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Aljoscha S Neubauer

Publications and source records attributed to Aljoscha S Neubauer.

At least 19 recordsLinked to original sources
PubMed2007

Endothelial cell density in donor corneas: a comparison of automatic software programs with manual counting.

PURPOSE: Several automated systems have become available to determine endothelial cell density (ECD) of donor corneas. The purpose of this study was the comparison of 2 systems, the Endothelial Analysis System EAT V1.4 (Rhinetec, Duesseldorf, Germany) and the NAVIS Cell Count Version 3.4.1 (Nidek Technologies, Erlangen, Germany), against manual ECD counts. METHODS: During organ culture, the endothelium of 50 human corneas was photographed on both conventional film and digitally. Manual fixed-frame counting was performed on 2 photographs by 3 experienced ophthalmologists. Three digital pictures of each cornea were analyzed semiautomatically on the Rhinetec EAT system V1.4. Images were imported and analyzed by the fully automatic mode of the NAVIS system V3.4.1 (which also offers a semiautomatic counting mode). In an additional experiment on 11 corneas, the NAVIS counts on the microscopy system previously used only for manual cell counts were directly compared with manual counts. RESULTS: Mean endothelial cell density obtained by manual counting of all observers was 2679 +/- 313 (SD) cells/mm. Values obtained by digital analysis with EAT were a mean of 1.3% higher (2713 +/- 286 cells/mm), which is not a significant difference. In contrast, analysis of the digital pictures with the fully automated NAVIS software mode showed a mean of 7.0% higher measurements (2867 +/- 111 cells/ mm), a significant difference (P = 0.0001). Altman-Bland analysis revealed that the fully automated NAVIS counts gave too low results for high ECDs and too high results for low ECDs. This result was confirmed by the direct comparison with manual counting. CONCLUSIONS: Fully automated analysis of ECD remains problematic. Validation of any computer-assisted system against manual counting is of importance.

Adolescent↗
PubMed2006

Visual quality of life after macular hole surgery: outcome and predictive factors.

BACKGROUND: In the present study we evaluated the functional success after macular hole surgery in correlation to visual quality of life and looked for predictive factors determining surgical success. METHODS: Fifty-nine patients that underwent pars plana vitrectomy for idiopathic macular hole were included. Follow-up visits were performed in regular intervals after surgery and included a clinical examination, optical coherence tomography (OCT) and measurement of visual acuity. To assess the visual quality of life patients filled out the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25) before and three months and one year after surgery. RESULTS: Macular hole closure was achieved in 57 of 59 patients (97%). Mean visual acuity increased from 20/100 preoperatively to 20/34 one year after surgery (p = 0.02). Despite good visual acuity (20/27) in the fellow eye, visual quality of life (VFQ composite score) rose from 75.9 +/- 14.4 (SD) to 81.5 +/- 14.2 one year after surgery (p<0.001). Although there was no correlation between the increase in visual quality of life and visual acuity, the increase in VFQ-25 could be well predicted: low visual acuity and significant impairment on VFQ-25 testing preoperatively made patients most likely to benefit from macular hole surgery. A relatively high retinal thickness measurement at the hole border measured on OCT further increases the predictive value. CONCLUSION: Macular hole surgery is associated with an increase in visual quality of life despite good visual acuity of the fellow eye. Preoperative visual acuity, VFQ-25 value and partly OCT may help to predict the increase in patients' vision related quality of life after surgery.

Aged↗
PubMed2006

Immunohistochemical findings after LASIK confirm in vitro LASIK model.

PURPOSE: To compare immunohistochemical findings in human donor corneas after successful laser in situ keratomileusis (LASIK) without clinical complications with a recently established human LASIK in vitro model. METHODS: Donor corneas with prior LASIK treatment were investigated. Cryostat sections were stained immunohistochemically for collagen types I, III, and VI and laminin and fibronectin. RESULTS: With light microscopy, the interface of the LASIK flap could hardly be detected. In all samples, fibronectin was consistently detected along the entire extent of the surgical wound. In contrast, collagen type III and laminin only stained the superficial portion of the LASIK incision site. Staining for collagen types I and VI showed no changes after LASIK. CONCLUSION: Histologic findings in donor corneas with prior LASIK treatment confirm histologic observations in a recently introduced human organ culture LASIK model. This strengthens the reliability of the latter LASIK model for further studies concerning wound healing after LASIK surgery.

