt solution (BSS). Check for tube occlusion or kinking, and increase irrigation and aspiration flow rates. If the wound is burned, do not continue phacoemulsification; prioritize wound closure. Manage in the order of hydration, air injection, and 10-0 nylon suturing.
Modern ultrasonic handpieces contain a piezoelectric element that vibrates at ultrasonic frequencies of 28,000–60,000 Hz when electrically stimulated. The vibration is transmitted to a titanium tip, which emulsifies the lens nucleus.
The ultrasonic handpiece has two heat sources:
Normally, irrigation fluid (BSS) cools the outer surface of the tip, and aspiration through the central lumen helps remove heat 2). If irrigation around the tip is blocked, this cooling mechanism fails.
Collagen fibers in the corneoscleral tunnel undergo irreversible denaturation when the temperature reaches 60°C or higher 2)4). Denatured collagen contracts and weakens, acquiring a texture like “irregularly cooled wax” 2). This is the direct cause of wound gap and difficulty in suturing.
Ophthalmic viscosurgical devices (OVDs) can obstruct the tip, impeding irrigation flow and causing a rapid temperature rise. Especially when the anterior chamber is filled with OVD, irrigation flow is poor, making the wound more prone to severe deformation. Ernest et al. showed that both cohesive and dispersive OVDs cause temperature elevation under similar conditions 2).
Giglio et al. (2024) reported that continuous ultrasound combined with divide-and-conquer or carousel techniques increases the risk of wound burn by 3 times compared to chopping with pulse/burst mode. 72% of wound burns occurred during nucleus removal, and tip occlusion is a key trigger for wound burn. 2)
The phenomenon in which gas bubbles collapsing at ultrasonic speed release a large amount of energy is called the cavitation effect. This is an auxiliary mechanism of phacoemulsification and can also serve as an additional heat source.
High-viscosity viscoelastic substances (such as Healon5) have a higher risk of perfusion obstruction due to tip occlusion. Dispersive viscoelastic substances (such as Viscoat) have high heat generation characteristics even at low viscosity and can cause temperature rise. On the other hand, HealonGV, despite its high viscosity, shows minimal temperature rise and is highly safe. Since not only the “viscosity” but also the “heat generation characteristics” of the viscoelastic substance affect the risk, it is recommended to remove the viscoelastic substance from the working space with I/A before starting PEA.
Mansour et al. (2021) reported a technique using autologous Tenon’s capsule as a patch1). Tenon’s capsule is rich in fibroblasts, accelerating wound healing and forming a firm scar. Since it is autologous tissue, there is no additional cost or risk of rejection. The timing of suture removal can be determined under anterior segment OCT, and good visual acuity (20/25) without astigmatism was achieved even when sutures were removed after 10 days1).
Ashena et al. (2021) first reported the management of wound burn using a Tutoplast pericardial patch graft. The pericardium is an absorbable graft material consisting of a multidirectional collagen matrix, which is absorbed in about 6 weeks. It induces less irregular astigmatism after suture removal and has a low risk of graft rejection. 3)
Giglio et al. (2024) reported a case of severe wound burn in a patient with Fuchs endothelial corneal dystrophy, in which PK was performed after corneal patch grafting, achieving a corrected visual acuity of 20/322). This report points out that most of the currently available literature is limited to case reports and case series, making it difficult to conduct prospective comparative studies2). A standardized treatment approach has not been established, and sharing cases is essential for the development of management methods.
Although the incidence has been decreasing due to improvements in fluidics and advances in power modulation, surgical techniques that do not rely on ultrasound, such as manual small incision cataract surgery (MSICS), may also be options for prevention in severe cases2).
Mansour HA, Mansour AM. Autologous tenon plug and patch in phacoburn. BMJ Case Rep. 2021;14:e238970.
Giglio R, Vinciguerra AL, Inferrera L, Tognetto D. Phacoemulsification wound burn and its management. Case Rep Ophthalmol. 2024;15:303-309.
Ashena Z, Holmes C, Nanavaty MA. Pericardium patch graft for severe corneal wound burn. J Curr Ophthalmol. 2021;33:342-344.
Sorensen T, Chan CC, Bradley M, Braga-Mele R, Olson RJ. Ultrasound-induced corneal incision contracture survey in the United States and Canada. J Cataract Refract Surg. 2012;38(2):227-233. doi:10.1016/j.jcrs.2011.08.039. PMID:22133549.
