Corneal Degeneration Research Articles

Post-Mortem Corneal Thickness Measurements with a Portable Optical Coherence Tomography System: a Reliability Study.

The purpose of this study was to determine the repeatability and reproducibility of post-mortem central corneal thickness (CCT) measurements by using a real-time, portable optical coherence tomography (OCT) system on an animal model, and to prospectively evaluate the time-course of post-mortem changes in CCT. Forty-six ocular globes of sheep (Ovis aries) were analyzed with a portable spectral-domain OCT device by two operators at different postmortem intervals (PMIs) as follows: immediately (i.e. within 10 minutes), at the 30th minute, at the 1st, 6th, 12th, 24th and 48th hour, and later (up to the 96th hour). The coefficient of repeatability ranged from 0.3% to 3.5%, and coefficients of reproducibility ranged from 0.2% to 3.7% in the central region of the cornea. The intraclass correlation coefficients were particularly high at different PMIs, thus confirming good measurement reliability with the portable OCT. The average CCT decreased immediately and then increased thereafter, with two peaks at 6 and 24 hours after death. Our results suggest that portable OCT is a reliable tool for monitoring CCT variations after death and may be useful in characterizing corneas before explantation, detecting quantitative variations during post-mortem corneal degeneration or assessing changes in CCT for forensic implications.

National survey of pellucid marginal corneal degeneration in Japan.

A national survey was conducted in Japan to analyze the clinical characteristics of pellucid marginal corneal degeneration (PMD). A questionnaire was sent to all members of the Japan Cornea Society requesting demographic and clinical findings on PMD patients who had been examined between 2008 and 2010. The presence of band-shaped peripheral corneal thinning, detected by slit-lamp biomicroscopy or by a pachymetric map, was set as the diagnostic criterion of PMD. Most of the participating facilities relied on either slit-lamp biomicroscopy or corneal topography as diagnostic tools for the detection of PMD. Data on 347 patients (579 eyes) were returned from the participating facilities for analysis, among which 162 eyes in 84 men and 24 women, with a median onset age of 37years, met the PMD criteria. Of the 108 patients (162 eyes) with classical PMD, unilateral involvement was found in 25 % of patients (27 eyes). In 17 of the 27 eyes for which topographic findings for the contralateral eye were available, seven eyes were either keratoconus or had a suspected diagnosis of keratoconus. An association with allergic disease was found in 24 eyes (22.2% of patients). Approximately half of the patients had 1.0 or better spectacle-corrected distance visual acuity, and only 5% showed 0.1 or worse. The mean keratometric value was 45.7 diopters. On corneal topography, 100 eyes (61.7%) showed the topographic "crab-claw pattern," and the remaining eyes showed other patterns, including inferior steepening (22.2%) and an irregular pattern (10.5%). We conducted the largest clinical survey of PMD to date and found a male predominance, a relatively high prevalence of unilateral involvement, and associated allergic diseases.

A Study of Risk Factors for Climatic Droplet Keratopathy in Elderly Persons from Western Rajasthan

Climatic Droplet Keratopathy is an acquired degeneration of cornea. It is characterised by the deposition of amber coloured oily spherules at and around the Bowman's membrane of the cornea. The disease occurs in areas where exposure to ultraviolet (UV) light is excessive. Climatic droplet Keratopathy is a common ocular morbidity in this part of country. Intense sunshine, excess UV radiation, micro trauma due to wind borne particles, extremes of high or low temperature, aridity, malnutrition and genetic factors were incriminated as the etiological factors for the development of Climatic Droplet Keratopathy. We studied about the relation of Climatic Droplet Keratopathy to age, sex, laterality, familial pattern and working hours in sunlight. Climatic droplet keratopathy may be prevented by wearing UV blocking sunglasses in areas of sand and dust. Side protectors of the sunglasses may have to be placed to prevent exposure to environmental irritants. Keywords Climatic droplet keratopathy, Corneal Degeneration

Dendritic cell dysfunction and diabetic sensory neuropathy in the cornea.

