Georg Hanselmayer

Astigmatism correction with a foldable toric intraocular lens in cataract patients.

PURPOSE To determine the efficacy and rotational stability of a toric posterior chamber silicone intraocular lens (IOL) to correct preoperative astigmatism in cataract patients. SETTING Department of Ophthalmology, University Hospital of Vienna, Vienna Austria. METHODS Between 1993 and 1998, foldable toric single-piece plate-haptic silicone IOLs were implanted in 37 eyes (30 patients). The cylindrical IOL power was 2.00 diopters (D) (n = 29), 3.50 D (n = 7), or 4.00 D (n = 1). Phacoemulsification was performed through a scleral or a corneal sutureless self-sealing incision. Outcomes of Snellen visual acuity (without, with spherical, and with best correction), refractive and keratometric astigmatism, and IOL rotation after early postoperative (mean 15.9 days +/- 10.1 [SD]) and long-term (mean 20.3 +/- 16.6 months) follow-ups were evaluated. RESULTS At last follow-up, 31 eyes (83.8%) had a spherically corrected and 34 (91.9%) a best corrected visual acuity of 0.5 (20/40) or better. Mean preoperative refractive and keratometric astigmatism was 2.68 and 2.70 D, respectively. At the last postoperative follow-up, mean refractive astigmatism was reduced to 0.84 D; keratometric astigmatism was 2.30 D. In 7 eyes (18.9%), the IOL axis was rotated a maximum of 25 degrees. In all 37 eyes, the axis of the toric IOL remained within 30 degrees of rotation. CONCLUSIONS Early postoperative and long-term follow-ups showed effective and stable correction of astigmatism after implantation of a foldable toric posterior chamber silicone IOL.

Halo size under distance and near conditions in refractive multifocal intraocular lenses

AIMS To calculate the diameter of halos perceived by patients with multifocal intraocular lenses (IOLs) and to stimulate halos in patients with refractive multifocal IOLs in a clinical experiment. METHODS Calculations were done to show the diameter of halos in the case of the bifocal intraocular lens. 24 patients with a refractive multifocal IOLs and five patients with a monofocal IOL were asked about their subjective observation of halos and were included in a clinical experiment using a computer program (Glare & Halo, FW Fitzke and C Lohmann, Tomey AG) which simulates a light source of 0.15 square degrees (sq deg) in order to stimulate and measure halos. Halo testing took place monoculary, under mesopic conditions through the distance and the near focus of the multifocal lens and through the focus of the monofocal lens. RESULTS The halo diameter depends on the pupil diameter, the refractive power of the cornea, and distance focus of the multifocal IOL as well as the additional lens power for the near focus. 23 out of 24 patients with a refractive multifocal IOL described halos at night when looking at a bright light source. Only one patient was disturbed by the appearance of halos. Under test conditions, halos were detected in all patients with a refractive multifocal IOL. The halo area testing through the distance focus was 1.05 sq deg ± 0.41, through the near focus 1.07 sq deg ± 0.49 and in the monofocal lens 0.26 sq deg ± 0.13. CONCLUSIONS Under high contrast conditions halos can be stimulated in all patients with multifocal intraocular lenses. The halo size using the distance or the near focus is identical.

