Changes of extracellular matrix of the cornea in diabetes mellitus.

PURPOSE: Differences in corneal viscoelasticity due to diabetes have been reported to have a protective effect on the progression of glaucoma and the development and progression of keratoconus. Due to longterm changes of tissue in diabetes mellitus, biomechanical changes of the cornea because of glycation and modified extracellular matrix may be detectable. The purpose of the study was to determine whether there is a difference in corneal biomechanical properties, characterized by corneal hysteresis (CH) and central corneal thickness (CCT), between diabetic and normal subjects, and relate these to the duration of diabetes. METHOD: In a cross sectional study, a group of 484 eyes including 99 eyes of diabetic individuals was evaluated. CH as measured with the Ocular Response Analyzer, CCT (Orbscan II), Goldmann applanation tonometry (GAT) and slit-lamp examination were obtained from each patient. Linear mixed models were applied for statistical evaluation. RESULTS: CH showed a significant decrease with age (-0.036 mmHg/year, p < 0.01) while CCT increased significantly (+0.7 microm/year, p < 0.001). CH was significantly higher in diabetic eyes with an average difference of +0.55 mmHg (after correcting for age, IOP and CCT). This was not related to the duration of diabetes (mean 12.6 +/- 9.0y, p = 0.522). CCT did not differ with regard to diabetes. Intraclass correlation coefficients were 81% and 50% for CCT and CH respectively. CONCLUSION: CH is assumed to be an indicator for acquired changes of tissue such as diabetes-mediated. CCT is a more characteristic parameter for the individual patient. CH may provide more information about changes of the extracellular matrix in diabetes, and therefore offer a new monitoring parameter.

[Methods of measuring intraocular pressure independently of central corneal thickness]. / Hornhautdickenunabhängige Methoden der Messung des Augeninnendrucks.

INTRODUCTION: Goldmann applanation tonometry (GAT) has been the gold standard for measuring intraocular pressure (IOP) for about 50 years. However, it depends on central corneal thickness (CCT) and is, therefore, prone to being incorrect. Dynamic contour tonometry (DCT) has recently been introduced to measure IOP independently of CCT; however, DCT is costly and difficult. IOP measurement using the ocular response analyzer (ORA) offers noncontact tonometry with declaration of the corneal-compensated IOP (IOPcc), which takes corneal hysteresis (CH) into account and is supposed to be independent of CCT. PATIENTS AND METHODS: Using the ORA instrument, IOPcc was determined in 192 glaucoma eyes and 59 nonglaucoma eyes. Subsequently, measurement by DCT and GAT was performed. IOP measurements were compared and analyzed with respect to CCT and CH. RESULTS: Average values were as follows: IOPcc, 18.38+/-6.3 mmHg; GAT, 14.69+/-4.5 mmHg; DCT, 15.17+/-3.9 mmHg; CH, 9.96+/-2.5 mmHg; CCT, 552+/-57 mum. Neither CCT nor CH differed between the two groups. There was a positive correlation between GAT and CCT that did not exist for IOPcc and DCT values. However, IOPcc and DCT differed significantly in Bland-Altman analysis (p<0.01). Furthermore, these two IOP values differed significantly with respect to CH and the level of IOP. CONCLUSION: Because IOPcc is not a primarily measured variable but also takes CH into account, a direct comparison of DCT and IOPcc values is not acceptable, and a simple correction factor may not be valid.

[Measurement of viscoelastic corneal parameters (corneal hysteresis) in patients with primary open angle glaucoma]. / Bestimmung viskoelastischer Hornhauteigenschaften (korneale Hysterese) bei Patienten mit primärem Offenwinkelglaukom.

BACKGROUND: The ocular response analyzer (ORA) uses an air-pressure-triggered, dynamic, bi-directional corneal applanation method to measure biomechanical parameters of the cornea. Corneal hysteresis (CH) is defined as the difference in intraocular pressure recorded during inward and outward applanation. CH is therefore an indicator for the viscoelastic properties of the cornea. PATIENTS AND METHODS: CH was recorded in non-glaucoma patients (80 eyes) as well as in patients with primary open angle glaucoma (POAG, 82 eyes). The correlation between CH and central corneal thickness (CCT) was analyzed. RESULTS: Mean CH was 10.6+/-2.2 mmHg in the non-glaucoma group and 9.3+/-2.2 mmHg in patients with POAG (p<0.01). CH and CCT showed a positive correlation in non-POAG patients, however no such correlation was found in the POAG group. CONCLUSION: Patients with POAG show an alteration of biomechanical corneal parameters with a significant decrease in corneal hysteresis. A positive correlation between CH and CCT, which was seen in the non-glaucoma group could not be detected in the POAG group.

