Ocular explosion during cataract surgery: a clinical, histopathological, experimental, and biophysical study.

Abstract INTRODUCTION: An increasing number of cases are being recognized in which a peribulbar anesthetic for cataract surgery has been inadvertently injected directly into the globe under high pressure until the globe ruptures or explodes. We reviewed the records of 6 such cases (one of which was reported previously by us), and one additional case has been reported in the literature. Surprisingly, 2 of these 7 cases went unrecognized at the time, and the surgeons proceeded with the cataract operation; all of the patients ultimately developed severe visual loss and/or loss of the eye. OBJECTIVES: To reproduce this eye explosion in a live anesthetized rabbit model and to perform a clinical, histopathological, experimental, biophysical, and mathematical analysis of this injury. METHODS: Eyes of live anesthetized rabbits were ruptured by means of the injection of saline directly into the globe under high pressure. The clinical and pathological findings of the ruptured human and animal eyes were documented photographically and/or histopathologically. An experimental, biophysical, and mathematical analysis of the pressures and forces required to rupture the globe via direct injection using human cadavers, human eye-bank eyes, and classic physics and ophthalmic formulas was performed. The laws of Bernoulli, LaPlace, Friedenwald, and Pascal were applied to the theoretical and experimental models of this phenomenon. RESULTS: The clinical and pathological findings of scleral rupture, retinal detachment, vitreous hemorrhage, and lens extrusion were observed. In the exploded human and rabbit eyes, the scleral ruptures appeared at the equator, the limbal area, or the posterior pole. In 2 of the 7 human eyes, the anterior segments appeared entirely normal despite the rupture, and cataract surgery was completed; surgery was canceled in the other 4 cases. In 4 of the 5 injected and ruptured rabbit eyes, the anterior segments appeared essentially normal. The experiments with human eye-bank eyes and the theoretical analyses of this entity show that the pressure required to produce such an injury is much more easily obtained with a 3- or 5-mL syringe than with a syringe 10 mL or larger. CONCLUSIONS: Explosion of an eyeball during the injection of anesthesia for ocular surgery is a devastating injury that may go unrecognized. The probability of an ocular explosion can be minimized by careful use of a syringe 10 mL or larger with a blunt needle, by discontinuing the injection if resistance is met, and by inspecting the globe prior to ocular massage or placement of a Honan balloon. When ocular explosion occurs, immediate referral to and intervention by a vitreoretinal surgeon is optimal. Practicing ophthalmologists should be aware of this blinding but preventable complication of ocular surgery.