Diabetic peripheral neuropathy (DPN) often leads to neurotrophic ulcerations in the cornea and skin; however, the underlying cellular mechanisms of this complication are poorly understood. Here, we used post-wound corneal sensory degeneration and regeneration as a model and tested the hypothesis that diabetes adversely affects DC populations and infiltration, resulting in disrupted DC-nerve communication and DPN. In streptozotocin-induced type 1 diabetic mice, there was a substantial reduction in sensory nerve density and the number of intraepithelial DCs in unwounded (UW) corneas. In wounded corneas, diabetes markedly delayed sensory nerve regeneration and reduced the number of infiltrating DCs, which were a major source of ciliary neurotrophic factor (CNTF) in the cornea. While CNTF neutralization retarded reinnervation in normal corneas, exogenous CNTF accelerated nerve regeneration in the wounded corneas of diabetic mice and healthy animals, in which DCs had been locally depleted. Moreover, blockade of the CNTF-specific receptor CNTFRα induced sensory nerve degeneration and retarded regeneration in normal corneas. Soluble CNTFRα also partially restored the branching of diabetes-suppressed sensory nerve endings and regeneration in the diabetic corneas. Collectively, our data show that DCs mediate sensory nerve innervation and regeneration through CNTF and that diabetes reduces DC populations in UW and wounded corneas, resulting in decreased CNTF and impaired sensory nerve innervation and regeneration.

The use of intracorneal ring segments in keratoconus.

Keratoconus is a corneal degeneration that usually appears during puberty and may seriously deteriorate the quality of life of the patients. This corneal disease is today the first indication of corneal transplantation in young patients. Until the last decade of the XX century, keratoplasty procedures were the only alternative to treat this pathological condition. In the beginning of the XXI century, intracorneal ring segments implantation was proposed as a therapeutic choice for treating keratoconus patients. Since then, several published articles have reported the benefits of this surgical procedure in treating this type of corneal ectatic disorder.The purpose of the present investigative work is to summarize the characteristic of the intracorneal ring segments and also to review the different features published in the literature in relation to this surgical technique for the treatment of keratoconus patients.

Lamellar keratoplasty in a referral center in northeastern Brazil

Objective : To clinically characterize some cases of lamellar keratoplasty performed in a referral center of Rio Grande do Norte state. Methods : This is a cross-sectional, retrospective study, which is the review of the medical records of 18 patients who underwent keratoplasty of lamellar type in a referral service in Natal/RN. Results : it was found that of 18 patients who underwent keratoplasty, 55.56% were male, being all patients with deep anterior lamellar. Regarding the age group, 66.67% were thirty years old or less. The corneal vascularization of tissue was a factor receptor absent in 77.78% of cases. The main indication for lamellar keratoplasty were keratoconus (66.66%). Of the cases in which transplantation was done with urgency, ocular diagnoses were not infectious ulcerative keratitis (50%), corneal degeneration (25%) and leukoma (25%). Conclusion : it is cocluded that the main indicator condition for lamellar keratoplasty was keratoconus. Patients who underwent the procedure were 30 years old or less, with minimum level of corneal vascularization and absence of glaucoma. Furthermore, the surgical technique predominantly used for lamellar transplantation was the deep lamellar keratoplasty due to its advantages over penetrating keratoplasty.

Intraoperative outcome of deep anterior lamellar keratoplasty using femtosecond laser versus manual trephine

Purpose The aim of this study was to compare the intraoperative data of femtosecond laser-assisted deep anterior lamellar keratoplasty (F-DALK) with those of manual trephine deep anterior lamellar keratoplasty (M-DALK). Setting The study was conducted in a single private centre (Alfat’h Eye Hospital). Design This is a nonrandomized comparative retrospective, single private centre clinical study. Materials and Methods The study was conducted between February 2013 and March 2016 on 40 eyes that underwent M-DALK and 24 eyes that underwent F-DALK, including moderate-to-advanced keratoconus (KC) intolerant to contact lenses, superficial corneal opacities or degenerations, and stromal corneal dystrophies (e.g. macular dystrophies, etc.) with best spectacle corrected visual acuity (BSCVA) less than or equal to 6/60 (0.1), and excluding those with KC (with acute hydrops or posthydrops scars), corneal opacities or corneal dystrophies involving the endothelium. The intraoperative data were retrieved and analysed. Results F-DALK had fewer intraoperative complications compared with M-DALK, such as the decentred cut, which was 0% in F-DALK versus 1/40 (2.5%) in M-DALK, with a statistically significant difference in the overall intraoperative complications between the two procedures (P=0.004). Conclusion The F-DALK technique results in fewer intraoperative complications such as the inadvertent premature entry of the anterior chamber, a better centration of the cuts in patients with KC, and more success of the big bubble formation and thereby less conversion to penetrating keratoplasty or to manual dissection, which has a lower visual outcome.