[Resolution of idiopathic macular holes after cryocoagulation of the vitreous base]. / Verschluss idiopathischer Makulaforamina nach Kryokoagulation der Glaskörperbasis.

BACKGROUND: There are only few reports on the spontaneous resolution of idiopathic macular holes. We report on 9 cases of resolution of idiopathic macular holes after cryocoagulation of the vitreous base. METHODS: We analyzed retrospectively 9 / 201 patients from 2005 - 2007, who were planned for a vitrectomy including peeling of the inner limiting membrane (ILM) due to an idiopathic macular hole. Each patient underwent cryocoagulation of the vitreous base 4 weeks ahead of the planned vitrectomy. At the first visit and the visit after cryocoagulation immediately before PPV was scheduled a complete clinical exam including OCT was performed. RESULTS: In all 9 cases macular hole had resolved within an average of 30 days after cryocoagulation. In 4 of these patients focal vitreoretinal adherences in the macula were detected in OCT before cryocoagulation was performed. These adhences had resolved after cryocoagulation. In 3 of these patients the posterior vitreous seemed still to adhere even after resolution of the macular hole after cryocoagulation. In 2 of these patients vitreous detachment seemed to have taken place before cryocoagulation as shown in the OCT scans, postoperatively an additional vitreous floater was detected by OCT so that a preoperative posterior vitreoschisis is assumed. CONCLUSION: Spontaneous resolution of idiopathic macular holes is very rare. After induction of vitreous detachment by cryocoagulation of the vitreous base, resolution of the macular hole seems to be more frequent. However, we do not recommend to delay vitrectomy due to a macular hole after cryocoagulation.

[Rate of reopening of macular holes following cataract operation]. / Wiedereröffnungsrate von Makulaforamina nach Kataraktoperation.

BACKGROUND: We set up this retrospective study to examine how different the functional and morphological results are following pars plana vitrectomy (ppV) for idiopathic macular holes in phakic eyes with later cataract surgery and in pseudophakic eyes, and to what extent cataract surgery can induce reopening of idiopathic macular holes after ppV. METHODS: A total of 189 eyes were vitrectomized because of idiopathic macular hole (37 pseudophakic, 152 phakic); 120 (22 pseudophakic, 98 phakic) of these eyes were examined at follow-up of an average of 19 months after vitrectomy. Cataract surgery was performed in 65 of the phakic eyes in this period. The functional and morphological results recorded for these 22 pseudophakic and 65 phakic eyes were evaluated. RESULTS: In the pseudophakic eyes preoperative visual acuity was 0.14, increasing to 0.20 postoperatively (p=0.16); in 1 case (4.5%) the macular hole was not closed at the time of the follow-up examination. Cataract extraction was performed in 65 of the phakic eyes an average of 10 months after ppV. The initial VA was 0.19 before ppV and increased to 0.37 (p<0.01) after cataract surgery; in 4 cases (6.2%) the macular hole was not closed by the time of the follow-up examination, but in each case this had already been noted when the cataract extraction was done. Reopening did not occur after cataract extraction in any of these cases. CONCLUSION: With a rate of 5.7% for reopening or persistence of macular holes, our results are comparable to those recorded in other studies. Cataract surgery following ppV does not influence the reopening rate of macular holes.

[The influence of corneal hysteresis and corneal resistance factor on the measurement of intraocular pressure]. / Der Einfluss von kornealer Hysterese und kornealem Resistenzfaktor auf die Messung des intraokularen Drucks.

