Anti-inflammatory and antiallergic effects of ketorolac tromethamine in the conjunctival provocation model

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

Comparative efficacy of medical treatments for vernal keratoconjunctivitis in children and young adults: a systematic review with network meta-analyses

PURPOSE

To systematically review the literature on the treatment of vernal keratoconjunctivitis (VKC) in children and young adults and conduct comparative efficacy analysis on clinical signs and symptoms using network meta-analyses.

METHODS

We systematically searched the databases PubMed/MEDLINE, EMBASE, Cochrane Central and Web of Science on 21 October 2019 for randomized controlled trials (RCT). Studies considered had patients with VKC < 20 years of age randomized into either intervention (any medical intervention) or comparator (active treatment, placebo treatment or non-treatment control), where pre-defined outcomes (data from ≥2 weeks and as close as possible to 2 months) of symptoms (itching, tearing, photophobia and foreign body sensation) and signs (hyperaemia, punctate keratitis, Horner-Trantas dots and macropapillae) were reported. Risk of bias within studies was evaluated using the Cochrane risk of bias tool. Comparisons were made using network meta-analyses.

RESULTS

We identified 39 studies with data on 2046 individuals. Twenty-three studies were eligible for quantitative analyses. None were systemic therapy. Temporal trend analysis showed that an initial focus on topical mast cell stabilizers turned to a focus on calcineurin inhibitors and a more diverse variety of pharmacological strategies. Studies varied in population, treatment duration and quality. The quantitative analysis revealed that efficacy of different therapies differed substantially across important clinical signs and symptoms, but there was a general trend of superior efficacy when using topical corticosteroids with stronger efficacy of the more potent corticosteroids.

CONCLUSION

We provide an overview of RCTs comparing the efficacy of treatments for VKC in children and young adults, which we find differs across symptoms and signs. Overall, we saw a general trend of superior efficacy with topical corticosteroids. However, our findings highlight the need for better studies, consensus on core outcomes and potential for individualized therapy.

[Effectiveness of a nonsteroidal anti-inflammatory drug in the treatment of chronic non-infectious blepharitis]

Anti-inflammatory therapy is a type of etiopathogenetic treatment of chronic mixed blepharitis. Nonsteroidal anti-inflammatory drugs (NSAIDs) have pronounced anti-inflammatory effect comparable to the action of corticosteroids.

PURPOSE

To assess of the effectiveness of a NSAID - 0.09% bromfenac - in the treatment of chronic blepharitis of non-infectious etiology.

MATERIAL AND METHODS

The study included 37 patients (74 eyes), 31 women (62 eyes) and 6 men (12 eyes) with chronic blepharitis. All patients underwent clinical, functional, instrumental and laboratory examination. The treatment of patients of the main group consisted of instillations of 0.09% bromfenac ('Broxinac', Sentiss, India) once per day and artificial tears with lipid component 3 times a day for 30 days. Patients in the control group only used artificial tears with lipid component 3 times a day for 30 days. The follow-up included examinations at one week, one and two months.

RESULTS

The positive clinical and functional response after treatment corresponded to optimization of the state of microvasculature in both groups, however, the dynamics of changes in the control group were less pronounced.

CONCLUSION

Elimination of microcirculatory disorders in the eyelids and signs of inflammation of the ocular surface determine the etiopathogenetic direction of using 0.09% bromfenac in the conservative treatment of chronic mixed blepharitis.

Melatonin as a Therapeutic Resource for Inflammatory Visual Diseases

BACKGROUND

Uveitis and optic neuritis are prevalent ocular inflammatory diseases, and highly damaging ocular conditions. Both diseases are currently treated with corticosteroids, but they do not have adequate efficacy and are often associated with severe side effects. Thus, uveitis and optic neuritis remain a challenging field to ophthalmologists and a significant public health concern.

OBJECTIVE

This review summarizes findings showing the benefits of a treatment with melatonin in experimental models of these inflammatory ocular diseases.

