AUGENHEILKUNDE 214/1999 – ISSUE 6

Abstracts:

S. 362-366 (Art. 465)

A survey of clinical used drugs in PVR
Frank Faude, Klaus Heimann, Peter Wiedemann

Colchicine, corticosteroids, daunomycin, fluorouracil, heparin and retinoids have been used in man and show an effect in different stages of the development of PVR. In this survey the effect of each drug is described and the clinical studies are discussed.

This survey shows that there are many drugs that in addition to surgery might influence the natural course of clinical PVR during different stages. However, the only drug for which a significant reduction in the number of reoperations has been demonstrated in a randomized prospective trial is daunomycin. Literature search by medline.

Key words PVR - colchicine - corticosteroids - daunomycin - fluorouracil - heparin - retinoids

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S. 367-371 (Art. 529)

PK using corneas of aged donors
Hans-Jürgen Meyer, Stefan Labjuhn

Background In the past corneas from young donors were favored. There are only few reports of PK with old donor corneas. Concerning donor age we were not very stringent in our patients. Therefore many old corneas were transplanted. We present long-term results of these patients and enter again into the unanswered question: Is there a correlation between graft failure and donor age?

Patients and Methods We retrospectively analyzed 615 PK out of 1986 to 1991. In addition to own records we requested reports from retreating ophthalmologists concerning graft clarity. Mean follow-up was 37.3 months. Two thirds of our recipients had favorable diagnoses for graft success (keratoconus 30.6%, Fuchs dystrophy 17.6%, bullous keratopathy in pseudophakia 14.1%, keratitis scrophulosa 5.5%).

Results The donor age was between 31 and 98 years, average age 71.2 years (SD 11.8). Out of 615 transplants 61 became cloudy. The mean age of all clear transplants was 71.0 years compared to 72.7 years in opaque transplants. The difference was not significant. Exlcuding all high-risk patients (herpes, varia, glaucoma, aphakia, Re-OP) 401 patients were left. In this group there also was no significant difference between donor age of clear and cloudy transplants. We finally compared all patients with endothelial problems (Fuchs dystrophy and bullous keratophathy). Even in this group donor age had no significant influence on graft survival.

Conclusion In spite of spare resources and hundreds of waiting patients in the past many corneas were rejected on the basis of donor age. Our results should encourage eye banks and cornea surgeons to accept even very old corneas, when other screening criteria are good.

Key words PK - success and donor age - very aged donors comparison of different receptor groups

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S. 372-377 (Art. 489)

Topography-based calculation of keratoconus dimensions
Achim Langenbucher, Gabriele C. Gusek-Schneider, Murat M. Kus, Berthold Seitz

Background Keratoconus is a corneal dystrophy which usually develops in the second or third decade of life and shows various speed of progression. This disease may degrade the image-forming properties of the eye even in its early stage. The purpose of this study was to support the conventional clinical qualitative diagnostic methods of keratoconus handling with a topography-based algorithm to quantify the "balooning" of the anterior corneal surface.

Patients and methods Eighty-eight patients with keratoconus (46 with mild and 42 with severe clinical signs) and a control group of 40 normal subjects were included in this study. Topographic height data were calculated from refraction data of a commercially available topographer (TMS-1) using a local approximation algorithm. A decomposition of corneal topography height data into orthogonal Zernike polynomials was performed to define a asphero-cylindrical model surface. From the difference of the raw height data and the model surface, the base, height and volume as well as the localization of the protrusion was quantified.

Results The height of the corneal protrusion (23 to 71 µm), the volume of the cone (0.066 to 0.141 mm3) and the horizontal dimension (0.67 to 1.32 mm) increased highly significantly. In contrast, comparing the early to the severe stage of the disease the vertical dimension of the cone (0.64 to 0.93) changed much less. In the severe stage, the center of the protrusion was much more decentred (1.33 mm) than in the early stage (0.44) due to a shift in the inferior direction.

