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Rheumatoid arthritis (RA) is an autoimmune disease that primarily affects the joints. Extra-articular manifestations (EAMs) are common and may affect up to 40.6% of patients. Ocular EAM can occur in 39% of the patients. The cornea is involved by different pathogenic mechanisms and corneal disease varies from mild symptoms to severe corneal ulceration and melting with visual loss. Severe corneal involvement is associated with increased mortality in RA patients. We aimed to review the prevalence, mechanisms, management and overall impact of corneal involvement in RA patients.Corneal involvement is frequent among RA patients. With the wider use of systemic immunosuppression, in particular the disease-modifying antirheumatic drugs (DMARDs), and with improvement of surgical techniques, spontaneous and surgery-related corneal ulceration and melting is becoming less common. However, RA patients are still at risk and should be carefully managed.RA-related corneal complications are associated with a decreased quality of life and poor ocular and systemic prognosis. Prompt recognition and a multidisciplinary approach involving topical ophthalmic management and systemic immunosuppression are the key factors to maintain ocular integrity and avoid a lethal outcome.

To review the neuroanatomy and physiology of the basal and reflex tearing and present the available and developing therapies using the concept of neurostimulation in dry eye disease (DED).The most prevalent current DED treatments seek to supplement low tear volume and tear components or reduce inflammation. Neurostimulation is a unique approach gaining momentum in recent years, geared toward increasing the production of all basal tear components by stimulating the nerves responsible for producing the various tear components. The neuroanatomy of the lacrimal unit provides several possible access points to stimulate tear production through two arms of the sensory trigeminal nerves. Modes of stimulation include chemical or energy in electrical or magnetic form. Research thus far has shown that neurostimulation can achieve lacrimal, goblet cell, and meibomian gland stimulation. Subjectively it improves symptoms of DED. Clinically, neurostimulation has improved the signs and symptoms of DED by increasing basal tear production and tear volume.Neurostimulation using electrical, mechanical, or chemical means is a novel concept to increase tear production and was demonstrated to be an effective, safe, and well-tolerated method for managing DED.

The purpose of this case report is to demonstrate the efficacy of an asymmetric peripheral design scleral contact lens in a case of highly irregular corneal-scleral pattern due to trauma. A 63-year-old patient was involved in a jeep accident which caused a partial-thickness penetrating injury to the peripheral cornea of his left eye. The subsequent corneal irregularity extended beyond the limbus into the sclera which made it difficult to stabilize a contact lens. A quadrant specific peripheral curve (quadrant asymmetric periphery) scleral contact lens successfully resulted in improved comfort and visual acuity. This is the first known published case to use this lens design to correct a post-trauma irregular cornea-scleral relationship. Quadrant asymmetric periphery scleral contact lenses can be effective in cases of severe irregular corneal-scleral patterns.

Purpose of review Ocular allergic contact dermatitis is a common yet challenging and frequently misdiagnosed condition. Inappropriate or delayed treatment can contribute to a variety of clinical symptoms such as tearing and itching with signs such as ptosis and cicatricial ectropion, resulting in deterioration of disease, for which the topical medication was originally prescribed to resolve. Recent findings Understanding previously unrecognized pathogenic mechanisms involving ocular contact dermatitis has driven new approaches to control the inflammatory process by neutralizing inflammatory mediators and their receptors. Summary Early diagnosis and removing the antagonizing substance is crucial to manage ocular contact dermatitis. Steroid therapy is usually required to reduce symptoms. As ocular allergic dermatitis often develops in patients using drugs for chronic conditions that necessitate chronic application, it may be difficult at times to discontinue or replace the offending agent.

Purpose of review Chemokines are a large group of low molecular weight cytokines that attract and activate leukocytes throughout the body and therefore have a key role in the framework of late-phase allergic responses. The purpose of this article is to provide an overview of the main chemokines involved in allergic conjunctivitis, their primary functions and their physiological roles, and therapies targeted at chemokines and their receptors for ocular allergic diseases. Recent findings In recent years, there have been considerable advances in the understanding of ocular pathophysiology of ocular surface inflammatory diseases including both allergic eye diseases and dry eye syndrome. Several therapies being developed for dry eye inflammation are recognized as possible therapies for ocular allergic diseases as there are often common chemokines involved in both disease spectra. Summary Chemokines represent an integral part of the late-phase cascade of ocular allergic inflammation. A deep understanding of specific chemokines and their interactions will help in targeting therapies to effectively manage ocular clinical findings and symptoms of allergic eye disease.