RESULTS

Oxidative and nitrosative damage, tumor necrosis factor, and prostaglandin production have been involved in the pathogeny of uveitis and optic neuritis. Melatonin is an efficient antioxidant and antinitridergic, and has the ability to reduce prostaglandin and tumor necrosis factor levels both in the retina and optic nerve. Moreover, melatonin not only prevents functional and structural consequences of experimental uveitis and optic neuritis, but it is also capable of suppressing the actively ongoing ocular inflammatory response.

CONCLUSIONS

Since melatonin protects ocular tissues against inflammation, it could be a potentially useful anti-inflammatory therapy in ophthalmology.

Management of vernal keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is a relatively rare, chronic form of ocular allergy that can potentially cause severe visual complications. Affecting mainly children and young adults, it is an IgE- and T cell-mediated disease, leading to a chronic inflammation in which eosinophil, lymphocyte and structural cell activation are involved. Treatment of VKC requires a multiple approach that includes conservative measures and pharmacologic treatment. Patients and parents should be made aware of the long duration of disease, its chronic evolution and possible complications. Treatment should be based on the duration and frequency of symptoms and the severity of corneal involvement. Mast cell stabilizers and antihistamines have been proven to be effective for the treatment of mild to moderate forms of VKC. In the most severe cases, topical steroids can be used as rescue medication to reduce conjunctival and corneal inflammation. Immunomodulators that have been investigated for VKC treatment include topical ocular preparations of cyclosporine A and tacrolimus. Topical cyclosporine A has been proven to be effective in the long-term treatment of VKC, significantly improving signs and symptoms without significant side effects.

Mediator profiles in tears during the conjunctival response induced by allergic reaction in the nasal mucosa

BACKGROUND

The allergic reaction occurring primarily in the nasal mucosa can induce a secondary conjunctival response of an immediate (SICR), late (SLCR), or delayed (SDYCR) type in some patients with allergic conjunctivitis (AC).

OBJECTIVES

To investigate the concentration changes of histamine, tryptase, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), leukotrienes (LTB 4, LTC4, LTE4), myeloperoxidase (MPO), interferon-γ (IFN-γ), and interleukins (IL-2, IL-4, IL-5) in tears during the SICR, SLCR, and SDYCR.

METHODS

In 32 patients with AC, 11 SICR (p<0.01), 13 SLCR (p<0.001), and eight SDYCR (p<0.01) to nasal challenges with allergens (NPTs), the NPTs and 32 control tests with PBS were repeated and supplemented with the determination of these factors in tears.

RESULTS

The SICRs were associated with significant concentration changes in tears (p<0.05) of histamine, tryptase, ECP, LTC4, and IL-4. The SLCRs were accompanied by significant changes in concentrations of histamine, ECP, LTB4, LTC4, MPO, IL-4, and IL-5. The SDYCRs were associated with significant concentration changes in tears (p<0.05) of LTB4, MPO, IFN-γ, and IL-2. No significant changes in these factors were recorded in tears during the 32 PBS controls (p>0.1) or in the ten control patients (p>0.1).

CONCLUSIONS

These results provide evidence for causal involvement of nasal allergy in some patients with AC, inducing secondary conjunctival response of immediate (SICR), late SLCR, or delayed SDYCR type, associated with different mediator, cytokine, and cellular profiles in the tears, suggesting involvement of different hypersensitivity mechanisms. These results also emphasize the diagnostic value of nasal allergen challenge combined with monitoring of the conjunctival response in some patients with AC.