Lipid corneal degeneration after trabeculectomy with mitomicin 0.02%

Um paciente com história de trabeculectomia com Mitomicina C 0,02%, sem doenças sistêmicas pré-existentes, apresentou infiltrado lipídico corneano unilateral associado à vascularização intraestromal profunda. Injeção subconjuntival de Bevacizumabe foi realizada e posterior ceratoplastia penetrante. Não houve sinais de recorrência em um ano. Degeneração lipídica da córnea após trabeculectomia com mitomicina C 0,02%

Involvement of ZEB1 and Snail1 in excessive production of extracellular matrix in Fuchs endothelial corneal dystrophy

Fuchs endothelial corneal dystrophy (FECD) due to corneal endothelial cell degeneration is a major cause of corneal transplantation. It is characterized by abnormal deposition of extracellular matrix (ECM), such as corneal guttae, accompanied by a loss of endothelial cells. Although recent studies have revealed several genomic factors, the molecular pathophysiology of FECD has not yet been revealed. In this study, we establish a cellular in vitro model by using immortalized corneal endothelial cells obtained from late-onset FECD and control patients and examined the involvement of epithelial mesenchymal transition (EMT) on excessive ECM production. We demonstrate that the EMT-inducing genes ZEB1 and SNAI1 were highly expressed in corneal endothelial cells in FECD and were involved in excessive production of ECM proteins, such as type I collagen and fibronectin through the transforming growth factor (TGF)-β signaling pathway. Furthermore, we found that SB431542, a specific inhibitor of TGF-β type I ALK receptors, suppressed the expression of ZEB1 and Snail1 followed by reduced production of ECM. These findings suggest that increased expression levels of ZEB1 and Snail1 in FECD cells were responsible for an increased responsiveness to TGF-β present in the aqueous humor and excessive production of ECM. In addition, these results suggest that the regulation of EMT-related genes by blocking the TGF-β signaling pathway may be a feasible therapeutic strategy for FECD.

