Different Course of Immune Reactions and Endothelial Cell Loss after Penetrating Low-Risk Keratoplasty and Descemet Membrane Endothelial Keratoplasty for Fuchs Endothelial Dystrophy. / Unterschiedlicher Verlauf von Immunreaktionen und Endothelzellverlust nach perforierender Low-Risk-Keratoplastik und Descemet Membrane Endothelial Keratoplasty bei Fuchs-Endotheldystrophie.

BACKGROUND: The aim of this study was to compare the incidence of immune reactions and endothelial cell loss after penetrating keratoplasty (PKP) vs. Descemet membrane endothelial keratoplasty (DMEK) in patients with Fuchs endothelial dystrophy (FED). PATIENTS AND METHODS: In the present retrospective study, a total of 962 surgeries (225 excimer laser PKP and 727 DMEK) of 700 patients performed between 28.06.2007 and 27.08.2020 in the Department of Ophthalmology at Saarland University Medical Center UKS were statistically evaluated. On the one hand, the prevalence and the temporal course of the immune reactions that occurred were analysed using the Kaplan-Meier method, as well as the effect of the immune reactions on the endothelial cells and corneal thickness. Secondly, endothelial cell density, pleomorphism, and polymegethism of the endothelial cells were evaluated for the time points U1 = preoperative, U2 = 6 weeks postoperative, U3 = 6 to 9 months postoperative, U4 = 1 to 2 years postoperative, and U5 = 5 years postoperative. In addition, statistical tests were carried out for differences between the two types of surgery and in the longitudinal course. RESULTS: A total of 54 immune reactions occurred during the observed period, whereby the probability of such a reaction was significantly greater in the PKP group with 8.9% than in the DMEK group with 4.5% (p = 0.011). The comparison of the two Kaplan-Meier curves also showed a significant difference between the two surgical techniques in the log-rank test (p = 0.012). The endothelial cell loss due to the immune reaction was only significant in PKP (p = 0.003). For all surgical procedures, endothelial cell density decreased significantly with time in both surgical techniques (p < 0.0001 in each case), but more strongly with DMEK than with PKP (p < 0.0001). Furthermore, this cell density was significantly higher with PKP than with DMEK for the whole observation time (p < 0.0001). Polymegethism decreased significantly in the DMEK group (p < 0.0001). Pleomorphism was significantly higher, on average, in DMEK than in PKP (p < 0.0001). CONCLUSION: The prognosis of DMEK in patients with FED seems to be more favourable after immune reactions than that of PKP, as not only were immune reactions less frequent, but they were also milder. However, endothelial cell density was significantly higher in the PKP group during the entire follow-up.

Analysis of Various Modalities for Intraocular Pressure Measurement in Relation to Keratoconus Severity in 246 Eyes of the Homburg Keratoconus Center.

PURPOSE: Intraocular pressure (IOP) measurement may be difficult in keratoconus (KC) due to corneal protrusion and irregular astigmatism. This study aimed to assess which IOP measurement modality is least affected by KC severity. METHODS: Data from 246 corneas of 246 patients with KC were retrospectively analyzed. KC stages were determined using the Topographic KC (TKC) and ABCD KC classifications derived from Pentacam (Oculus, Germany). IOP was measured using Goldmann applanation tonometry (GAT), Ocular Response Analyzer (ORA, Reichert Instruments, USA), and Corvis ST (CST, Oculus, Germany). Cronbach alpha (CA), analysis of variance with Bonferroni correction, Dunnett T3, and Pearson correlation were performed. RESULTS: Using CA, the reliability of measurements using various modalities increased to 0.764 to 0.943 when excluding IOP Goldmann overall and in each KC stage (TKC and ABCD). Analysis of variance revealed significant differences between TKC and ABCD stages for almost all IOP modalities. The Bonferroni post hoc test showed significant differences between the measured IOP in earlier and advanced KC stages, except for the biomechanically CST-corrected IOP (bIOP). Pearson correlation analysis showed a significant correlation between IOP and thinnest corneal thickness (TCT) for all IOP modalities except bIOP. CONCLUSIONS: CST-based bIOP seems to be best suited for IOP measurement in KC because it did not correlate with TCT in contrast to IOP measurements by ORA or GAT. The measurement results from GAT in patients with KC should be interpreted with care and always in view of corneal thickness. As a thumb rule, we suggest to add at least 2 mm Hg to the measured GAT value.

