Marcus Blum

Photographic image analysis system of posterior capsule opacification.

Purpose: To describe a morphological scoring system of posterior capsule opacification (PCO) that is not based on visual acuity testing. Setting: Department of Ophthalmology, University of Heidelberg, Germany. Methods: Following dilation of the pupil, standardized photographs of the pseudophakic anterior segments were obtained using a photo slitlamp. Posterior capsule opacification was scored by evaluating retroillumination photographs. The individual PCO score was calculated by multiplying the density of the opacification (graded from 0 to 4) by the fraction of capsule area involved behind the intraocular lens (IOL) optic. To evaluate the reliability of the morphological scoring system, six observers examined photographs of five eyes each (Experiment A, interindividual reliability). The same observer scored the PCO in three eyes on five different days (Experiment B, intraindividual reliability). Results: Morphological PCO scores were very reliable. With PCO scoring from 0 to 4, the interindividual reliability showed standard deviations between 0.08 and 0.25. The intraindividual reliability showed standard deviations between 0.06 and 0.19 of the mean individual PCO scores. Standard deviation was 0.12 when different photographs of the same eye were scored. Conclusion: The morphological scoring system evaluates the entire area behind the IOL optic and thus includes a larger area of the posterior capsule than does visual acuity testing. The method revealed high reliability and insignificant investigatordependent variations. When using a standardized photographic setup, systematic errors by the photographic technique were not relevant. This method may be an important tool to accurately test for differences in PCO formation with various IOL styles and surgical methods.

LASIK for Myopia Using the Zeiss VisuMax Femtosecond Laser and MEL 80 Excimer Laser

PURPOSE To assess the efficacy, safety, and predictability of the VisuMax femtosecond laser (Carl Zeiss Meditec). METHODS In a prospective, multicenter clinical trial, 32 eyes of 17 patients underwent LASIK and flap creation with the VisuMax femtosecond laser and ablation with the MEL 80 excimer laser (Carl Zeiss Meditec). Mean patient age was 35 years (range: 23 to 52 years). Mean preoperative spherical equivalent refraction was -4.04 +/- 1.39 diopters (D) (range: -1.50 to -7.25 D), and the planned flap thickness was 110, 120, 140, and 150 microm. RESULTS At the 3-month postoperative examination, all eyes had best spectacle-corrected visual acuity of 20/25 and uncorrected visual acuity (UCVA) of 20/40; 91% of eyes reached UCVA of 20/20 or better. Ninety-four percent of eyes were within +/- 0.50 D of the planned correction. Complications were limited to one case of suction loss, and no other adverse events were noted at 3 months. The flaps were planar and the mean achieved central flap thickness was 118 +/-9.2 microm for an attempted thickness of 120 microm. CONCLUSIONS The investigators achieved LASIK outcomes exceeding the US Food and Drug Administration guidelines for refractive procedures in this series of myopic eyes using the VisuMax femtosecond laser and MEL 80 excimer laser. The curved contact lens of the applanation glass combined with low suction permitted continuous fixation during treatment.

Surface quality of human corneal lenticules after femtosecond laser surgery for myopia comparing different laser parameters.

BackgroundTo determine the surface characteristics of human corneal lenticules after femtosecond laser surgery for myopia.MethodsThe Carl Zeiss Meditec AG VisuMax® femtosecond laser system was used for refractive correction called Femtosecond Lenticule Extraction on 24 myopic eyes. The surface regularity on the refractive corneal lenticules recovered was evaluated by assessing scanning electron microscopy images using an established scoring system. Three different energy levels 150, 180, and 195 nJ were compared (n = 8 in each group).ResultsSurface irregularities were caused by tissue bridges, cavitation bubbles, or scratches. The surface regularity index (R2 = 0.74) decreased as pulse energy increased. The average surface regularity score obtained was 7.5 for 150 nJ, 7.25 for 180 nJ, and 6.25 for 195 nJ.ConclusionsThe human corneal lenticules created with the VisuMax® femtosecond laser system are of predictable, good-quality surface. This study shows the influence of pulse energy on surface regularity in human eyes. Further studies should focus on optimization of laser parameters as well as surgical technique to improve the regularity of the corneal stromal bed and so make the advantages of the femtosecond laser technology over conventional techniques clearer in the future.