This issue of ACTA, printed and electronic

The cover photograph shows the effect of eye drops on diabetic macular oedema. The dexamethasone cyclodextrin nanoparticle eye drops are described by Ohira et al. in this issue of Acta. Kessel et al. review the literature and conclude that cataract surgery does not increase the risk of progression of AMD to the exudative stage. Jellema et al. in the Netherlands and Switzerland review strabismus surgery in patients with Graves' disease and find the field to be poorly standardized. They propose new criteria for measuring surgical success. Ohira et al. in Japan, Sweden and Iceland describe novel eye drops containing dexamethasone in cyclodextrin nanoparticles. The eye drops improve visual acuity and decrease retinal thickness in patients with diabetic macular oedema. Rassmussen et al. in Copenhagen found that delay in diagnosis and treatment of exudative AMD results in poorer visual outcome. Vottonen et al. in Finland associate increased amplitude of visually evoked potential with improved visual acuity and decreased retinal thickness following anti-VEGF treatment in wet AMD. Ceynowa et al. in Sweden found morning glory anomaly in 3/100 000 children. This was frequently associated with macular oedema, cerebral abnormalities and cutaneous vascular abnormalities. Raffa et al. in Sweden and Saudi Arabia found increased ocular morbidity in moderate to late preterm infants. They found a correlation between gestational age and visual acuity. van Leeuwen et al. in the Netherlands examined rehabilitation needs of visually impaired young adults. Need for employment was most prevalent, followed by peer interaction and social and civic life. Thomseth et al. in Denmark found no association between ocular use of chloramphenicol in first trimester of pregnancy and congenital malformations. Stenwall et al. in Uppsala point out that cytokine content of serum influences the anti-inflammatory effect of serum eye drops. Nielsen et al. in Aarhus used mass spectroscopy to characterize proteins that adhere to contact lenses. Ramberg et al. in Copenhagen find squamous cell dysplasia of the conjunctiva to be relatively rare and mostly in old men. It tends to recur and may progress to carcinoma. Van Bergen et al. in Belgium recommend bevacizumab to complement mitomycin-C in glaucoma filtering surgery. Sundelin and Dafgård Kopp in Stockholm found high complication rates in secondary orbital implants and 28% needed reoperation. Uusitalo et al. in Finland describe an infected tarsal cyst. The following articles and letters are published electronically only and are accessible on www.actaophthalmologica.com as all are articles published in ACTA from the beginning. Jonas et al. in China and Germany correlate high cerebrospinal pressure with retinal vein occlusions. Lopez Torres et al. in Switzerland associate reduced retinal vessel diameter in the peripapillary area with reduced responses on multifocal ERG. Debellemanière et al. in France used adaptive optics imaging to observe cone loss related to subclinical hydroxychloroquine toxicity. Pastor-Idoate et al. in Spain, Portugal, UK and the Netherlands describe possible genetic biomarkers that predict proliferative vitreoretinopathy. Ji et al. in China describe increasing macular pigment density with age in healthy people. Lens opacities affect the one-wavelength reflectometry. Chen et al. in China measured vascular endothelial growth factor and placenta growth factor and aqueous humour of patients with neovascular glaucoma. Munk et al. in USA, Austria and Switzerland found vitreoretinal adhesion to slow resolution of cystoid macular oedema in uveitis, but not affect visual outcomes. Jiang et al. in China study pterygium surgery and recommend a sutureless limbal conjunctival autograft using tissue glue. Yuksel et al. in Turkey compared two methods to obtain corneal donor buttons. ‘Morgue trephination technique’ resulted in less donor disfigurement than ‘classic sclerocorneal removal technique’, while transplant quality and outcome was similar. Bittersohl et al. in Germany found retinal nerve fibre thickness not to be a reliable diagnostic tool for Parkinson's disease. Gupta et al. in Singapore report thin choroid in high myopia. Chihaia et al. in Germany comment on the recent paper by Jarventauata et al. on peripheral hypertrophic subepithelial corneal degeneration. They add their experience and dispute the nomenclature. Yoo et al. in Korea and USA suggest that sleeping position may influence asymmetrical glaucoma damage. Shiraya et al. in Japan report greater burn expansion with endolaser compared to transpupillary retinal photocoagulation. Sugihara et al. in Japan describe pseudoexfoliation material on intraocular lenses. Jouve et al. in France used intravitreal anti-VEGF treatment in a pregnant woman and discuss pros and cons. Pratyusha and Votruba in the United Kingdom describe retinal changes in acquired lipodystrophy. Cinar et al. in Turkey found myelinated nerve fibres on fundus photographs in 0.3% of people. Clemens et al. in Germany describe microrips in retinal pigment epithelium that may precede RPE tears. Mittal et al. in India and United Kingdom show histopathology of lymphoma with crystal storing histiocytosis. Stoyanova et al. in the Netherlands recommend bandage and scleral contact lenses for ocular graft-versus-host disease. I hope you enjoy this issue of Acta.

Degeneration and Regeneration of Subbasal Corneal Nerves after Infectious Keratitis: A Longitudinal In Vivo Confocal Microscopy Study

To investigate the longitudinal alterations of subbasal corneal nerves in patients with infectious keratitis (IK) during the acute phase, cessation of treatment, and the recovery phase by in vivo confocal microscopy (IVCM). Prospective, longitudinal, case-control, single-center study. Fifty-six eyes of 56 patients with the diagnosis of bacterial (n=28), fungal (n=15), or Acanthamoeba (n=13) keratitis were included in the study. Thirty eyes of 30 normal volunteers constituted the control group. Corneal sensation and serial IVCM of the central cornea were performed prospectively using the Heidelberg Retina Tomograph 3/Rostock Cornea Module (Heidelberg Engineering, Heidelberg, Germany). The IVCM images were assessed at 3 time points: at the acute phase (first visit to the cornea service), at cessation of antimicrobial treatment, and up to 6 months after the resolution of infection. Total nerve number and length, main nerve trunks, branching, and corneal sensation were assessed during the follow-up period. Corneal nerves were reduced significantly during the acute phase in eyes with IK compared with controls across all subgroups, with total nerve length of 5.47±0.69 mm/mm2 versus 20.59±1.06 mm/mm2 (P<0.0001). At the cessation of treatment, corneal nerves in patients with IK had regenerated, including total nerve length (8.49±0.94 mm/mm2; P=0.02) and nerve branch length (4.80±0.37 mm/mm2; P=0.005). During the recovery phase, after resolution of infection, corneal nerves regenerated further, including total nerve length (12.13±1.97 mm/mm2; P=0.005), main nerve trunk length (5.80±1.00 mm/mm2; P=0.01), and nerve branch length (6.33±0.76 mm/mm2; P=0.003) as compared with the acute phase, but were still significantly lower when compared with controls (P<0.05 for all parameters). Corneal degeneration and regeneration correlated with corneal sensation (r=0.47; P=0.0009). Patients with IK who sustain profound loss of corneal nerves during the acute phase of infection demonstrate increased corneal nerve density during the first 6 months after the resolution of infection. However, despite significant nerve regeneration, corneal nerve density does not recover fully and remains low compared to controls. By providing an objective methodology to monitor corneal re-innervation, IVCM adds potentially important findings that may have implications for clinical management and surgical planning.