Purpose To evaluate predictors for success in corneal crosslinking (CXL) for keratoconus in a large cohort and extended follow-up. Design A retrospective study based on a prospectively built database. Methods Participants underwent CXL for keratoconus from 2007 to 2018. Statistical analysis was performed for patients with at least 1-year follow-up. We analyzed effects of CXL type (Epithelium-on or Epithelium-off and Accelerated (9mW/cm2@10min) or Standard (3mW/cm2@30min)) and pre-operative factors including age, gender, baseline LogMAR visual acuity (LogMARpre), maximal corneal power (Kmaxpre), pachymetry, refractive and topographic cylinders, spherical equivalent (SEpre), mean corneal power (MeanK) and follow-up time on outcome measures. The outcome measures were the final change of Kmax (Delta Kmax) and the final change in LogMAR visual acuity (Delta LogMAR). A more negative Delta Kmax or Delta LogMAR represents a favorable effect of crosslinking. Results 517 eyes had Kmax results, and 385 eyes had LogMAR results with more than one year follow-up. These eyes were included in the study. The mean follow-up time was 2.29 years. Mean Kmax decreased from 54.07±5.99 diopters to 52.84±5.66 diopters (ppre, high SEpre, high MeanKpre, and non-accelerated procedure. Multivariate analysis showed three factors associated with negative Delta LogMAR: high LogMARpre, high SEpre, and Low MeanKpre. After excluding corneas with Kmaxpre >65 D or Pachymetrypre, high SEpre, and non-accelerated CXL were associated with negative Delta Kmax while high LogMARpre and high SEpre were associated with negative Delta LogMAR. Conclusion CXL for keratoconus is a highly effective treatment, as evident by its effects on the outcome measures: Delta Kmax and Delta LogMAR. CXL was more successful in eyes with high Kmaxpre, high SEpre, and high LogMARpre, which express disease severity. The non-accelerated epithelium-off protocol was associated with greater flattening of corneal curvature but did not show a better effect on visual acuity as compared to the other CXL protocols.

PURPOSE OF REVIEW Vernal keratoconjunctivitis (VKC) is a severe allergic inflammatory disease affecting the conjunctiva in children and young adults. Keratoconus (KC) is a progressive corneal disease characterized by thinning of the corneal stroma, increased and asymmetric corneal curvature, with a potential for significant visual deterioration and is one of the most common corneal complications of VKC. We aimed to review the association of these two diseases, with focus on the mechanisms, prevalence, natural history and treatment strategies of KC associated with VKC. RECENT FINDINGS KC is a common complication of VKC. KC prevalence can be as high as 26.8% among VKC patients, whereas abnormal corneal topography may appear in up to 71% of them. It is more severe and progresses faster in the setting of VKC (P

The spectrum of allergic eye diseases includes a variety of conditions, each characterized by complex immunopathologies.Antiallergic drugs, such as antihistamines and mast cell stabilizers, are often insufficient without concomitant topical corticosteroid treatment. The chronic course of the more severe allergic eye diseases, such as vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC), limits the treatment with topical corticosteroids to short courses. In addition, topical corticosteroid treatment puts patients at high risk of developing severe ocular complications, particularly during childhood when VKC most frequently occurs.The immunopathology of chronic diseases, such as VKC and AKC, involves predominantly T lymphocytes, and as such, immunomodulators that inhibit T-cell activation seem to be the appropriate treatment for these chronic diseases. In the past years, there is an increased incidence of managing chronic allergic eye diseases with the immunomodulator tacrolimus. The current review presents an update of the recent clinical experience with topical tacrolimus for the management of chronic allergic eye diseases.Topical tacrolimus significantly improves the symptoms and signs of the various forms of chronic allergic eye disease. Recent studies also demonstrate the efficacy of low concentrations of topical tacrolimus for VKC.Early medical treatment with topical tacrolimus can also prevent the development of serious ocular complications of VKC, such as shield ulcers or limbal stem cell deficiency.Topical tacrolimus has significantly changed the management approaches in severe and chronic allergic eye diseases and has minimized the need for topical corticosteroids.

