Zonular Stress Research Articles

V-style phacoemulsification

A technique designed to reduce zonular stress and ensure safe intercapsular phacoemulsification is described. This one-handed method is especially effective in eyes with strong adhesions between nucleus and cortical layers where hydrodissection is not possible. Early experiences in 150 eyes yielded a reduction in emulsification time and such intraoperative complications as posterior capsule rupture and zonulysis.

Prospective study of posterior capsule-zonular disruption during extracapsular cataract extraction: Eliminating iatrogenic disruption

We modified our surgical techniques after analyzing the mechanisms responsible for posterior capsule-zonular disruption with or without vitreous loss in 250 consecutive extracapsular cataract extraction cases. We applied the derived principles and prospectively studied the subsequent 1,500 cases. Modifications in our surgical protocol included the use of a Honan balloon for a longer interval (at least 60 minutes preoperatively) and more aggressive surgical expansion of poorly dilating pupils. Furthermore, complete YAG anterior capsulotomy performed after the retrobulbar block appeared to minimize zonular stress associated with mechanical anterior capsulotomv. We reduced the risk of posterior capsule-zonular disruption from 4.8% (2.4% vitreous loss) to zero, eliminating this complication completely in our last 1,000 cases.

Minimizing Zonular Stress During Extracapsular Extraction in Pseudoexfoliation Syndrome

To the Editor. —Concerning the recent article by Skuta and colleagues 1 : The various degrees of zonular laxity or localized rupture that may accompany pseudoexfoliation syndrome constitute a direct difficulty for planned extracapsular cataract extraction. To minimize intraoperative zonular stress as much as possible, I take the following precautionary measures when performing an extracapsular cataract extraction in the presence of pseudoexfoliation syndrome: I perform an invariable peripheral iridectomy with radial iridotomy when the pupil is insufficiently dilatable. A 150° corneoscleral incision is made and then secured with three temporary Barraquer silk sutures (8-0). Sodium hyaluronate is instilled into the anterior chamber. Instillation is followed by point-focal opening of the anterior lens capsule with a 20-gauge needle at the 12 o'clock position and circular excision of the anterior capsule with special capsulotomy scissors (Figure).2 This practically eliminates any traction on the zonular apparatus in contrast to conventional anterior capsulotomy. The lens

Hydrodissection of soft nuclei

I describe a technique for freeing the nucleus in extracapsular cataract surgery that uses simple cannulas and balanced salt solution in a closed anterior chamber, produces no zonular stress, requires no assistant, needs no iris or capsule manipulation, and is compatible with all methods of nucleus removal including phacoemulsification.

An insertion technique for the double-closed-loop posterior chamber lens

We have developed a technique for inserting double-closed-loop posterior chamber implants that minimizes zonular stress with both ciliary sulcus and capsular bag insertion and facilitates in-the-bag placement if desired.

Surgical management of zonular dehiscence and posterior capsular rents.

GENERAL PRINCIPLES Because the most satisfactory treatment is prevention , let us consider some surgical principles applicable to both planned extracapsular extraction and phacoemulsification that offer the best prophylaxis against rent occurrence and zonular dehiscence. 1. The eye should be soft. 2. A sharp instrument capable of easy capsular cutting should be used for the anterior capsulectomy. 3. Superficial capsule tears adequate for capsulectomy avoid zonular stress. 4. Dislocating the nucleus is performed very slowly to separate the nucleus and cortex, while minimizing stress to the zonules. 5. A sharp instrument should not be placed behind the nucleus in an effort to achieve its prolapse. 6. The phacoemulsification should be maneuvered parallel to the iris (rather than toward the optic nerve) regardless of whether the nucleus is emulsified in the anterior chamber, iris plane, or posterior chamber. 7. When sculpting the nucleus the emulsification tip should remain fully visible within the anterior position of the nucleus. 8. Anterior chamber depth must be carefully monitored during ultrasound (watch inflow, outflow, kinking of sleeve, exte rnal pressure, etc.). 9. A s econd dull instrument may be used during two-handed phacoemulsification to control the nucleus and protect the endothelium and posterior capsule. The incision should not be large enough to shallow the anterior chamber. 10. Removing an ante rior capsular fragment using the toilet paper maneuver is generally safe when applied to pedunculated rather than broad-based flaps. 11. Vacuuming the posterior capsule should be performed on minimum aspiration with a 0 .3 port directed tangentially rather than posteriorly. The tip should be moved constantly to avoid engaging posterior capsule in the port. If engagement occurs , the vacuum is immediately broken by prompt footswitch control. Rarely is reverse aspiration nece,ssary to spit ,out capsule.