Elsevier

Ophthalmology

Volume 109, Issue 8, August 2002, Pages 1421-1426
Ophthalmology

Evaluation of neodymium:yttrium-aluminum-garnet capsulotomies in eyes implanted with AcrySof intraocular lenses1,

https://doi.org/10.1016/S0161-6420(02)01116-8Get rights and content

Abstract

Purpose

As of December 31, 2000, the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser posterior capsulotomy rate for the Alcon AcrySof intraocular lens (IOL) as measured in our database was 3.3%. This was the lowest of any IOL model used in the United States. Only 12 of 361 cases required treatment. We analyzed possible surgical reasons that may have been responsible for the posterior capsule opacification (PCO) in this small group. Special attention was given to the three surgical factors that we had previously identified as being important for PCO reduction: (1) quality of cortical clean up, (2) type of haptic fixation, and (3) continuous curvilinear capsulorhexis (CCC) size and shape.

Design

Comparative autopsy tissue analysis.

Participants

Three hundred sixty-one human eyes obtained postmortem with Alcon AcrySof IOLs, accessioned between January 1995 and December 2000 from Lions Eye Banks.

Methods

The eyes were evaluated by the Miyake-Apple posterior photographic technique.

Main outcome measures

The area and intensity of Soemmering’s ring and type of fixation were studied in 361 eyes. The size and shape of the CCC and relation of the CCC edge to the IOL’s optic rim were analyzed in 168 eyes.

Results

The amount of Soemmering’s ring formation was significantly larger in the group of IOLs requiring Nd:YAG capsulotomy (Nd:YAG group). The not in-the-bag fixated IOLs required more Nd:YAG capsulotomies. Although the trend was clear, the number of specimens was not large enough to acquire statistical significance. The Nd:YAG group showed a highly significant difference compared with the No Nd:YAG group with regard to the amount of clock hours of the CCC edge on the optic rim’s surface (P < 0.001). Mean CCC diameters were significantly larger in the Nd:YAG group (P < 0.05).

Conclusions

The amount of Soemmering’s ring correlates with the quality of cortical clean up. Cells within the Soemmering’s ring are the direct precursors of PCO. This study confirms our previous laboratory studies and the clinical assumption that the incidence of PCO and thus the need for Nd:YAG capsulotomy is correlated with the cortical clean up. A second clinical assumption, that poor IOL fixation increases the risk of PCO, is also strongly suggested in this study. This study also verifies the relation of the CCC to PCO and the Nd:YAG laser, namely that a relatively small CCC without tears is best to prevent this complication. Use of a high-quality IOL combined with diligent attention to these three surgical factors should lower further the incidence of PCO.

Section snippets

Material and methods

To calculate the Soemmering’s ring scores and the haptic fixation in both the Nd:YAG group and the No Nd:YAG group, all AcrySof globes in our autopsy eye database were used (all AcrySof globes through December 2000, n = 361; 12 with Nd:YAG capsulotomies). We analyzed CCC diameters and relation of the anterior CCC edge to the optic rim of the IOL in 168 eyes with Alcon AcrySof IOLs, obtained postmortem, accessioned between January 1999 and December 2000. A total of 193 globes from a database of

Results

Table 1 shows the mean values of the Soemmering’s ring scores (SRA × SRI), the percentage of not in-the-bag fixated IOLs, the CCC mean diameter, and nonoverlapping clock hours of the CCC edge in relation to the optic rim in each group. The Soemmering’s ring score was significantly larger in the Nd:YAG group (P < 0.05, Mann-Whitney rank sum test). Three of the 12 IOLs (25.0%) with Nd:YAG capsulotomies (Nd:YAG group) showed loop positions not in the capsular bag, whereas only 19 of 349 IOLs

Discussion

After several experimental studies on the pathogenesis and treatment of PCO in our laboratory, and after compiling information derived from other laboratory and clinical studies from several centers worldwide, we have ascertained six specific factors that play an important role in the origin of PCO and subsequent Nd:YAG capsulotomy.1 Although all steps of the cataract operation are, of course, important in reducing any complication, we have identified three surgery-related factors and three

References (37)

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Supported in part by Research to Prevent Blindness, Inc., New York, New York; and a Max Kade Postdoctoral Research Grant (JMS), Max Kade Foundation, New York, New York.

1

The authors have no financial or proprietary interest in any products mentioned in this paper.

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