A novel class of Mn(III) and Fe(III) complexes of L-tyrosine-based ligand has been synthesized and characterized through various analytical and spectroscopic techniques. These complexes were found to exhibit efficient binding properties with the biomolecules viz . calf thymus DNA and BSA. The ability of complexes to bind with such biomolecules has been explored through absorption, emission and viscosity measurements. Based on spectroscopic techniques we can conclude that the complexes could bind to DNA via intercalation. It was observed that these complexes can cleave pBR322 DNA in gel-electrophoresis technique through oxidative mechanism. The BSA was quenched by the complexes around 340 nm adopting a mechanism of static mode. The binding constants, thermodynamic parameters and the donor to acceptor distance were calculated. Besides, molecular docking simulations were carried out for the complexes with human DNA topoisomerase and BSA protein. The docked poses are visualized to provide supportive evidence to the interaction of the synthesized complexes with DNA/BSA.

Purpose of review To address the current trends of therapeutic mechanisms for treatment of allergic conjunctivitis (AC), based on topical antihistamines and mast cell stabilizers (MCS). Recent findings The antihistamine drug alcaftadine has H4 receptor inverse agonism, anti-inflammatory and MCS activities. The antihistamines levocabastine and azelastine are more effective than placebo in treatment of AC symptoms in randomized controlled trials (RCTs). The topical dual-action antihistamines/MCS olopatadine, azelastine, ketotifen, and epinastine are commonly used in Europe and in the United States for mild subtypes of AC. For the main symptoms of AC, ocular itch and conjunctival hyperemia, epinastine 0.05% was superior to placebo, but equal or more effective than olopatadine 0.1%, while the later was more effective than ketotifen. High concentration olopatadine 0.77% had longer duration of action, better efficacy on ocular itch, and a similar safety profile to low-concentration olopatadine 0.2%. The new formulas of topical dual-action agents present longer duration of action, leading to a decreased frequency of use. Summary The topical dual-action agents are the most effective agents treating signs and symptoms of mild forms of AC. There is superiority to the high-concentration olopatadine drug over other agents on ocular itch, with prolonged effect when used once-daily.

To review the updated literature regarding eye rubbing complications and its association with ocular allergy disorders.Atopy and ocular allergy disorders, mainly vernal keratoconjunctivitis (VKC), are strongly associated with rubbing-related complications, most probably via itching and watery eye sensations that trigger the habit of chronic eye rubbing. Vigorous and prolonged rubbing may lead to establishment of corneal remodeling and ectatic disorders, such as keratoconus. Keratoconus development in rubbed eyes can be caused by mechanical mechanisms of corneal thinning and its loss of rigidity, by elevated temperature of the epithelium during rubbing, by increased intraocular pressure (IOP) because of distending forces, and by inflammatory molecules that may serve as a causal mediator between eye rubbing and keratoconus. Other eye rubbing complications include acute hydrops and perforation, IOP spikes, iris prolapse and iridoschisis rupture of lens capsule and IOL dislocation, and even posterior segment disorders, such as glaucomatous optic neuropathy, retinal detachment and extrusion of implanted silicone oil in the eye.Chronic eye rubbing in allergic eye diseases can lead to progression of keratoconus, and to other rare anterior and posterior segment complications. Strategies eliminating eye rubbing and its consequences are vital, mainly among at-risk populations, such as young children and individuals with allergic ocular disorders or corneal transplants.

