Reis-Bücklers corneal dystrophy

In the literature two types of anterior corneal dystrophy are referred to as Reis-Bücklers' dystrophy. These are the one originally described by Bücklers in 1949 and known by us as the geographical form, and a honeycomb form. On the basis of electron-microscopic findings the geographical form is considered by some authors today to be a superficial variant of the granular dystrophy (Groenouw I), while the honeycomb form is looked upon as the "true" Reis-Bücklers' dystrophy. However, there is no clinical resemblance between the honeycomb type and the dystrophy described by Bücklers. Clinically it is easy to distinguish the geographical and the honeycomb type, and this is important for the prognosis of a corneal graft. The present authors do not agree that the term granular dystrophy should include the dystrophy described by Bücklers. There is a lack of clarity concerning this type of dystrophy, and clinically it bears no resemblance to granular dystrophy. In the authors' opinion it would be preferable to speak of the geographical and the honeycomb form of Reis-Bücklers' dystrophy.     

What is causing the corneal ulcer? Management strategies for unresponsive corneal ulceration

Infectious keratitis represents a significant cause of ocular morbidity in the United States. The work-up and treatment of presumed infectious keratitis (PIK) has changed in the past two decades. The development of newer topical antibiotics has enabled broad-spectrum antibiotic coverage with good tissue penetration. The majority of PIK cases respond well to this strategy. The small numbers of cases that do not respond to the treatment are the cases that offer a diagnostic and therapeutic challenge. This review will describe different algorithms that can be followed for the successful management of patients with difficult or progressive PIK. These algorithms are based on scientific work and on our empirical clinical experience. The review will also present three different clinical cases of PIK that were managed according to the algorithms presented in this review.     

Xenotransplantation--the future of corneal transplantation?

Although corneal transplantation (Tx) is readily available in the United States and certain other regions of the developed world, the need for human donor corneas worldwide far exceeds supply. There is currently renewed interest in the possibility of using corneas from other species, especially pigs, for Tx into humans (xeno-Tx). The biomechanical properties of human and pig corneas are similar. Studies in animal models of corneal xeno-Tx have documented both humoral and cellular immune responses that play roles in xenograft rejection. The results obtained from the Tx of corneas from wild-type (ie, genetically unmodified) pigs into nonhuman primates have been surprisingly good and encouraging. Recent progress in the genetic manipulation of pigs has led to the prospect that the remaining immunological barriers will be overcome. There is every reason for optimism that corneal xeno-Tx will become a clinical reality within the next few years.     

Agreement among measurements of the Q value and corneal power of the anterior corneal surface with Pentacam， iTrace and Orbscan Ⅱz corneal topography

Objective To compare the myopic anterior corneal surface measurements of the Q value and corneal power provided by Pentacam, iTrace and Orbscan Ⅱz and evaluate the agreement among the 3 methods. Methods This was a cross-sectional study. One hundred eyes were chosen from 100 myopic patients and the Q value and mean Sim K of the anterior corneal surface was measured by Pentacam, iTrace and Orbscan Ⅱz in the same patient′s eye. Measurement results were compared using analysis of variance and agreement among the measurements was assessed using Bland-Altman plots. Results The Q value measurements were -0.09±0.12, -0.09±0.09, and -0.18±0.10 with Pentacam, iTrace and Orbscan Ⅱz, respectively. The Q value measurements with Orbscan Ⅱz were lower than those with Pentacam and iTrace （F=43.06, P<0.01）. For the Q value measurements, the 95% limits of agreement （LoA） was small between iTrace and Orbscan Ⅱz （from -0.08 to 0.26） and the 95% LoA was large between iTrace and Pentacam （from -0.23 to 0.23）. The respective mean Sim K measurements were 43.34±1.37 D, 43.30±1.35 D and 43.56±1.36 D with Pentacam, iTrace and Orbscan Ⅱz. The mean Sim K measurements with Orbscan Ⅱz were greater than that with Pentacam and iTrace （F=23.25, P<0.01）. For the mean Sim K measurements, the 95% LoA was small between iTrace and Pentacam （from -0.68 to 0.59 D） and the 95% LoA was large between iTrace and Orbscan Ⅱz （from -1.15 D to 0.63 D）. Conclusion Measurements of Q value and mean Sim K of the anterior corneal surface of myopes showed statistically significant differences among the 3 instruments. The agreement among the 3 instruments was not comparable for Q value measurements. The agreement between iTrace and Pentacam had comparable results for mean Sim K, and can refer to one another.     

