Investigation of scleral thermal injuries caused by ultrasonic pars plana phacoemulsification and aspiration using pig eyes

PURPOSE

The purpose of this study was to investigate the thermal injuries caused by ultrasonic pars plana phacoemulsification and aspiration (PPPEA) using pig eyes.

METHOD

Using a 20-gauge (G) vitrectomy system (Accurus^®, Fragmatome; Alcon Laboratories) in both the 'open-tip' and 'closed-tip' techniques, PPPEA was performed in pig eyes and the subsequent thermal injuries generated around the scleral wound were measured by infrared thermal imaging (thermography). Post surgery, the state of the scleral wound was observed under a microscope, and a tissue slice containing the scleral wound was then prepared and observed under an optical microscope.

RESULTS

Thermography measurements revealed a slight temperature rise around the scleral wound in the open-tip case, yet a marked temperature rise in the closed-tip case. The scleral wound incision produced by the open tip was linear, while that produced by the closed tip was expanded. Histological examination revealed mild degeneration of the sclera around the wound in the open-tip case, yet marked tissue degeneration by thermal injuries in the closed-tip case.

CONCLUSION

Our findings showed that in PPPEA, the temperature of the tip of a 20G vitrectomy system rapidly increases due to the closed-tip technique, thus producing obvious thermal damage to the scleral wound. In order to prevent thermal injuries to the scleral wound during PPPEA, it is important to shorten the time of ultrasonic oscillation during surgery as much as possible while the tip is occluded with nuclear fragments.

Conservative management of penetrating ocular trauma caused by a nail gun

Purpose

To report the conservative management of a penetrating ocular trauma caused by a nail gun with a six-month follow up.

Observations

A 21 year-old healthy female suffered an ocular penetrating trauma with a nail gun. She presented with a metallic foreign body that partially entered her left eye through the nasal sclera via pars plana, 3 mm posterior to the limbus, but did not reach the retina. Surgical removal of the foreign body and closure of the scleral wound, without vitrectomy, was performed 16 h after the injury. Intravitreal prophylactic antibiotic was administered. Retinal atrophy developed in the areas that had commotio retinae at presentation, but no further complications were observed.

Conclusions and importance

Pars plana vitrectomy may not be necessary in all penetrating ocular traumas with intraocular foreign body, as long as the foreign body is accessible from the exterior of the eye and there are no other conditions (such as vitreous hemorrhage, retinal detachment, endophthalmitis, etc) that are an indication for vitrectomy.

Cauterization of Ozurdex wound for the prevention of scleral leakage in vitrectomized eyes

PURPOSE

To study if cauterization of the scleroconjuctival wound secondary to intravitreal dexamethasone implant in vitrectomized eyes is effective to avoid scleral leakage and hypotony.

METHODS

A total of 35 vitrectomized eyes of 35 consecutive patients with macular edema who underwent a single intravitreal dexamethasone implant injection in the operating room at the Eye Clinic of the University of Bari, Italy, from 2013 to 2017 were retrospectively reviewed. At the end of the injection, transconjuctival/scleral bipolar cauterization was applied at the injection site and the presence or absence of leakage or hypotony was studied.

RESULTS

At the end of the procedure, no patient showed fluid leakage from the cauterized scleroconjuctival wound. No ocular hypotony of other ophthalmic complications were observed at 1 hour and 1 day from injection and intraocular pressure did not change significantly from baseline at 1 hour and 1 day after injection.

CONCLUSIONS

Cauterization of the scleral wound after intravitreal dexamethasone implant injection in vitrectomized eyes is safe and effective to avoid scleral leakage with secondary hypotony, obtaining a watertight wound closure.