Five-year results of Small Incision Lenticule Extraction (ReLEx SMILE)

Background To evaluate the 5-year results of Refractive Lenticule Extraction (ReLEx) as Small Incision Lenticule Extraction (SMILE) technique for treatment of myopia and myopic astigmatism. Methods In 2008/2009, the worldwide first 91 eyes were treated using a novel surgical technique (SMILE), where a refractive lenticule of intrastromal corneal tissue is removed though a small incision completely eliminating flap-cutting. 56 out of 91 eyes of the original treatment group volunteered for re-examination 5 years after surgery. Uncorrected distance visual acuity and corrected distance visual acuity after 5 years, objective and manifest refractions as well as evaluation of the interface and corneal surface by slit-lamp examination were documented. Late side effects like corneal scars, corneal ectasia, persistent dry eye symptoms or cataract were documented. Results 5 years postoperatively, no significant change to the 6-month data was found. Spherical equivalent was −0.375 D and therefore close to target refraction (emmetropia). 32 of the 56 eyes had gained 1–2 Snellen lines. There was no loss of 2 or more lines over the 5-year period. Regression in the long term was 0.48 D. Conclusions This first long-term study demonstrates SMILE to be an effective, stable and safe procedure for treatment of myopia and myopic astigmatism. Clinical trial number DE/CA93/KP/07/001. Post-results.

Femtosecond Lenticule Extraction (FLEx) - Results after 12 Months in Myopic Astigmatism

BACKGROUND This clinical trial is focussed on the 12-month results of a new method for refractive correction, femtosecond lenticule extraction (FLEx). PATIENTS AND METHODS In a prospective 6-month study 108 eyes were treated in Erfurt and Marburg. Both a flap and a lenticule of intrastromal corneal tissue were simultaneously cut utilising the Carl Zeiss Meditec AG (Jena, Germany) VisuMax femtosecond laser system. Thereafter, the lenticule was manually removed and the flap repositioned. 31 patients all treated in Erfurt volunteered for a 12-month follow-up. UCVA and BSCVA after 12 months, objective and manifest refraction as well as slit-lamp examination and late side effects were documented. RESULTS 62 eyes of 31 patients were examined in this study. The spherical equivalent before surgery was -4.81 (± 1.16) D; after 12 months -0.15 (± 0.46) D were manifest. No significant change was observed after the 6 months control. Starting with UCVA of 0.12 (± 0.09) before surgery UCVA was 1.10 (± 0.26) after 12 months. In one patient corneal ectasia was diagnosed. All other patients did not have any late side effects. CONCLUSION The stability of the correction of myopic astigmatism with the FLEx procedure is very good. The fact that one patient presented with a corneal ectasia demonstrates that one general problem of refractive corneal surgery persists with this new fs technology.

Abnormal retinal autoregulation is detected by provoked stimulation with flicker light in well-controlled patients with type 1 diabetes without retinopathy.

AIMS Investigation of retinal vasodilation under flickering light is considered a dynamic analysis in contrast to the static analysis of retinal vessel equivalents (mean retinal vessel diameter). We investigated whether dynamic analysis apart from the static one in type 1 diabetic patients without diabetic retinopathy with well-controlled diabetes could lead to additional information regarding retinal autoregulation. METHODS 18 normotensive type 1 diabetic patients without retinopathy and 19 healthy subjects were included. Diameter of retinal vessels was measured with Dynamic Vessel Analyzer. Changes in vasodilation are expressed as percent change over baseline values. RESULTS HbA(1c) was 7.5+/-1.0% in diabetic patients. In arteries, the response to flicker was diminished in diabetic patients compared to healthy volunteers (p<0.023). In patients flicker stimulation increased arterial diameter by +2.7% in contrast to +4.4% in controls. Venous vessel diameter increased by +3.1% in diabetic individuals and by +5.3% in the control group (p<0.002). There were no differences in static analysis between both groups. CONCLUSIONS Diabetic patients without retinopathy with relatively good glycemic control show reduced retinal vasodilation after flicker indicating dysfunction in retinal autoregulation. The use of provocation test in conjunction with static analysis could lead to additional information regarding abnormal retinal autoregulation.

Repeatability and agreement in optical biometry of a new swept-source optical coherence tomography–based biometer versus partial coherence interferometry and optical low-coherence reflectometry

