Il-Joo Limberger

Influence of 360-degree enhanced optic edge design of a hydrophilic acrylic intraocular lens on posterior capsule opacification

PURPOSE: To compare the rate of posterior capsule opacification (PCO) with the single‐piece hydrophilic acrylic foldable Rayner Centerflex 570H intraocular lens (IOL), which has a sharp optic edge design excluding the optic–haptic junction, and the Rayner C‐flex 570C IOL, which has an improved 360‐degree sharp edge. SETTING: Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. METHODS: As part of a multicenter U.S. Food and Drug Administration (FDA) study, 42 patients who had implantation of a C‐flex IOL in 1 eye after uneventful phacoemulsification were enrolled. Six and 12 months postoperatively, PCO was evaluated by retroillumination photographs using Evaluation of Posterior Capsule Opacification (EPCO) 2000 image‐analysis software. The data were then compared with those in a matched group of patients with a Centerflex IOL who participated in a previous FDA study. RESULTS: The mean age of the patients with the C‐flex IOL was 71.5 years ± 8.2 (SD) There was a statistically significant difference in EPCO scores between the C‐flex group and Centerflex group. Six months after surgery, the mean EPCO value (total IOL optic) was 0.07 ± 0.17 in the C‐flex group (n = 37) and 0.20 ± 0.20 in the Centerflex group (n = 36) (P<.01, Wilcoxon test). By 12 months, the mean had increased to 0.16 ± 0.20 in the C‐flex group (n = 37) and 0.35 ± 0.22 in the Centerflex group (n = 31) (P<.01, Wilcoxon test). CONCLUSIONS: The C‐flex IOLs showed good functional results and significantly lower PCO formation than the earlier model Centerflex IOL. The enhanced edge of the C‐flex IOL seemed to improve PCO prevention clinically.

Long‐term results of sealed capsule irrigation using distilled water to prevent posterior capsule opacification: a prospective clinical randomised trial

Background: We investigated long-term safety and efficacy of sealed capsule irrigation (SCI) during cataract surgery to prevent posterior capsule opacification (PCO). Methods: One eye of each of 17 patients (mean age: 70.1±9.7 years) who presented with bilateral cataracts was randomly chosen for SCI treatment. After phacoemulsification, the capsular bag was vacuum sealed with the PerfectCapsule device (Milvella) followed by SCI using distilled water for two minutes. No vacuum loss occurred during irrigation. Each patient’s fellow eye served as a control. One hydrophilic acrylic intraocular lens model was implanted in all eyes. Five patients had to be excluded due to deep anterior chamber, small pupil or unilateral surgery. Follow-up examinations took place one day and one, three, six, 12 and 24 months after surgery. We evaluated safety parameters, anterior capsule (AC) overlapping and PCO. Results: Postoperatively, mean best corrected visual acuity, pachymetry, endothelial cell count, intraocular pressure, AC overlapping and PCO showed no statistically significant difference between SCI and the control group (p>0.05, Wilcoxon test). Conclusion: SCI is a safe procedure and enables the specific pharmacological targeting of lens epithelial cells inside the capsular bag. Using distilled water, however, it is not possible to reduce PCO development significantly. Thus, alternative substances should be evaluated.

Impact of axis misalignment of toric intraocular lenses on refractive outcomes after cataract surgery