Adult↗
PubMed2006

Comparison of optical coherence tomography and fundus photography for measuring the optic disc size.

PURPOSE: To assess the agreement and repeatability of optic nerve head (ONH) size measurements by optical coherence tomography (OCT) as compared to conventional planimetry of fundus photographs in normal eyes. METHODS: For comparison with planimetry the absolute size of the ONH of 25 eyes from 25 normal subjects were measured by both OCT and digital fundus photography (Zeiss FF camera 450). Repeatability of automated Stratus OCT measurements were investigated by repeatedly measuring the optic disc in five normal subjects. RESULTS: Mean disc size was 1763 +/- 186 vertically and 1632 +/- 160 microm horizontally on planimetry. On OCT, values of 1772 +/- 317 microm vertically (p = 0.82) and a significantly smaller horizontal diameter of 1492 +/- 302 microm (p = 0.04) were obtained. The 95% limits of agreement were (-546 microm; +527 microm) for vertical and (-502 microm; +782 microm) for horizontal planimetric compared to OCT measurements. In some cases large discrepancies existed. Repeatability of automatic measurements of the optic disc by OCT was moderately good with intra-class correlation coefficients (ICC) of 0.78 horizontally and 0.83 vertically. The coefficient of repeatability indicating instrument precision was 80 microm for horizontal and 168 microm for vertical measurements. CONCLUSIONS: OCT can be used to determine optic disc margins in moderate agreement with planimetry in normal subjects. However, in some cases significant disagreement with photographic assessment may occur making manual inspection advisable. Automatic disc detection by OCT is moderately repeatable.

Adult↗
PubMed2006

Potential role of tissue transglutaminase in glaucoma filtering surgery.

PURPOSE: Scarring of the filtering bleb site is the main cause of failure in glaucoma filtration surgery. In the present study, the role of tissue transglutaminase (tTgase) in the accumulation of extracellular matrix (ECM) proteins in these scars was investigated. Transglutaminases are enzymes capable of cross-linking ECM proteins to proteolysis-resistant complexes. METHODS: Expression of tTgase, its reaction product epsilon-(gamma-glutamyl)-lysine, and fibronectin and their colocalization were investigated immunohistochemically in failed blebs and in an in vitro trabeculectomy model. Failed blebs were analyzed by RT-PCR for the presence of tTgase mRNA. Human Tenon fibroblasts (HTFs) were treated with transforming growth factor-beta2 (TGF-beta2). The effect was studied with immunohistochemistry, Northern blot analysis, and Western blot analysis. tTgase activity was assayed by incorporation of biotinylated cadaverine into fibronectin. RESULTS: Expression of tTgase and epsilon-(gamma-glutamyl)-lysine was present in all failed blebs. Staining was most prominent at the rim of the Tenon cyst. In the in vitro trabeculectomy model, tTgase and epsilon-(gamma-glutamyl)-lysine were barely present at the incision side of the flap but were perspicuously increased by TGF-beta2 treatment. Enzyme and its reaction product were colocalized with fibronectin. Cultured HTFs contained a basal level of tTgase mRNA. After treatment with TGF-beta2, expression and activity of tTgase significantly increased. CONCLUSIONS: The findings demonstrated that tTgase is present and functionally active in failed blebs. Expression and activity of tTgase appeared to be stimulated by TGF-beta2, a growth factor known to be increased in primary open angle glaucoma. Intervention at this pathway might open a new approach to prevent scarring after glaucoma filtration surgery.

Adult↗
PubMed2006

Keratinocyte transglutaminase in proliferative vitreoretinopathy.

PURPOSE: Proliferative vitreoretinopathy (PVR) is an excessive wound-healing process and the major complication in rhegmatogenous retinal detachment. The present study was designed to investigate the expression of keratinocyte transglutaminase (kTgase) in PVR membranes and retinal pigment epithelial (RPE) cells and to evaluate its expression in response to growth factors known to be increased in PVR disease. METHODS: Distribution of kTgase and its relation to fibronectin have been investigated immunohistochemically. PVR membranes and native and cultured RPE cells were analyzed by RT-PCR for the presence of kTgase mRNA. In vitro, RPE cells were treated with transforming growth factor (TGF)-beta2, basic fibroblast growth factor, interleukin-6, and interleukin-1beta. Expression of kTgase was studied by Northern and Western blot analysis. The effect of connective tissue growth factor (CTGF) silencing on the TGF-beta2-modulated expression of kTgase was investigated by transfection with CTGF small interfering (si)RNA before TGF-beta2 treatment. RESULTS: mRNA expression of kTgase was present in all PVR membranes. Immunohistochemical staining for kTgase showed an inhomogeneous pattern with localized accumulation and little colocalization with fibronectin. Although native RPE cells contained only a basal level of kTgase mRNA, the expression of kTgase was increased under culture conditions and was further enhanced by TGF-beta2 treatment. Silencing of CTGF expression did not attenuate the TGF-beta2-mediated induction of kTgase. CONCLUSIONS: The findings demonstrate that kTgase is present in PVR membranes. Its amount is related to the differentiation state of RPE cells and stimulation by TGF-beta2. TGF-beta2-mediated increase seems to be independent of CTGF.

