Nino Hirnschall

Rotational stability of a single-piece toric acrylic intraocular lens

PURPOSE: To assess the rotational stability of a single‐piece toric hydrophobic acrylic intraocular lens (IOL) during the first 6 postoperative months. SETTING: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. DESIGN: Prospective case series. METHOD: Eyes with age‐related cataract and corneal astigmatism (1.00 to 3.00 D diopter [D]) were measured by partial coherence interferometry (IOLMaster). Preoperatively, the horizontal axis was marked. Surgical technique included a standardized temporal clear corneal incision, phacoemulsification, and in‐the‐bag implantation of a toric IOL (AcrySof SN60TT). Rotational stability of the IOL was assessed using retroillumination photographs postoperatively at 1 hour and at 1 and 6 months. Uncorrected (UDVA) and corrected distance visual acuities, residual refractive error, and keratometric and refractive cylinders were measured. RESULTS: The study enrolled 30 eyes (30 patients). The mean absolute IOL rotation was 2.44 degrees ± 1.84 (SD) at 1 month and 2.66 ± 1.99 degrees at 6 months. The photographic technique had high reproducibility of axis measurement, with consecutive measurements varying by less than 2.0 degrees. The mean UDVA was 0.16 logMAR (range 0.42 to −0.18 logMAR) at 1 month and 0.20 logMAR (range 0.60 to −0.20 logMAR) at 6 months. The residual refractive cylinder by autorefraction was −0.84 D (range −2.00 to 0.00 D) and −0.80 D (range −1.75 to 0.00 D), respectively. CONCLUSIONS: The acrylic toric IOL was rotationally stable within the first 6 months postoperatively. The photographic and axis analysis method to evaluate stability had high reproducibility and detected small changes in rotation. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Evaluation of 2 new optical biometry devices and comparison with the current gold standard biometer

PURPOSE: To compare 2 new optical biometry devices with the present gold standard biometer. SETTING: Vienna Institute for Research in Ocular Surgery, Department of Ophthalmology, Hanusch Hospital, Vienna, Austria. DESIGN: Evaluation of diagnostic test or technology. METHODS: In patients scheduled for cataract surgery, measurements performed with the current gold standard optical biometer (IOLMaster) were compared with those of 2 new optical biometers, the Lenstar LS 900 (optical low‐coherence reflectometry [OLCR] device; substudy 1) and the IOLMaster 500 (partial coherence interferometry [PCI] device; substudy 2). The duration of patient data entry and of the actual measurement process and the time from intraocular lens power calculation to printout were calculated. RESULTS: The mean difference in axial length measurements was 0.01 mm ± 0.05 (SD) between the gold standard device and the new OLCR device and 0.01 ± 0.02 mm between the gold standard device and the new PCI device (P=.12 and P < .001, respectively). Measurements with the new OLCR device took significantly longer than with the gold standard device (mean difference 209 ± 127 seconds), and measurements with the gold standard device took significantly longer than with the new PCI device (mean difference 82 ± 46 seconds) (both P < .001). CONCLUSIONS: All 3 devices were easy to use for biometry before cataract surgery. Measurements with the new PCI device took half as long as those with the gold standard device. Measurements with the new OLCR device took twice as long as those with the gold standard device. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Correction of moderate corneal astigmatism during cataract surgery: Toric intraocular lens versus peripheral corneal relaxing incisions