Background Cytokines are known to be key players in dry eye syndrome (DES) and Sjogren’s syndrome (SS) pathogenesis. In this study we compared single nucleotide polymorphism (SNP) variations in genes encoding cytokine levels among SS and DES patients in Israel. Methods We recruited 180 subjects, 82 with SS and 98 with DES. Using a candidate gene approach and allele-specific PCR technique for genotyping, proportions of risk alleles in Tumor Necrosis Factor α (TNFα) (rs1800629), IinterLeukin-10 (IL-10) (rs1800896) and TNFAIP3 (rs2230926) SNPs were compared between study groups. Results Allelic distribution was found very similar to Caucasian (CEU – Utah residents with Northern and Western European roots) population distributions in these SNPs. While none of the SNPs’ variants were significantly associated with SS or DES in a recessive model, in an additive model the TNFα G risk allele was found higher among SS patients compared to DES (Homozygote-G: 84.2% vs. 70.8%; Heterozygote: 26.9% vs. 11.2%, respectively, p = 0.02). After adjustment for age, gender and ethnicity, these variants weren’t associated with SS. Genetic scoring reveals that SS patients are more likely to present variants of all three SNPs than DES subjects. Conclusions This is the first study evaluating these SNP variations among both patients with DES and patients with SS. We found the allelic distribution in each SNP to be very similar to that found in healthy Caucasian populations presented in the HapMap project. We found the TNFα allele significantly associated with DES for homozygotes, and associated with SS for heterozygotes in the additive model.

Dry eye disease (dry eye) is a multifactorial disorder of the ocular surface. Dry eye is one of the most frequent ocular disorders, affecting 5% to 50% of the entire population at all ages. Evidence suggests that inflammation and hyperosmolarity are considered core mechanisms in the development of dry eye. Dry eye is accompanied by changes in tear composition including enhanced hyperosmolarity and secretion of pro-inflammatory mediators such as cytokines, chemokines, matrix metalloproteinases (MMPs) and adhesion molecules. All these factors may act as mediators of tissue damage leading to lysis of cell membranes and tight junctions in epithelial cells. Eventually these processes lead to corneal and conjunctival epithelial cells death as well as conjunctival goblet cell dysfunction and death. Anti-inflammatory agents for dry eye include corticosteroids, immunomodulator agents and essential fatty acids. Recently, an integrin lymphocyte function-associated antigen-1 (LFA-1) antagonist, lifitegrast ophthalmic solution (Xiidra) was approved in the USA for the treatment of dry eye. Lifitegrast blocks the binding of intercellular adhesion molecule-1 (ICAM-1) to LFA-1. The following review attempts to present a current update of the available anti-inflammatory agents for dry eye disease.

Objectives. To assess whether there are shared exposures associated with Sjogren’s syndrome (SS), dry eye syndrome (DES), and B-cell non-Hodgkin lymphoma (B-NHL), in order to determine whether they are etiologically related. Methods. In a clinic-based case-control study, 702 participants (91 SS, 120 DES, 211 (age and sex frequency-matched) controls, and 280 B-NHL cases) were recruited and interviewed regarding exposures, medical history, and family history. Results. Female predominance was noted in SS (ratio 9.2 : 1). Eye dryness was severest in SS compared to DES and controls (P<0.001). Compared to controls, alcohol consumption was inversely associated with NHL, DES, and SS (odds ratio OR=0.47, 95% confidence interval (CI): 0.31-0.71; OR=0.54, 95% CI: 0.33-0.88; and OR=0.26, 95% CI: 0.14-0.49, respectively), while a previous history of infection requiring hospitalization was positively associated with all three conditions: NHL (OR=1.92; 95% CI: 1.23-2.99), DES (OR=3.29; 95% CI: 1.97-5.47), and SS (OR=4.74; 95% CI: 2.66-8.44). NHL patients were more likely to report first-degree relatives with hematologic cancer, while having first-degree relatives with an autoimmune disease (AID) was associated with SS (OR=5.25; 95% CI: 2.59-10.63) and DES (OR=3.55; 95% CI: 1.83-6.91) compared to controls. Conclusions. Some exposures are associated with all three conditions (such as an inverse association with alcohol consumption and a positive association with serious past infection), while a family history of AID appears to be shared by DES and SS, but not NHL subjects. Shared risk factors for all three conditions indicate possible mutual etiological pathways.