PURPOSE: To theoretically and clinically evaluate the impact of axis misalignment of toric intraocular lenses (IOLs) on postoperative refraction. SETTING: International Vision Correction Research Center, University of Heidelberg, Heidelberg, Germany. DESIGN: Case series. METHODS: A method based on mathematical solutions to obliquely crossed spherocylinders was derived according to the pseudophakic refractive properties and used to analyze the impact of toric IOL misalignment on postoperative refraction. The refractive outcomes were theoretically analyzed and actual postoperative outcomes assessed to confirm the theoretically identified impact. RESULTS: The mean IOL misalignment was 12.5 degrees ± 6.7 (SD). Three main factors had an impact on refractive outcomes: hyperopic change in refractive sphere, reduction in astigmatic correction, and rotation of the astigmatic axis. The mean calculated spherical change was 0.32 ± 0.23 diopters (D) and the actual change, 0.36 ± 0.71 D. The mean calculated reduction in astigmatic correction was 0.65 ± 0.45 D and the actual reduction, 0.95 ± 0.54 D, indicating undercorrection of preexisting astigmatism. The mean calculated absolute astigmatic rotation was 32.7 ± 13.2 degrees (range 8 to 55 degrees) and the actual rotation, 29.1 ± 17.4 degrees. There was a correlation between the calculated and actual reduction (r2 = 0.51; P = .001) and between the calculated and actual rotation (r2 = 0.86; P<.001). CONCLUSION: In addition to a reduction in astigmatic correction, misalignment of toric IOLs induced hyperopic spherical change and astigmatic rotation. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Comparison of ray-tracing method and thin-lens formula in intraocular lens power calculations

PURPOSE: To compare the accuracy of the thin‐lens and ray‐tracing methods in intraocular lens (IOL) power calculations in normal eyes and eyes after corneal refractive surgery. SETTING: International Vision Correction Research Centre, University of Heidelberg, Heidelberg, Germany. METHODS: Pseudophakic eye models were constructed using Zemax optical software, importing corneal radii (normal ray tracing) and corneal surface elevation data (individual ray tracing) measured by Pentacam Scheimpflug photography. Algorithms to predict IOL position (effective lens position [ELP]) or postoperative anterior chamber depth [ACDpost]) (Haigis, Hoffer Q, Norrby, Olsen 2) were used in the thin‐lens and ray‐tracing methods. Intraocular lens power was calculated in 25 eyes after corneal refractive surgery using normal and double‐K modified thin‐lens and ray‐tracing methods. RESULTS: Back‐calculation of ELP and ACDpost were well correlated. Using algorithms of Haigis, Hoffer Q, Norrby, and Olsen 2 to predict IOL position, mean absolute prediction errors (MAEs) of the thin‐lens formula were 0.64 diopters (D) ± 0.52 (SD), 0.57 ± 0.46 D, 0.59 ± 0.42 D, and 0.61 ± 0.47 D, respectively; MAEs of normal ray‐tracing method were 0.64 ± 0.50 D, 0.58 ± 0.44 D, 0.59 ± 0.41 D, and 0.62 ± 0.45 D, respectively; MAEs of individual ray‐tracing method were 0.66 ± 0.52 D, 0.59 ± 0.45 D, 0.59 ± 0.43 D, and 0.62 ± 0.50 D, respectively. No statistical differences were found between the thin‐lens and ray‐tracing methods. CONCLUSION: Theoretical thin‐lens formulas were as accurate as the ray‐tracing method in IOL power calculations in normal eyes and eyes after refractive surgery.

Intraocular lens power calculation after laser refractive surgery: Corrective algorithm for corneal power estimation

