Christian Skorpik

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.

Long-term results of implantation of phakic posterior chamber intraocular lenses

Purpose: To study the incidence and progression of lens opacification after implantation of phakic posterior chamber intraocular lenses for myopia and its correlation with vaulting and endothelial cell density (ECD). Setting: Department of Ophthalmology, University of Vienna Medical School, Vienna, Austria. Methods: An implantable contact lens (ICL V4, Staar Surgical Inc.) was inserted in 76 myopic eyes. Patients were prospectively followed preoperatively and at 1, 3, 6, 12, 24, and 36 months. The uncorrected visual acuity and best corrected visual acuity (BCVA) were determined. Vaulting was measured optically with a Jaeger II pachymeter, and the crystalline lens was examined at the slitlamp for the presence and characteristics of opacification. Endothelial cell morphometry was performed by specular microscopy, and the ECD was calculated. Eyes in which lens opacification developed were followed for at least 12 months to determine the degree and course of visual impairment. Results: Lens opacification occurred in 11 eyes (14.5%). Opacification was correlated with intraoperative trauma to the crystalline lens, age older than 50 years, and decreased ECD values throughout the observation period. Vaulting of the ICL did not correlate with the risk for lens opacification. After onset of lens opacification, 6 eyes (55%) had a stable BCVA within ±0.5 lines and 5 eyes had progressive opacification, losing between 3.5 lines and 0.5 lines (mean 1.8 lines ± 1.1 [SD]). Three eyes (3.9%) in the progressive group had a 1‐ to 2‐line loss of BCVA over preoperative values and subsequently had cataract surgery. Conclusions: Risk factors for lens opacification after implantation of the model V4 ICL included intraoperative trauma to the crystalline lens and older age. Decreased ECD in eyes with opacification suggests ongoing inflammation as a cause. Patients younger than 45 years may have a significantly lower incidence of opacification.

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.

Contrast sensitivity and glare disability with diffractive and refractive multifocal intraocular lenses

Purpose: To compare contrast sensitivity and glare disability provided by diffractive and refractive multifocal intraocular lenses (IOLs). Setting: University Eye Clinic Vienna, Austria. Method: This study evaluated the contrast sensitivity and glare disability in 29 eyes with a diffractive multifocal IOL (3M815LE) and 12 with a three‐piece, five‐zone refractive multifocal IOL (AMC Array SSM 26 NB). The Brightness Acuity Tester (Mentor, Inc.) was used with stationary sinusoidal gratings at spatial frequencies of 0.5, 1, 3, 6, 11.4, and 22.8 cycles per degree (cpd) generated on a television monitor (Nicolet CS 2000). Results: The contrast sensitivity functions of both multifocal IOL groups were within the reference range and were identical at 0.5, 1, and 22.8 cpd spatial frequencies. At 3, 6, and 11.4 cpd, the contrast sensitivity function in the diffractive IOL group was 6, 9, and 10% lower than in the refractive IOL group, and the difference between groups was statistically significant at 6 cpd. When glare was present, contrast sensitivity in the diffractive IOL group was generally in the lower limit of the reference range and remained below at 3 and 6 cpd. Contrast sensitivity in the refractive IOL group remained below the reference range at 3 cpd. At 0.5 and 1 cpd, there were no differences between the groups. At the middle and high spatial frequencies (3, 6, 11.4, 22.8 cpd), contrast sensitivity in the diffractive group was 8, 16, 11, and 12% lower than in the refractive group. At 6 cpd, the between‐group difference was statistically significant. Conclusion: Diffractive multifocal IOLs provided decreased contrast sensitivity and greater glare disability than refractive multifocal IOLs.

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.

Comparison of ultrasound pachymetry and partial coherence interferometry in the measurement of central corneal thickness

Purpose: To compare central corneal thickness (CCT) measurements obtained with 3 ultrasound pachymeters and with partial coherence interferometry (PCI) and evaluate the effect of repeated contact by a pachymetry probe on corneal thickness. Setting: Department of Ophthalmology, University of Vienna, Vienna, Austria. Methods: Central corneal thickness was measured in 20 eyes of 20 healthy volunteers with 3 different ultrasound pachymeters (DGH 500, DGH Technology Inc.; SP 2000, Tomey Inc.; Paxis, Biovision Inc.) and with PCI. In each eye, 5 measurements with PCI were followed by 5 measurements with each ultrasound pachymetry device and another 5 measurements with PCI. Results: The mean CCT measured with the DGH 500, SP 2000, and Paxis was 541.0 &mgr;m, 539.2 &mgr;m, and 545.1 &mgr;m, respectively. Although the differences among the 3 ultrasound pachymetry devices were within 6.0 &mgr;m, they were statistically significant (P< .05). The PCI measurements were significantly smaller (P <.05) than the ultrasound measurements: 518.8 &mgr;m before and 517.5 &mgr;m after repeated contact with the ultrasound pachymetry probe (P <.05). The mean precision (standard deviation) was 0.77 &mgr;m for PCI and between 2.40 &mgr;m and 3.58 &mgr;m for ultrasound pachymetry measurements. The correlation coefficients for the intraobserver variability were 0.999 for PCI and between 0.987 and 0.995 for ultrasound pachymetry measurements. Conclusions: Partial coherence interferometry was the more precise method of measuring CCT and had better intraobserver variability. Repeated contact by a pachymetry probe reduced corneal thickness by 1.3 &mgr;m. However, the reason for the smaller measurements with PCI than with ultrasound pachymetry remains unclear.

Long-term course of induced astigmatism after clear corneal incision cataract surgery

Purpose: To determine whether a small clear corneal temporal incision produces less surgically induced astigmatism than a larger incision. Methods: One hundred three consecutive cases of postoperative astigmatism after clear corneal incision cataract surgery were studied for a minimum of 1 year. Only self‐sealing incisions from the temporal side were made as follows: 3.2 mm (Group A); 4.0 mm (Group B); 5.2 mm (Group C). We considered the amount and axes of the keratometric readings at different times as well as their course over time. Induced astigmatism was calculated using three methods. Axial changes were also analyzed. Results: Immediately after the surgery, there was a small, surgically induced, withthe‐rule astigmatic shift in all groups, which in most cases decreased to near preoperative levels with time. One year postoperatively, mean induced astigmatism was 0.09 diopter (D) in Group A, 0.26 D in Group B, and 0.54 D in Group C. Most cases had minimal axial changes. In Group A, 86% had an axial change of fewer than 30 degrees; in Group B, 76%; and in Group C, 73%. Conclusion: The smallest incision group had the least surgically induced astigmatism and axial change. All incision groups remained stable and had satisfactory clinical results.

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.