Inflammatory cytokine TNF-α promotes corneal endothelium apoptosis via upregulating TIPE2 transcription during corneal graft rejection

Graefe's Archive for Clinical and Experimental Ophthalmology - Endothelial dysfunction accounts for 50% of total corneal transplantation failures, suggesting that corneal endothelial damage is...     

A five-year follow-up study of posterior corneal curvature and central corneal thickness after LASIK using OrbscanⅡ

Objective To study the long-term （five-year follow-up） changes in posterior corneal curvature and central corneal thickness by using the OrbscanⅡ topographer in patients who had undergone laser in situ keratomileusis （LASIK） for myopia. Methods Forty-eight eyes of 48 patients who had undergone LASIK for myopia were included in a retrospective observational case series study. The mean preoperative refractive error was -6.25±2.87 D. The preoperative and postoperative changes in the posterior corneal curvature and central corneal thickness of each eye were measured by OrbscanⅡ. The posterior corneal curvature was obtained from the central 6mm zone of the OrbscanⅡ. The postoperative follow-up period was at 1, 3, 6, 9, 12, 24, 36 and 60 months. Using SPSS 16.0 software, a comparison of the least-significant difference （LSD） pairwise was used to analyze the difference in the posterior corneal curvature and central corneal thickness at each follow-up visit. Results ①The posterior corneal curvature was higher in the 1st month postoperatively compared to preoperative curvature （t=8.211, P<0.01）. There was no statistically significant difference for the change in posterior corneal curvature from the 1st month to the 9th month （P>0.05）. The posterior corneal curvature slowly decreased over time from the 9th month to the 24th month （the values of t were -4.640 and -2.659, the values of P were <0.001 and 0.014）. The posterior corneal curvature did not become stable until after the 24th month （P>0.05）. ②The central corneal thickness was lower in the 1st month postoperatively than preoperative thickness （t=10.08, P<0.01）. The central corneal thickness slowly increased over time from the 1st month to the 9th month （the values of t were -5.402, -4.428 and -2.334, the values of P were <0.001, <0.001 and 0.027）. The central corneal thickness did not become stable until after the 9th month （P>0.05）.③The posterior corneal curvature was correlated with corneal thickness （r=-0.703, P<0.01）. Conclusion The posterior corneal curvature and the central corneal thickness both increase shortly after LASIK surgery and stabilize after this initial period. There is a negative correlation between posterior corneal curvature and central corneal thickness.     

What does overnight lens wear do to the corneal epithelium?: is corneal refractive therapy different?

The corneal epithelium plays a central role in preventing infectious keratitis. It is a layer that functions both as a physical barrier and as an active component of the ocular surface defense system. Contact lens wear is capable of altering the structure and physiology of the corneal epithelium, potentially increasing the risk of infectious keratitis. This brief review summarizes the effects of continuous contact lens wear and corneal refractive therapy on the physiology and structure of the corneal epithelium.     

Does blunt ocular trauma induce corneal astigmatism?

PURPOSE: To determine the effect of blunt ocular trauma on refractive astigmatism. METHODS: Eighty-six eyes of 86 patients with known previous refractive status exposed to blunt ocular trauma were included in the study. Trauma-induced astigmatism (TIA) was calculated using vector analysis. In eyes with TIA, central corneal thickness was assessed by ultrasound pachymetry, and corneal topographies were obtained. Anterior-chamber angles were examined by Goldmann 3-mirror lens to find microhemorrhages, scarring, or recession. Patients were followed up between 8 and 12 months (average, 9.2 months). RESULTS: In 18 eyes (21%), TIA was detected. Six (7%) of these eyes had lenticular astigmatism caused by traumatic lens subluxation. In the remaining 12 eyes (14%), corneal topography showed regular astigmatic patterns, which were symmetrical in 3 eyes and asymmetric in the remaining 9. The etiologic factor was a game marble in 6 eyes and a stone in the remaining 6. The mean central corneal thickness was 535.75 microm (range, 498-570 microm) in these 12 eyes. In 9 of these 12 eyes, recession or scarring in the anterior-chamber angle was detected at 1 edge of the steepest axis. CONCLUSIONS: Blunt trauma can induce astigmatism. Hard and small objects are more likely to induce astigmatism.     