Purpose To compare the astigmatism‐reducing effect of a toric intraocular lens (IOL) and peripheral corneal relaxing incisions (PCRIs). Setting Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. Design Prospective masked bilateral randomized study. Methods Cataract patients with a preoperative corneal astigmatism of 1.0 to 2.5 diopters (D) were included. All patients received a toric IOL in 1 eye and a nontoric IOL plus a PCRI in the other eye. Postoperative follow‐up was at 1 hour, 1 month, and 6 months. The uncorrected distance visual acuity, corrected distance visual acuity, autorefraction (Topcon RM‐8800), and subjective refraction were recorded. The IOL axis was assessed using retroillumination photographs. Results The study enrolled 60 eyes of 30 patients. The mean astigmatism vector reduction was 1.74 D ± 0.64 (SD) in the toric IOL group and 1.27 ± 0.76 D in the PCRI group; the difference was statistically significant (P=.042). The mean absolute rotation of the toric IOL was 2.5 ± 1.8 degrees (maximum 6.3 degrees) in the first 6 postoperative months. Astigmatism increased in the PCRI group between the 1‐month and 6‐month follow‐up (mean 0.38 ± 0.27 D; maximum 1.00 D) (P<.001). Conclusion Toric IOLs and PCRIs both reduced astigmatism; however, toric IOLs reduced astigmatism to a higher extent and they were more predictable. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Impact of intraocular lens haptic design and orientation on decentration and tilt

PURPOSE: To assess the effect of intraocular lens (IOL) orientation (vertical versus horizontal) and haptic design (1‐piece versus 3‐piece) on centration and tilt using a Purkinje meter. SETTING: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. DESIGN: Randomized pilot study with intrapatient comparison. METHODS: In part 1 of this study, patients received plate‐haptic IOLs (Akreos Adapt) in both eyes that were positioned vertically in 1 eye and horizontally in the other eye. In part 2, patients received a 1‐piece IOL (Acrysof SA60AT) in 1 eye and a 3‐piece IOL (Acrysof MA60AC) in the contralateral eye. Decentration and tilt were measured 1 month and 3 months postoperatively with a new Purkinje meter. RESULTS: In part 1 (n = 15), the mean decentration of plate‐haptic IOLs was 0.4 mm ± 0.2 (SD) with vertical orientation and 0.4 ± 0.2 mm with horizontal orientation and the mean tilt, 1.5 ± 1.1 degrees and 2.9 ± 0.9 degrees, respectively. In part 2 (n = 15), the mean decentration was 0.4 ± 0.3 mm with 1‐piece IOLs and 0.6 ± 0.8 mm with 3‐piece IOLs and the mean tilt, 2.2 ± 7.2 degrees and 5.3 ± 2.4 degrees, respectively. CONCLUSIONS: Three‐piece IOLs had a greater tendency toward more decentration than 1‐piece IOLs, perhaps because of slight deformation of 1 or both haptics during implantation or inaccuracies in production when the haptics are manually placed into the optic. The IOL orientation for plate‐haptic IOLs appeared to have no effect on IOL position. The Purkinje meter was useful in assessing the capsule bag performance of the IOLs. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Evaluation of 4 corneal astigmatic marking methods

PURPOSE: To compare 4 devices used to mark the cornea before astigmatism‐reducing surgery. SETTING: Hanusch Krankenhaus, Vienna, Austria. DESIGN: Randomized examiner‐masked clinical trial. METHODS: Patients were randomly allocated to 1 of 4 groups for preoperative corneal marking in the sitting position. The 4 methods used were marking at the slitlamp with an insulin needle, a pendular marker, a bubble marker, and a tonometer marker. The marks were then documented with a standardized photographic technique, and the rotational deviation and vertical misalignment were assessed. RESULTS: The study enrolled 60 patients. The pendular‐marking device showed the least rotational deviation to the reference meridian (mean 1.8 degrees). There was no statistically significant difference between slitlamp marking and pendular marking (P = .05); however, there was a significant difference between the pendular marker and the bubble marker and between the pendular marker and the tonometer marker (P = .01 and P < .01, respectively). The least vertical misalignment was observed with the slitlamp‐marking device (mean 0.28 mm). There was no statistically significant difference in vertical misalignment between the 4 groups. CONCLUSIONS: All marking devices showed a slight deviation to the horizontal reference meridian. Because small deviations of the meridian can result in a relevant reduction in the astigmatism‐reducing effect with toric intraocular lenses, accurate marking of the cornea before surgery is critical due to the variable cyclotorsion caused by a change from the upright to the supine position. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Predicting the Postoperative Intraocular Lens Position Using Continuous Intraoperative Optical Coherence Tomography Measurements