Conclusions The quantification of cone dimensions using corneal topography height data has the potential to assist qualitative clinical graduation in keratoconus independent of the system currently used. The knowledge about the exact amount of corneal protrusion and position of the cone may improve the assessment of the progression of the disease, thus being helpful for indication of a penetrating keratoplasty.

Key words keratoconus - corneal topography - dimensions - localization

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S. 378-385 (Art. 482)

Scanning laser topometry and polarimetry before and after cataract surgeries with implantation of intraocular lenses
Stephan Kremmer, Andrea Pflug, Arnd Heiligenhaus, Farsad Fanihagh, Klaus-Peter Steuhl

Background In the last years, scanning laser measurements were established in glaucoma diagnostics. Techniques of special interest are scanning laser topometry (SLT) for exact measurements of the optic disc and its cup and scanning laser polarimetry (SLP) for precise assessment of the retinal nerve fiber layer thickness. As glaucoma patients often suffer from a cataract, too, and a trabeculectomy additionally favors the advance of lens opacities, in the follow up of glaucoma patients cataract surgery is often necessary.

Patients and methods The influence of cataract surgery in phacotechnique with intraocular lens implantation (31 PMMA-IOLs, Pharmacia/Upjohn, model 811 B, and 25 HEMA/MMA-IOLs, Technomed, Memory Lens) on SLT and SLP was evaluated before and 3 to 4 weeks after cataract surgery in 56 eyes of otherwise healthy patients. Lens opacities were classified according to LOCS III. For SLT, we applied a TopSS, and for SLP a Nerve Fiber Analyzer II and a GDx (LDT, USA).

Results Our results show that SLT and SLP are mostly performable at lens opacities with visual acuity reductions down to 0.16. In SLT, we usually found no big differences in the assessed parameters before and after cataract surgeries with IOL implantation. Standard deviations between three single measurements were mostly smaller postop. In SLP, nerve fiber layer patterns were very similar before and after cataract surgeries with IOL implantation whereas total nerve fiber layer thickness values postoperatively were slightly higher.

Conclusions Our results indicate that cataract surgeries with IOL-implantation have only mild influence on SLT and SLP. These findings seem to be of clinical interest especially in the follow up of glaucoma patients.

Key words lens opacities - cataract surgery - glaucoma diagnostics - scanning laser topometry - scanning laser polarimetry

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S. 386-390 (Art. 479)

Postoperative ultrasound biomicroscopic evaluation of the haptic position of black diaphragm posterior chamber lenses in congenital and traumatic aniridia in comparison with gonioscopy
Nils Schweykart, Thomas Reinhard, Sascha Engelhardt, Rainer Sundmacher

Background Ultrasound biomicroscopy (UBM) allows to determine the haptic position of posterior chamber lenses (PCL) in relation to adjacent structures. In transsclerally sutured PCLs, the comparison between intraoperatively endoscopically and postoperatively localized haptic positions via UBM showed a correspondence of only 81%. The different localisation of 19% of the examined haptic postions was explained with postoperative dislocation without any proof for this assumption. The purpose of this study therefore was the correlation of UBM results with simultaneously determined haptic positions via gonioscopy in aniridia after black diaphragm PCL implantation.

Patients and methods The haptic positions of black diaphragm PCL implants in 20 patients with congenital and 13 patients with traumatic aniridia were determined via UBM (50-MHz-probe) and gonioscopy 44,4 (6-75) months postoperatively.

Results 39/66 haptic positions could be localized in gonioscopy as well as in UBM. 38 haptics (97,4%) showed the same position in both examination techniques. Determination of the haptic position through one of the two examination techniques was impossible in 27/66 haptics (11 haptics in gonioscopy, 16 haptics in UBM). Reasons for this were primarily haptic position behind iris remnants and corneal opacities in gonioscopy and scarring of the ciliary body in UBM.

Conclusions The validity of UBM in localization of PCLs was confirmed gonioscopically, which also confirms our prior assumption of postoperative displacement of IOL-haptics after transscleral suturing in about 20% of cases. Scarring of the ciliary body was the most important obstacle in the determination of PCL haptic positions in relation to adjacent structures.