BACKGROUND: The influence of central corneal thickness (CCT) on the measurement of intraocular pressure (IOP) has been discussed extensively in recent years. The problem, however, has not been solved so far. In addition to CCT there are probably further biomechanical properties that play a role in IOP measurement. We wanted to find out whether these properties are related to Goldmann applanation tonometry (GAT), noncontact tonometry (NCT), or CCT. MATERIAL AND METHODS: Biomechanical properties of the cornea such as corneal hysteresis (CH) and corneal resistance factor (CRF) can be measured with the Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY, USA). Furthermore, a corneal compensated IOP (IOPcc) is given. We examined 156 normal eyes of 80 patients who did not show corneal pathology nor glaucoma. In each eye GAT, NCT, and ORA data as well as CCT were measured. Data were statistically analyzed with respect to agreement and the influence of CH and CRF on IOP measurement. RESULTS: In our patients the following average values were calculated: GAT 14.8+/-3.0 mmHg, NCT 16.4+/-3.9 mmHg, IOPcc 16.2+/-4.1 mmHg, CH 10.6+/-2.3 mmHg, CRF 10.9+/-2.4 mmHg, and CCT 557+/-36 microm. IOPcc was not related to CCT in normal eyes and the only IOP value related to CH (p<0.01). CRF, however, was related to GAT and NCT values (p<0.01). DISCUSSION: In our group of normal eyes IOPcc, i.e., the value that is adjusted by measurement of viscoelastic properties of the cornea, in contrast to GAT and NCT does not depend on central corneal thickness. Corneal hysteresis and corneal resistance factor provide further information about biomechanical properties of the cornea beyond central corneal thickness.

[Bilateral serous detachment of the neurosensory retina and retinal pigment epithelium with rip of the peripheral pigment epithelium]. / Bilaterale seröse Abhebung der neurosensorischen Retina und des retinalen Pigmentepithels mit Riss des peripheren Pigmentepithels.

HISTORY: A 52-year-old patient with atypical plasmocytoma presented with a bilateral serous detachment of the retina as well as a huge detachment of the pigment epithelium (PE) in the periphery. Shortly thereafter the PE ruptured. In the left eye this led to substantial central macular fibrosis. DIAGNOSIS: The clinically healthy patient showed a nephrotic syndrome; neither typical monoclonality was detectable nor was erythropoiesis or myelopoiesis reduced. THERAPY: To avoid further reduction of VA pars plana vitrectomy (ppV) with silicone oil tamponade and laser coagulation was performed. Clinical findings were reduced significantly and VA was stabilized for 2.5 years. DISCUSSION: PE detachments and serous retinal detachments in patients with nephrotic syndrome are only mentioned in a few cases. However, a peripheral rupture of the PE to this extent seems to be very rare. Early ppV with silicone oil and laser coagulation may prevent further macular fibrosis.

[Intraocular pressure and corneal thickness. A comparison between non-contact tonometry and applanation tonometry]. / Augeninnendruck und Hornhautdicke. Ein Vergleich zwischen Non-Contact-Tonometrie und Applanationstonometrie.

OBJECTIVE: Corneal thickness and deformation seem to have a considerable influence on intraocular pressure measurement. Due to differences in the corneal deformation in either non-contact tonometry or applanation tonometry, both methods should be compared in the same patient group depending on central corneal thickness. METHODS: In 106 eyes of 55 patients (18 males, 37 females, age 17-89 years, mean 63.3 years) with glaucoma and central corneal thickness between 409 and 644 microm (Orbscan II pachymetry) intraocular pressure was measured in each eye with non-contact tonometry (Reichert AT550) and 30 min later with Goldman applanation tonometry. RESULT: Non-contact tonometry as well as applanation tonometry showed a positive correlation between measured intraocular pressure and corneal thickness. The steepness of the line of regression was 0.33 mmHg per 10 microm of corneal thickness in non-contact tonometry and 0.17 mmHg per 10 microm of corneal thickness in applanation tonometry. CONCLUSION: Independently of the large differences in individual pressure measurements between non-contact tonometry and applanation tonometry, we found higher IOP values with non-contact tonometry in thicker corneas as compared with applanation tonometry. In thinner corneas there was a better correspondence between both methods. Thus, it seems very likely that corneal rigidity increases with corneal thickness.

[Analysis of optical parameters after cataract surgery and implantation of foldable lens]. / Analyse der optisch wirksamen Parameter nach Kataraktoperation mit Faltlinsenimplantation.

