Diplopia cases after periocular anesthesia without hyaluronidase

Lens cell targetting for gene therapy of prevention of posterior capsule opacification

Posterior capsule opacification is the main complication of cataract surgery. Using adenovirus-mediated gene transfer, we recently reported that it was feasible to prevent PCO by overexpressing pro-apoptotic molecules such as pro-caspase 3 or Bax in the residual lens epithelial cells post-cataract surgery. However, this approach is feasible only if gene transfer can be restricted to the residual cells responsible for PCO. Initially, we tested an adenovirus (human serotype 5, HAd5), a lentivirus (HIV) and an oncoretrovirus (MLV) vector for the their in vivo transduction efficiency of rabbit lens cells. We found that HAd5 vectors were the most efficient (>90% of the cells could be transduced). Six potential lens-specific promoters were then cloned into HAd5 vectors and assayed for their ability to target expression to a specific population of cells, using in vitro, ex vivo and in vivo rabbit tissues and human lens capsular bags. We found that the LEP503, MIP and Filensin promoters induced strong lens-specific expression of a reporter gene, in human lens cells. Following this ex vivo assay, we showed in a rabbit PCO model that gene transfer could be spatially restricted to the capsular bag by confining the vector with Matrigel. Our combined approach using a lens-specific promoter and a biocompatible gel should render feasible a novel therapeutic strategy for PCO that targets the remaining lens cells.

Persistent strabismus after cataract extraction

BACKGROUND

Transient ocular misalignment as a complication of parabulbar and peribulbar anesthesia has already been reported in the literature. The aim of our study was to present a case of irreversible iatrogenic vertical strabismus after cataract surgery, which had to be operated on.

METHODS

Clinical and orthoptic evaluation of a female patient with vertical diplopia after phacoemulsification cataract surgery.

RESULTS

One week after the uneventful surgery, a 68-year-old patient complained of a sudden vertical deviation in the operated eye. The patient had not had a history of previous motility disorders. On examination, the patient showed hypertropia in the left eye of 15-20 degrees in primary position. Three and 6 months postoperatively, there was no a spontaneous improvement, while the persistent vertical deviation was 40 prism dioptres. Strabismus surgery was required 1 year after the cataract surgery.

CONCLUSION

Diplopia is a complication of peribulbar anesthesia which could be persistent. The superior and inferior rectus muscle are especially vulnerable. Its occurrence may be technique--related and the incidence increases when hyaluronidase is not available.

Diplopia following cataract extraction

Diplopia following cataract extraction occurs in approximately 1% of cases or less. With over 1.5 million cataract extractions per year, this can lead to a considerable morbidity. It is typically a small vertical deviation and is distressing if unanticipated. The most common etiologies include surgical manipulation of orbital tissue from a bridle suture, extraocular muscle trauma from a retrobulbar needle or anesthetic, and unmasking an underlying strabismus or systemic condition with extraocular muscle involvement. Care must therefore be taken by obtaining a complete preoperative history and examination, document any preexisting strabismus and systemic condition, and avoid any direct extraocular muscle trauma or manipulation.

Second cluster of strabismus cases after periocular anesthesia without hyaluronidase

We describe a second cluster of cases of iatrogenic strabismus that occurred in clinical practices following cataract surgeries that occurred in 2000 when hyaluronidase was once again unavailable for use in periocular anesthetic regimens. Twelve cases of transient or permanent strabismus were referred by 4 anterior segment surgeons who had no previous cases of postcataract strabismus when performing periocular injections with hyaluronidase. The charts of the patients were reviewed retrospectively. Recurrence of an increase in postoperative strabismus when hyaluronidase became unavailable for a second time supports the concept that this enzyme may be more important than previously suspected in preventing damage to the extraocular muscles after periocular anesthetic injections.

Diplopia and ptosis following injection of local anesthesia without hyaluronidase

In a university ophthalmology department, a cluster of postoperative diplopia and ptosis cases occurred in the initial 3 months after hyaluronidase (Wydase) became unavailable for use with injection anesthesia. These cases suggest that hyaluronidase, when used with injection anesthesia, may protect extraocular muscles and nerves from the toxic effects of local anesthetic agents. The spreading action of hyaluronidase facilitates uniform diffusion of anesthetic agents. This prevents elevated extracellular tissue pressure, a cause of ischemic damage to extraocular muscles or nerves. Hyaluronidase may also prevent focal accumulations and concentrations of local anesthetic agents, which at high enough levels may cause myotoxic or neurotoxic damage, fibrosis, and contracture of extraocular muscles or nerves.