Impact of Hypothyroidism on Tomography and Biomechanics in Keratoconus - Cross-Sectional and Longitudinal Assessment within the Homburg Keratoconus Center at the Time of Inclusion and after 1 Year.

BACKGROUND AND PURPOSE: The etiology of keratoconus (KC) is probably multifactorial but remains essentially unknown. Previous scientific observations have suggested that hypothyroidism might play a role in the development and progression of KC. The purpose of this study was to analyze the tomographic and biomechanical parameters in KC patients with or without hypothyroidism. METHODS: Twenty-eight patients with KC and hypothyroidism (HT group) and fifty-six KC patients without thyroid dysfunction (WHT group) with matching gender and age were analyzed. Mean age was 40.3 years (range 14 - 57) in the HT group and 40.3 years (range 14 - 57) in the WHT group. Routine ophthalmic examinations consisted of corneal tomography and biomechanical parameters. We extracted the following KC parameters from the Pentacam (Pentacam HR, Oculus, Wetzlar, Germany): Keratoconus Index (KI), maximum keratometry (Kmax), astigmatism, and thinnest pachymetry (TP). From the ocular response analyzer (ORA, Reichert Ophthalmic Instruments, Depew, NY, USA), we extracted corneal hysteresis (CH), corneal resistance factor (CRF), and KC match index (KMI). RESULTS: The comparison of the tomographic and biomechanical values from cross-sectional and longitudinal analyses showed no significant differences between the HT and WHT groups. CONCLUSION: The severity of KC based on tomographical and biomechanical parameters does not seem to depend on the presence of hypothyroidism.

Prevalence and Impact of Cornea Guttata in the Graft After Penetrating Keratoplasty in Germany.

PURPOSE: The aim of this study was to analyze the prevalence and severity of corneal guttata (CG) in grafts after penetrating keratoplasty (PKP) and to determine its clinical significance. METHODS: This retrospective study included 1758 PKP performed in 1522 patients. In total, 6662 postoperative endothelial images revealed the prevalence and severity of CG (divided into categories G0 without CG and G1-G3 with increasing severity). Origin of the graft, postoperative corneal thickness, visual acuity, pleomorphism, polymegethism, and endothelial cell density (ECD) were analyzed. RESULTS: CG was detected in 14.9% of the grafts within 9 months after PKP, most of them were low-grade G1 (13.6%). Grafts from Homburg/Saar showed significantly less CG cases compared with other eye banks ( P = 0.034). The mean corrected distance visual acuity (logMAR) did not differ between G1 (0.45 ± 0.31) and G0 (0.46 ± 0.31). The mean ECD was lower in G1 compared with G0 ( P < 0.001). The mean corneal thickness was higher in G3 (597 ± 101 µm) compared with G0 (541 ± 65 µm) ( P < 0.001). Pleomorphism and polymegethism were correlated with CG ( P < 0.001). A progression of CG severity was detected in 13.5% of the cases during a follow-up time of 25.0 ± 19.9 months. CONCLUSIONS: Our study suggested that CG are transplanted in 14.9% of PKP, most of which are low-grade CG not affecting the visual acuity but already leading to an increase in corneal thickness, loss of ECD, and alteration of endothelial cell morphology. In 13.5% of the cases, a progression was demonstrated in the postoperative course.

Recurrent ligneous conjunctivitis after cataract surgery in a 67-year-old male patient: a case report.