Fairness, Benefiting by Lottery and the Chancy Satisfaction of Moral Claims

This article offers a new theory about how using lotteries to distribute scarce benefits satisfies beneficiaries' claims. In the first section of the article I criticize John Broome's view and on the basis of these criticisms set out four desiderata for a philosophically adequate account of claim satisfaction by lottery. In section II I propose and defend a new view called the dual structure view, so called because it posits that claimants have two types of claims in the relevant scarce benefit distribution cases under discussion. This view meets all the desiderata set out in section I. Section III draws out the practical implications of my view for a variety of temporally extended cases, including the distribution of corneas to patients who have suffered corneal degeneration.

Transient Corneal Edema After Phacoemulsification.

To determine the association between pre-operative and intra-operative factors leading to transient corneal edema after phacoemulsification. Cohort study. Department of Ophthalmology, Shifa Foundation Community Health Centre, Islamabad, from October 2011 to September 2012. Patients undergoing phacoemulsification and Intraocular Lens (IOL) implantation were enrolled in the study using consecutive non-probability sampling. Pre-operative risk factors including peripheral corneal degenerations, the type and density of cataract were documented. Surgical risk factors included the incision site, the type of intraocular lens, the phacotechnique and the phacopower time. Postoperatively the patients were assessed for corneal clarity and the degree of striate keratopathy. Statistical analysis was done using SPSS version 17. There were 43% male and 57% female patients (n = 182). Mean age was 58.92 ± 13.00 years (median and mode-60 years). Factors which increased the risk of transient corneal edema after phacoemulsification included hypertension (p = 0.022), dense nuclear cataracts (p=0.006), divide and conquer technique (p = 0.008), duration of phacopower use (p < 0.001) and peripheral corneal degenerations (p < 0.001). Patients with peripheral corneal degenerations and dense nuclear cataracts had significantly higher rates of postoperative corneal edema. Use of phaco-chop technique and less phaco-power time helps in decreasing corneal edema.

Staging of development in Terrien's degeneration based on corneal curvatures detected by optical coherence tomography.

We aimed to explore a new classification system based on the change of focal corneal curvatures and corneal thickness in Terrien's corneal degeneration with optical coherence tomography. This was a cross-sectional study. Ninety eyes of 59 patients with Terrien's degeneration were examined with slit lamp biomicroscopy, Orbscan II corneal tomography and the Visante OCT system, and were staged according to Süveges's classification. The ratio of female to male patients was 1.57:1. The ratio of bilateral to unilateral lesions was 1.27:1. The occurrence of bilateral lesion was higher in males than in females (x(2) = 7.791, p = 0.005). There was no difference in the mean age between female and male patients (t = 1.859, p = 0.068), or between patients with bilateral and unilateral lesions (t = 1.797, p = 0.078).The minimum corneal thickness at the thinnest point (MinCT) and anterior curvature of the peripheral cornea were almost normal in the initial stages of disease. The anterior curvature was flattened when MinCT became less than 0.56 mm, returned to normal when MinCT was no more than 0.24 mm, and bowed forward when MinCT was no more than 0.13 mm. The posterior corneal curvatures were bowed forward from their normal curvatures in 42 of 90 eyes when MinCT was no more than 0.41 mm. These eyes' MinCT ranged from 0 to 0.41 mm. There was a strong correlation between change of corneal curvatures and MinCT (r = -0.943, p < 0.01). A new classification of six stages based on corneal curvatures is proposed for evaluating the development of Terrien's degeneration. Statistically, there was a moderate correlation between either the Süveges staging or the new staging and the width and circumference of corneal lesions, visual acuity, and simulated keratometric value (all r < 0.6). The correlation of MinCT with the new classification based on corneal curvatures was higher than that with Süveges's classification (r 1 vs. r 2 , -0.943 vs. -0.801). The proposed new classification based on focal corneal curvatures is closely associated with corneal thinning, is valuable for evaluating the development of Terrien's degeneration and may enhance surgical planning.