PURPOSE: Within the first few weeks after cataract surgery, changes of refraction can occur in patients with "clear cornea" surgery and implantation of foldable lenses. The possible reasons were analyzed. METHOD: In 71 consecutive patients we determined axial length, anterior chamber depth, corneal refraction, and corneal thickness prior to cataract surgery, on the 1st postoperative day, and at a follow-up control after obtaining stable refraction. We divided the patients into three groups: patients with no change of refraction between the 1st postoperative day and the follow-up (group A), patients with hyperopic shift of refraction (group B), and patients with myopic shift of refraction (group C). RESULTS: In all three groups we measured no significant postoperative change of the axial length. Central corneal thickness increased by approximately 37 microm on the 1st postoperative day and had normalized at the time of control. Anterior chamber depth decreased in all groups by approximately 0.44 mm between the 1st postoperative day and the follow-up. Central corneal refraction showed an decrease in groups B and C and an increase in group A. The standard deviation was very high in all groups. CONCLUSIONS: The postoperative change of refraction depends on multiple factors among which changes of the anterior chamber depths, the corneal refraction, the swelling of the cornea, and the axial length can play a role.

[Anatomical and functional results after elective macular surgery]. / Anatomische und funktionelle Ergebnisse nach elektiver Makulachirurgie.

PURPOSE: The purpose of this paper is to assess the anatomical and functional results after macular surgery in a large group of patients. METHODS: Between June 1995 and December 2001, 381 eyes underwent vitreous surgery for macular pucker (n=244) or macular holes (n=137) with a standard pars plana vitrectomy (PPV) with induction of posterior vitreous separation, membrane peeling, peeling of the internal limiting membrane (no ICG staining was used), and gas instillation (SF(6)). RESULTS: A second surgical intervention due to vision-threatening complications after PPV had to be performed in 8 of 381=2.1%. In the macular pucker group, metamorphopsias improved in 46.6% and the median of visual acuity (VA) improved from preoperative 0.3 to postoperative 0.5. Hole closure of macular holes was obtained in 92.2%; the median of VA improved in this group from preoperative 0.2 to postoperative 0.4. CONCLUSION: In our group a second vitreoretinal procedure due to vision-threatening complications had to be performed in 2.1%. Compared to the spontaneous course, PPV for macular pucker or macular hole has a very positive influence on functional parameters.

Complications of retinal xenon-arc photocoagulation.

The perioperative complications of xenon-arc photocoagulation of 245 eyes of 165 patients were reviewed. The follow-up ranged from 5 days in case of no complication to 5-30 days in case of complications. In 210 eyes (approximately 86%) photocoagulation could be carried out without any complication. Severe complications occurred in only 8 cases (approximately %). Among these were retrobulbar hematoma, keratopathy, secondary glaucoma, and persistent choroidal detachment. The number of burns per eye was of minor influence to the occurrence of complications.

Vitreopapillary traction in proliferative diabetic vitreoretinopathy [ssee comments].

AIM: To present the clinical profile of a new entity in advanced proliferative diabetic vitreoretinopathy (PDVR). Mechanisms of vision loss due to vitreopapillary traction on the nasal optic disc are described, followed by an introduction of methods for prevention and treatment in such cases. METHODS: 17 patients with PDVR and traction on the nasal side of the optic disc, pallor of the optic nerve head, and reduced visual acuity were included in the study. Six patients were observed retrospectively and 11 patients prospectively before and after pars plana vitrectomy. Pre- and postoperative examinations included visual acuity, Goldmann's visual field, fluorescein angiography, and measurements of visual evoked potentials (VEP). RESULTS: During a postoperative follow up period of 3 to 24.5 months (mean 14.5 months) an improvement in optic disc appearance combined with an increased visual acuity (mean increase in VA = 0.171) was observed in 15/17 (88.3%) patients. In addition, 8/17 (47%) of these patients showed higher VEP amplitudes (mean 3.83 microV), and eight (6/8 of the same patients as VEP amplitudes) patients showed a reduction of latency (mean reduction 22.25 ms) during VEP assessment. CONCLUSION: These results suggest that vitreopapillary traction may damage the anterior optic nerve, via decreased axoplasmatic flow in the optic nerve fibres and/or mechanical reduction of perfusion in the posterior ciliary arteries. The effects of each mechanism appear to be reversible, but in the long term might lead to irreversible optic nerve atrophy. Therefore, in patients with vitreopapillary traction, early vitrectomy should be considered as a method to prevent optic neuropathy.

