Hans E. Völcker

Multilayer amniotic membrane transplantation for reconstruction of deep corneal ulcers

PURPOSE To evaluate the efficacy of multilayer amniotic membrane transplantation for reconstruction of corneal epithelium and stroma in the context of deep corneal ulcers. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Eleven consecutive patients with deep corneal ulcers refractory to conventional treatment; six patients had herpetic keratitis and five had other forms of neurotrophic keratitis. INTERVENTION Multilayer amniotic membrane transplantation with kryopreserved human amniotic membrane. MAIN OUTCOME MEASURES Integrity of corneal epithelium and stroma, opacification, and appearance of grafted membrane during 12 months follow-up. RESULTS Amniotic membrane transplantation markedly reduced ocular inflammation in all patients. Epithelium healed above all corneal ulcers within 4 weeks and remained stable in 9 of 11 patients for 1 year. Two patients with recurrent epithelial defect suffered from severe neurotrophic keratitis. Following transplantation the amniotic membranes gradually dissolved over a period of 12 months, but stromal thickness remained stable. CONCLUSION Amniotic membrane transplantation allows corneal surface reconstruction in patients with persistent epithelial defects. The multilayer technique is useful for treating deep corneal ulcers and even descemetoceles. Because the procedure results in stability of the ocular surface over a period of more than 12 months in most patients, it may be considered an alternative to conventional surgical techniques for ocular surface reconstruction.

Reproducibility of the Optic Nerve Head Topography with a New Laser Tomographic Scanning Device

BACKGROUND Laser scanning tomography has been shown to be an accurate and reliable method for the assessment of the three-dimensional optic disc topography. The authors investigate the reliability of morphometric measurements with the Heidelberg retina tomograph, a new instrument which was designed based on this technology, which simplifies handling and is much smaller than the laser tomographic scanner. METHODS Three independent measurements of the optic disc were performed in 39 eyes of 39 patients which were equally divided into the following three groups: glaucoma, glaucoma suspects, and controls. RESULTS The mean coefficient of variation for measurement in the glaucoma, glaucoma suspect, and control groups was 2.9%, 5.0%, and 3.4%, respectively, for cup area; 4.9%, 4.6%, and 4.6%, respectively, for cup volume; 5.2%, 3.8% and 3.3%, respectively, for mean cup depth; and 5.2%, 4.1%, and 4.0%, respectively, for maximal cup depth. The mean standard deviation for one pixel of the total image was 30 +/- 6 microns, 28 +/- 7 microns, and 22 +/- 6 microns for the three groups, respectively. CONCLUSION The Heidelberg retina tomograph enables fast and reliable measurement of the optic disc topography and therefore may allow exact follow-up of patients.

Patterns of increased in vivo fundus autofluorescence in the junctional zone of geographic atrophy of the retinal pigment epithelium associated with age-related macular degeneration

Abstract · Purpose: To determine in vivo lipofuscin (LF)-induced topographic variations of fundus autofluorescence in eyes with geographic atrophy (GA) of the retinal pigment epithelium (RPE) associated with age-related macular degeneration (ARMD). · Methods: Fundus autofluorescence was examined with a confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph) after excitation with an argon laser (488 nm) and detection of the emitted light above 500 nm. Fifty-seven eyes of 38 patients with uni- or multifocal GA associated with ARMD were studied. The findings were compared with 43 eyes with GA secondary to other etiologies, including juvenile macular dystrophies. · Results: An increased autofluorescence outside the GA was observed in 47 (82.5%) of 57 eyes with GA associated with ARMD in contrast to 4 (9.3%) of 43 eyes with GA of other causes (P<0.001). Three different patterns were noted: a continuous band at the margin with variable peripheral extension in 36 eyes (76.6%), a diffusely increased autofluorescence at the entire posterior pole in 6 eyes (12.8%), and small focal spots of increased autofluorescence in the junctional zone in 3 eyes (6.4%). Of 19 patients with bilateral GA, 17 (89.5%) had an identical pattern in both eyes. · Conclusions: The different patterns of autofluorescence in the presence of GA associated with ARMD may reflect variable forms of reactive changes in the surrounding RPE cells, and may indicate the extend of compromised RPE secondary to ageing changes in the outer retina, Bruch’s membrane and choriocapillaris. Since GA spreads over time, increased LF accumulation in the junctional zone may precede cell death and may, therefore, be of prognostic value. Knowledge of the topographic variation in LF accumulation is important because heterogeneity may reflect underlying differences in cell kinetics, metabolism and biochemistry.

