Stefan Pieh

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.

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.

Gonioscopic changes after implantation of a posterior chamber lens in phakic myopic eyes

Purpose: To evaluate the effects of posterior chamber implantation of phakic intraocular lenses on angle structures and the correlation with intraocular pressure (IOP). Setting: Department of Ophthalmology, University Hospital of Vienna, Vienna, Austria. Methods: A Staar implantable contact lens (ICL) was implanted in 20 white patients (34 eyes) with high myopia. The patients were followed for a mean of 2.3 years (range 0.8 to 6.0 years). Two subgroups were created: One had a follow‐up of 2.4 to 6.0 years and the other, 0.8 to 2.3 years. The mean spherical power of the implanted ICL was −16.8 diopters (D) (range −9.0 to −21.0 D). The angle structures were examined by gonioscopy using the Spaeth technique, and optical pachymetry and IOP were measured in dilated and undilated pupils. Trabecular pigmentation was measured semiquantitatively. The ICL models included a few prototypes (6 eyes), the V2 model (10 eyes), the V3 model (6 eyes), and the V4 model (12 eyes). Results: The anterior chamber angle was between 11 and 20 degrees in 41% of eyes, between 21 and 30 degrees in 21%, larger than 30 degrees in 21%, and 10 degrees or smaller in 17%. An apparent iris root insertion was above Schwalbes line in 6% of eyes, behind Schwalbes line in 12%, at the scleral spur in 67%, and in a deep angle recess behind the scleral spur in 15%. The curvature of the iris was regular in 19 eyes and steep in 15 eyes. The mean pigmentation in all 4 quadrants was 1.3. (Grade 1 was defined as trace pigmentation.) The mean pachymetry from the endothelium to the ICL anterior surface was 2.7 mm and from the endothelium to the anterior surface of the crystalline lens, 3.2 mm. The mean IOP was 14.1 mm Hg in undilated pupils and 12.1 mm Hg in dilated pupils. There was no correlation between angle pigmentation and IOP. Conclusion: Trace pigmentation in the trabecular meshwork was common after ICL implantation. However, there was no direct influence on IOP. Long‐term follow‐up is necessary to evaluate the effect and progress of trabecular pigmentation in eyes with an ICL.

Comparison of pseudoaccommodation and visual quality between a diffractive and refractive multifocal intraocular lens

Purpose: To determine depth of focus and visual quality after implantation of a diffractive intraocular lens (IOL) and a refractive IOL. Setting: University Eye Clinic, Vienna, Austria. Method: This study comprised 10 eyes of 9 patients with a diffractive IOL (3M 825x +4) and 13 eyes of 9 patients with a refractive lens (AMO Array SSM 26NB). Depth of focus was evaluated in a defocused range of −6.0 to +3.0 diopters (D), and Snellen visual acuity was recorded. Results: Distance acuity peaked at 1.0 ± 0.2 (3M group) and 0.91 ± 0.13 (AMO group). The near acuity peaks were at 0.82 ± 0.15 and 0.55 ± 0.14, respectively. Visual acuity of 0.5 was possible in a range of defocus of +1.0 to −4.0 D (3M) and +1.0 to −3.5 D (AMO). Conclusion: Pseudoaccommodation and full distance visual acuity were realized with both types of multifocal lenses. For intermediate distances, visual acuity may be limited to activities that do not require optimal vision. At near distances, the 3M lens provided statistically significantly better visual acuity.

Upregulation of αvβ6 integrin, a potent TGF-β1 activator, and posterior capsule opacification

Purpose: To identify the predominant activation pathway of transforming growth factor (TGF)‐β1 in the lens capsule, studying the spatial and temporal expression pattern of αvβ6 and thrombospondin‐1. Other PCO‐related proteins were also studied. Setting: Departments of Ophthalmology and Optometrics and Clinical Pathology, Medical School, University of Vienna, Vienna, Austria. Methods: The lens capsules of 12 human donor eyes were cultivated in a protein‐free medium for up to 28 days (cultivated lens capsules [CLCs]) after lens extraction. Ten intact lenses (ILs) served as the control group and were also cultured. During the culture period, cell dynamics were observed by phase‐contrast microscopy. Proteins were detected by double immunofluorescence on frozen sections. Results: In ILs, αvβ6 was absent but 91.6% of the CLCs showed extensive staining. Remnant lens epithelial cells (LECs) expressed αvβ6 immediately after lens extraction. The αvβ6 was detected throughout the culture period in all regions of the capsule. Thrombospondin‐1 was absent in ILs and CLCs, suggesting that this protein is not significant in TGF‐β1 activation in the lens. Transforming growth factor‐β1 was abundantly expressed in all ILs and CLCs, slightly decreasing during intensive LEC proliferation and migration. The TGF‐β receptor II (RII) was expressed equally in all specimens, decreasing with culture time. Nonresident extracellular matrix proteins and α‐smooth muscle actin were partially detected in CLCs but not in ILs. Latent TGF‐β binding protein 1 and collagen III were absent in all specimens. All cells found in the cultures expressed vimentin and alphaB‐crystallin (LEC markers). Conclusion: Alphavβ6 is the main activator of TGF‐β1 in the lens capsule and represents a new target for PCO prevention.

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.