Experimental study of viscoelastic in the prevention of corneal endothelial desiccation injury from vitreal fluid-air exchange

Different patterns in the corneal endothelial cell loss after pars plana and pars limbal insertion of the Baerveldt glaucoma implant

PURPOSE

To assess corneal endothelial cell (CE) loss after pars plana (PP) and pars limbal (PL) insertion of a Baerveldt glaucoma implant (BGI).

DESIGN

Retrospective multicenter interventional comparative study.

METHODS

We studied central CE loss for 5 years after BGI surgery in 192 eyes.

RESULTS

The prevalence of bullous keratopathy (BK) was greater in the PL cohort than in the PP cohort (P = .003). The CE loss after simultaneous PP vitrectomy and tube insertion into the vitreous cavity was 11.9% in the first year, which was greater than that of 2.9% in eyes where the tube was inserted simply into the vitreous cavity after a prior vitrectomy (P = .046). The annual percentage CE loss after the first year decreased unidirectionally in both of those groups and was 1.3% and 1.0% in the fifth year, respectively (P < .001). For limbal insertion, the CE loss in the simple PL cohort was biphasic, decreasing from 10.5% in the first year to 7.0% in the fifth year. Simultaneous cataract and BGI surgery enhanced the CE loss slightly in the first year in the PP and PL cohorts to 13.0% and 14.0%, respectively. However, these increases were not significant (P = .816 and .358, respectively). Low preoperative CE density (P < .001) and insertion site (P = .020) were significant risk factors for the development of BK.

CONCLUSIONS

CE loss in the PL and PP cohorts was biphasic and unidirectional, respectively. The difference in annual CE loss became evident over time. PP tube implantation may be advantageous when the preoperative CE density is low.

Comparison of Viscoelastic Substance Injection Versus Air Filling in the Anterior Chamber During Foldable Capsular Vitreous Body (FCVB) Implant Surgery: A Prospective Randomized Controlled Trial

INTRODUCTION

To compare the outcomes of viscoelastic substance injection with air filling in the anterior chamber during foldable capsular vitreous body (FCVB) implant surgery in patients with severe retinal disease.

METHODS

Thirty eyes with severe retinal diseases were randomly divided into two groups. In the viscoelastic group, 0.15-0.2 mL of 1.7% sodium hyaluronate was injected into the anterior chamber after FCVB implantation; in the air group, the anterior chamber was maintained by filling the air after FCVB implant surgery. The eyes of treated patients were examined during a 24-week follow-up appointment. Data, including intraocular pressure (IOP), the difference between preoperative and postoperative IOP, and postoperative complications, were recorded.

RESULTS

Data collected from 27 eyes were used in the final analysis. The IOP of the air group was lower than that of the viscoelastic group from the first to third postoperative day (P < 0.01). Moreover, the difference between preoperative and postoperative IOP in the viscoelastic group was significantly smaller than that in the air group from the first to third postoperative day (P < 0.01). After the 1st postoperative week, postoperative IOP values were similar in the two groups (P > 0.05). Postoperative complications in the air group and the viscoelastic group included corneal blood staining (1 eye vs. 0 eyes), transient postoperative diffuse hemorrhage (5 eyes vs. 1 eye), inflammation reaction (9 eyes vs. 4 eyes), and postoperative fibrin exudation (4 eyes vs. 1 eye), respectively.

CONCLUSION

The use of viscoelastic substances in the anterior chamber during FCVB implant surgery was associated with less fluctuation in postoperative IOP and could reduce postoperative complications.

REGISTRATION NUMBER

ChiCTR-TNC-00000396.

Crystalline lens capsule staining with trypan blue

A 1-step method for staining the anterior lens capsule with trypan blue is described. The dye is instilled via a paracentesis port at the start of cataract extraction. As aqueous humor is allowed to exit the anterior chamber (AC), which consequently shallows, the resulting pupil block confines the dye to the AC. An ophthalmic viscosurgical device (OVD) is used to flush dye-stained aqueous from the AC, circumventing the need for AC washout. Although the OVD may be tinged with dye, this does not impede performing capsulorhexis. This method does not add to the surgical time, requires no additional instruments or materials, and is safe.

Survey of ophthalmic viscosurgical devices

PURPOSE OF REVIEW

Cataract treatment is evolving, thanks to new phaco systems and innovative surgical techniques. Recent ophthalmic viscosurgical devices (OVDs) play an important role in the development of new approaches to surgery. Knowledge of the new techniques and advances in new OVDs is crucial to performing routine and complicated surgeries.

RECENT FINDINGS

Viscoadaptive substances have been introduced as a particular kind of OVD and are distinguished by high viscosity at a low flow rate and a tendency to fracture at higher flow rates, assuming pseudodispersive behavior. The ultimate soft shell technique emphasizes the rheology of viscoadaptive OVDs to perform phacoemulsification procedures, exploiting all the useful properties of these OVDs in terms of space maintenance and tissue protection. Recent studies have highlighted some new and interesting aspects of the use of OVDs. Current reports suggest that the association of lidocaine and OVD seems to be safe and useful in providing anesthesia during cataract surgery. Concern has been expressed in other studies regarding the presence of contaminants, such as endotoxins, which may be responsible for postoperative uveitis-like reactions. Finally, OVDs are widely known to protect the corneal endothelium during cataract surgery. Their role is also assuming relevance in vitreoretinal surgery.

SUMMARY

New OVDs and related techniques represent an advancement in cataract surgery.