[Haze and regression after photoreactive keratectomy (PRK)]. / Haze und Regression nach photorefraktiver Keratektomie (PRK).

UNLABELLED: According to the recommendations of the German Ophthalmological Society (DOG), PRK in myopic patients between -1.0 dpt and -6.0 dpt is a scientific acknowledge treatment. The risks of the treatment, however, increase in myopia above -6.0 dpt. MATERIAL AND METHODS: Between june 1994 and october 1997 we performed PRK on 338 eyes from 212 myopic patients in the ALZ Eye Clinic Hamburg. Myopia ranged between -1.25 and -11.25 diopters. All treatments were performed with the Keracor 116 (Fa. Chiron Technolas). The procedure was the same in all cases: mechanical abrasion, excimer laser treatment, antibiotic and nonsteroidal antiphlogistic drops for three days followed by a corticosteroid therapy for 5 months. RESULTS: Out of these 338 eyes, 17 eyes after 12 months had a persistent haze grade 1-2 or more according to Stein, Cheskes and Stein. These 17 eyes had also an average regression of -1.67 diopters (SD 1.8) and lost at least in minimum two lines of the best corrected visual acuity 12 months postoperatively. The refraction of the 17 eyes was more than -6 dpt preoperatively. CONCLUSION: Haze after PRK is in most cases only transient. Haze of grade 1-2 or more after 12 months postoperatively is correlated with regression and a loss of best corrected visual acuity. PRK below -6 dpt in our hands never showed haze grade 1-2 or more 12 months postoperatively. Therefore patients with a refraction of more than -6 dpt before PRK should be informed about this potential risks. In these cases LASIK should be taken into consideration.

["Refractive" cataract surgery. PMMA IOLs versus foldable IOLs]. / "Refraktive" Kataraktchirurgie. PMMA-Linsen versus Faltlinsen.

OBJECTIVE: Modern cataract surgery claims to achieve the desired refractive result immediately after surgery. METHODS: In 104 consecutive patients who were operated on with phacoemulsification and scleral incision and received a 6 mm PMMA IOL and in 70 consecutive patients operated on with temporal clear cornea incision and implantation of a foldable 6 mm IOL (Acrysof) visual acuity, refraction and astigmatism were determined preoperatively, between days 1 and 3 postoperatively and controlled again at least 5 months after surgery. The results were compared with the desired preoperative refraction. RESULTS: At days 1-3 postoperatively,a deviation of not more than +/-1.0 D (spherical equivalent) from the desired refraction occurred in 73.1% of the PMMA IOL patients and in 77.2% of the foldable IOL patients. At control 76.0% of the PMMA and 85.7% of the foldable lens patients showed a deviation of not more than +/-1.5 D,88.5% of the PMMA and 98.6% of the foldable lens patients showed a deviation of not more than +/-1.5 D and 96.2% of the PMMA and 100% of the foldable lens patients showed a deviation of not more than +/-2.0 D from the desired refraction. The individual changes of the refraction (spherical equivalent) between the first and the third postoperative day and the time of control, however,were considerable and reached more than +/-1.0 D in 20.0% of the foldable lens patients and 16.3% in the PMMA lens patients. Only 6.7% of the patients in the PMMA lens group and not more than 12.8% patients of the foldable lens group showed no change of refraction (spherical equivalent). CONCLUSION: The goal of modern cataract surgery, which is to achieve a stable refraction corresponding to the desired preoperative refraction immediately after surgery, has not yet been achieved. At present the refractive changes in scleral incision techniques as well as in clear cornea techniques make an immediate postoperative prescription of glasses impossible.

[Change in twilight vision and glare sensitivity after PRK]. / Veränderung des Dämmerungssehens und der Blendempfindlichkeit nach PRK.