Topical ophthalmic NSAIDs: a discussion with focus on nepafenac ophthalmic suspension

The removal of diclofenac sodium ophthalmic solution as a viable pharmaceutical entity in September 1999 from the US market spurred considerable interest in the general safety and effectiveness of topical ophthalmic NSAIDs for treatment of anterior segment inflammation. In late 1999 the use of topical ocular NSAIDs declined in the US as a result of incidents involving corneal melts and toxicity surrounding use of generic diclofenac. However, since the removal of diclofenac sodium ophthalmic solution from the marketplace, ophthalmic NSAIDs have regained use as viable pharmacotherapeutic entities. Moreover, several new ophthalmic NSAID products have recently been introduced for commercial use in the US including the novel chemical entity nepafenac. The purpose of this report is to revisit the use of topical ophthalmic NSAIDs for the treatment of surgically induced anterior segment inflammation with a particular focus on nepafenac. Nepafenac is unique among ophthalmic NSAIDs in that it is a prodrug deaminated to amfenac, a highly effective non-selective cyclooxygenase inhibitor. In the case of topical ophthalmic NSAIDs, practitioners should carefully weigh the cost-benefit of implementing “highly potent” new drug products because perturbations in pharmacodynamic response due to the inherent novelty in terms of chemical designs may outweigh the demonstrated replicative pharmacologic action of all topical ophthalmic NSAIDs.

Comparison of ocular tolerability between preserved and preservative-free diclofenac sodium drops

PURPOSE

To compare the tolerability of preserved diclofenac sodium 0.1% (Voltaren Ophtha) and preservative-free diclofenac (Dicloftil).

METHODS

Thirty healthy volunteers received a single drop of Voltaren Ophtha in 1 eye, and a single drop of Dicloftil in the other. Both drops were instilled at the same time, in a single-blind manner. Visual analog scale grading was used to measure ocular discomfort, itch, burn, and pain. Grading was obtained before drop instillation and after 15 s, 1 min, 5 min, 15 min, and 30 min.

RESULTS

Both preparations caused discomfort, itch, burn, and pain, with a peak effect on all 4 parameters at 15 min. However, preservative-free Dicloftil proved to be more tolerable than preserved Voltaren Ophtha. Data show significantly lower reported levels of discomfort and itch up to 15 min, lower levels of burn at the first minute, and less pain immediately after instillation.

CONCLUSION

This is the first study to compare subjective ocular tolerability of a single drop. Our results indicate that Dicloftil has better tolerability than Voltaren Ophtha. Ophthalmologists should be aware of this significant difference when prescribing diclofenac, especially in patients with low compliance or who require prolonged therapy.

Tear levels of neuropeptides increase after specific allergen challenge in allergic conjunctivitis

PURPOSE

Growing evidence is showing a role of neurogenic inflammation in allergic reactions, with sensory and autonomic nerve fibers releasing neuromediators, which may actively participate in the allergic inflammatory cascade. Although the cornea is the most densely innervated tissue of the human body, little is known on the role of neuromediators at the ocular surface. In this study, we aimed at evaluating the role of substance P (SP), calcitonine gene related peptide (CGRP), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) in allergic reactions of the ocular surface.

METHODS

Fifteen patients with allergic conjunctivitis (6 female, 9 male, mean age 30±8 years) in non-active phase, and 10 age-matched healthy subjects were included in this study. The conjunctival provocation test (CPT) with allergen was performed in all allergic patients and in 5 healthy subjects. Tear samples were collected and the tear content of VIP, NPY, CGRP, and SP was measured by ELISA at baseline and after CPT. The Mann-Whitney U-test and Wilcoxon test were used to compare neuromediator tear levels.

RESULTS

No significant differences in neuropeptide tear levels were observed between healthy and allergic patients in non-active phase. CPT induced conjunctival hyperemia and itching in all allergic patients, while no reaction was observed in the control eyes and in healthy subjects. In allergic patients SP, CGRP, and VIP, but not NPY, were significantly higher after CPT as compared to baseline (SP: 3.9±1.3 ng/ml versus 5.8±1.1 ng/ml, p=0.011; CGRP: 5.5±2.3 ng/ml versus 7.3±2.7 ng/ml; p=0.002; VIP: 4±0.9 ng/ml versus 5.1±1.5 ng/ml, p=0.007). No significant changes were observed in the control eyes of allergic patients challenged with diluent and in healthy subjects after allergen provocation.