Sterile non-traumatic corneal perforation treated with Tachosil®

Case reportAn 83 year-old male reported to the emergency room with red eye and ocular pain. The slit-lamp examination showed a central corneal perforation of 1 mm in diameter, with no associated infection or inflammatory process. The patient had no history of trauma. It was decided to apply a patch of Tachosil^® at the site of corneal perforation. After 36 hours of occlusion, a layer of fibrin covered the perforation, closing the defect. Successful healing of the corneal perforation was observed in the follow-up, with no recurrences of the process.ConclusionsTachosil^® is collagen sponge with human fibrin and human thrombin used in cardiological and neurosurgical surgery for haemostasis and the occlusion of vessels and meninges. We present the first indication in ophthalmology of Tachosil^® as an effective alternative in the treatment of sterile non-traumatic corneal perforations less than 1.5 mm in size.     

Does corneal ocular "pseudo-hypertension" exist?]

BACKGROUND: The relation between Goldmann applanation tonometry and central corneal thickness (CCT) was evaluated in several studies during the last thirty years. Patients with ocular hypertension were found to have a significantly higher CCT compared with normals and glaucomas. PATIENTS: To report on two sisters with elevated CCT and ocular hypertension diagnosed by raised intraocular-pressure (IOP) readings on Goldmann applanation tonometry. RESULTS: In both patients, there were no signs for early functional or morphological glaucomatous changes. Maximum IOP was 30 mm Hg and 26 mm Hg. The corneal pachymetry revealed an increased CCT in both patients (700 and 680 microns, respectively), while corneal morphology was normal. CONCLUSIONS: Ocular hypertension can be misdiagnosed by too high applanation tonometer readings in patients with markedly elevated CCT. Before the onset of treatment thus, corneal pachymetry should be performed in patients with ocular hypertension to exclude ocular "pseudohypertension" and to avoid unneccessary treatment.     

How "safe" is corneal transplantation? A contribution on the risk of HSV-transmission due to corneal transplantation

INTRODUCTION: We have attempted in this article to summarise the present literature on the risks of virus transmission via corneal transplantation, with special emphasize on Herpes simplex virus (HSV). METHODS: We conducted a literature search from Medline. RESULTS: HSV is now acknowledged as a cause of primary graft failure, and this entity has been attributed to donor-to-host HSV infection. HSV is the primary cause of graft failure, and may induce reactivation in the recipient in the dendritic form, or in atypical forms. CONCLUSIONS: Corneal transplantation is a potential route for HSV infection as a possible transmittable disease which now has to be taken into consideration in eye banks.     

Electrophilic PPARγ ligands inhibit corneal fibroblast to myofibroblast differentiation in vitro: a potentially novel therapy for corneal scarring

A critical component of corneal scarring is the TGFβ-induced differentiation of corneal keratocytes into myofibroblasts. Inhibitors of this differentiation are potentially therapeutic for corneal scarring. In this?study, we tested the relative effectiveness and mechanisms of action of two electrophilic peroxisome proliferator-activated receptor gamma (PPARγ) ligands: cyano-3,12-dioxolean-1,9-dien-28-oic acid-methyl ester (CDDO-Me) and 15-deoxy-Δ(-12,14)-prostaglandin J(2) (15d-PGJ(2)) for inhibiting TGFβ-induced myofibroblast differentiation in?vitro. TGFβ was used to induce myofibroblast differentiation in cultured, primary human corneal fibroblasts. CDDO-Me and 15d-PGJ(2) were added to cultures to test their ability to inhibit this process. Myofibroblast differentiation was assessed by measuring the expression of myofibroblast-specific proteins (αSMA, collagen I, and fibronectin) and mRNA (αSMA and collagen III). The role of PPARγ in the inhibition of myofibroblast differentiation by these agents was tested in genetically and pharmacologically manipulated cells. Finally, we assayed the importance of electrophilicity in the actions of these agents on TGFβ-induced αSMA expression via Western blotting and immunofluorescence. Both electrophilic PPARγ ligands (CDDO-Me and 15d-PGJ(2)) potently inhibited TGFβ-induced myofibroblast differentiation, but PPARγ was only partially required for inhibition of myofibroblast differentiation by either agent. Electrophilic PPARγ ligands were able to inhibit myofibroblast differentiation more potently than non-electrophilic PPARγ ligands, suggesting an important role of electrophilicity in this process. CDDO-Me and 15d-PGJ(2) are strong inhibitors of TGFβ-induced corneal fibroblast to myofibroblast differentiation in?vitro, suggesting this class of agents as potential novel therapies for corneal scarring warranting further study in pre-clinical animal models.