***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The objective of this study was to evaluate the efficacy of 0.05 % levocabastine , a new antihistamine formulated for ophthalmic use , compared with the placebo vehicle for the treatment of allergic conjunctivitis induced by ocular allergen challenge . Subjects who reacted . positively in both eyes on two separate occasions to ocular allergen challenge with grass , ragweed , or cat d and er ( N = 47 ) received one dose of 1 to 2 drops of 0.05 % levocabastine in one eye and its vehicle in the other eye . After 10 minutes , the predetermined dose of allergen was instilled in both eyes . Signs and symptoms of allergic conjunctivitis were evaluated with biomicroscopy and subjective evaluation of itching after 3 , 5 , and 10 minutes . Four hours after drug administration , subjects were rechallenged and reevaluated to determine levocabastine 's duration of action . Results showed that levocabastine was significantly more effective than placebo in inhibiting itching , hyperemia , eyelid swelling , chemosis , and tearing after the initial challenge and in inhibiting all parameters except eyelid swelling after the rechallenge 4 hours later ( p < 0.05 ) . These results demonstrate that levocabastine , currently the only ophthalmic antihistamine available that is not combined with a vasoconstrictor , is efficacious in the inhibition of itching , as well as all of the allergic signs of a vascular origin , with a duration of action of at least 4 hours . Because of its strong effects on itching and hyperemia , chemosis , lid swelling , and tearing , levocabastine would be a valuable therapeutic agent to add to the heterogeneous family of antiallergic compounds presently available for the treatment of seasonal allergic conjunctivitis Levocabastine is a recently developed , potent H1‐receptor blocker intended for topical application . Seventeen healthy non‐atopic volunteers participated in this r and omized , double‐blind , placebo‐controlled study undertaken to investigate the speed of onset of action , efficacy and tolerability of levocabastine eye‐drops after a histamine challenge . The degree of histamine‐induced ocular inflammation was found to be significantly less after administration of levocabastine compared with placebo . Furthermore , levocabastine was shown to be rapidly effective with an onset of action within 10 min . Levocabastine eye‐drops were well‐tolerated and no adverse reactions to the study drug were reported . Levocabastine eye‐drops appear to be a valuable therapeutic approach for the treatment of histamine‐mediated ocular allergies A double blind group comparative trial comparing 2 % nedocromil sodium with placebo in treating  seasonal allergic conjunctivitis  over a four week period is reported . Sixty-four patients were analysed . During the period of peak pollen challenge , statistically significant differences in favour of nedocromil sodium  for itching and soreness were demonstrated . During a longer period of a less high pollen count , a significant difference in favour of nedocromil sodium was shown only for the symptom of soreness Forty patients suffering from allergic conjunctivitis , due to birch pollen , participated in a double‐blind parallel group comparison between levocabastine ( a potent new specific histamine ( H1 ) antagonist ) and placebo , both given as eye drops . Symptom scores were recorded during a 4‐week period . A 1‐week run‐in period was followed by a 3‐week treatment period . To enable a fair evaluation of the treatment effect on the ocular symptoms only , all patients were treated with topical nasal glucocorticoids for possible rhinitis symptoms during the whole study period . Plasma levels of levocabastine were determined in all subjects at the end of the 3 weeks ' treatment period . Pollen counts for birch pollen were followed simultaneously . The evaluation of the symptom score cards revealed a significant reduction of ocular symptoms following use of the active compound . The resorption of the active substance through the conjunctiva was low . In accordance with the present trend of more topical treatment for allergic rhinitis , levocabastine may constitute a valuable compound for the topical treatment of allergic conjunctivitis Previous studies have shown the effectiveness of topical cromolyn solution in the treatment of allergic conjunctivitis .  