BACKGROUND: Ligneous conjunctivitis is a rare form of chronic pseudomembranous conjunctivitis which usually starts during infancy. We report on an unsual case of recurrent ligneous conjunctivitis after cataract surgery in a 67-year-old male patient. METHODS: The equipment used for the slit-lamp images was a Haag Streit slit lamp BX900 Sn 00,406 with 16 × magnifications. The used batch number of the camera was sn00406 and the software was from the company CCS Pawlowski Merge Eye. There were no filters used. The images were saved with a resolution of 300 DPI. Neither downstream nor averaging was used to enhance the resolution of the image in the case presentation section or the figure legend. The equipment used for the cross-sectional histologic images was a Zeiss Axioskop 40 microscope with an objective lens Zeiss A-Plan × 20/0.45 (Zoom 6.3 × TV 2/3″″C). The used camera was AxioCam MRc5 and the software was ZEN 3.2. The cross-sectional histologic images were saved with a resolution of 2584 × 1936 Pixels. Neither downstream nor averaging was used to enhance the resolution of the image in the case presentation section or the figure legend. CASE PRESENTATION: This is a rare case report of ligneous conjunctivitis in a 67-year-old male patient who presented a recurrent conjunctival granuloma after five excisions following cataract surgery in his left eye. We performed a tumor excision with free conjunctival autograft. The histology showed a fibrin crust including macrophages, granulocytes, lymphocytes, and reactively altered squamous cell nests. These findings were consistent with a ″pseudomembrane in conjunctivitis lignosa″. We administered a topical combination of plasminactivator, heparin, cortisone and cyclosporine. CONCLUSION: This treatment with the combination of plasminactivator, heparin, cortisone and cyclosporine has proven to be effective in preventing the recurrence of ligneous conjunctivitis.

Endothelial Cell Density and Central Corneal Thickness following Penetrating Keratoplasty of Acanthamoeba Keratitis Patients - A Retrospective Cross-Sectional Observational Study.

PURPOSE: To analyze endothelial cell density (ECD) and central corneal thickness (CCT) following penetrating keratoplasty (PKP) in Acanthamoeba keratitis (AK) patients. PATIENTS AND METHODS: In this retrospective, clinical, single-center, cross-sectional, observational study, patients were enrolled who underwent PKP at the Department of Ophthalmology of Saarland University Medical Center, Homburg/Saar, Germany between May 2008 and December 2016 with the diagnosis of AK. In all, 33 eyes of 33 patients (14 males, 42%) were enrolled; their mean age at the time of surgery was 39.5 ± 14.3 years. Postoperatively, AK patients received topical polyhexamethylene biguanide, propamidine isethionate, neomycin sulphate/gramicidin/polymixin B sulfate, and prednisolone acetate eye drops (5 ×/day each), and the topical treatment was tapered sequentially with 1 drop every 6 weeks over 6 months. CCT was recorded using Pentacam HR Scheimpflug tomography and ECD with the EM-3000 specular microscope before surgery and 3 and 6 months after surgery as well as after the first and second (complete) suture removal. RESULTS: ECD tended to decrease significantly from the time point before surgery (2232 ± 296 cells/mm2) to the time point 3 months after surgery (1914 ± 164 cells/mm2; p = 0.080) and to the time point after the first suture removal (1886 ± 557 cells/mm2; p = 0.066) and decrease significantly to the time point after the second suture removal (1650 ± 446 cells/mm2; p = 0.028). CCT did not change significantly over the analyzed time period (p ≥ 0.475). CONCLUSION: In AK, endothelial cell loss does not seem to be accelerated following PKP, despite the postoperative use of diamidine and biguanide. A subsequent prospective comparative study should confirm our retrospective longitudinal analysis.

Simultaneous Bilateral Primary Occlusion of the Ophthalmic Artery due to Florid Giant Cell Arteritis.