PURPOSE: To evaluate an algorithm for corneal power estimation in intraocular lens (IOL) power calculation after myopic laser refractive surgery using direct corneal measurements. SETTING: International Vision Correction Research Centre, University of Heidelberg, Heidelberg, Germany. METHODS: Corneal parameters in normal eyes and eyes of refractive surgery cases were evaluated by rotating Scheimpflug imaging. Corneal optical power (Koptical) calculated by a Gaussian optics formula was simplified as Koptical = Kanterior + K2 (Kanterior = anterior corneal power; Kposterior = posterior corneal power; K2 = Kposterior − Kanterior × Kposterior × corneal thickness/1.376). The variation and change in K2 induced by refractive surgery were analyzed. A corrective algorithm to calculate Koptical using mean K2 (−6.10 diopters [D]), Kcorrective = 1.114 × measured K − 6.10, was derived based on statistical analysis, which was in accordance with the modified Maloney method. The IOL power after refractive surgery was calculated using Kcorrective. RESULTS: The mean K2 of normal and post‐refractive corneas was −6.10 ± 0.23 D and −6.16 ± 0.17 D, respectively (P = .17). The mean refractive surgery–induced change in K2 was −0.06 ± 0.10 D. The variations in K2 were small (95% confident interval, −6.55 to −5.65 [normal cornea]; −6.48 to −5.70 [pre‐refractive]; − 6.49 to −5.83 [post‐refractive)]. Using Kcorrective for IOL power calculation in post‐refractive cases yielded mean absolute prediction errors of 0.58 ± 0.52 D (Haigis), 0.59 ± 0.49 D (double‐K Hoffer Q), and 0.58 ± 0.47 D (double‐K SRK/T). CONCLUSION: The algorithm that induced low error in corneal power estimation was relatively reliable in IOL calculation after myopic laser refractive surgery. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Pseudophakic eye with obliquely crossed piggyback toric intraocular lenses.

A 72-year-old man presented with high astigmatism (2.25 -5.0 x 45) induced by long-term rotation of a toric intraocular lens (IOL). Corneal astigmatism was 3.78 diopters (D). The corrected distance visual acuity (CDVA) was 20/32. Because of the risk of repositioning, a secondary toric IOL of -3.0/6.0 D especially designed for sulcus implantation was piggybacked through 3.5 mm sutureless clear-corneal incision with a cylindrical axis obliquely crossed with that of the primary IOL. Eight months postoperatively, the corneal astigmatism was 5.04 D. The CDVA was 20/25 with a refraction of 1.0 -2.5 x 70. No interlenticular opacification or significant rotation or decentration of the secondary toric IOL was observed. The refractive properties of this pseudophakic eye were analyzed using a mathematical approach. The calculated postoperative refraction was 0.84 -1.7 x 47. A piggyback toric IOL can be implanted in an obliquely crossed style that allows a secondary toric IOL to correct astigmatism induced by long-term toric IOL rotation.

Transscleral fixation of a toric intraocular lens to correct aphakic keratoplasty with high astigmatism

A 71-year-old man with penetrating keratoplasty (PKP) and aphakia in the right eye and a preoperative refraction of +20.0 -11.0 x 38 and logMAR visual acuity of 20/60 presented to our hospital. The capsular support was absent because of previous complicated intracapsular cataract extraction. The implanted IOL was a custom-made Rayner 570T with +20.5 diopters (D) sphere and +11.0 D cylinder. The IOLs special haptics allowed it to be safely fixated in the sagittal plane. The postoperative refraction was +1.0 -2.0 x 5 with logMAR acuity of 20/60. Follow-up of 2 years revealed no IOL decentration. Transscleral fixation of a toric IOL requires exact outlining. Our case shows that this is possible and can result in improved visual rehabilitation.

Corneal endothelial cell coating during phacoemulsification using a new dispersive hyaluronic acid ophthalmic viscosurgical device

Purpose To compare the corneal endothelial coating of a new hyaluronic acid ophthalmic viscosurgical device (OVD) with dispersive properties with that of a standard hyaluronic acid OVD with cohesive properties. Setting David J. Apple International Laboratory for Ocular Pathology, Department of Ophthalmology, University of Heidelberg, Germany. Design Experimental study. Methods The corneal endothelial cell coating of a new dispersive OVD (sodium hyaluronate 3% [Healon Endocoat]) and a standard cohesive hyaluronic acid OVD (sodium hyaluronate 1.4% [Healon GV]) as well as their combination using the soft‐shell technique were evaluated. All OVDs were stained with fluorescein. Each of the 3 test groups comprised 10 porcine eyes. Cataract surgery was performed with identical phacoemulsification settings and time frames. Afterward, the cornea was trephined and a photograph taken of the endothelial side under blue light. The corneal coating with OVD was evaluated using planimetric image‐analysis software. Results The least endothelial coating was in the cohesive group (71%), while the dispersive group had statistically significantly higher adherence to the endothelium (87%) (P=.0009). The greatest endothelial coating was in the soft‐shell technique group (93%); however, the difference between that group and the dispersive group was not statistically significant (P=.0962). Conclusion The new dispersive hyaluronic acid OVD with a low molecular weight showed a greater adherence to the endothelial surface than the standard cohesive hyaluronic acid OVD with a higher molecular weight. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Quantitative evaluation of acrylic and silicone intraocular lenses with a sharp optic edge design