Key words Aniridia - posterior chamber lens - ultrasound biomicroscopy - gonioscopy

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S. 391-394 (Art. 527)

Rehabilitation with bone anchored facial prostheses
Martin Klein

Background Rehabilitation of orbita defects with loss of eyelids is difficult to achieve with plastic surgery. Here defect coverage with a facial prosthesis shows good results.

Patients and Methods 105 patients with orbita defects were treated since 1991 with bone anchored facial prostheses. Preoperatively we measured the bone availability with computed tomography. We inserted Brånemark-titanium implants (Fa. Nobel Biocare), with a two-stage procedure. After a period of at least three months we exposed implants and connected the supraconstruction. Then our anaplastologist produced the facial prosthesis, either a "soft" facial prosthesis of silicone or a "solid" prosthesis of polymethylmetacrylate (PMMA). Not later than every three months patients came to recall.

Results For all patients we found enough bone for implantation. The implants were screwed into the lateral bony orbital margin. There were no intraoperative complications accompanying implant insertion. For 96 patients we chose the silicone material; for nine patients we did produce the facial prosthesis of PMMA. In about 10.5% of the implants we had to remove subcutaneous tissue in local anesthesia because of recurrent periimplantary inflammations. Three years after insertion 95.8% of the implants were still firmly anchored in the bone.

Conclusions Performed by the experienced specialist the prosthetic treatment of orbita defects with a bone anchored facial prosthesis is a cosmetically satisfactory procedure with good long-term outcome. While modern plastic materials can replace the lost tissue with deceptively natural results, the implants guarantee firm secure retention of the facial prosthesis.

Key words orbital exenteration - facial prosthesis - craniofacial implant

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S. 395-400 (Art. 538)

Clinical use of a new method for the objective estimation of the minimum visual acuity
Michael Gräf, Herbert Kaufmann

Purpose Recently, a new method for the objective estimation of the minimum visual acuity (OEM) by means of suppression of the optokinetic nystagmus has been presented (Klin Monatsbl Augenheilkd 1998; 212 : 196-202). This study reports on the clinical use of this method.

Methods In 120 individuals referred to our clinic either to procure an opthalmological expert opinion or for differential diagnosis of an unclear visual impairment, an OEM was performed. The result of the OEM was compared to the clinical findings (history, biomicroscopy of anterior and posterior segments, objective refractometry, pupillary responses, binocular alignment, motility, binocular vision, colour vision, applanation tonometry, electrophysiology, fluorescein angiography, neurologic, radiologic, psychiatic findings, reproducibility of visual acuity and visual field statements under different conditions, comparison of subjective and objective visual field data, statistical prove of false visual acuity and visual field statements) which were critically interpreted concerning the credibility of the subject's statements.

Results As a result of the clinical examinations, the stated visual acuity of 62 individuals was credible. In one of these individuals, the OEM pointed to a slightly (1dB) better visual acuity. The statements of 7 individuals could not be categorized clinically. The OEM pointed to a better acuity in 3 cases. The stated vision of the remaining 51 individuals was not credible. In 38 of these cases, the OEM pointed to a better acuity, or false statements could be proven by the OEM.

Conclusion A significant rate (75%) of the individuals whose statements were not credible was detected by the computer-aided, nystagmographic method of OEM. The method allows an estimation of the actual minimum visual acuity and yields evidence of false statements concerning the detection acuity.

Key words nystagmography - visual acuity - psychophysical methods - functional visual loss - malingering

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S. 401-406 (Art. 492)

Influence of luminance to contrast sensitivity and glare in the mesopic range
Bernhard Rassow

Background Elderly persons applying for driving licence frequently are not able to fulfil the recommendations given by DOG and relating to twilight vision without and with glare. One reason may be the low level of luminance used for this test.