CONCLUSIONS

Locally-released neuromediators may participate in modulating the allergic response of the ocular surface.

Vernal conjunctivitis

Vernal conjunctivitis is a bilateral, seasonal, external ocular inflammatory disease of unknown cause. Afflicted patients experience intense itching, tearing, photophobia, and mucous discharge, and usually demonstrate large cobblestone papillae on their superior tarsal conjunctiva and limbal conjunctiva. It primarily affects children, may be related to atopy, and has environmental and racial predilections. Although usually self-limited, vernal conjunctivitis can result in potentially blinding corneal complications. Treatment of chronic forms of ocular allergies may necessitate collaborative efforts between the ophthalmologist and the allergist or immunologist.

Canine and feline uveitis

The clinical signs of uveitis occur as a result of inflammation within the vascular coat of the eye, which causes breakdown of the blood-aqueous barrier and blood-retinal barrier. Many infectious and noninfectious causes can incite episodes of uveitis. Although a complete diagnostic evaluation is highly recommended to identify any underlying etiologic agent, many cases remain idiopathic in nature. The goals of therapy are preserving vision, minimizing pain, and halting inflammation.

Topical non-steroidal anti-inflammatory drugs in allergic conjunctivitis: meta-analysis of randomized trial data

PURPOSE

To assess the effect of topical Non-Steroidal Anti Inflammatory drugs in the treatment of allergic conjunctivitis.

METHOD

Systematic Review.

DATA SOURCES AND STUDY SELECTION

Reports of comparative randomized trials of topical NSAIDs and placebo identified by searches of Medline, Embase, the Cochrane Register of Controlled Trials.

DATA EXTRACTION AND SYNTHESIS

Two reviewers assessed trials for eligibility and quality and extracted data independently. Data were synthesized (random effects model) and results expressed results for dichotomous outcomes as relative risk and continuous outcomes as weighted mean difference. Sensitivity analysis was used to examine potential heterogeneity by differences in study quality.

RESULTS

Eight studies incorporating 712 patients were included. The difference between the decrease in allergic sign and symptom score for NSAID treatment compared to placebo was between 4 and 19 percentage points. Topical NSAIDs produced significantly greater relief for conjunctival itching (cardinal symptom) than did placebo (combined standardized mean difference -0.54 (p < 0.001; 95% confidence interval -0.84 to -0.24). The results for the other allergic symptoms: ocular burning/pain, eyelid swelling, photophobia and foreign sensation were not significant. Topical NSAIDs produced significantly greater reduction of conjunctival injection than did placebo (combined standardized mean difference -0.51 (p = 0.03; 95% confidence interval -0.97 to -0.05). Topical NSAIDs did not reduce the allergic signs of conjunctival chemosis, conjunctival mucus, eyelid swelling and corneal disturbance. Topical NSAIDs had a significantly higher rate of burning/stinging on application of medication compared to placebo (P < 0.0001; odds ratio 3.97 (95% CI 2.67 to 5.89).

CONCLUSION

This meta-analysis confirms that topical NSAID are significantly more effective at relieving the cardinal symptom: conjunctival itching and improving the cardinal sign: conjunctival injection than placebo treatment. A systematic review comparing topical NSAIDs to topical antihistamines/mast cell stabilizers in treatment of allergic conjunctivitis is warranted as this will compare the topical NSAIDs to current therapeutic guidelines.