Adolescent↗
PubMed2005

Mapping of the retinal pigment epithelium in exudative age related macular degeneration.

PURPOSE: To evaluate a novel technique for three-dimensional mapping of the retinal pigment epithelium (RPE) layer in patients with subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration. METHODS: Scanning with a recent generation retinal thickness analyzer (RTA) was performed in consecutive patients undergoing fluorescein angiography. From a 3 x 3 mm area centered on the fovea, three-dimensional area maps of the RPE level were calculated by external spreadsheet software. Included were 18 eyes with classic CNV, 18 eyes with occult CNV and 18 eyes from age-matched normal subjects. Repeatability was assessed by measuring 17 eyes with CNV 3 times. In ten additional patients, RTA imaging results were compared with cross-sections obtained by optical coherence tomography. RESULTS: By both methods, distinctive changes in RPE level maps were observed in classic and occult CNV. In classic CNV with the lesion extending over the RPE, only focal irregularities in the anteriorly displaced RPE surface were observed. In contrast, mapping of occult CNV showed a more irregular displacement of the RPE layer. The RPE map standard deviation indicating surface irregularity differed statistically significantly between the groups, with coefficients of variance of 5.9% for controls, 6.1% for classic and 8.8% for occult CNV (P < 0.001). Regarding repeatability, RPE level maps showed 1.2% coefficient of variance and an intra-class correlation coefficient of 0.87 for triplicate measurements in CNV patients. CONCLUSIONS: Topographic mapping of CNV lesions offers a fast, reproducible method for obtaining three-dimensional morphometric information on the RPE level and to quantify changes.

Adult↗
PubMed2005

Age effect on retina and optic disc normal values.

PURPOSE: To investigate retinal thickness and optic disc parameters by the Retinal Thickness Analyzer (RTA) glaucoma program in older normal subjects and to determine any age effect. METHODS: Subjects over 40 years of age without any prior history of eye diseases were recruited. Only subjects completely normal on clinical ophthalmologic examination and on visual field testing by Humphrey Field Analyzer (HFA) using the SITA 24-2 program were included. A total of 74 eyes from 74 subjects with even age distribution over the decades were enrolled and underwent topographic measurements of the posterior pole and of the optic disc by RTA. The 'glaucoma full' program in software version 4.11B was applied. RESULTS: Mean patient age was 59.9 +/- 10.3 years with a range from 40 to 80 years. The only parameter intraocular pressure (IOP) correlated with was retinal posterior pole asymmetry (r = 0.27, p = 0.02). IOP itself increased significantly with age (r = 0.341, p = 0.003). Mean defect and pattern standard deviation of the HFA did not correlate with any of the retinal or optic disc measurements. Increasing age correlated significantly with some of the morphologic measurements of the RTA: decreasing perifoveal minimum thickness (r = -0.258, p = 0.026), increased cup-to-disc area ratio (r = 0.302, p = 0.016) and increased cup area (r = 0.338 p = 0.007). CONCLUSIONS: An age effect exists for some of the retina and optic disc measurements obtained by the RTA.

Adult↗
PubMed2005

Comparison of prednisolone 1%, rimexolone 1% and ketorolac tromethamine 0.5% after cataract extraction: a prospective, randomized, double-masked study.