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.

Thalidomide inhibits corneal angiogenesis induced by vascular endothelial growth factor

Abstract · Background: Ocular diseases caused by neovascularization are among the leading causes of blindness. No specific pharmacological treatment is available. Among potential drugs, thalidomide deserves special interest since a wide body of clinical experience exists. However, its antiangiogenic effect is controversial. We therefore investigated the effect of thalidomide on corneal angiogenesis induced by vascular endothelial growth factor (VEGF), which has a special role among angiogenic growth factors. · Methods: Corneal neovascularization was induced in NZW rabbits by an intrastromal pellet loaded with 500 or 750 ng VEGF. Animals received two daily feedings of 200 mg/kg thalidomide. · Results: Significant inhibition of corneal angiogenesis (P<0.0001) was caused by the teratogenic dose of thalidomide after the 5th day of treatment and persisted for more than 16 days. No obvious side effects were recorded. · Conclusions: Thalidomide has a significant antiangiogenic effect against VEGF-induced neovasclar growth. Together with earlier findings this observation indicates that the drug inhibits two angiogenic pathways which are mediated through integrin adhesion molecules.

Keratoconus evaluation using the Orbscan Topography System.

PURPOSE To evaluate corneal topography in a series of keratoconus patients using the Orbscan Topography System. SETTING Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS Seventy-one eyes of 38 patients with keratoconus were evaluated. Quantitative topographic parameters were analyzed with special reference to the central point of the cornea, the apex (the point with maximum reading on the anterior elevation best-fit sphere map), and the thinnest point. Evaluation included location, elevation (compared to a best-fit sphere), pachymetry, tangential curvature, and composite curvature. The mirror-image symmetry between the right and left eyes of a patient was also investigated. RESULTS Mean patient age was 31.2 years +/- 12.2 (SD). Thirty-three patients (86.8%) had bilateral keratoconus and 5 (13.2%), unilateral keratoconus. Most cones (68/71) were located in the inferior temporal quadrant; 3 were above the horizontal meridian. Mean distance between the apex and the thinnest point was 0.917 +/- 0.729 mm (P < .001). The correlations between apex elevation and apex composite curvature and apex tangential curvature were high (r = 0.94 and r = 0.91, respectively; P < .001). In right and left eyes, there was a correlation between the apex and the thinnest point semi-meridians (r = 0.47 and r = 0.65, respectively; P < .05) but not between the radii of the apex and the thinnest point (r = 0.21 and r = 0.24, respectively). CONCLUSIONS The Orbscan system can provide useful and accurate information in defining the morphology of keratoconus and detecting subtle topographic changes present in early keratoconus. It may also improve the results of contact lens fitting and surgical management.

Quantification of posterior capsule opacification with round and sharp edge intraocular lenses

PURPOSE To quantitatively evaluate and compare intraocular lenses (IOLs) with a round or sharp optic edge design for posterior capsule opacification (PCO). STUDY DESIGN Prospective comparative observational case series. PARTICIPANTS/MATERIALS: Photographs from 174 eyes were analyzed for PCO at the Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. MAIN OUTCOME MEASURES Part I: 121 eyes of 121 patients were analyzed for quantification of PCO. IOLs evaluated were Corneal ACR6 (n = 21), Alcon Acrysof (n = 20), Allergan AR40 (n = 27), Pharmacia 811 one-piece polymethyl methacrylate (PMMA) IOL (n = 24), and Pharmacia 911A silicone IOL (n = 29). Mean follow-up was 14.01 +/- 2.81 months; mean patient age was 73.2 +/- 7.3 years. The morphologic PCO formation was evaluated for the entire optic and in the central 3-mm zone. Part II: In 53 eyes of 46 patients aged 73.4 +/- 10.8 years with an Alcon Acrysof IOL, PCO formation and capsulorrhexis/optic overlapping were analyzed 34.2 +/- 4 months after cataract surgery using EPCO Software. RESULTS Part I: The PCO values of the entire optic were for Corneal ACR6, 1.93 +/- 0.62; PMMA, 0.64 +/- 0.63; AR40, 0.55 +/- 0.28; Alcon Acrysof, 0.145 +/- 0.27; and 0.161 +/- 0.181 for the Pharmacia 911A IOL (P < 0.01). The PCO values of the central 3-mm zone were for Corneal ACR6, 1.64 +/- 0.96; PMMA, 0.49 +/- 0.39; AR40, 0.22 +/- 0.32; Alcon Acrysof, 0.08 +/- 0.21; and 0.06 +/- 0.11 for the Pharmacia 911A IOL (P < 0.01). Part II: Average overlapping of capsulorrhexis and Acrysof IOL optic was 40.5% +/- 12.4%. There was a significant correlation between PCO values and overlapping (r = -0.69, P < 0.001). CONCLUSIONS The sharp-edge IOL types (Alcon Acrysof and Pharmacia 911A silicone IOL) resulted in statistically significantly lower PCO values for analysis of the entire optic area and central 3-mm zone. There was no statistically significant difference in PCO values between the two sharp-edge optic IOLs. An overlapping of capsulorrhexis rim and the anterior IOL optic surface of more than 20% resulted in significantly lower PCO values with the Acrysof IOL.