The role of NSAIDs in the management of postoperative ophthalmic inflammation

Recent advances in cataract surgery, such as phacoemulsification, small-incision surgery and advances in foldable intraocular lenses, have resulted in the decrease of physical trauma associated with cataract surgery. The decrease in the physical surgical trauma decreases the release of prostaglandins, which are the main players in postoperative ocular inflammation. However, postoperative inflammation continues to be a cause of patient discomfort, delayed recovery and, in some cases, suboptimal visual results. Left untreated, this inflammation might interfere with patients' rehabilitation and/or contribute to the development of other complications, such as cystoid macular oedema.NSAIDs are commercially available, in topical or systemic formulations, for the prophylaxis and treatment of ocular conditions. Topically applied NSAIDs are commonly used in the management and prevention of non-infectious ocular inflammation and cystoid macular oedema following cataract surgery. They are also used in the management of pain following refractive surgery and in the treatment of allergic conjunctivitis. Despite their chemical heterogeneity, all NSAIDs share the similar therapeutic property of inhibiting the cyclo-oxygenase enzyme. The appeal of using NSAIDs in the treatment of ocular inflammation hinges on the complications associated with corticosteroids, the other commonly used therapy for ophthalmic inflammation.

[Ocular surface investigations in dry eye]

Dry eye is a complex clinicopathological entity involving tear film, lacrimal glands, eyelids, and a wide spectrum of ocular surface cells, including epithelial, inflammatory, immune, and goblet cells. From the tightly regulated lacrimal film functions and structure, a large variety of investigations have been developed, including tear meniscus measurements, fluorophotometry, meibometry, interference pattern analysis, evaporation rate, tear osmolarity, and thermography. Dry eye conditions also interfere with the ocular surface, causing corneal irregularities that may be explored using the techniques of videokeratography and in vivo confocal microscopy, or optical impairment, as confirmed by aberrometry. At the level of ocular surface cells, impression cytology remains a standard for assessing cell alterations. It has greatly benefited from new confocal microscopy, molecular biology, and flow cytometry techniques. Biological assessment of tear proteins or other mediators is also useful. Major limits should be acknowledged, however, such as technical issues in tear film collection, especially in dry eyes, and the lack of standardization of most measurements. Tear osmolarity, electrophoresis, and dosage of normal tear proteins, such as lysozyme or lactoferrin, remain the most useful tests. Finally, some extraocular explorations such as accessory gland biopsy or serum antinuclear antibody dosage may be useful for assessing the diagnosis of Sjögren's syndrome.

Les tests de provocation conjonctivaux

The conjunctival provocation test (CPT) is a human model of ocular allergy that has been used to study the ocular response to allergenic stimuli and to evaluate antiallergic therapy. Considerable useful information has been gained on the ocular allergic response and drug efficacy using the conjunctival provocation test and naturally occurring seasonal allergic conjunctivitis. The safety and the efficacy of these CPTs has resulted in many authors using this tool in the etiologic diagnosis of allergic conjunctivitis. This article summarizes the possibilities of these CPTs as a tool for the study, evaluation, diagnosis, and therapeutic follow-up of allergic conjunctivitis.

The effects of topical ketorolac and indomethacin on measles conjunctivitis: randomized controlled trial

PURPOSE

To compare the effect of topical ketorolac and indomethacin on measles conjunctivitis.

DESIGN

Prospective double-masked placebo-controlled randomized trial.

METHODS

Sixty-two patients with severe measles conjunctivitis were included in this study. All patients were hospitalized and randomly assigned to receive ketorolac 0.5% or indomethacin 0.1% in the right eye and artificial tears in the left eye. Conjunctival hyperemia, burning sensations, foreign-body sensations, and photophobia scores were conducted at baseline and at days seven and 14. A satisfaction score was evaluated at the end of the study.

RESULTS

The conjunctival injection score of the control eyes was significantly higher than those of the ketorolac- and indomethacin-treated eyes at day seven (P < .05). The conjunctival injection score of the ketorolac-treated eyes was lower than that of the indomethacin-treated eyes at days seven and 14, but this did not reach statistical significance. There was no significant difference in the burning and foreign-body sensations and in the photophobia scores among the study eyes at baseline, day seven, and day 14 (P > .05). There was no significant difference in the satisfaction score among the study eyes at the end of the study (P > .05).