BACKGROUND At the Department of Ophthalmology, Heidelberg, Germany, posterior capsule opacification (PCO) of a silicone and an acrylic intraocular lens (IOL) with a sharp optic edge design was evaluated. PATIENTS AND METHODS In a prospective study either the AMO ClariFlex silicone IOL or the Sensar AR40e hydrophobic acrylic IOL were implanted in 47 patients following uneventful phacoemulsification. Mean patient age was 76.2+/-7.8 (ClariFlex) and 73.4+/-12.9 years (AR40e), respectively. The mean follow-up time was 19.7+/-5.34 in the ClariFlex and 21.9+/-1.89 months in the AR40e group. PCO development was evaluated postoperatively using the EPCO 2000 analysis software (scale 0-4). Areas of interest were the total IOL optic, the central 3-mm zone as well as the capsulorhexis. RESULTS In both groups, all patients achieved a BCVA of 20/32 (AR40e) and 20/25 (ClariFlex), respectively. There was a very low incidence of PCO development with a mean EPCO score of 0.07+/-0.2 (ClariFlex and 0.15+/-0.2 (AR40e). Within the 3-mm zone and the capsulorhexis, there was a tendency for even lower EPCO scores in both groups. We calculated a statistically significant difference for the two lens materials for all investigated IOL areas (Wilcoxons test, p<0.05). CONCLUSION Both IOLs with a sharp edge design showed good functional results, a stable position in the capsular bag as well as a low incidence of PCO development. However, the silicone IOL showed statistically significantly lower PCO scores.

Quantitative Nachstarevaluierung von Acrylat- und Silikonintraokularlinsen mit scharfem Kantendesign

BACKGROUND At the Department of Ophthalmology, Heidelberg, Germany, posterior capsule opacification (PCO) of a silicone and an acrylic intraocular lens (IOL) with a sharp optic edge design was evaluated. PATIENTS AND METHODS In a prospective study either the AMO ClariFlex silicone IOL or the Sensar AR40e hydrophobic acrylic IOL were implanted in 47 patients following uneventful phacoemulsification. Mean patient age was 76.2+/-7.8 (ClariFlex) and 73.4+/-12.9 years (AR40e), respectively. The mean follow-up time was 19.7+/-5.34 in the ClariFlex and 21.9+/-1.89 months in the AR40e group. PCO development was evaluated postoperatively using the EPCO 2000 analysis software (scale 0-4). Areas of interest were the total IOL optic, the central 3-mm zone as well as the capsulorhexis. RESULTS In both groups, all patients achieved a BCVA of 20/32 (AR40e) and 20/25 (ClariFlex), respectively. There was a very low incidence of PCO development with a mean EPCO score of 0.07+/-0.2 (ClariFlex and 0.15+/-0.2 (AR40e). Within the 3-mm zone and the capsulorhexis, there was a tendency for even lower EPCO scores in both groups. We calculated a statistically significant difference for the two lens materials for all investigated IOL areas (Wilcoxons test, p<0.05). CONCLUSION Both IOLs with a sharp edge design showed good functional results, a stable position in the capsular bag as well as a low incidence of PCO development. However, the silicone IOL showed statistically significantly lower PCO scores.