PURPOSE: To compare the efficacy, safety and patient comfort of two topical steroids (prednisolone 1% and rimexolone 1%) and a topical non-steroidal anti-inflammatory agent (ketorolac tromethamine 0.5%) after extracapsular cataract extraction. METHODS: Forty-five patients were enrolled in this prospective, randomized, double-blind study. They were assigned to receive topical treatment with either prednisolone, rimexolone or ketorolac tromethamine ophthalmic solution after phacoemulsification for cataract extraction. On postoperative days 1, 3, 5, 14 and 28 best-corrected visual acuity, intraocular pressure (IOP), slit-lamp examination of the anterior segment and report of the patients' comfort were assessed and compared by Friedman rank time analysis. RESULTS: Regarding the primary outcome efficacy of inflammation control the assessment of cells did not differ (p=0.165), while flare in the anterior chamber was lowest (p=0.008) in the non-steroidal anti-inflammatory drug (NSAID) group. Surface inflammation was lowest with prednisolone (p=0.002). Regarding safety, visual acuity did not differ among the groups. In the prednisolone group one patient, however, responded to steroid treatment with elevated IOP and had to be excluded. In the remaining patients IOP was even lower in the two steroidal treatment groups than with ketorolac (p=0.030). One patient receiving ketorolac had to be excluded because a corneal erosion developed. Patient comfort was highest with prednisolone (p=0.041). CONCLUSIONS: Ketorolac tromethamine provides good control of intraocular inflammation after cataract extraction without the risk of a steroidal IOP increase, which was also not observed under rimexolone therapy. The best surface inflammation control and patient comfort was observed with prednisolone, which remains a good choice.

Administration, Topical↗
PubMed2005

Absence of scar formation in human donor cornea with prior laser in situ keratomileusis.

PURPOSE: To investigate transglutaminases (enzymes capable of cross-linking extracellular matrix proteins to proteolysis-resistant complexes during scar tissue formation) in a human donor cornea after successful laser in situ keratomileusis (LASIK) without clinical complications and to compare with the results in a human donor cornea with corneal scarring after corneal injury. SETTING: Department of Ophthalmology, Ludwig-Maximilians University, Munich, Germany. METHODS: A donor cornea with prior uneventful LASIK treatment and 1 with corneal scarring after penetrating injury were investigated. Cryostat sections were stained immunohistochemically for tissue transglutaminase (tTG), keratocyte transglutaminase (kTG), and their reaction product epsilon-(gamma-glutamyl)-lysine. RESULTS: With light microscopy, the flap interface of the LASIK-treated eye could hardly be detected, while in the injured eye, infiltration of cells and a clear margin next to the scar formation were present. Immunohistochemistry demonstrated a distinct staining for tTG, kTG, and epsilon-(gamma-glutamyl)-lysine in the corneal scar. In contrast, neither transglutaminase nor epsilon-(gamma-glutamyl)-lysine staining could be observed at the flap margin or in the interface of the LASIK-treated donor eye. CONCLUSIONS: Irreversible protein cross-linking of transglutaminases via epsilon-(gamma-glutamyl)-lysine connections seem to be indicators for scarring in corneal wound healing. The absence of transglutaminases and their reaction product epsilon-(gamma-glutamyl)-lysine in a LASIK-treated cornea supports the idea of missing scar tissue formation after LASIK surgery.

Adult↗
PubMed2004

Detection of laser in situ keratomileusis in a postmortem eye using optical coherence tomography.

With more individuals having laser in situ keratomileusis (LASIK), eye banks are challenged to detect prior refractive surgery in donor tissue. We report the case of a donor who had LASIK 9 months before his death. Slitlamp biomicroscopy, corneal topography, and optical coherence tomography (OCT) were performed to evaluate the corneas. Few changes were detected under slitlamp examination and corneal topography. We demonstrate that OCT is capable of detecting LASIK-induced structural changes in the immediate postmortem evaluation and during the early and late period of organ culture. We recommend OCT screening of potential donor corneas before organ culture and between days 9 and 12 of organ culture.

Cornea↗
PubMed2004

The multifocal pattern electroretinogram in glaucoma.