Measuring anterior chamber depth with the Orbscan Topography System

Purpose: To assess the reliability of the Orbscan Topography System in measuring anterior chamber depth (ACD). Setting: Department of Ophthalmology, Ruprecht‐Karls‐University of Heidelberg, Heidelberg, Germany. Methods: The Orbscan Topography System is a 3‐D, scanning slit beam system for analyzing corneal surfaces as well as structures of the anterior segment, e.g., iris, lens. Reflected surface data points are measured in the x, y, and z axes, creating color‐coded true surface topography maps. We measured ACID prior to cataract surgery in 56 eyes of 37 patients (mean age 70.4 years + 13.2 [SD]) using the Orbscan system and, as a control, the Grieshaber Biometric System (ultrasound) and the Jager ACD slitlamp measurement system. Results: Mean ACD values measured with the Orbscan system were 3.23 0.55 mm; ultrasound measurements were 3.27 ± 0.54 mm and Jäger measurements, 3.10 ± 0.55 mm. The average difference between Orbscan and ultrasound values was 0.04 ± 0.15 mm. The correlation coefficient between Orbscan and ultrasound was 0.96 (P < .00001) and between Orbscan and Jäger, 0.899 (P < .0001). Conclusion: The ACID measurements by the Orbscan system were equivalent to common reference measurements.

Scanning laser ophthalmoscope fundus perimetry before and after laser photocoagulation for clinically significant diabetic macular edema

PURPOSE To prospectively evaluate functional and funduscopic changes after laser treatment in patients with diabetic retinopathy and clinically significant macular edema by scanning laser ophthalmoscope fundus perimetry. METHODS Thirty eyes of 30 patients with clinically significant macular edema as a result of diabetic retinopathy were prospectively examined before and at least 3 months after focal laser treatment with automatic fundus threshold perimetry using the scanning laser ophthalmoscope. Thresholds of light sensitivity were compared with age-corrected normal values and correlated with corrected visual acuity and subjective appraisal of visual function. RESULTS In 30 eyes, fundus perimetry lasted for 10.5+/-2.7 (mean+/-SD) minutes with 322+/-67 stimulus presentations for each eye. Whereas eight eyes remained stable (< +/-1 dB change), 15 improved concerning mean deviation (MD) (3.1+/-1.7 dB) after focal laser treatment. Stability of fixation remained the same after focal laser treatment (0.75+/-0.57 degree). Laser scars showed marked loss of function (MD > 13 dB). CONCLUSIONS Although light sensitivity was reduced in areas of macular edema, there was no correlation between the amount of edema and visual function. Fundus perimetry allows the creation of exact maps of retinal dysfunction before and after laser treatment. It may help in making management decisions in diabetic and nondiabetic patients by offering a sensitive parameter in addition to visual acuity.

Reproducibility of topometric data acquisition in normal and glaucomatous optic nerve heads with the laser tomographic scanner

The reproducibility of optic disc cup measurements was analyzed in 24 eyes of 24 patients [8 normals, 8 glaucoma patients, 8 glaucoma suspects] using the Laser Tomographic Scanner. The mean coefficient of variation in triple measurements was 5.0% for the cup area, 5.4% for the rim area, 7.0% for the cup volume, 4.0% for the mean cup depth, and 4.3% for the maximum cup depth. Mean reliability between two of the three measurements performed in each eye was better than 0.988 for the cup area, 0.995 for the cup volume and 0.996 for the mean cup depth readings. These results suggest that laser scanning tomography allows highly reproducible measurements in living eyes and adds an important tool to the ophthalmologists armamentarium for the diagnosis and follow-up of glaucoma patients.