However , the preservative , phenylethanol , produces an immediate burning or stinging sensation when the drops are first instilled in the eye . A double-blind , crossover , placebo controlled study using 2 % cromolyn solution was conducted , without the preservative and supplied in unit doses . Twenty six patients took part in the trial . They had ragweed pollen-induced conjunctivitis . The results of the trial indicate that the active drug was effective in controlling the signs and symptoms of allergic conjunctivitis in 22 of the 26 patients , i.e. , 84.6 % ( p less than 0.001 ) . Two patients preferred the placebo . There were no complaints of stinging or burning sensation after the instillation of the drops in the eyes . There were no cases of infection of the eye . Without the preservative , the cromolyn solution does not damage the soft contact lens This multicenter , double-masked , r and omized , parallel-group study compared the efficacy and safety of ketorolac tromethamine 0.5 % ophthalmic solution with levocabastine 0.05 % and ketorolac tromethamine vehicle in patients with seasonal allergic conjunctivitis . One drop of ketorolac , levocabastine , or vehicle was instilled in each eye four times daily for 6 weeks . In the majority of efficacy variables , ketorolac produced the greatest improvements , followed by levocabastine and vehicle . Ketorolac was significantly more effective ( P<.05 ) than vehicle in reducing mean itching scores , palpebral hyperemia , bulbar hyperemia , and edema . Patients treated with ketorolac reported significant improvements ( P<.05 ) in their ability to sleep and to concentrate on work , compared with those who received vehicle . No significant differences were noted among the treatment groups in safety or tolerability .  Ketorolac tromethamine 0.5 % ophthalmic solution instilled four times daily is effective and safe in reducing the signs and symptoms of seasonal allergic conjunctivitis PURPOSE This study was conducted to evaluate the efficacy of 0.05 % levocabastine compared with 4 % cromolyn for treating allergic conjunctivitis induced by ocular allergen challenge . METHODS Subjects who met all entry criteria and reacted positively to ocular allergen challenge at two previous visits ( n = 50 ) received placebo in one eye and cromolyn in the fellow eye , four times daily for 2 weeks . On day 18 , subjects received the final dose of cromolyn in the pretreated eye and one drop of levocabastine in the fellow eye . Subjects were challenged and evaluated after 3 , 5 , and 10 minutes . Four hours after drug administration , subjects were rechallenged and evaluated after 3 , 5 , and 10 minutes . RESULTS Levocabastine was significantly more effective than cromolyn in inhibiting itching , hyperemia , eyelid swelling , chemosis , and tearing after the initial challenge and 4-hour rechallenge ( P < 0.05 ) . CONCLUSION These results suggest that levocabastine is superior to cromolyn for treating allergen-induced conjunctivitis and has a duration of action of at least 4 hours A controlled , double-blind comparison of naphalzoline hydrochloride 0.05 % , antazoline phosphate 0.5 % , a combination of both components and a placebo was performed on 51 ragweed sensitive patients presenting allergic conjunctivitis . Evaluation of response at various times after instillation of medication for lacrimation , conjunctival inflammation , pruritus , photophobia and pain showed naphazoline hydrochloride , antazoline phosphate and the combination product superior to placebo . The combination product was statistically significantly superior for conjunctival inflammation and photophobia . The need for post-challenge treatment with epinephrine hydrochloride  was significantly less in those eyes treated with the combination product . demonstrating prophylactic efficacy During peak ragweed season , 86 patients with seasonal allergic conjunctivitis participated in a 9-week , multicenter , double-masked , placebo-controlled , group-comparative study testing the efficacy and safety of bid nedocromil sodium , 2 % ophthalmic solution . The clinical effectiveness of nedocromil sodium was measured by analyzing the means of patient daily symptom scores and eye examinations after 1 , 3 , 5 , and 8 weeks of treatment . The use of nedocromil sodium during peak ragweed pollen season reduced symptom scores with statistically significant treatment differences as compared with the placebo for itchy eyes , tearing , overall eye condition , and symptom summary score . Clinician assessment s also favored the use of nedocromil sodium as indicated by significant improvements in tearing , conjunctival injection , and conjunctival edema . No significant side effects were reported by the patients , allergists , or ophthalmologists . We conclude that nedocromil sodium , 2 % ophthalmic solution , administered bid is more effective in the relief of symptoms