PURPOSE The aim of this study was to assess, if measuring the position of the lens capsule intraoperatively with a continuous intraoperative optical coherence tomography (OCT) device could be useful to improve the prediction of the intraocular lens (IOL) position. METHODS This prospective study included patients who were scheduled for cataract surgery. A prototype operating microscope with an integrated continuous OCT device was used to measure the anterior and posterior lens capsule position at different time points during cataract surgery. In all cases, a capsular tension ring (CTR) was used to tauten the lens capsule. Partial coherence interferometry was used to measure anterior chamber depth (ACD) immediately before, and 1 hour and 3 months postoperatively. Partial least squares regression (PLSR) was used to assess the influence of different pre- and intraoperatively measured parameters. RESULTS In total, 70 eyes of 70 patients were included. Mean axial eye length was 23.6 mm (range, 20.6 mm-30.8 mm), mean used IOL power was 22.2 diopters (D; range, 6.0 D-31.5 D). PLSR showed that the anterior lens capsule measured after removing the crystalline lens and after implanting a CTR was a significantly better predictor for the postoperative ACD compared with preoperative ACD measurements. CONCLUSIONS The main problem of IOL power calculation, the prediction of the IOL position after surgery, could possibly be reduced by using intraoperative lens capsule measurements instead of preoperative ACD measurements. (ClinicalTrials.gov number, NCT01867541.).

Rotational Stability of a Single-Piece Toric Acrylic Intraocular Lens: A Pilot Study

PURPOSE To evaluate the visual performance and rotational stability of the Tecnis Toric 1-piece intraocular lens (IOL) during the first 3 postoperative months. DESIGN Prospective, single-center study. METHODS In this study, patients with age-related cataract and corneal astigmatism of 1.0 to 3.0 diopters measured with the IOLMaster 500 (Carl Zeiss Meditec AG) were included. Before surgery, rotating Scheimpflug scans (Pentacam HR; Oculus) were performed and the cornea was marked in the sitting position at the slit lamp. Patients received a single-piece toric hydrophobic acrylic IOL (Tecnis Toric; AMO). Immediately and 3 months after surgery, retroillumination photographs were obtained to assess the rotational stability of the IOL. Additionally, Autorefraction (Topcon), subjective refraction, uncorrected and distance-corrected visual acuity, keratometry, and Scheimpflug and ocular wavefront (WASCA, Carl Zeiss Meditec AG) measurements were performed at the 3-month follow-up. RESULTS Thirty eyes of 30 patients were included in this study. Mean absolute difference between the IOL axis at the 3-month and 1-hour follow-up was 2.7 degrees (standard deviation, 3.0 degrees). The IOL rotation was less than 3 degrees and less than 6 degrees in 62% and 95% of all cases, respectively. CONCLUSIONS The Tecnis Toric 1-piece IOL is rotationally stable and shows excellent capsule bag performance and refractive outcomes.

Reproducibility of intraocular lens decentration and tilt measurement using a clinical Purkinje meter.

PURPOSE: To determine the reproducibility of intraocular lens (IOL) decentration and tilt measurements with a new Purkinje meter instrument. SETTING: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. METHODS: After pupil dilation, images of pseudophakic eyes with a plate‐style IOL (Akreos Adapt) were obtained using a recently developed Purkinje meter. Intraocular lens decentration and tilt were evaluated by analyzing the captured images using a semiobjective method by marking the reflexes in the images and automatic calculation using a dedicated software program. In study 1, examiner 1 examined the eyes first followed by examiner 2. Ten minutes later, examiner 1 performed a second measurement, after which the intraexaminer and interexaminer reproducibility were determined. In study 2, a Purkinje meter was used to measure pseudophakic eyes with slitlamp finding of clinical IOL decentration, IOL tilt, or both. The results were compared with retroillumination photographs and slitlamp findings. RESULTS: In study 1, there was high intraexaminer reproducibility for decentration (r = 0.95) and tilt (r = 0.85) and high interexaminer reproducibility for decentration (r = 0.84) and tilt (r = 0.75). In study 2, even in extreme cases of decentration and/or tilt, the Purkinje meter measurements were possible and appeared to correlate well with slitlamp findings. CONCLUSIONS: Acquisition of images in pseudophakic eyes with the Purkinje meter was simple and rapid. The method was highly reliable for 1 examiner and between 2 examiners. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Using continuous intraoperative optical coherence tomography measurements of the aphakic eye for intraocular lens power calculation