Materials and methods We compared contrast threshold with and without glare in the mesopic range of vision measured by two types of Rodenstock Nyktometers. One instrument was the standard, commercially available instrument (500) and in the other instrument (500 S) the luminance of the viewing field was raised by a factor of three and the luminance of the glare source by a factor of 2.2. We tested 50 persons divided in three groups aged 20 to 49, 50 to 59 and over 60 years.

Results With the standard instrument, some of the younger persons and nearly all of the elder ones were not able to fulfil the requirements for driver licensing. With the modified instrument (500 S), the group of the elder was divided in a greater part now able to fulfil the recommendations and a smaller one unable even at this luminance level. The standard deviation of the measured contrast sensitivity was one step of the contrast scale of the instruments. We also tested the influence of adaptation time on the contrast sensitivity. Only very few persons showed slightly better results after 15 minutes of adaptation compared to 5 minutes.

Discussion The luminance of today's headlights of motor cars is significantly higher than those at the time when the DOG rules where acquired. Testing contrastsensitivity without and with glare on a higher luminance level will reduce the number of those persons not able to fulfil the requirements for drivers licensing. The revision of these rules is discussed.

Key words Mesopic-vision - glare - contrast-sensitivity

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S. 407-411 (Art. 535)

Endothelial evaluation of corneal transplants by digital imaging
Thomas Reinhard, Helga Spelsberg, Dirk Holzwarth, Norbert Dahmen, Erhard Godehardt, Rainer Sundmacher

Background Evaluation of corneal graft endothelium in organ culture comprises judgement of cell area, cell form and cell density by phase contrast microscopy after cell border swelling in hypotonic solution. Up to now, cell density has been determined via counting cells by hand within a fixed frame on polaroid images regarding the magnification factor. It was the purpose of this paper to establish a facilitated and reliable method for endothelial cell count by digital imaging and to compare it with our standard procedure of endothelial cell count by hand.

Material and methods After cell border swelling in hypotonic solution endothelial images are recorded by a digital camera that is connected to a computer system where the grey scale images are processed into binary images using specialized enhancement and thresholding techniques. A fuzzy logic based computer program was developed in order to differentiate between single and multiple objects, i.e. living and necrotic cells. This digital imaging system determines endothelial cell density automatically and offers the possibility to correct the data in any case of misinterpretation. Twenty corneal grafts were evaluated with this system by two experienced investigators and the results were compared with endothelial cell count by hand.

Results Using the new system, intra- and interindividual variability of endothelial cell count was statistically significantly lower compared with evaluation by hand. Furthermore, less time for evaluation and documentation was necessary.

Conclusions In a reduced period of time endothelial cell density of corneal grafts in organ culture can be determined reliably and reproducibly with the new digital imaging system if the possibility of data correction is used in case of misinterpretation. In the future, the necessity of corrections should be reduced and the use of multiple fixed frames should further improve quality control of corneal grafts.

Key words Corneal endothelium - digital image processing - endothelial cell density - fuzzy logic - organ culture

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S. 412-414 (Art. 462 DF)

Crystalline keratopathy as presenting sign of multiple myeloma
Jeannette Gabel, Berthold Seitz, Arnold Hantsch, Gottfried O. H. Naumann

Background Noninfectious crystalline corneal degenerations can be classified from the clinical and genetical point of view into 3 groups: 1. primary hereditary (Schnyder), 2. secondary hereditary (cystinosis) and 3. secondary non-hereditary in association with disorders of serum protein or lipid composition.

Patient We report on a 63-year-old man with reduced vision and grey-white, crystalline, monomorpheous deposits in the corneal stroma. Further investigation revealded IgG myeloma.

Results We performed a penetrating keratoplasty for visual improvement. On histpathological examination, typical eosinophilic, PAS-positive, interlamellar deposits staining brilliant red with Masson`s trichrome were found diffusely scattered throughout the stroma. Electron microscopy showed intracellular, rhomboid-shaped deposits enveloped by a membrane.

Conclusion The appearance of a crystalline keratopathy should be followed by an internal examination for early detection and adequate treatment of a systemic disease.

Key words crystalline keratopathy - multiple myeloma - penetrating keratoplasty

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