Over the past decade Deep Anterior Lamellar Keratoplasty (DALK) has been proposed as a preferred surgical option over Penetrating Keratoplasty (PKP) for the management of keratoconus (KC) and other anterior stromal diseases. However DALK is associated with a considerable number of problems which still prevent its acceptance by most corneal surgeons. DALK is a time consuming procedure, technically demanding, and is associated with a long and steep learning curve, even for experienced corneal surgeons. At the same time patients after DALK have comparable visual results to those of PKP, as well as comparable results in terms of refractive errors and residual astigmatism. In addition DALK is more costly compared to PKP as a result of the longer surgical time and higher number of follow-up visits. On a long-term follow-up PKP is associated with higher rates of graft rejection, while in DALK there is more interface haze as a result of retained host stroma. Whereas DALK is a procedure limited for anterior stromal corneal disorders with an intact descemet’s membrane, PKP can be used for all corneal pathologies that require replacement of the cornea, including descemet abnormalities such as hydrops in severe KC, penetrating trauma and herpetic infections where the endothelium is likely to be involved. The consistent reports of comparable visual outcomes for both PKP and DALK suggest there is no preference in choosing DALK over PKP. As long as more efficient, reproducible and easy to perform steps in DALK are developed, PKP will remain a valid and more popular option in corneal transplantation for keratoconus and other anterior stromal disorders.

Purpose To evaluate the predictive factors for safety and efficacy in laser refractive surgery for myopia Setting A singular refractive surgery center, at a University-affiliated tertiary medical center. Design Retrospective cohort study Methods Study population—A total 8,775 eyes having laser refractive laser procedures for myopia (in4,623 patients). Observation procedures–Using a prospective database of refractive procedures performed over the span of 13 years, variables such as gender, age, type of surgery, date of surgery, pre-operative corneal thickness and Spherical Equivalent (SEQ) were evaluated. Main outcome measures—Proportion of patients with Safety index higher than 0.85 and Efficacy index higher than 0.80. Results 91.9% and 86.0% of all evaluated eyes were above the safety and efficacy cut-off levels, respectively. Younger age was significantly correlated with safety and efficacy indices above the cut-off levels (p

Objectives To compare hematologic and serological parameters among patients with Sjogren’s syndrome (SS), dry eye syndrome (DES) and controls, and validate a novel multiplex-serology method for identifying auto-antibodies in these populations. Methods In a clinic-based case-control study a total of 422 participants were recruited, including 91 with SS, 120 DES, and 211 controls (age and sex frequency-matched). We measured blood counts, anti-nuclear-antibodies (ANA), anti-SSA/SSB, anti-ribonucleoprotein (RNP), anti-double-stranded-DNA (DS-DNA), and rheumatoid factor (RF) using the “Immunodot” qualitative-ELISA assay. Immunoglobulins, C3 and C4 were measured by immune-fluorescence. Autoantibodies were also quantified with a newly-developed method using glutathione-S-transferase fusion proteins of SSA/Ro 52 and 60kD and SSB/La (multiplex-serology), measuring median fluorescence intensity (MFI). Results Among DES patients, only 2% (95%CI: 0.36–6.3) had positive immune serology. SS patients had lower lymphocyte, hemoglobin and C3 levels but higher prevalence of RF, ANA, anti-SSA/B and higher IgG and MFI levels, compared to DES and controls (P Conclusions Serologic parameters distinguish SS from DES patients and controls. A newly-developed multiplex-serology technique may be useful to detect autoantibodies in large epidemiologic studies.

Purpose of review Contact lens-induced papillary conjunctivitis (CLPC) is a common ocular allergic disease in contact lens wearers. In its more severe form, it can cause giant papillary conjunctivitis, resulting in contact lens intolerance and the need to discontinue the use of contact lenses. This review presents the pathogenesis, clinical manifestations and management guidelines of this common disorder. Recent findings Different types of contact lenses are associated with differences in the severity of CLPC. Refitting patients with silicone hydrogel contact lenses or with daily disposable contact lenses may improve the signs and symptoms of CLPC. The recent introduction of the topical immunomodulatory agent tacrolimus in other severe allergic eye diseases may apply in suppressing the allergic inflammation in CLPC as well. Summary CLPC is a common ocular disorder in contact lens wearers, with a significant impact on the quality of vision. It should be promptly recognized by healthcare practitioners and managed by modifications of the types and wearing schedules of contact lenses, as well as novel treatment options with topical immunomodulators.