BACKGROUND: The pattern ERG can be used to detect early glaucomatous change, because the response of cells in the inner retina from (typically) 20 degrees -40 degrees of area is reduced before perimetric abnormality is certain. The multifocal pattern electroretinogram (mfPERG) allows analysis of many local regions within this area. The aim of this study was to investigate whether in patients with presumed glaucoma the mfPERG permits diagnosis and discrimination from normals. METHODS: Measurements on 25 age-related normal eyes were compared to those on 23 eyes with different stages of glaucoma. A RETIScan system was used to generate a stimulus pattern of 19 hexagons, each consisting of six triangles. The triangles pattern-reversed black to white at 75 Hz. Those 19 hexagons were grouped into three stimulus regions: a central field, a middle, and a peripheral ring. The complete array subtended 48 degrees at the eye. The hexagons alternated between black and white, in a temporal pattern that followed a corrected binary m-sequence (length 512, 10 cycles with 39 s each). The amplitudes and latencies of positive responses at approximately 50 ms (P-50) and negative responses at approximately 95 ms (N-95) were analyzed. RESULTS: In patients with glaucoma the P-50 and N-95 components of the mfPERG were significantly reduced for the central area and both outer rings compared to normal volunteers (p<0.001, Mann-Whitney-U). The most distinct reduction was observed for N-95 and the central ring. Changes in latencies were not conclusive. The reduction of the components increased with the stage of glaucoma. A predictive model for detecting early glaucomatous changes was designed based on P-50-N-95 with 88% sensitivity and 76% specificity. CONCLUSION: In glaucoma a marked reduction of components, especially centrally is observed in the mfPERG. This hints to an early involvement of central ganglion cells and may be useful for future functional tests.

Adult↗
PubMed2004

Laser in situ keratomileusis in human corneas: new organ culture model.

PURPOSE: To establish an in vitro model of laser in situ keratomileusis (LASIK) in human donor eyes and to test its validity in comparison with animal models. SETTING: Department of Anatomy, Friedrich-Alexander Unviersity, Erlangen, Germany. METHODS: Laser in situ keratomileusis was performed on 20 organ-cultured human corneal buttons. The excimer laser ablations ranged from 0 to 12.0 diopters. The corneas were maintained in culture for up to 6 months and then evaluated with light microscopy and transmission electron microscopy. In addition, corneal sections were immunohistochemically stained for collagen type III, laminin, and fibronectin. The main outcome measures were the ultrastructural and immunohistochemical features of the stromal incision interface. RESULTS: Ultrastructural investigations in the peripheral cornea revealed a disarrangement of collagen fibers, indicating scar formation. These findings were not observed in the central area. Immunohistochemical staining for fibronectin and collagen type III was detected over the entire stromal incision interface, whereas laminin staining was related to the ingrowth of epithelial cells. CONCLUSIONS: The morphological changes after LASIK in an organ culture model can simulate the in vivo situation. Therefore, this model appears appropriate to use in further study of corneal wound-healing changes after LASIK.

Adult↗
PubMed2004

TGF-beta2-induced cell surface tissue transglutaminase increases adhesion and migration of RPE cells on fibronectin through the gelatin-binding domain.

PURPOSE: Migration and adhesion of dislocated retinal pigment epithelial (RPE) cells to a fibronectin-rich extracellular matrix is an initial step in proliferative vitreoretinopathy (PVR). In the present study, the functional role of cell surface tissue transglutaminase (tTG) in adhesion and migration of RPE cells on fibronectin (Fn) and collagen type I (Col I) after stimulation with TGF-beta2 was investigated. METHODS: Cultured human RPE cells were treated with 1.0 ng/mL TGF-beta2 for 24 hours. Cell surface tTG expression was determined by cell fraction analysis. Attachment on Col I, full-length Fn, and its 45-kDa gelatin-binding and 110-kDa cell-binding fragment was measured with an MTT assay. Migration of RPE cells was measured by a Boyden chamber assay, and cell spreading was determined. Experiments were performed in the presence or absence of anti-tTG antibodies and anti-integrin alpha5 and beta1 antibodies. RESULTS: TGF-beta2 markedly induced expression of cell-surface tTG on RPE cells and increased attachment and migration on Fn and Col I. Blocking cell surface tTG inhibited attachment, migration, and spreading on Fn and its 45-kDa gelatin-binding fragment, whereas no effect was seen on Col I and the 110-kDa cell-binding Fn fragment. In contrast, blocking of integrin alpha5 and beta1 suppressed adhesion and migration on full-length Fn and the 110-kDa Fn fragment. CONCLUSIONS: These data demonstrate that TGF-beta2 increases expression of cell surface tTG, which in turn strengthens adhesion, migration, and spreading of RPE cells on Fn through the 45-kDa gelatin-binding Fn fragment. At the onset of PVR, this mechanism may help RPE cells to attach and migrate on Fn-containing matrices.

Adolescent↗
PubMed2003

Evaluation of minimally invasive therapies and rationale for a prospective randomized trial to evaluate selective intra-arterial lysis for clinically complete central retinal artery occlusion.