Repeatability of corneal phase retardation measurements by polarization-sensitive optical coherence tomography.

Polarization-sensitive optical coherence tomography (PS-OCT) can evaluate internal tissue structures of the cornea, such as collagen fibers, by phase retardation measurement. In this study, we assessed the repeatability of corneal phase retardation measurements using anterior segment PS-OCT. A total of 173 eyes of 173 patients were measured using PS-OCT. In total, 58 eyes of young subjects with normal corneas, 28 eyes of old subjects with normal corneas, 26 eyes with corneal dystrophy or degeneration, 37 eyes with corneal transplantation, and 24 eyes with keratoconus were evaluated. The 3-mm diameter average of en face phase retardation of the posterior corneal surface was examined using PS-OCT. To evaluate the repeatability, intraclass correlation coefficients (ICCs) were calculated for intraobserver repeatability and interobserver repeatability analysis. Polarization-sensitive OCT showed good repeatability for corneal measurements. Intraclass correlation coefficients of intraobserver and interobserver repeatability of all the subjects were 0.989 and 0.980, respectively. Intraclass correlation coefficients of the intraobserver for each group, that is, young and old subjects with normal cornea, cornea dystrophy/degeneration, corneal transplantation, and keratoconus, were 0.961, 0.975, 0.984, 0.978, and 0.996, respectively. Interobserver ICCs for the above-mentioned respective groups were 0.952, 0.964, 0.988, 0.959, and 0.975, respectively. Polarization-sensitive OCT showed good repeatability for phase retardation measurements of central corneas not only for normal corneas, but also for various diseased corneas. Polarization-sensitive OCT might be useful for evaluating corneal phase retardation, which is one of the parameters that defines birefringence.

Loss of corneal epithelial heparan sulfate leads to corneal degeneration and impaired wound healing.

Heparan sulfate (HS) is a highly modified glycosaminoglycan (GAG) bound to a core protein to form heparan sulfate proteoglycans (HSPGs) that are vital in many cellular processes ranging from development to adult physiology, as well as in disease, through interactions with various protein ligands. This study aimed to elucidate the role of HS in corneal epithelial homeostasis and wound healing. An inducible quadruple transgenic mouse model was generated to excise Ext1 and Ndst1, which encode the critical HS chain elongation enzyme and N-deacetylase/N-sulfotransferase, respectively, in keratin 14-positive cells upon doxycycline induction. EXT(Δ/ΔCEpi) mice (deletion of Ext1 in corneal epithelium) induced at P20 presented progressive thinning of the corneal epithelium with a significant loss in the number of epithelial layers by P55. EXT(Δ/ΔCEpi) mice presented tight junction disruption, loss of cell-basement membrane adhesion complexes, and impaired wound healing. Interestingly, EXT(Δ/ΔCEpi) and NDST(Δ/ΔCEpi) mice presented an increase in cell proliferation, which was assayed by both Ki67 staining and 5-ethynyl-2'-deoxyuridine (EdU) incorporation. Moreover, EXT(Δ/ΔCEpi) mice presented compromised epithelial stratification 7 days after a debridement wound. The conditional knockout of HS from keratocytes using the keratocan promoter led to no corneal abnormalities or any disruption in wound healing. Corneal epithelial cells require HS for maintaining corneal homeostasis, and the loss of epithelial HS leads to both impaired wound healing and impaired corneal stratification.

Ocular surface changes in type II diabetic patients with proliferative diabetic retinopathy.