ObjectiveTo present an established practice protocol for safe and effective hospital-setting ophthalmic practice during the coronavirus disease 2019 (COVID-19) pandemic.Methods and AnalysisLiterature was reviewed to identify articles relevant to COVID-19 pandemic and ophthalmology. The following keywords were used: COVID-19, SARS-CoV-2 and telemedicine, combined with eye, ophthalmology, conjunctivitis and tears. Data were extracted from the identified manuscripts and discussed among subspecialists to obtain consensus evidence-based practice.ResultsA protocol for ophthalmic practice in the era of COVID-19 pandemic was established. The protocol covered patient screening, clinic flow, required personal protective equipment and modifications of ophthalmic equipment for improved safety.ConclusionImportant literature emerged with respect to the practice of ophthalmology in the era of COVID-19. An evidence-based ophthalmic practice protocol was established and should be modified in the future to accommodate new insights on the COVID-19 pandemic.

Observations show robust changes in the circulation, temperature, and salinity of the Southern Ocean in recent decades. To what extent these changes are related to the formation of the ozone hole in the late twentieth century is an open question. Using a comprehensive chemistry-climate Earth system model, we contrast model runs with varying and with fixed surface concentrations of ozone depleting substances (ODS) from 1955 to 2005. In our model, ODS cause the majority of the summertime changes in surface wind stress which, in turn, induce a clear poleward shift of the ocean's meridional overturning circulation. In addition, more than 30% of the model changes in the temperature and salinity of the Southern Ocean are caused by ODS. These findings offer unambiguous evidence that increased concentrations of ODS in the late twentieth century are likely to have been been an important driver of changes in the Southern Ocean.

Ocular hypertension is a potentially serious complication after penetrating keratoplasty (PKP). Our objective is to determine the risk factors, incidence, patient characteristics, response to pressure-lowering medical therapy, and graft outcome associated with elevation of intraocular pressure after PKP.One hundred forty-six consecutive eyes that had PKP between June 2001 and June 2003 were operated and managed at Hadassah-Hebrew University Medical Center. Chart review was performed seeking preoperative and postoperative data on risk factors for ocular hypertension after PKP. Univariate and logistic regression analysis were performed to identify significant risk factors.After surgery, 70 eyes (47.9%) had at least 1 period of ocular hypertension, with a mean intraocular pressure (IOP) of 27.15±5.66 mm Hg. Ocular hypertension appeared after a mean postoperative period of 70.3±15.8 days, and continued for an average period of 15.6±2.0 days. In 35 eyes (23.9%), a second episode of IOP elevation was noted 212.2±46.8 days after the surgery. Logistic regression analysis revealed that preexisting glaucoma (P=0.009) and an additional surgical procedure combined with PKP (P=0.007) were the main factors predicting ocular hypertension after PKP. In 11 eyes (7.53%) the topical pressure-lowering therapy failed, and they required glaucoma filtering surgery.The incidence of ocular hypertension after PKP is high, and at least 1 episode of high IOP was noted in almost half of our patients. A history of preexisting glaucoma and an additional surgical procedure combined with PKP were found to be significant factors predicting the occurrence of ocular hypertension.

The quasi-biennial oscillation (QBO) is the dominant mode of variability in the tropical stratosphere, which is in large part driven by upward propagating atmospheric waves. For over three decades researchers have investigated an extratropical impact due to the vacillation of the tropical winds. The choice of a single altitude to define the QBO introduces an ambiguity into the analysis of correlations between the tropical and extratropical manifestations of this wave-driven phenomenon. It has been previously demonstrated that using empirical orthogonal functions, this ambiguity can be resolved, by calculating the phase of the QBO from the first two principal components of the stratospheric zonal mean wind. As general circulation models begin to simulate the QBO, a standard and objective means of comparing simulations with observations should be adopted. This objective analysis of the extratropical QBO is presented for the ERA-Interim reanalysis and a version of the Community Atmosphere Model, version 5, which exhibits a spontaneously generated QBO.