Outcome after treatment of ametropia with implantable contact lenses

OBJECTIVE To evaluate long-term results after insertion of implantable contact lenses (ICLs) in phakic eyes. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Seventy-five phakic eyes (65 myopic, 10 hyperopic eyes) of 45 patients aged 21.7 to 60.6 years were included. INTERVENTION STAAR Collamer Implantable Contact Lenses (STAAR Surgical Inc., Nidau, Switzerland) were implanted for correction of high myopia and hyperopia. MAIN OUTCOME MEASURES Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and intraocular pressure (IOP) were determined. Presence of lens opacification and the distance between the ICL and the crystalline lens were assessed by slit-lamp examination before surgery and at 1, 3, 6 months, and yearly after lens implantation. RESULTS Preoperative mean spherical equivalent was -16.23+/-5.29 diopters (D) for myopic eyes and +7.88 +/-1.46 D for hyperopic eyes. After ICL implantation, mean residual refractive error was -1.77+/-2.17 D in myopic patients and +0.44+/-0.69 D in hyperopic patients. Preoperative mean UCVA was Snellen 0.03+/-0.03 for myopic patients and Snellen 0.12+/-0.16 for hyperopic patients. Preoperative mean BCVA was Snellen 0.49+/-0.23 for myopic patients and Snellen 0.82+/-0.23 for hyperopic patients. After ICL implantation, mean UCVA up to the end of individual observation time was Snellen 0.36+/-0.36 for myopic patients and Snellen 0.58+/-0.28 for hyperopic patients. Mean BCVA was Snellen 0.73+/-0.26 for myopic and Snellen 0.80+/-0.24 for hyperopic patients. Mean preoperative IOP was 14.2+/-2.7 mmHg, and mean postoperative IOP was 13.46+/-2.1 mmHg over all follow-up investigations. The main complication was the development of subcapsular anterior opacifications of the crystalline lens in 25 eyes (33.3%), 2 of which showed direct contact to the ICL. Eleven eyes (14.7%) were stable in opacification and 14 eyes (18.7%) had progressive opacifications. The median time to opacification was 27.1 months. In 8 patients (10.7%), the subjective visual impairment mandated cataract surgery. CONCLUSIONS The most significant long-term complication after ICL implantation is the formation of opacifications of the crystalline lens with the risk of the necessity of subsequent cataract surgery (10.7%). Old age, female gender, and contralateral opacification are independent significant risk factors for early formation of opacifications in this patient group.

Long-term endothelial changes in phakic eyes with posterior chamber intraocular lenses

Purpose: To evaluate the long‐term endothelial cell changes in phakic eyes after implantation of a posterior chamber phakic intraocular lens to correct high ametropia. Setting: Department of Ophthalmology, University Hospital of Vienna, Vienna, Austria. Methods: Thirty‐four eyes of 21 patients having implantation of an implantable contact lens (ICL, Staar Surgical) for high myopia or hyperopia were prospectively examined. The minimum follow‐up was 2 to 4 years. Preoperative and serial postoperative specular microscopy (Noncon Robo SP 8000, Konan) was performed to evaluate the long‐term endothelial cell changes. Results: The mean preoperative endothelial cell density was 2854 cells/mm2. The mean endothelial cell loss from preoperatively was 1.8% at 3 months, 4.2% at 6 months, 5.5% at 12 months, 7.9% at 2 years (n = 34), 12.9% at 3 years (n = 13), and 12.3% at 4 years (n = 11). All other endothelial cell characteristics remained stable during the 4‐year follow‐up. Conclusions: Continuous endothelial cell loss was observed after ICL implantation during a 4‐year follow‐up. There was rapid cell loss until 1 year postoperatively, after which the rate of loss was no longer statistically significant. The percentage of hexagonal cells (polymorphism) and the coefficient of variation (polymegethism) remained stable during the 4‐year follow‐up.

Glare and halo phenomena after laser in situ keratomileusis

Purpose: To simulate and measure subjectively observed glare and halos after laser in situ keratomileusis (LASIK). Setting: University of Vienna, Medical School, Department of Ophthalmology, Vienna, Austria. Methods: In 16 eyes of 10 patients, the best corrected visual acuity (BCVA) and subjectively observed glare and halo size under mesopic conditions were measured before LASIK and 1, 3, and 6 months postoperatively. Infrared pupillography was used to ensure that all patients had a larger ablation zone than the measured pupil size under mesopic conditions. Results: Preoperatively, the mean Snellen BCVA was 0.88 ± 0.17 (SD) and the mean glare and halo size was 1.97 ± 1.20 square degrees (sqd) before the treatment. One month after LASIK, the BCVA was 0.83 ± 0.29 and the mean glare and halo size, 2.61 ± 3.14 sqd. Three months after LASIK, the mean values were 0.90 ± 0.26 and 1.88 ± 2.37 sqd, respectively. Six months after LASIK treatment, they were 0.85 ± 0.28 and 1.30 ± 1.63 sqd, respectively. The 95% confidence interval for the difference between preoperative glare and halo and glare and halo at 6 months was −1.56 to + 0.51 sqd. Conclusion: Subjectively observed glare and halo size after LASIK reached a peak after 1 month and decreased in the following postoperative period.

