Dislocation of an intraocular lens (IOL) with the capsular bag is a late complication of cataract surgery, reported with increasing frequency in recent years. Pseudoexfoliation, uveitis, myopia, and other diseases associated with progressive zonular weakening and capsular contraction are the predisposing conditions. Capsular tension rings probably help but do not prevent this complication. Management includes IOL exchange, replacement with an anterior or a sutured posterior chamber IOL, or suturing the IOL through the bag to the iris or the sclera.

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The development of the continuous circular capsulorhexis (CCC) technique has contributed significantly to the safety and effectiveness of cataract extraction and intraocular lens implantation. This technique facilitates every size of smooth, circular, capsular opening, and it produces a strong capsular rim that resists tearing even when stretched during lens material removal or lens implantation. Maintaining the general integrity of the eye and facilitating such procedures as hydrodissection, endolenticular phacoemulsification, capsule polishing, and safe lens implantation in both adults and children are some of the advantages of CCC. This procedure can be performed in several ways, and it has been proven to be consistently reproducible by experienced surgeons.

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We compared the predictive accuracy of the SRK/T formula to the SRK II, Binkhorst II, Hoffer, and Holladay formulas in seven series of cases totaling 1,050 eyes. In the combined group, the SRK/T and Holladay formulas performed only slightly better than the other formulas. In short eyes (less than 22 mm), all formulas performed well, with the SRK/T, SRK II, and Holladay formulas performing marginally better. In moderately long eyes (greater than 24.5 mm, less than or equal to 27 mm), the Hoffer and Binkhorst II formulas had a greater proportion of cases with greater than 2 diopters (D) of error and the SRK/T and Holladay were again marginally better. In the very long eyes (greater than 27 mm and less than or equal to 28.4 mm), there were only 11 cases and all formulas performed well since none had greater than 2 D of prediction error. In an extremely long eye data set (greater than 28.4 mm), the SRK II formula clearly gave the poorest result. Eyes of this length occurred in only 0.1% of cases in our unselected series. Results support the contention that the present second and third generation IOL power formulas give fairly equivalent accuracy. Other factors, such as availability, ease of use, and ability to tailor or individualize, become major considerations.

The accuracy of intraocular lens (IOL) power calculation was evaluated in a multicenter study of 822 IOL implantations using the Binkhorst II, Sanders/Retzlaff/Kraff (SRK I, SRK II, SRK/T), Holladay, and Olsen formulas. All but the first of these were optimized in retrospect with calculation of the SRK A-constant, the Holladay surgeon factor, and the Olsen pseudophakic anterior chamber depth (ACD) for each lens style. The ACD prediction of the Olsen formula was based on a previously described regression formula incorporating preoperative ACD, corneal height, axial length, and lens thickness. Among the optical IOL power calculation formulas, the highest IOL power prediction error was found with Binkhorst's and the lowest with Olsen's, which was more accurate than the SRK/T and the Holladay formulas (P < .05). The SRK/T formula was significantly more accurate than the original SRK regression formulas (P < .001). When analyzed for axial length dependence, all formulas showed the least error in the normal range. Error of the Olsen formula was lower than that of the others in the axial length interval 20 mm to 26 mm. No differences in accuracy were found between the optical IOL calculation formulas in eyes with an axial length above 26 mm (P < .05). The accuracy of IOL power calculation can be improved with optical formulas using newer-generation ACD-prediction algorithms.

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Cataract extraction by phacoemulsification of the lens in situ can be accomplished by a technique incorporating continuous curvilinear capsulorhexis (CCC), deep central sculpting of the nucleus, and manual cracking ("nucleofractis") and subsequent fragmentation and emulsification of the remaining nucleus. This "divide and conquer" nucleofractis technique of phacoemulsification is uniquely suited to the constraints that CCC, which provides excellent conditions for well-centered in-the-bag placement of intraocular lenses, imposes upon cataract extraction. The cracking and fragmentation maneuvers allow phacoemulsification to be extended to patients with hypermature and brunescent lenses, as well as small pupils, who are not normally considered good candidates for the technique.