The veterinarian is daily faced with the challenge of diagnosing several disease conditions in different animals. Quantifying cortisol levels has been used in the evaluation of anxiety and distress initiated by infectious and non-infectious disease conditions, mismanagement, transportation, adverse environmental temperature and surgical operations. The hormone-cortisol has been implicated in several immunologic and metabolic processes and can thus serve as a marker to monitor animal welfare. Several factors affect the specific test to be carried out and which sample is to be used. Recently, RIA has been identified as the gold standard for determination of cortisol levels. However it also has its own short comings hence the need to utilize other assay techniques such as ELISA, fluorescence techniques and chemical assays which are more common in our environment. There is also prospect for the analysis of cortisol using non-invasive samples such finger nails as well as ear wax for enhanced test results.

During Northern Hemisphere winter, polar stratospheric winds and temperatures exhibit significant variability that is due to the vertical propagation of planetary-scale waves. The most dramatic intraseasonal variations in temperature are associated with sudden stratospheric warmings (SSWs), which are wave-breaking events that occur approximately every other year. This paper will introduce the concept of wave activity events (WAEs), which are periods of enhanced pseudomomentum density in the polar stratosphere that occur every year. It will be demonstrated that all SSWs are associated with WAEs; furthermore, minor warmings and many final warmings in the polar spring are also WAEs, and therefore a better understanding of these more frequent wave events can provide additional insights into stratospheric wave-induced variability. Employing the Interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) for 1979–2011, 119 WAEs are identified and their life cycle is compared with that of the 23 SSWs observed during this period.

a b s t r a c t Purpose: To evaluate the success rate of highly gas permeable scleral contact lenses (SCL) for visual rehabilitation after penetrating keratoplasty (PK), over a period of up to 9 years. Methods: A total database of 31 consecutive patient fitted with SCL between January 2004 and December 2009 was retrospectively reviewed. Demographic data, etiology prior to lens fitting, visual outcomes, follow up time and complications were analyzed. Results: All eyes were fitted due to inadequate spectacle-corrected vision after successful penetrating keratoplasty or failure of other contact lens modalities. Out of 31 patients fitted, 28 (33 eyes) continue to wear SCL for periods between 0.5 and 8.8 years. The mean duration of follow-up after contact lens fitting was 5.2 ± 2.2 years. The mean age of corneal graft was 17.6 ± 11.4 years (range 4.3-42), and the mean interval between PK and initial contact lens fitting was 12.2 ± 10.7 years (range 0.7-36.0). The average steepest keratometry of our cohort was 55.0 ± 7.5 diopter (D) and the refractive astigmatism was 8.0 ± 4.4 D. The mean contact lens corrected visual acuity (BCVAcl) was 0.78 ± 0.25 (range 0.3-1.2). Twenty-three (82%) patients achieved a functional vision of 0.5 or more. During the studied period, ten (30.0%) eyes presented at least one graft rejection episode and two eyes (6%) had an episode of microbial keratitis. Corneal transplants of 20 years or more show a higher rate of refits due to ectasia recurrence. Conclusions: Scleral lenses should be considered as lens of choice in eyes with complex corneal geometry, as besides visual rehabilitation, their use may delay or prevent further surgical involvement.

Horizontal resolution of general circulation models (GCMs) has significantly increased during the last decade, however these changes were not accompanied by similar changes in vertical resolution. In our study, the Community Atmosphere Model, version 5 (CAM5) is used to study the sensitivity of climate to vertical resolution and nonorographic gravity wave drag. Nonorographic gravity wave drag is typically omitted from low-top GCMs, however as we show, its influence on climate can be seen all the way to the surface. We show that an increase in vertical resolution from 1200 to 500 m in the free troposphere and lower stratosphere in CAM5 improves the representation of near-tropopause temperatures, lower stratospheric temperatures, and surface wind stresses. In combination with nonorographic gravity waves, CAM5 with increased vertical resolution produces a realistic Quasi-Biennial Oscillation (QBO), has an improved seasonal cycle of temperature in the extratropics, and represents better the coupling between the stratosphere and the troposphere.