Abstract
Purpose: :
The most common sight threatening complication of cataract surgery is posterior capsular rupture associated with vitreous presentation into the anterior chamber. The goals of anterior vitrectomy are to completely remove the vitreous in the anterior chamber while maintaining lens capsule integrity, minimizing retinal traction and the amount of vitreous removed. This study compares anterior vitrectomy via limbal versus pars plana approach in an induced posterior capsular rupture during phacoemulsification in cadaveric pig eyes.
Methods: :
Cataract extraction via phacoemsulsification was performed on five cadaveric pig eyes. A posterior capsular rupture was induced using a cystotome, and pressure was applied to fill the anterior chamber with vitreous. Indocyanine green (ICG) was injected to enhance vitreous visualization. A limbal anterior vitrectomy (LAV) was performed in 2 eyes and a pars plana anterior vitrectomy (PPAV) in 3 eyes. The length of time to completely remove the ICG stained vitreous from the anterior chamber was recorded.. The posterior capsule was explored for posterior capsular tear extension, and the retina was grossly examined for retinal tears.
Results: :
The vitrectomy time in the LAV group was 3 minutes and 2 minutes and 50 seconds and in the PPAV group was 1 minute and 40 seconds, 1 minute and 30 seconds, and 1 minute. Less vitreous was removed from the PPAV group as evidenced by less globe deformation during surgery. The posterior capsular rupture extended during surgery in one LAV eye; however, the other four eyes had no posterior capsular rupture extension. None of the five eyes exhibited gross evidence of a retinal detachment.
Conclusions: :
In this study, PPAV appears to be a more efficient alternative to LAV requiring less surgical time, removing less vitreous, and maintaining capsular integrity. We believe this is due to the mechanical advantage of a pars plana approach since the vitrector is posterior to the prolapsed vitreous and capsular rent, thus minimizing the amount of vitreous removed and likelihood of capsular damage. With a limbal approach, the vitrector must be placed through the prolapsed vitreous and capsular rent increasing the likelihood of capsular damage and the amount of vitreous removed. The advantages of PPAV must be weighed against the inconvenience of making a separate pars plana incision and the potential risk of retinal tears near the incision, although none were observed in this study. LAV offers the ease of a limbal incision, but was associated in this study with longer surgical times, more extensive vitrectomy, and enlargement of the posterior capsular rent.
Keywords: cataract • vitreous • anterior segment