PURPOSE: To report a case of simultaneous bilateral ophthalmic artery occlusion in diagnosed giant cell arteritis (GCA). OBSERVATIONS: A 77-year-old male patient presented to the emergency department with simultaneous vision loss in both eyes for 3 hours. Headache at both temples and jaw claudication had been present for 3 weeks. Laboratory values demonstrated an initially increased C-reactive protein (CRP) of 202.0 mg/L and an erythrocyte sedimentation rate (ESR) of 100 mm within the first 20 minutes. Duplex sonography of the right and left temporal arteries revealed a "halo sign." A case of GCA was suspected, and intravenous high-dose methylprednisolone therapy was immediately administered. The clinical examination revealed a bilateral central retinal artery occlusion and fluorescein angiography showed a hot optic disc in the right eye and patchy choroidal hypoperfusion in both eyes. Biopsy of the left temporal artery was performed, which confirmed a florid temporal arteritis with complete thrombotic occlusion of the vascular lumen. Despite a good response to the administered therapy (CRP 17.0 mg/L 1 week after initiation), the visual prognosis was significantly limited through retinal and optic nerve involvement. By the follow-up examination 8 weeks later, the near visual acuity was 20/400 in the right and left eye at a distance of 16 inches. CONCLUSION AND IMPORTANCE: We hereby present a simultaneous bilateral ophthalmic artery occlusion as a rare complication of GCA. The combination of central retinal artery occlusion, arteritic anterior ischemic optic neuropathy, and choroidal hypoperfusion suggests an acute inflammatory involvement of the ophthalmic artery. In cases of the slightest suspicion of giant cell arteritis, an immediate high-dose steroid therapy initiation is of utmost importance.

Impact of Pre- and Intraoperative Factors on Endothelial Cell Density in the Early and Late Stage after Penetrating Keratoplasty. / Prä- und intraoperative Einflussgrößen auf die Endothelzellentwicklung in der Früh- und Spätphase nach perforierender Keratoplastik.

AIM: This retrospective investigated the impact of donor age, recipient age, donor endothelial cell density, vis-à-tergo, and additional intraoperative lens exchange (triple-procedure) on overall early and late phase postoperative endothelial cell density (ECD) following penetrating keratoplasty (PKP) in various diagnosis groups. PATIENTS AND METHODS: In 590 cases with diagnosed keratoconus (KC), Fuchs dystrophy (FD) and herpes simplex virus infection (HSV) who underwent PKP or triple surgery, the ECD in cells/mm2 was analysed, both preoperatively, with all-sutures-in (early postoperative stage), and after last suture removal. The factors were tested by Mann-Whitney U-test, correlation analysis and linear regression analysis. OUTCOME: Correlation analysis demonstrated a weak negative correlation between the patient's ECD and donor age (early postoperative stage: r = - 0.25, p < 0.001; after last suture removal: r = - 0.16; p = 0.003). Regression analysis revealed that donor age did not impact postoperative patient ECD. There was a weak negative correlation between postoperative ECD and recipient age (early postoperative stage: r = - 0.31, p < 0.001; after last suture removal: r = - 0.34, p < 0.001). Regression analysis confirmed the negative impact of recipient age on patient ECD (early postoperative stage: ß = - 13.2, p = 0.001; after last suture removal: ß = - 4.6, p < 0.001). Correlation analysis determined a weak positive correlation between postoperative ECD and donor endothelial cell density (early postoperative stage: r = 0.37, p < 0.001; after last suture removal: r = 0.32, p < 0.001). Regression analysis also determined that donor endothelial cell density had a positive impact on postoperative ECD following last suture removal (ß = 0.4, p < 0.001). Vis-à-tergo and additional lens exchange (triple procedure) had no significant effect on postoperative ECD (p > 0.05). This was also confirmed by the results of the regression analysis after last suture removal. CONCLUSION: Recipient age and donor endothelial cell density have a significant impact on postoperative ECD following PKP. Not all of the statistical tests proved donor age to be a significant influencing factor. Vis-à-tergo and additional lens exchange (triple procedure) had no significant effect on postoperative ECD following PKP.

Keratoconus staging by decades: a baseline ABCD classification of 1000 patients in the Homburg Keratoconus Center.