CONCLUSIONS

In patients with measles during the first two weeks of infection, ketorolac and indomethacin were more effective than artificial tears in decreasing conjunctival hyperemia, but burning sensations, foreign-body sensations, and photophobia were unaffected.

[Ocular allergies]

Recent developments indicate that ocular allergy is more than an IgE-mediated allergic conjunctivitis. Ocular allergy is a disease affecting the entire ocular surface including conjunctiva, lids, cornea, lacrimal gland and tear film. Besides an IgE-mediated reaction, a complex chronic inflammation is involved in the pathogenesis of many ocular allergies. According to their pathogenesis and clinical picture, ocular allergies are classified into mild forms, such as seasonal and perennial allergic conjunctivitis as well as giant papillary conjunctivitis, and chronic, potentially blinding forms such as atopic keratoconjunctivitis and vernal keratoconjunctivitis. New therapeutics act on the entire inflammatory process or try to modulate the allergic reaction early and specifically. The association with non-ocular allergic symptoms requires an interdisciplinary approach.

Nonsteroidal anti-inflammatory drugs in veterinary ophthalmology

Uveitis is a common sequela to many ocular diseases. Primary treatment goals for uveitis should be to halt inflammation, prevent or control complications caused by inflammation, relieve pain, and preserve vision. Systemic and topical NSAIDs are essential components of the pharmaceutic armamentarium currently employed in the management of ocular inflammation by general practitioners and veterinary ophthalmologists worldwide. NSAIDs effectively prevent intraoperative miosis; control postoperative pain and inflammation after intraocular procedures, thus optimizing surgical outcome; control symptoms of allergic conjunctivitis;alleviate pain from various causes of uveitis; and circumvent some of the unwanted side effects that occur with corticosteroid treatment. Systemic NSAID therapy is necessary to treat posterior uveitis, because therapeutic concentrations cannot be attained in the retina and choroid with topical administration alone, and is warranted when diseases, such as diabetes mellitus or systemic infection, preclude the use of systemic corticosteroids. Risk factors have been identified with systemic and topical administration of NSAIDs. In general, ophthalmic NSAIDs may be used safely with other ophthalmic pharmaceutics; however, concurrent use of drugs known to affect the corneal epithelium adversely, such as gentamicin, may lead to increased corneal penetration of the NSAID. The concurrent use of NSAIDs with topical corticosteroids in the face of significant preexisting corneal inflammation has been identified as a risk factor in precipitating corneal erosions and melts in people and should be undertaken with caution[8]. Clinicians should remain vigilant in their screening of ophthalmic and systemic complications secondary to drug therapy and educate owners accordingly. If a sudden increase in patient ocular pain (as manifested by an increase in blepharospasm, photophobia, ocular discharge, or rubbing)is noted, owners should be instructed to contact their veterinarian promptly.

Impression cytology of the ocular surface: a review

PURPOSE

To historically review the technique of impression cytology as a minimally invasive diagnostic tool for ocular surface pathology.

METHODS

A comprehensive review of published literature cited in PubMed since the first description of impression cytology in 1977 up to date has been undertaken.

RESULTS

A wide range of processing methods have been adapted to the technique of impression cytology (from conjunctiva, cornea or limbus): regular light microscopy with different stainings, transmission and scanning electron microscopy, immunofluorescence, immunocytochemistry, polymerase chain reaction analysis, immunoblotting analyses, or flow cytometry. At present, it is widely used as a non-invasive alternative to the full-thickness biopsy for the obtention of epithelial cells from the ocular surface.

CONCLUSIONS

Impression cytology represents a non- or minimally invasive biopsy of the ocular surface epithelium with no side effects or contraindications. It has demonstrated to be a useful diagnostic aid for a wide variety of processes involving the ocular surface. In addition, and mainly during the last decade, its use as a research tool has experienced an enormous growth and has greatly contributed to the understanding of ocular surface pathology.

