Calculations in Gaussian optics should be replaced by state-of-the-art numerical methods, which can be run on any standard personal computer.

A prospective, randomized study compared the surgically induced astigmatism after 3.5 mm, 4.0 mm, and 5.0 mm temporal corneal tunnel incisions over six months. We studied 60 eyes of 60 patients who had phacoemulsification through a two-step clear corneal tunnel incision and implantation of one of three posterior chamber intraocular lenses (IOLs). Patients were divided into three groups of 20 each: Group A, cartridge injection of a foldable plate-haptic silicone IOL through a 3.5 mm self-sealing incision; Group B, cartridge injection of a disc silicone IOL through a 4.0 mm self-sealing incision; Group C, 5.0 mm optic poly(methyl methacrylate) IOL through a 5.0 mm incision with one radial suture. Corneal topography data were obtained using a computerized videokeratographic analysis system preoperatively and one week and six months postoperatively. Vector analysis was performed to calculate the surgically induced astigmatism. After the first postoperative week, mean induced astigmatism was 0.63 diopters (D) (+/- 0.41) in Group A, 0.64 D (+/- 0.35) in Group B, and 0.91 D (+/- 0.77) in Group C. After six months, it was 0.37 D (+/- 0.14) in Group A, 0.56 D (+/- 0.34) in Group B, and 0.70 D (+/- 0.50) in Group C. Surgically induced astigmatism was significantly lower in Group A than in Group B (P < .05) and Group C (P < .005) after six months. Vector analysis demonstrated that temporal corneal tunnel incisions induced clinically minimal astigmatism over six months postoperatively depending on incision size.

Cycloplegia is often necessary to obtain accurate autorefractor results.

Aims-This study investigated the eVect of tissue plasminogen activator (tPA) in patients with severe intracameral fibrin after extracapsular cataract extraction or phacoemulsification with posterior chamber intraocular lens implantation. Methods-A randomised prospective multicentre study was carried out in 86 patients with intraocular fibrin formation 2-8 days after cataract surgery. While the first group (n=41) received only antiinflammatory drugs, a single anterior chamber injection of tPA (10 µg) as an additional treatment to the standard was given in the second group (n=44). On days 1, 2, 14, and 90 after randomisation, the visual acuities, slit lamp findings, and intraocular pressures were documented in standardised protocols. EYcacy of treatment was judged by the rate of fibrinolysis (primary objective), the frequency of synechiae, and central capsular fibrosis (secondary objectives). Results-The incidence and quantity of intraocular fibrin were significantly lower in the patients treated with tPA than in the control group (p<0.05). The frequencies of synechiae were reduced by tPA injection. The capsule fibrosis noted after 3 months was significantly lower in the tPA group (p=0.027). No ocular side eVects were noted after the tPA injections.Conclusions-Lysis of postcataract fibrin formation is accelerated and increased by a single intracameral injection of 10 µg tPA in addition to standard antiinflammatory treatment. The findings suggest that the tPA injection reduces posterior capsule fibrosis, which still has to be addressed in larger study populations and with a long term follow up. (Br J Ophthalmol 1998;82:810-815)