 |
||||||||||||||
|
||||||||||||||
|
||||||||||||||
|
||||||||||||||
RETAINED NUCLEAR LENS FRAGMENT
Vitreoretinal News for the Medical Community
Posterior dislocation of lens fragments may complicate phacoemulsification cataract surgery. Portions of the lens nucleus and surrounding cortex may slip through posterior capsular tears and sink through liquid vitreous to the retinal surface. Occasionally the entire lens dislocates because of weak zonular support. Dislocation of lens fragments during cataract extraction, although an unexpected event, is not necessarily an emergency. Typically there is a thin layer of posterior vitreous which protects the retinal surface and retinal damage occurs more from efforts to retrieve the fragments. Some cataract surgeons recommend attempting to "float" the nucleus with irrigation or retrieve the fragment with a lens loop. Placing a cover slip over the cornea to visualize posterior structures have been advocated by some. These are potentially hazardous techniques which cause traction to the vitreous base. Retinal tears, retinal detachment, vitreous hemorrhage, and hyphema can complicate an otherwise straightforward case. What should be done if lens fragments drop into the vitreous during cataract phacoemulsification? Don't panic and attempt to retrieve the fragments blindly. If the lens clears the posterior capsule then remove as much cortex as possible and do an anterior vitrectomy. Every attempt should be made to preserve the anterior or posterior capsule and insert a PC-IOL. A central anterior capsulorhexis provides excellent support for a posterior chamber lens to be placed in the sulcus. Sutureless scleral incisions should probably be strenghthened with a single stitch. Subconjunctival steroids will reduce inflammation. Referral to a vitreoretinal surgeon may be made within the next few days. It is not necessary to remove the lens fragments during the initial cataract surgery and in most cases the equipment is not readily available. Pars plana vitrectomy provides a closed surgical environment and proper illumination to locate and remove all lens fragments. There is not universal aggreement on timing of vitrectomy. In most cases the cornea is somewhat edematous in the early post-op period, often due to elevated intraocular pressure, which clears within a week. Systemic or sub-tenon's steroids if not contraindicated, may help control inflammation prior to vitrectomy. The prognosis following pars plana vitrectomy and fragmentation of lens fragments is usually excellent. Intraocular lenses placed during the initial cataract procedure do not interfere with posterior vitrectomy., do provide early visual rehabilitation, decrease surgical time during vitrectomy, and may lessen patient anxiety since the goal of IOL insertion was accomplished. Anterior chamber IOLs may not compromize vitrectomy either. |