Topical nonsteroidal anti-inflammatory therapy in ophthalmology

Topically applied nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used in the management and prevention of ocular inflammation and cystoid macular edema related to cataract surgery and the maintenance of mydriasis during cataract surgery. Other common uses are the reduction of discomfort after refractive surgery or in allergic conjunctivitis. NSAIDs primarily act as cyclooxygenase inhibitors and thus reduce the formation of endogenous PGs. Today, several NSAIDs are commercially available: diclofenac, flurbiprofen, indomethacin, ketorolac and suprofen. At present the ophthalmologist has to make a decision between the use of topical corticosteroids, with their potential adverse effects, or of topical NSAIDs, with their possibly increased benefit, unknown effect on ocular pressure, wound healing and corneal tissue, higher costs and limited track record. However, the improvement of surgical techniques might support an increasing use of NSAIDs in the future. Preoperative anti-inflammatory treatment should be considered in eyes at a higher risk of developing severe postoperative inflammatory reactions. This decision has to be made carefully and has to be guided by the clinical circumstances, the spectrum of diagnosis and the individual benefit-risk ratio of each patient.

Conjunctival provocation testing: overview of recent clinical trials in ocular allergy

PURPOSE OF REVIEW

The conjunctival provocation test is a human model of ocular allergy that has been used to study the ocular response to allergenic stimuli and to evaluate antiallergic therapy. The review will discuss recent studies using the conjunctival provocation test and other models of ocular allergy, and evaluate the relative merits of different models.

RECENT FINDINGS

The conjunctival provocation test has allowed investigators to recruit large numbers of allergic individuals who, although asymptomatic, can be challenged with the conjunctival administration of allergen. Observations of the eye can be made before and after challenge, and cells and mediators may be sampled from the ocular surface. In addition, the effectiveness of antiallergic therapy can be evaluated, usually by pretreating the two eyes with different forms or doses of drug.

SUMMARY

Considerable useful information has been gained about the ocular allergic response and drug efficacy using the conjunctival provocation test and naturally occurring seasonal allergic conjunctivitis.

Topical nonsteroidal anti-inflammatory drugs for ophthalmic use: a safety review

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used agents that despite chemically heterogeneity, share similar therapeutic properties and adverse effects. Topical ophthalmic NSAIDs are limited to the relatively water soluble phenylacetic and phenylalkanoic acids as well as indole derivatives, which are more suitable for ophthalmic use. Topical ophthalmic NSAIDs are commonly used in the treatment of post-operative inflammation following cataract extraction and various surgical refractive procedures. They are also used in the prevention and treatment of cystoid macular oedema and for the treatment of allergic conjunctivitis. Absorption of topical ophthalmic NSAIDs through the nasal mucosa results in systemic exposure and the occurrence of adverse systemic events, including exacerbation of bronchial asthma. Local irritant effects of topical ophthalmic NSAIDs include conjunctival hyperaemia, burning, stinging and corneal anaesthesia. A more serious complication involves the association of topical ophthalmic NSAIDs with indolent corneal ulceration and full-thickness corneal melts. Analysis of NSAID-associated corneal events implicates the now defunct generic dicolfenac product, diclofenac sodium ophthalmic solution as the agent primarily responsible. However, these events generated a renewed interest in the safety of ophthalmic NSAIDs and a scrutiny of the pharmacology regarding NSAID action in the eye. An elucidation of possible pharmacodynamic explanations of NSAID-induced corneal injury includes the role of epithelial hypoxia, which not only appears to aid in determining the metabolic destination of arachidonate, it may play a key role in orchestrating a novel inflammatory response unrelated to prostanoid formation. The use of NSAIDs under conditions of corneal hypoxia may therefore not only result in a disappointing therapeutic response, it may result in a paradoxical inflammatory exacerbation. Other potential mechanisms include the relationship between NSAIDs and corneal matrix metalloproteinase and direct toxicity due to cytotoxic excipients such as surfactants, solubilisers and preservatives found in topical NSAID ophthalmic preparations. In general, ophthalmic NSAIDs may be used safely with other ophthalmic pharmaceuticals; however, concurrent use of agents known to adversely effect the corneal epithelium, such as gentamicin, may lead to increased corneal penetration of the NSAID. The concurrent use of NSAIDs with topical corticosteorids in the face of significant pre-existing corneal inflammation has been identified as a risk factor in precipitating corneal erosions and melts and should be undertaken with caution. Until clinical evidence dictates otherwise, data supporting theories of potential pharmacodynamic mechanisms of NSAID injury do not alter the favorable benefit-risk ratio of ophthalmic NSAID use when employed in an appropriate and judicious manner.

