Ang and coauthors1 have described an interesting finding of “retrocapsular lens fragments” in 84 of 506 patients who had uneventful phacoemulsification cataract surgery. The incidence of retrocapsular lens matter is reported to be 16.6% with an experienced surgeon using standard techniques. However, the observations of Ang and coauthors are inconsistent with our cytological examinations of the anterior vitreous specimens immediately after phacoemusification in combined phacovitreoretinal surgery.
We studied the ultracentrifuge cytospin preparation for 12 anterior vitreous samples from patients who had just had uneventful phacoemulsification. No lens matter or anything similar could be identified under microscopic examination by an experienced pathologist (P.C.) (unpublished data). This finding obviously deviates from the finding of Ang and coauthors. Because of the discrepancy, we are interested in the possibilities of the so-called lens fragments, especially as the authors failed to demonstrate an association between nuclear density and retrocapsular fragments. If the postulation of phacoemulsification-induced lens fragments is true, one might expect that the harder the lens, the easier it would be for the fragments to project through the zonules.
We wonder whether the lens fragments, which appear as multiple uniform, crystalloid, multifaceted silvery particulates in the figure, might be reminiscent of metallic fragments after phacoemulsification. In fact, various groups of researchers have indicated the presence of metallic foreign bodies after uneventful phacoemulsification; these are titanium fragments from the phaco tip coating.2–5 This is surprisingly common; in a prospective study of 56 patients, the incidence was 86%.5 Wear and tear due to cavitation erosion and ultrasonic vibration, especially during prolonged use of a phacoemulsifier, have been proposed as the mechanism for metallic particles shedding from the phaco tip.2–5 These mechanistic explanations are in accord with the data from Ang and coauthors that only effective phaco time showed a statistically significant association with the presence of retrocapsular fragments.
Another explanation of the lens fragments might be preexisting vitreous opacities. These can be the result of degenerative processes in the vitreous, which are particularly common in the elderly and become more prominent only on examination after the lens opacity is removed.
Until we have further cytological proof, we question the authors' conclusion that a high incidence of retrocapsular lens fragments occurs after uneventful phacoemulsification.
David T.L. Liu MRCS
Paul C.L. Choi FRCPA
Wai-Man Chan FRCP, FRCS
Dennis S.C. Lam MD, FRCOphth
Hong Kong, China
1. Ang A, Menezo i Rallo V, Shepstone L, Burton RL. Retrocapsular lens fragments after uneventful phacoemulsification cataract surgery. J Cataract Refract Surg 2004; 30:849-853
2. Kőse S, Mentes J, Űretmen O, et al. The nature and origin of intraocular metallic foreign bodies appearing after phacoemulsification. Ophthalmologica 2003; 217:212-214
3. Davis PL, Mastel D. Anterior chamber metal fragments after phacoemulsification surgery. J Cataract Refract Surg 1998; 24:810-813
4. Martínez-Toldos JJ, Elvira JC, Hueso JR, et al. Metallic fragment deposits during phacoemulsification. J Cataract Refract Surg 1998; 24:1256-1260
5. Dunbar CM, Goble RR, Gregory DW, Church WC. Intraocular deposition of metallic fragments during phacoemulsification: possible causes and effects. Eye 1995; 9:434-436