Biometry and refractive outcome of eyes filled with silicone oil by standardized echography and partial coherence interferometry.

BACKGROUND: We evaluated the validity of calculations for refractive outcome in cataract surgery in silicone oil-filled eyes. The retrosilicone space (RSS) was included in these calculations. METHODS: In a prospective study the axial length (AL) of silicone oil-filled eyes was measured. with standardized A-scan echography (SAE) and partial coherence interferometry (PCI). Meldrum's formula was used to transform the velocity of ultrasound within the vitreous cavity. To investigate whether refractive outcome can be calculated accurately, we assessed the difference between precalculated and final refractive outcome. Furthermore, we determined the advantages and disadvantages of SAE and PCI. A minor aim was to assess whether the AL of the two eyes differed significantly. RESULTS: In 85% of 117 eyes the difference between precalculated and postsurgical refraction was smaller than 1 diopter spherical and statistically not significant (p>0.2). The mean AL was 24.1 mm (range 20.0-31.4 mm). The difference in outcome between the two methods was without statistical significance: the AL difference was 0.4 (+/-2.6) mm on measurement with SAE and 0.04 (+/-0.46) mm with PCI. PCI has the advantage that it can be performed more easily, without contact, while echography is advantageous in the presence of advanced cataracts. In supine position an oil-free fluid space behind the silicone oil was detected with echography. The mean dimension of this space was 1.9 (+/-0.67) mm and it was taken into consideration for IOL calculation. The mean AL difference between the two eyes was 0.4 mm, but the difference was greater than 1 mm in 26% of the patients. CONCLUSION: The AL of eyes filled with silicone oil can be measured reliably with SAE and PCI. In supine position the RSS has to be considered to obtain more accurate IOL calculations.

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.

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)-alpha/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-alpha 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-alpha 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-alpha and FGF-2 had an additive effect on corneal fibroblast migration on a fibronectin matrix.

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. CONCLUSIONS: Subjectively observed glare and halo size after LASIK reached a peak after 1 month and decreased in the following postoperative period.

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). CONCLUSIONS: 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.

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

Long-term impairment of the lacrimal glands after radioiodine therapy: a cross-sectional study.

Impairment of the lacrimal glands after external radiation has been well documented, but there are only a few reports on the effects of radioiodine therapy on the lacrimal glands. Long-term effects of high-dose radioiodine therapy on tear secretion have not previously been studied. We investigated 175 eyes of 88 patients with a history of radioiodine therapy for thyroid carcinoma (68 females, 20 males; mean age 55+/-16 years, range 17-81 years) and compared them with a sex- and age-matched control group ( n=39). All patients had been given at least 2.96 GBq iodine-131 (maximal administered activity 22.3 GBq (131)I). An ophthalmological investigation was performed 64+/-71 months (range 3-317 months) after initial radioiodine therapy by a single ophthalmologist. Lacrimal gland function was evaluated with three different function tests. External eye morphology was considered, and detailed ophthalmological history-taking was performed. Patients with factors known to affect lacrimal gland function (contact lenses, autoimmune disorders, history of additional radiation exposure) were excluded from the study. A total of 81 patients (92%) had at least one abnormal function test indicating impaired lacrimal gland function. Schirmer's tear test was decreased (<10 mm/5 min) in 47 of the 88 patients and definitely abnormal (<5 mm/5 min) in 35 patients. A tear film break-up time of <10 s was found in 78 patients, and 62 patients had a definitely abnormal break-up time of <5 s. The lacrimal lipid layer was impaired in 43 patients. The function tests were all significantly altered in the study group as compared with the controls ( P<0.005, P<0.001, P<0.001, respectively). Both subjective symptoms of dry eye ( P<0.01) and changes in the external eye morphology ( P<0.001) were significantly more prevalent in the study group. Our findings suggest that in the majority of patients, lacrimal gland function may be permanently impaired after high-dose radioiodine therapy. All three layers of the tear film are involved and there is a pronounced long-term effect on the tear film stability.

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/mm(2). 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.

Quantitative performance of bifocal and multifocal intraocular lenses in a model eye: point spread function in multifocal intraocular lenses.

OBJECTIVE: To compare the optical properties of bifocal diffractive and multifocal refractive intraocular lenses. METHODS: A model eye with a pupil 4.5 mm in diameter was used to determine the point spread function (PSF) of the distance focus and near focus of a diffractive bifocal intraocular lens (IOL) (model 811E; Pharmacia Inc, Columbus, Ohio) and of a refractive multifocal IOL (model SA40N; Allergan Optical Inc, Irvine, Calif) to compare them with PSFs of foci of corresponding monofocal lenses. For interpreting the PSFs the through focus response, the modulation transfer function, and the Strehl ratio were evaluated. RESULTS: The intensity of the distance focus of the bifocal diffractive lens reached 58.5% and the near focus attained 42.7% of the intensity of a corresponding monofocal lens. The maximal halo intensity surrounding both foci was approximately 4.5%. The distance peak of the refractive multifocal IOL was 73.4% and the near peak 25.1% of a corresponding monofocal lens. The out-of-focus image overlaying the distance focus of the refractive multifocal IOL was approximately 3% of the light intensity of the distance focus, whereas the PSF of the near focus of the multifocal IOL is substantially affected by out-of-focus images. The computed modulation transfer functions show better results for the monofocal lenses, similar results for the tested distance foci, and clear advantages for the bifocal diffractive near focus. CONCLUSIONS: Modulation transfer functions reveal comparable properties for distance vision and a superiority of the bifocal diffractive lens over the refractive multifocal lens for near vision.