Three-year clinical outcome after penetrating keratoplasty for keratoconus with the guided trephine system

PURPOSE To determine the long-term clinical outcome after keratoplasty with the guided trephine system in keratoconus eyes. METHODS In a prospective study, all consecutive cases of penetrating keratoplasty had trephination performed with the guided trephine system, with which both donor and recipient cornea are trephined from the epithelial side with a same-sized blade. For wound closure, a double running antitorque suture technique with 10-0 nylon was used. Uncorrected and best-corrected Snellen visual acuity, subjective refraction, and astigmatism by keratometry were evaluated after final suture removal, 2 and 3 years postoperatively. RESULTS In the 31 patients (31 eyes) enrolled, mean best-corrected visual acuity improved from 0.72 +/- 0.16 (20/30) after final suture removal to 0.88 +/- 0.15 (20/25) 3 years postoperatively (P < .001). The mean spherical equivalent increased from -0.86 +/- 2.10 diopters after final suture removal to -2.35 +/- 2.65 diopters 3 years postoperatively (P < .001). Mean keratometric astigmatism decreased from 4.68 +/- 1.76 diopters after final suture removal to 3.57 +/- 1.37 diopters 3 years postoperatively (P = .001). Furthermore, an increase in mean keratometric levels with time (P = .01) was observed and associated with myopic shift (r(s) = -.46, P = .008). CONCLUSION With the guided trephine system, we attained favorable visual results, with prolonged improvement of visual acuity during the entire follow-up period. Our data show low and decreasing degrees of corneal astigmatism over time. During the follow-up period, a myopic shift was found after final suture removal. Nevertheless, this technique of performing same-sized grafts reduces postoperative residual myopia.

Effect of tenascin and fibronectin on the migration of human corneal fibroblasts

Purpose: To investigate the effect of fibronectin and tenascin on the migration of corneal fibroblasts. Setting: Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria. Methods: Using human corneal fibroblasts, a monolayer migration assay was performed to measure corneal fibroblast movement. The migration on collagen I, fibronectin, and tenascin with and without transforming growth factor (TGF)‐&agr;/fibroblast growth factor (FGF)‐2 stimulation and the effect of soluble tenascin and fibronectin on corneal fibroblast migration on collagen‐I‐coated wells were investigated. Results: The cytokines TGF‐&agr; and FGF‐2 stimulated migrational activity of corneal stromal cells in a dose‐dependent manner, reaching the maximum effect at 100 ng/mL and 10 ng/mL, respectively. The migration of corneal fibroblasts on fibronectin was significantly higher (P < .05) than the migration on collagen I. Transforming growth factor‐&agr; and FGF‐2 increased radial cell displacement independent of the provided matrix composition. Tenascin had a negative effect on corneal fibroblast adhesion/migration in this in vitro model. Conclusion: Fibronectin and tenascin influenced corneal fibroblast migration and adhesion, respectively, and may play a role in stromal cell movement during wound healing. The cytokines TGF‐&agr; and FGF‐2 had an additive effect on corneal fibroblast migration on a fibronectin matrix.

Comparison of visual acuities at different distances and defocus curves

Purpose: To evaluate how visual acuities at different distances correlate with results from defocus curves. Setting: Department of Ophthalmology and Institute of Medical Physics, University of Vienna, Medical School, Vienna, and Department of Ophthalmology, Krankenhaus St. Pölten, St. Pölten, Austria. Methods: This study comprised 15 eyes of 14 patients with a mean age of 67.9 years ± 9.7 (SD) with a monofocal silicone intraocular lens (911A, Pharmacia). The best corrected distance visual acuity was determined at viewing distances of 6 m, 2 m, 1 m, 67 cm, 50 cm, 40 cm, and 33 cm using logMAR charts. Defocus curves were then evaluated from −3.0 to −0.5 diopter (D) at 0.5 D increments from the best distance correction at a viewing distance of 6 m. Results: The mean distance visual acuity was logMAR 0.08 ± 0.07. The visual acuity graph from the testing at different distances was above the defocus graph at all testing points. Comparison of the visual acuity results from the 2 tests revealed statistically significant differences in the range from 2 m (–0.5 D) to 33 cm (–3.0 D). Conclusion: Results of defocus curves disregard the diminutions of minus glasses, the normally restricted viewing distance to 6 m for distance acuity determination, and in particular the physiological miosis caused by the near‐point reaction.