OBJECTIVES: To determine the effect of commonly used minimally invasive treatments for clinically complete nonarteritic central retinal artery occlusion (CRAO) and design a prospective randomized trial to evaluate selective intra-arterial lysis for this condition. METHODS: In this retrospective noncomparative case series, all medical records of patients with a diagnosis of CRAO treated at the Department of Ophthalmology, Ludwig-Maximilians-Universität, Munich, Germany, from 1994 through 1999 were reviewed for treatments administered and course of visual acuity. MAIN OUTCOME MEASURES: Best-corrected visual acuity (BCVA) at initial and last visit. RESULTS: We identified 102 patient medical records; 71 were suitable for further analysis. Forty-four (62%) of the 71 patients included were treated with oral acetylsalicylate; 44 (62%), with oral acetazolamide; 32 (45%), with ocular massage; 22 (31%), with isovolemic hemodilution; 19 (27%), with oral pentoxifylline; 8 (11%), with topical beta-blocker; 6 (8%), with paracentesis of the anterior chamber; 4 (6%), with subcutaneous heparin. A mean +/- SD number of treatments of 2.5 +/- 1.4 was administered per patient, and BCVA increased by a mean +/- SD number of Snellen lines of 0.7 +/- 2.8. The BCVA in 11 patients (15%) increased by 3 or more lines. Multivariate stepwise regression did not reveal any single or combination treatment as a significant factor for improvement in BCVA. Patient age and duration of visual impairment before initial examination were not significant predictors of final BCVA. CONCLUSIONS: Commonly used minimally invasive treatments of CRAO do not improve the natural course of the disease. A prospective trial by the European Assessment Group for Lysis in the Eye is under way to evaluate selective intra-arterial lysis, and in this trial some of these minimally invasive treatments are used in the control group.

Acetazolamide↗
PubMed2003

Indocyanine green for successful repair of a long-standing macular hole.

PURPOSE: To report on the successful closure of a persistent chronic macular hole using indocyanine green (ICG) during the second surgical approach. DESIGN: Interventional case report. METHODS: A patient with a long standing macular hole (18 years) underwent pars plana vitrectomy with peeling of the internal limiting membrane (ILM). While no dye was used during the first operation, ICG (0.05%, Pulsion) was applied during the second procedure. The light source was turned off immediately after the ICG application until the dye was washed out after a period of 15 seconds. Tissue harvested during the second surgical approach was prepared for electron microscopy. RESULTS: After the failure of the first operation, areas of incomplete ILM peeling could be stained using ICG and a thorough ILM removal was achieved. Postoperatively, the macular hole was closed, as confirmed by optical coherence tomography. Visual acuity increased from 20/200 to 20/50. No visual field defects were seen postoperatively. There were only few cellular elements adherent to the retinal surface of the ILM as seen during electron microscopy. CONCLUSION: In cases where tractional forces due to incomplete ILM removal are considered responsible for the persistence of a macular hole, ICG is useful to identify areas of unpeeled ILM. Under certain safety precautions no adverse effect on functional outcome was seen.

Aged↗
PubMed2003

Optical coherence tomography for the detection of laser in situ keratomileusis in donor corneas.

PURPOSE: In 2001, more than one million laser in situ keratomileusis (LASIK) procedures were performed worldwide. Considering the increasing number of refractive procedures, eye banks will be increasingly confronted with the problem of how to identify those donors with prior refractive surgery. To date, efficient screening methods to identify LASIK surgery in donor eyes have not been established. Therefore, the purpose of the current study was to determine whether optical coherence tomography (OCT) can be used to detect the presence of LASIK-induced changes in human corneas. METHODS: Laser in situ keratomileusis was performed on 20 organ-cultured human cornea disks. The excimer laser ablation performed ranged from 0 to 12 diopters. The corneas were maintained in culture, and the visibility of flap-stromal interface by OCT was assessed up to 6 months after the LASIK procedure. Additionally, two donor corneas with the history of LASIK treatment before death were screened for structural changes. RESULTS: Optical coherence tomography scans were able to detect the interface between the corneal flap and the residual stromal tissue in all corneas and at all examined time intervals. There were no differences in signal intensity among the different depths of ablation. The relative signal intensity of the interface compared with the averaged stromal intensity ranged from 2.1 to 6.0. In both donor corneas with suspected prior LASIK surgery, OCT scanning showed the characteristic stromal interface as found in the in vitro model. CONCLUSIONS: Corneal examination by OCT could be an appropriate technique for eye banks to screen donor corneas for prior LASIK surgery.

Adult↗