BACKGROUND: This retrospective cross-sectional study aims to analyse the keratoconus (KC) stage distribution at different ages within the Homburg Keratoconus Center (HKC). METHODS: 1917 corneae (1000 patients) were allocated to decades of age, classified according to Belin's ABCD KC grading system and the stage distribution was analysed. RESULTS: 73 per cent (n=728) of the patients were males, 27% (n=272) were females. The highest KC prevalence occurred between 21 and 30 years (n=585 corneae, 294 patients). Regarding anterior (A) and posterior (B) curvature, the frequency of A was significantly higher than B in all age groups for stage 0, 1 and 2 (A0>B0; A1>B1; A2>B2; p<0.03, Wilcoxon matched-pairs test). There was no significant difference between the number of A3 and B3, but significantly more corneae were classified as B4 than A4 in all age groups (p<0.02). The most frequent A|B combinations were A4|B4 (n=451), A0|B0 (n=311), A2|B4 (n=242), A2|B2 (n=189) and A1|B2 (n=154). Concerning thinnest pachymetry (C), most corneae in all age groups were classified as C0>C1>C2>C3>C4 (p<0.04, Wilcoxon matched-pairs test). For the best distance visual acuity (D), a significantly higher number of corneae were classified as D1 compared to D0 (p<0.008; D1>D0>D2>D3>D4). CONCLUSION: The stage distributions in all age groups were similar. Early KC rather becomes manifest in the posterior than the anterior corneal curvature whereas advanced stages of posterior corneal curvature coincide with early and advanced stages of anterior corneal curvature. Thus, this study emphasises the necessity of posterior corneal surface assessment in KC as enabled by the ABCD grading system.

Hypothyroidism is Not Associated with Keratoconus Disease: Analysis of 626 Subjects.

PURPOSE: To analyze the association between hypothyroidism and keratoconus, we examined blood thyroid hormone levels and corneal tomographic parameters in healthy subjects and patients with keratoconus. METHODS: We included 626 subjects (304 left eyes, 49%; 431 males, 69%; age 38.4 ± 14.3 y). Patients with keratoconus were from our Homburg Keratoconus Center (HKC) (n = 463); patients with hypothyroidism were from the Department of Internal Medicine of Saarland Medical University, Homburg/Saar, Germany (n = 75); and healthy subjects were from the Department of Ophthalmology of Saarland University Medical Center (n = 88). We included only one randomly selected eye of each subject and the first examination data. EXCLUSION CRITERIA: Previous thyroid medication, previous ocular surgery, and patients with suspected keratoconus (topographic keratoconus classification, [TKC]: 0 < 1). Patient eyes were classified (TKC) with dedicated, instrument-based, keratoconus detection software provided with the Pentacam. TKC = 0 was considered "normal," and TKCs ≥ 1 were considered keratoconus. Subjects were also classified as euthyroid or hypothyroid, based on blood thyroid hormone status (i.e., TSH, FT3, and FT4). A multiple logistic linear regression model was constructed to determine the effects of age (covariate), gender, and hypothyroidism (effect sizes) on "TKC-positive" disease. RESULTS: The significance levels for a constant parameter, sex, thyroid condition, and age were p < 0.0001, p < 0.0001, p < 0.0001, and p=0.003, respectively. The odds ratios for age, sex, and hypothyroidism were 0.98, 3.05, and 3.34, respectively. Male sex and a euthyroid condition had significantly positive, clinically relevant effects, and age had a significantly negative, but clinically irrelevant effect on the estimated TKC index. CONCLUSIONS: Keratoconus appeared to occur more often in patients classified as euthyroid than in patients with hypothyroidism. Thus, hypothyroidism alone could not support the development of keratoconus. Based on these results, it should not be mandatory to screen patients with hypothyroidism for keratoconus or patients with keratoconus for hypothyroidism.

Reactive uveitis, retinal vasculitis and scleritis as ocular end-stage of Acanthamoeba keratitis: a histological study.

We analysed histologically two Acanthamoeba keratitis (AK) eyes with anterior and posterior segment inflammation and blindness. Two enucleated eyes of 2 patients (age 45 and 51y) with AK (PCR of epithelial abrasion positive) were analysed. Histological analysis was performed using hematoxylin-eosin, periodic acid-Schiff and Gömöri-methenamine silver staining. We could not observe Acanthamoeba trophozoites or cysts neither in the cornea nor in other ocular tissues. Meanwhile, we found uveitis, retinal vasculitis and scleritis in these eyes, due to the long-standing, recalcitrant AK. So in this stage of AK, systemic immune suppression may be necessary for a longer time period.

In Vivo Confocal Microscopic Imaging of the Cornea After Femtosecond and Excimer Laser-assisted Penetrating Keratoplasty.