Tritan colour contrast sensitivity function in refractive multifocal intraocular lenses

AIMS To compare tritan colour contrast sensitivity (CCS), without and with glare, in patients with refractive multifocal intraocular lenses (IOLs) and with monofocal intraocular lenses. METHODS Tritan CCS was determined (Moorfields Vision System, CH Electronics) in 15 eyes (14 patients, 75.7 (±6.6) years) with a refractive multifocal IOL (Allergan SA 40N) and in 11 eyes (10 patients, 73.7 (±6.4) years) with a monofocal IOL (Allergan SI 40 NB). Measurements were made monocularly under mesopic conditions at a distance of 2 metres from the monitor with best distance refraction plus 0.5 D at 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd). The test was then repeated for the multifocal IOLs, adding minus 2.5 D to the best distance refraction to force the patient to use the near focus. Both lenses were also investigated under glare conditions with the same set-up and using the brightness acuity tester (BAT). RESULTS The tritan CCS function without glare in multifocal lenses through the distance focus was nearly identical to that through the near focus. The following statistically significant differences were measured: the CCS function without glare for the multifocal lens was worse at 0.5 cpd and 1.0 cpd than that of the monofocal lens. In CCS testing of the multifocal group with glare at 6 cpd, the results through the distance focus were better than the results through the near focus. For the CCS function with glare, the values for the distance focus in the multifocal lens were worse than the values for the monofocal lens at 0.5 cpd and 1 cpd. In CCS testing with glare through the near focus and CCS testing through the monofocal lens, the monofocal lens performed better at 0.5 cpd, 1 cpd, 3 cpd, and 6 cpd. CONCLUSION Refractive multifocal intraocular lenses influence tritan CCS function compared to monofocal lenses.

Changes of axial length and keratometry after keratoplasty for keratoconus using the guided trephine system

PURPOSE The purpose of this study was to examine the cause of increasing myopia after penetrating keratoplasty for keratoconus with the guided trephine system. DESIGN Prospective interventional study cohort. METHODS Thirty eyes (28 patients) after keratoplasty for keratoconus were examined. Preoperatively and 1, 3, 6, 12, and 24 months postoperatively subjective refraction was evaluated. Keratometry was calculated with a computerized videokeratoscope (TMS-1). Axial length was measured using applanation ultrasonography before surgery and 2 years after surgery. Anterior chamber depth, lens thickness, and vitreous length were taken into consideration. RESULTS The mean spherical equivalent was + 2.22 +/- 3.47 diopters 1 month postoperatively and had a continuous myopic shift to -1.02 +/- 2.65 diopters 2 years postoperatively. This was associated with a significant increase in mean keratometric levels from + 41.72 +/- 2.96 diopters 1 month postoperatively to + 43.77 +/- 2.29 diopters 2 years postoperatively (r(s) = -0.36, P =.05). Overall, no significant changes in axial length were observed. However, vitreous length showed a small but statistically significant increase. As expected, mean anterior chamber depth decreased significantly postoperatively (P </=.05). In eyes with a decrease in keratometric values (n = 8) a myopic shift was also observed. In this group a significant elongation of the axial length and the vitreous length was found. CONCLUSIONS A study of eyes after keratoplasty for keratoconus demonstrated continuous myopic shift over time. Increasing myopia was associated with increasing keratometric values. Thus, the major cause of increasing myopia after keratoplasty in keratoconus eyes seems to be continuing keratectasia. However, ongoing bulbus growth may contribute to continuing myopia in some eyes.