BACKGROUND: Morphological changes in the corneal surface after PRK may result not only in refraction fluctuations and reduction in visual acuity, but also in changes of contrast sensitivity. The aim of this study was to investigate whether PRK has an influence on contrast sensitivity with and without glare with a subsequent effect on the ability to drive cars. PATIENTS AND METHODS: Anonymous inquiries were made by means of a questionnaire sent to 114 patients after bilateral PRK in which the patients were asked to assess subjectly their driving ability. Additionally, in 66 eyes of 66 patients with a mean myopia of -5.3 D, an investigation on contrast sensitivity was performed according to the recommendations of the DOG (German Ophthalmological Society) using a Rodenstock nyctometer. RESULTS: Postoperatively, 55% of the patients felt more comfortable driving a car than preoperatively, 31% did not recognize any change, and 14% felt more uncomfortable driving car. Contrast sensitivity with or without glare 2 weeks postoperatively was so much reduced in 77% or 53%, respectively, of the patients that the criteria for driving a car in Germany were not fulfilled. Within the first 12 months after PRK the number of impaired patients diminished but even 1 year after PRK the number of patients with reduced contrast sensitivity with and without glare was higher than before PRK. Surprisingly, however, the criteria for driving a car with respect to contrast sensitivity with and without glare were not fulfilled even before PRK by as much as 44% and 24% of the patients, respectively. CONCLUSIONS: All patients must be in formed about the possible impairment for driving a car before PRK is performed.

[Intraocular pressure after cyclophotocoagulation with the diode laser]. / Tensionsverlauf nach Zyklophotokoagulation mit dem Diodenlaser.

BACKGROUND: The reduction of intraocular pressure (IOP) following a single cyclophotocoagulation (CPC) procedure with a diode laser was investigated retrospectively. METHOD: CPC was performed on 150 eyes with a diode laser using standard parameters. The decrease of IOP between the 1st and 3rd day after surgery, after 6 months and after 1 year was investigated for different types of glaucoma and complications were documented. RESULTS: Overall and also in the individual groups the mean reduction of IOP within the first 3 days postoperation was 35%. The main effect, however, occurred within the 1st day after CPC. In the long-term results for 6 months and 1 year, the mean pressure values remained relatively stable but with a high standard deviation. A postoperative inflammatory reaction in the anterior chamber was observed in 15 eyes, 1 eye showed a temporary hypotension and 2 eyes a phthisis. Success of CPC was almost identical in all treatment groups with a 38% decrease of IOP after the 1st year. Additionally IOP was stable at a low level during the 1st year after CPC. After 1 year 42% of all eyes were still successfully treated: 38% of eyes needed further CPC treatment. CONCLUSIONS: CPC is an effective procedure for surgical reduction of intraocular pressure. The initial pressure-reducing effect of CPC was not related to the type of glaucoma. The individual predictability of the effect of CPC, however, is difficult because of the high interindividual differences. The rate of complications is low.

[Failures in primary surgery of retinal detachment with cerclage]. / Misserfolge bei primärer Ablatio-Operation mit Cerclage.

In a retrospective study we analysed 30 unsuccessful circumferential buckling operations being performed in the years 1990 and 1991 as primary interventions on simple retinal detachments without PVR, directing our attention to the cause of the failure. 13 eyes (43%) showed simple retinal detachments with holes located anterior (20%) or posterior (23%) to the circumferential buckle. In 12 of these eyes (40%) the retina could be reattached permanently by a re-operation with a second scleral buckling procedure. Another 15 eyes (50%) showed retinal holes not being sealed by the circumferential buckle. In addition, however, the retina in these eyes was kept from reattachment by a PVR grade C or D at the time of the re-operation. In 9 eyes (30%) of this group reattachment could be achieved after vitrectomy with endotamponade, in 6 eyes (20%) the retina could not be reattached. Only 2 eyes (7% of all patients) showed a PVR detachment without detectable retinal breaks. Thus, failures of primary circumferential buckling operations in numerous cases are caused by either inadequate surgical procedures or by a poor surgical technique.

[Keratomileusis in situ in high grade myopia. Initial results]. / Keratomileusis in situ bei hoher Myopie. Erste Ergebnisse.

