The Verhoeff capsule forceps: clinical and experimental results.
Lenses were pulled from rabbit and human eyes with a Verhoeff forceps suspended from a pulley. One human lens capsule ruptured with 10 gm and one with 14 gm. Eight human lenses were pulled out intact with 10 to 18 gm. One rabbit lens capsule ruptured with 18 gm and one with 20 gm. Eight rabbit lenses were pulled out intact with 12 to 24 gm. The cryoprobe on the pulley did not rupture any lenses. Thirty grams of counter pressure reduced the pull required to extract rabbit lenses by 50%. Weights were added to a Verhoeff forceps suspended from a rabbit lens supported by a lens loop. One lens was ruptured at 17 gm, and nine lenses were pulled through the loop with 17 to 27 gm. Capsule rupture occurred in 2.4% of 500 consecutive senile immature cataract extractions done with the Verhoeff forceps and counter pressure. Counter pressure did not disturb the vitreous body.
D000368:Aged; D000818:Animals; D002387:Cataract Extraction / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007908:Lens, Crystalline / Q000601:surgery*; D008875:Middle Aged; D011312:Pressure; D011817:Rabbits; D013314:Stress, Mechanical; D013525:Surgical Instruments / Q000592:standards*