Purpose To estimate the repeatability of biometric parameters obtained with a new swept‐source biometer and to compare the agreement with that of partial coherence interferometry (PCI) and optical low‐coherence reflectometry (OLCR). Setting Department of Ophthalmology, Helios Hospital Erfurt, Erfurt, Julius‐Maximilians University, Würzburg, and Philipps University, Marburg, Germany. Design Prospective comparative multicenter clinical study. Methods Biometry was taken with the use of 3 different biometers: the IOLMaster 700 swept‐source biometer, the PCI‐based IOLMaster 500, and the OCLR‐based Lenstar LS 900. Axial length (AL), anterior chamber depth (ACD), and spherical equivalent (SE) were compared between swept‐source and PCI biometry and central corneal thickness (CCT) and lens thickness (LT) between swept‐source and OLCR biometry. The repeatability of swept‐source biometry was evaluated on the basis of 3 measurements captured for each patient. Results One hundred twenty cataract eyes were included in the study. The mean difference between swept‐source and PCI biometry for AL, ACD, and SE measurements was 4 &mgr;m ± 25 (SD), 17 ± 122 &mgr;m, and −0.001 ± 0.19 diopter (D), respectively. The mean difference between swept‐source and OLCR biometry for LT and CCT measurements was 21 ± 122 &mgr;m and 0.15 ± 4.51 &mgr;m, respectively. Differences between swept‐source biometry and the other devices distributed around zero without statistical significance. The standard deviation of repeatability for AL, ACD, LT, CCT, and SE was 8.8 &mgr;m, 9.8 &mgr;m, 2.3 &mgr;m, 19.5 &mgr;m, and 0.1 D, respectively. Conclusions Swept‐source biometry showed high repeatability performance for all biometric parameters. The agreement of AL, ACD, and SE between swept‐source and PCI biometry as well as that of LT and CCT between swept‐source and OLCR biometry was excellent. It remains to be validated whether high repeatability shown by swept‐source biometry will result in better postoperative refractive outcomes. Financial Disclosure Drs. Blum and Sekundo are members of the Scientific Advisory Board of Carl Zeiss Meditec AG. Drs. Peter and Bühren are employees of Carl Zeiss Meditec AG.

Age-related changes of the ciliary sulcus: Implications for implanting sulcus­ fIXated lenses

Purpose: To examine age‐related anatomical changes of the ciliary sulcus and the implication of these changes for placement of posterior chamber intraocular lenses (IOLs). Setting: Department of Ophthalmology, University of Heidelberg, Germany. Methods: In this study, 64 human autopsy eyes from 38 donors were divided by age into six groups from younger than 40 years (Group 1) to 80 years and older (Group 6) in 10 year increments. External diameter, capsular bag size, and lens thickness were determined for each eye. The horizontal and vertical diameters of the ciliary sulcus were measured and histological sectioning, staining, and light microscopy performed. Results: The external diameters of the eyes showed no age correlation; the lenses exhibited the expected increase in thickness with age. The mean vertical diameter of the ciliary sulcus decreased in all age groups from 12.02 mm ± 0.12 (SD) to 10.71 ± 0.91 mm and the mean horizontal diameter, from 11.36 ± 0.24 mm to 10.33 ± 0.76 mm. Statistical analysis confirmed the overall significance (P < .05) of the differences among age groups. Conclusion: The ciliary sulcus became smaller with age. This might affect the size of sulcus‐implanted IOLs and should be noted for transsclerally sutured IOLs.

Surface Quality of Porcine Corneal Lenticules after Femtosecond Lenticule Extraction

Purpose: To determine the surface characteristics of porcine corneal lenticules after Femtosecond Lenticule Extraction. Methods: The Carl Zeiss Meditec AG VisuMax® femtosecond laser system was used to create refractive corneal lenticules on 10 freshly isolated porcine eyes. The surface regularity on the corneal lenticules recovered was evaluated by assessing scanning electron microscopy images using an established scoring system. Results: All specimens yielded comparable score results of 5–7 points (SD = 0.59) per lenticule (score range minimum 4 to maximum 11 points). Surface irregularities were caused by tissue bridges, cavitation bubbles or scratches. Conclusion: The Femtosecond Lenticule Extraction procedure is capable of creating corneal lenticules of predictable surface quality. However, future studies should focus on the optimization of laser parameters as well as surgical technique to improve the regularity of the corneal stromal bed.

Treatment of traumatic cataracts

Purpose: To analyze the postoperative outcome and complication rate following cataract extraction because of post‐traumatic lens opacification. Setting: University medical center. Methods: A retrospective analysis was done of 148 eyes with traumatic cataracts operated on between 1978 and 1992. Age, sex, traumatic sequelae, surgical strategies, and postoperative complications were reviewed for all eyes. Results: In 85 eyes, Group A, a history of blunt trauma could be ascertained. In 63 eyes, Group B, there had been a penetrating injury. Secondary glaucoma was observed more frequently in patients with blunt trauma. A posterior chamber intraocular lens was implanted in 85% of Group A eyes and in 67% of Group B eyes. Mild or moderate postoperative complications occurred in 15% of all cases. Postoperatively, the incidence of glaucoma remained unchanged. Visual acuity improved in 90% of eyes. Ten percent of eyes did not benefit from cataract surgery because of severe traumatic involvement of the retina or optic nerve. Conclusions: In this study, a majority of eyes with traumatic cataract were safely rehabilitated with posterior chamber lens implantation. Visual acuity improved in 90% of eyes; complications were seen in 15%.