PURPOSE: To examine the microstructure of the cornea after excimer and femtosecond laser-assisted penetrating keratoplasty (ELAK and FLAK) in eyes with Fuchs' dystrophy and keratoconus. METHODS: Fifty-seven patients were divided into four groups according to corneal disease and surgical technique: Fuchs' dystrophy and ELAK (n = 9; mean age: 70.4 ± 10.6 years); Fuchs' dystrophy and FLAK (n = 13; mean age: 64.3 ± 11.2 years); keratoconus and ELAK (n = 9; mean age: 47.4 ± 13.9 years); and keratoconus and FLAK (n = 9; mean age: 43.5 ± 13.8 years). The control group comprised individuals without ocular disease (n = 17; mean age: 39.9 ± 17.3 years). In vivo investigation of the corneal graft and graft-host junction zone was performed with confocal corneal microscopy. RESULTS: All corneal grafts were transparent and no rejection reaction could be observed during the follow-up period. Confocal microscopy revealed no difference in basal epithelial cell density compared to controls. Anterior keratocyte density was lower than in the control group (818 ± 131 cells/mm(2)) in all four treatment groups (596 ± 174, 586 ± 113, 529 ± 75, 552 ± 91 cells/mm(2)). Langerhans cells could barely be seen; there was no difference in the cutting edge configuration and wound integrity. CONCLUSIONS: In vivo confocal microscopy provided evidence that good alignment of graft-host junction could be created with both techniques. The excimer laser was not inferior to the femtosecond laser in performing corneal cuts. The low density of Langerhans cells revealed well-controlled cellular immunological response and sustained corneal integrity in both laser groups.

Correlation of corneal thickness, endothelial cell density and anterior chamber depth with ocular surface temperature in normal subjects.

PURPOSE: To analyze corneal surface temperature profile in a young and healthy study population and to determine the impact of corneal thickness (CT), anterior chamber depth (ACD), and endothelial cell density (ECD) on surface temperature. METHODS: In this prospective, single-center study 61 healthy right eyes of 61 subjects without tear film pathologies (mean age 24.9 ± 6.7 years) were recruited. Ocular surface temperature (OST) was measured with the Ocular Surface Thermographer TG-1000. From Pentacam HR CT and ACD, and from specular microscopy ECD and central corneal thickness (CCT) were acquired. From the raw measurement data (OST, CT and ACD) we extracted a) local OST the corneal center and 3mm away from the center at the 3, 6, and 9 o'clock positions, and b) Zernike parameters Z1, Z2 and Z3 to evaluate the general temperature profile within a 6mm circular area around the center. RESULTS: Overall, there was no correlation between OST and CT, ACD or ECD. Local OST did not correlate with CT at any measurement position. On average local OST was highest at measurement positions where CT was lowest, but without reaching statistical significance. Baseline OST was highest at thin corneal regions and temperature decay over time was smallest in those regions. Z1, Z2 and Z3 correlated well with CT. CONCLUSIONS: In healthy subjects corneal thickness, endothelial cell density and anterior chamber depth have no effect on corneal surface temperature. The general temperature profile seems to be influenced by the corneal thickness profile effecting a higher temperature and lower decay at thinner corneal regions.

Interaction between topographic/tomographic parameters and dry eye disease in keratoconus patients.