The central role of conjunctival mast cells in the pathogenesis of ocular allergy

Ocular allergic diseases are characterized by specific activation of conjunctival mast cells with subsequent release of preformed and newly formed mediators. Mast-cell numbers on the ocular surface are increased in all forms of allergic conjunctivitis. Mast-cell activation plays a central role in the development of the ocular allergic reaction, which can be divided into an early and a late inflammatory phase. Mast-cell mediators have been measured in tears of patients suffering from various forms of allergic conjunctivitis, and in sensitized patients after specific ocular allergen challenge. Histamine and tryptase are the most studied mediators in tears of allergic patients. Several cytokines, such as IL-4 and TNF-a, are also produced and released by conjunctival mast cells, and probably play a role in the immunoregulation on the ocular surface. In vitro studies of the characteristics and biologic functions of conjunctival mast cells highlight their central role in the pathogenesis of ocular allergy, and have led to new opportunities to evaluate anti-allergic compounds. This review discusses the role of conjunctival mast cells in the development of ocular allergic diseases.

Advances in ocular allergy: basic mechanisms, clinical patterns and new therapies

Ocular allergy presents unsolved mysteries in molecular and cellular mechanisms, and at the same time continues to challenge ophthalmologists daily in a wide array of disease forms. The recent understanding of the key role of the T helper type 2 cytokines, adhesion molecules and chemokines may provide future avenues for pharmacological targeting of releasable inflammatory mediators. More potent topical mast cell stabilizers and H1 receptor antagonists have become commercially available for the management of the prevalent and benign forms of allergic conjunctivitis. Immunostimulatory DNA sequences present an innovative and promising route for the treatment of ocular allergy, but clinical studies are needed to demonstrate their efficacy in humans. Surgical methods are suggested to reconstruct the ocular surface in the sight-threatening diseases vernal keratoconjunctivitis and atopic keratoconjunctivitis. This review presents an update of the major advances in both the basic mechanisms and clinical and therapeutic aspects of ocular allergic diseases that were reported during the past year.

Vernal keratoconjunctivitis: pathogenesis and treatment

Vernal keratoconjunctivitis (VKC) is a recurrent or chronic ocular allergic disease that affects mostly children and young adults living in warm climates worldwide. Understanding and treating VKC has been a challenge for ophthalmologists since the pathogenesis is unclear and anti-allergic therapy often unsuccessful. In this paper, the culmination of 11 years of research into the immunological characteristics of this disease in a group of 221 VKC patients will be presented. Cytological, biohumoral, immunohistological and molecular biological studies indicate that VKC is a Th2 lymphocyte-mediated disease. Mast cells, eosinophils and their mediators play major roles in the clinical manifestation of VKC. In addition to typical Th2-derived cytokines, IL-4, IL-5 and IL-13, other cytokines, chemokines, growth factors and enzymes are over-expressed in the conjunctiva of VKC patients. Furthermore, structural cells, such as epithelial cells and fibroblasts, are involved both in the inflammatory process and in the tissue remodeling phase, ultimately resulting in the formation of giant papillae. Interactions between specific (IgE- and Th2-mediated) and non-specific triggers and mechanisms may account for treatment failure. New insights into the pathogenesis of VKC should generate the means to better design the strategies for this complex disease.