To detect and analyze the changes on ocular surface and tear function in type II diabetic patients with proliferative diabetic retinopathy (PDR), an advanced stage of diabetic retinopathy (DR), using conventional ophthalmic tests and the high-resolution laser scanning confocal microscopy. Fifty-eight patients with type II diabetes were selected. Based on the diagnostic criteria and stage classification of DR, the patients were divided into the non-DR (NDR) group and the PDR group. Thirty-six patients with cataract but no other ocular and systemic disease were included as non-diabetic controls. All the patients were subjected to the conventional clinical tests of corneal sensitivity, Schirmer I Test, and corneal fluorescein staining. The non-invasive tear film break-up time (NIBUT) and tear interferometry were conducted by a Tearscope Plus. The morphology of corneal epithelia and nerve fibers was examined using the high-resolution confocal microscopy. The NDR group exhibited significantly declined corneal sensitivity and Schirmer I test value, as compared to the non-diabetic controls (P< 0.001). The PDR group showed significantly reduced corneal sensitivity, Schirmer I test value, and NIBUT in comparison to the non-diabetic controls (P < 0.001). Corneal fluorescein staining revealed the progressively injured corneal epithelia in the PDR patients. Moreover, significant decrease in the corneal epithelial density and morphological abnormalities in the corneal epithelia and nerve fibers were also observed in the PDR patients. Ocular surface changes, including blunted corneal sensitivity, reduced tear secretion, tear film dysfunction, progressive loss of corneal epithelia and degeneration of nerve fibers, are common in type II diabetic patients, particularly in the diabetic patients with PDR. The corneal sensitivity, fluorescein staining scores, and the density of corneal epithelial cells and nerve fibers in the diabetic patients correlate with the duration of diabetes. Therefore, ocular surface of the patients with PDR should be examined regularly by conventional approaches and confocal microscopy to facilitate early diagnosis and treatment of keratopathy.

Cirugía de pterigio: Hospital de San José de Bogotá DC

Pterygium, non-involuntary corneal degeneration, is an inflammatory and proliferative alteration of the ocular surface with thickening and elastotic degeneration of the conjunctiva. Exposure to ultraviolet solar radiation, heat, dust and viral agents participate in its evolution. Objective: to describe the results of pterygium surgery at the San José Hospital in Bogotá DC. Method: case series of all patients with this diagnosis operated between January 2010 and December 2011. Results: 176 stories were reviewed and 113 eyes were included. The most frequent complications were corneal del 7.9%, reproduction 5% and retraction of plasty 3.5%, identified in the first three months postoperatively. The reproduction frequency was higher in the cases of pterygium reproduced (33%), compared to the primary 4.4%. Conclusion: despite the known side effects of mitomycin, those who used it in the postoperative period in low doses did not present adverse effects and its use was safe. Given the low percentage of reproduction in this study, it is recommended that in the resection of extensive or reproduced pterigios, the use of amniotic membrane be considered.

Management of Descemet Detachment following Crescentic Lamellar Excision with Autolamellar Dissection for Pellucid Marginal Corneal Degeneration

A 35 year-old male patient with pellucid marginal corneal degeneration underwent crescentic lamellar excision with autolamellar dissection on his left eye. One month later, the patient developed localized corneal edema overlying the area of the crescentic resection due to Descemet membrane detachment. The Snellen corrected visual acuity reduced from 6/15 one week postoperatively to 2/60 following the development of corneal edema. The fluid that collected in the interface was removed with a blunt 30-gauge cannula, and air was injected into the anterior chamber to oppose the two corneal layers. Corrected visual acuity improved to 6/12 over 1 month, and to 6/9 seven months later. The corneal edema resolved over 2 months. Crescentic lamellar excision with autolamellar dissection could be associated with Descemet membrane detachment and corneal edema; however, this complication has a very good outcome when managed with a minimally invasive procedure.

Climatic droplet keratopathy: an old disease in new clothes.

Climatic droplet keratopathy (CDK) is an acquired and potentially handicapping cornea degenerative disease that is highly prevalent in certain rural communities around the world. It predominantly affects males over their forties. It has many other names such as Bietti's band-shaped nodular dystrophy, Labrador keratopathy, spheroidal degeneration, chronic actinic keratopathy, oil droplet degeneration, elastoid degeneration and keratinoid corneal degeneration. CDK is characterized by the haziness and opalescence of the cornea's most anterior layers which go through three stages with increasing severity. Globular deposits of different sizes may be histopathologically observed under the corneal epithelium by means of light and electron microscopy. The coalescence and increased volume of these spherules may cause the disruption of Bowman's membrane and the elevation and thinning of the corneal epithelium. The exact aetiology and pathogenesis of CDK are unknown, but they are possibly multifactorial. The only treatment in CDK advanced cases is a corneal transplantation, which in different impoverished regions of the world is not an available option. Many years ago, the clinical and histological aspects of this disease were described in several articles. This review highlights new scientific evidence of the expanding knowledge on CDK's pathogenesis which will open the prospect for new therapeutic interventions.