PURPOSE: To determine the interaction between corneal topographic and tomographic parameters and dry eye syndrome (DES) in keratoconus (KC) patients. METHODS: Seventy-seven eyes of 49 patients with KC (age 34.4 ± 11.6 years) were enrolled in this study. In these 77 eyes we recorded surface regularity index (SRI), surface asymmetry index (SAI) and Klyce/Maeda KC index (KCI) using the Topographic Modeling System (TMS-5, Tomey, Tennenlohe, Germany), Index of Surface Variance (ISV), Index of Vertical Asymmetry (IVA), KC Index (KI), Center KC Index (CKI), Index of Height Asymmetry (IHA) and Index of Height Decentration (IHD) using Pentacam (Pentacam HR, Oculus, Germany). Patients were subdivided into mild (grade 1-2) and severe stage (grade 3-4) KC groups according to Pentacam grading. To analyse tear film parameters we assessed in 77 KC eyes McMonnies questionnaire, Schirmer test and break-up time and in 26 eyes (10 eyes with mild KC, 16 eyes with severe KC) high-speed videokeratoscopy (during interblinking interval) using a novel commercially not available system (Tear Inspect). With Tear Inspect the analysed tear film parameters were (1) time of first irregularities of Placido rings and (2) time of eyelid closure. Patients were also subdivided into McMonnies questionnaire positive and negative groups. RESULTS: We did not find significant difference between patients with mild and severe KC in any of the examined tear film parameters (p > 0.66). There was no significant difference in SRI, SAI, KCI, ISV, IVA, KI, CKI, IHA and IHD in McMonnies test positive and negative KC patients (p > 0.07). There was no correlation between SRI, SAI, KCI, ISV, IVA, KI, CKI, IHA and IHD and any of the examined tear film parameters (without high-speed videokeratoscopy) neither in 77 KC patients nor in mild or severe KC eyes (r < 0.3). CONCLUSIONS: There is no interaction between DES and topographic/tomographic changes in KC-patients.

Diurnal and zonal analysis of corneal surface temperature in young healthy adults.

OBJECTIVE: To determine diurnal changes and zonal differences of corneal surface temperature in young healthy adults following blinking.
 METHODS: In this prospective, longitudinal, single-center study, 19 healthy left eyes of 19 healthy subjects (age 23.6 ± 2.2 years) were recruited. Corneal surface temperature (CST) was measured by the Ocular Surface Thermographer TG-1000 (Tomey, Germany) at 3 different time points: 8:00-10:00, 11:00-13:00, and 15:00-18:00. The CST was measured every second for 10 seconds immediately after blinking. We assessed the temperature at the corneal center and at 3 peripheral quadrants at 3 (temporal), 6 (inferior), and 9 (nasal) o'clock at the corneal limbus.
 RESULTS: Mean central/temporal/nasal/inferior corneal surface temperatures were, between 11:00 and 13:00, 34.1 ± 0.5°C/34.2 ± 0.6°C/34.4 ± 0.5°C/34.6 ± 0.5°C. During 10 seconds following eye opening and between time points 1, 2, and 3, the observed corneal surface temperature parameters did not change significantly (p>0.3 for all). However, there was a significant difference between temperatures at the nasal limbal area and the center of the cornea (p<0.03 at each time point). In addition, the temperature was warmer nasally than temporally until 6 seconds and 8-10 seconds after blinking (p<0.05 for seconds 0-6; 8-10 at time points 1, 2, and 3).
 CONCLUSION: In healthy subjects, corneal surface temperature does not change diurnally and is warmer nasally than centrally and temporally during the interblinking interval. Our study leads to the assumption that diurnal changes of corneal temperature indicate ocular surface abnormality or corneal pathology.

Elevated intraocular pressure in the early postoperative period following excimer laser penetrating keratoplasty for keratoconus.

BACKGROUND AND OBJECTIVE: To assess the incidence of elevated intraocular pressure (IOP) in the early postoperative period after excimer laser penetrating keratoplasty for keratoconus and reveal potential associations with anterior segment parameters. PATIENTS AND METHODS: This prospective, interventional study consisted of 40 patients with keratoconus who were treated with excimer laser penetrating keratoplasty. Corneal pachymetry, anterior chamber depth, anterior chamber volume, and anterior segment angle were measured by Scheimpflug camera preoperatively and 2 months postoperatively. IOP was obtained using Goldmann applanation tonometry. Student's t tests and Pearson correlation were applied. A P value of .05 or less was considered significant. RESULTS: IOP increased from 16.3 ± 3.5 preoperatively to 19.3 ± 5.2 mm Hg postoperatively (P = .007). Significant differences were detected in corneal pachymetry (P < .008), anterior chamber depth (P < .001), and anterior chamber volume (P = .03). Postoperative IOP was significantly correlated with anterior segment angle, anterior chamber depth, and corneal pachymetry. CONCLUSION: Elevated IOP in the early postoperative period after excimer laser penetrating keratoplasty is significantly correlated with changes in the anterior chamber architecture.