Besides photorefractive keratectomy (PRK) with the excimer laser, different methods of intrastromal keratectomy are now available for refractive corneal surgery in myopic patients. The first results of keratomileusis in situ in high-grade myopia are presented. Keratomileusis in situ was performed with a semiautomatic mechanical microkeratome in 15 amblyopic eyes with a refraction (spherical equivalent) between -12 and -25 D (mean -18.18 D). The principle of the method consists in a change of the anterior corneal curvature by resection of a refractive lenticulus out of the corneal stroma. The first step is the removal of a superficial corneal lamella consisting of epithelium, Bowman's layer, and superficial stroma. After this, the refractive lenticulus is resected out of the stroma, and the superficial lamella is sutured back to the cornea. The postoperative refraction (spherical equivalent) 4 weeks after the operation ranged between + 1.5 and -4.5 D (mean -1.37 D). Best corrected preoperative visual acuity was achieved again postoperatively within 4 weeks in most of the patients; in some patients the postoperative visual acuity even exceeded the preoperative values. After an uncomplicated healing process in 14 of the 15 eyes the cornea remained completely transparent in the optical zone, and the effect of treatment remained stable. Scar formation was observed in one eye only, where the lamellar cut was inadvertently performed in Bowman's layer and not in the stroma. Thus, keratomileusis in situ is a supplementary technique to conventional refractive surgery in high-grade myopia. Its advantages are quick optical rehabilitation and an almost scar-free optical zone, because the integrity of Bowman's layer is almost completely maintained with this technique.

[Vitreoretinal secondary procedures following elective macular surgery]. / Vitreoretinale Zweiteingriffe nach elektiver Makulachirurgie.

OBJECTIVE: The spectrum of reoperations after macular surgery was investigated retrospectively in a large group of patients. All secondary surgical procedures except for cataract surgery were considered. METHODS: Between July 1995 and June 2001 353 eyes underwent macular surgery (218 due to macular pucker, 135 due to macular hole) with a pars-plana vitrectomy (PPV), creation of vitreous detachment, membrane peeling and SF(6)/air-instillation. The vitrectomies were performed by 4 different surgeons. In all patients a preoperative circular peripheral cryoretinopexy was performed 3-4 weeks before macular surgery. The follow-up was 20.9 months on average. The number of revitrectomies as well as the postoperative retinal detachment rate were investigated. RESULTS: In 33 cases (9.3%) a second vitrectomy had to be performed due to an unsatisfying postoperative macular finding: 17/218 (7.8%) after macular pucker surgery with a recurrent pucker and 16/135 (11.8%) after macular hole surgery with persistent or recurrent macular hole. In 7/353 (2.0%) a postoperative rhegmatogenous retinal detachment was observed and in 2/353 (0.6%) a postoperative endophthalmitis had to be treated. CONCLUSION: In 9.3% of our patients a second PPV due to an unsatisfying macular finding became necessary. The rate of postoperative retinal detachment of 2.0% is considerably lower than in most other studies. Therefore, a possible prophylactic effect of the preoperative circular peripheral cryoretinopexy is suggested to reduce the risk of postoperative retinal detachment.

[Traction vitreoretinal opticopathy in proliferative diabetic vitreoretinopathy]. / Traktive vitreoretinale Optikopathie bei proliferativer diabetischer Vitreoretinopathie.

UNLABELLED: In patients with proliferative diabetic vitreoretinopathy the authors noticed tractive vitreoretinal distortion of the optic disk to the nasal side. As a result of this distortion a reduction in visual acuity, pallor of the optic disk, and changes in the visual evoked potentials were registered. The disease in called "tractive vitreoretinal opticopathy." METHOD: We examined 15 diabetics with vitreoretinal traction and temporal pallor of the optic disk, as well as a reduction in visual acuity. Six patients were observed retrospectively and 9 patients prospectively before and after vitrectomy. Pre- and postoperative examinations included visual acuity, visual field, fluorescence angiography, and the conduction of visual evoked potentials (VEP). RESULTS: Within a postoperative follow-up of 2-8 months (mean 6.5 months) a return of optical vitality combined with an increase in visual acuity could be seen in 14 of 15 patients. In addition, some of the patients showed an improvement in the amplitudes and a reduction in the latency of the VEP. CONCLUSIONS: The authors assume that the axoplasmatic flow in the optic nerve fibers is reduced according to vitreoretinal traction. Furthermore, the traction may cause elongation of the capillaries, resulting in reduced perfusion of the optic disk. For these reasons early vitrectomy in patients with tractive vitreoretinal opticopathy is recommended.