Background/aims To include intraoperative measurements of the anterior lens capsule of the aphakic eye into the intraocular lens power calculation (IPC) process and to compare the refractive outcome with conventional IPC formulae. Methods In this prospective study, a prototype operating microscope with an integrated continuous optical coherence tomography (OCT) device (Visante attached to OPMI VISU 200, Carl Zeiss Meditec AG, Germany) was used to measure the anterior lens capsule position after implanting a capsular tension ring (CTR). Optical biometry (intraocular lens (IOL) Master 500) and ACMaster measurements (Carl Zeiss Meditec AG, Germany) were performed before surgery. Autorefraction and subjective refraction were performed 3 months after surgery. Conventional IPC formulae were compared with a new intraoperatively measured anterior chamber depth (ACD) (ACDIntraOP) partial least squares regression (PLSR) model for prediction of the postoperative refractive outcome. Results In total, 70 eyes of 70 patients were included. Mean axial eye length (AL) was 23.3 mm (range: 20.6–29.5 mm). Predictive power of the intraoperative measurements was found to be slightly better compared to conventional IOL power calculations. Refractive error dependency on AL for Holladay I, HofferQ, SRK/T, Haigis and ACDintraOP PLSR was r2=−0.42 (p<0.0001), r2=−0.5 (p<0.0001), r2=−0.34 (p=0.010), r2=−0.28 (p=0.049) and r2<0.001 (p=0.866), respectively, Conclusions ACDIntraOP measurements help to better predict the refractive outcome and could be useful, if implemented in fourth-generation IPC formulae.

Evaluation of Factors Influencing the Remaining Astigmatism After Toric Intraocular Lens Implantation

PURPOSE To evaluate the influencing factors on remaining astigmatism after implanting a toric intraocular lens during cataract surgery. METHODS In this observational study, consecutive patients with cataract from three different centers who received toric intraocular lenses were included. Keratometry was performed with an optical biometry device preoperatively. The IOLMaster 500 (Carl Zeiss Meditec AG, Jena, Germany) was used in Vienna, Lenstar (Haag-Streit, Köniz, Switzerland) in Castrop-Rauxel, and IOLMaster (Carl Zeiss Meditec AG) in London. Partial least squares regression was used to detect the influence of different parameters on remaining astigmatism. RESULTS In total, 235 eyes of 200 patients were included. Mean corneal astigmatism measured preoperatively with the optical biometry device was -2.24 ± 0.87 diopters (D) (range: -5.75 to -1.00 D). Mean absolute and vector difference between the aimed for and the postoperatively measured astigmatism were 0.48 ± 0.37 D (range: 0.00 to 2.05 D) and 0.73 ± 0.46 D (range: 0.031 to -2.20 D), respectively (P = .576). Partial least squares regression showed a significant effect of preoperatively measured corneal astigmatism and deviation between preoperative measurements of the cornea on the postoperative (unintended) remaining astigmatism. CONCLUSIONS The main source of error when using toric intraocular lenses is the preoperative measurement of corneal astigmatism, especially in eyes with low astigmatism. The influence of the postoperative anterior chamber depth on the cylindrical power of toric intraocular lenses and the effect of misalignment on the reduction of the astigmatism-reducing effect can be easily calculated.