of seasonal allergic conjunctivitis than placebo and causes no major side effects Purpose The aim of the study was to assess the efficacy and safety of 0.05 % levocabastine eyedrops ( H1 receptor blocker given BID + vehicle BID ) compared with 0.1 % lodoxamide ophthalmic solution ( mast-cell stabilizer instilled QID ) in reducing ocular signs and symptoms of allergic conjunctivitis . Methods A r and omized , double-masked , parallel-group study was conducted in seven centres in France , in which 93 patients suffering from seasonal or perennial allergic conjunctivitis were r and omly allocated to either 0.05 % levocabastine ( n = 47 ) or 0.1 % lodoxamide ( n = 46 ) in both eyes for a 14-day period . Efficacy was evaluated by subjective ( prickling , burning , photophobia , itching ) and objective ( redness , chemosis , eyelid edema , tearing ) sign scores at visits on days 7 and 14 , and from data noted daily by the patient in a self-evaluation form . Safety was assessed as tolerance upon instillation and adverse event reports . Results The ocular allergy symptom and sign scores were comparable in the two treatment groups at baseline . With time , statistically and clinical ly significant reductions ( p < 0.001 ) from baseline were observed for the subjective and objective scores , with no difference between the treatment groups . After the first instillation , signs were alleviated more rapidly in levocabastine-treated patients than in the lodoxamide group ( p < 0.001 ) . Overall assessment s by the patient and investigator were similar in both groups . No serious adverse events were reported . Conclusions Levocabastine ophthalmic suspension 0.05 % ( BID ) appears to be as effective and safe as lodoxamide 0.1 % ( QID ) in the management of allergic conjunctivitis Lodoxamide is an antiallergic compound . The present study evaluated the efficacy on clinical and cytological parameters and safety of topical lodoxamide compared to placebo in the treatment of allergic conjunctivitis . The trial , design ed as double-blind , r and omized , placebo-controlled and parallel group treatment , was carried out in 30 patients , suffering from seasonal allergic conjunctivitis due to grass pollen , during the pollen season . Patients received lodoxamide tromethamine 0.1 % eye drops or placebo eye drops , one drop in each eye t.i.d . for 4 weeks . The clinical and cytological evidence was investigated by clinicians on admission and after 4 weeks ' treatment . At the end of the trial , only the lodoxamide-treated group showed a significant clinical improvement , associated with a reduction of inflammatory cells . No serious side effects were observed . The results show the clinical efficacy of lodoxamide in the treatment of pollen-induced allergic conjunctivitis . In addition , lodoxamide exerts its antiallergic activity by reducing inflammatory infiltrate ( mainly eosinophils ) Levocabastine is a new , highly potent , and specific H1 antagonist . The effects of this drug , administered topically , were evaluated in a conjunctival provocation test ( CPT ) with allergens . CPT was performed by the instillation of one drop of allergen at increasing concentrations in the inferior conjunctival sac of each eye , alternatively , and stopped when both itching and redness of the conjunctiva were present . The concentration of allergen at this step was considered as the reaction threshold . Eleven patients , allergic to grass pollen , underwent , in winter , a first CPT without pretreatment ( screening test ) ; the CPT was then repeated twice after a 24-hour treatment , once , with a placebo , and once , with levocabastine ( one drop twice a day , 0.5 mg/ml ) , administered in a double-blind fashion and in r and om order . The minimal interval between the two tests was 1 week . There was no significant difference between the thresholds determined in the two CPTs performed without medication ( screening test and placebo ) , whereas the threshold was significantly increased ( p less than 0.001 ) after pretreatment with levocabastine . Individually , the threshold increased in 10/11 patients ( p less than 0.01 ) . Levocabastine prevented both redness and itching . A late allergic reaction was observed by the patient in 6/11 CPTs performed after placebo treatment and 8/11 after levocabast 
    Output:
    
Limited evidence suggests that antihistamines might have a faster therapeutic effect compared to mast cell stabilisers .
Overall , these findings confirm the benefit of topical mast cell stabilisers and antihistamines over placebo for the treatment of allergic conjunctivitis .
There is , however , insufficient evidence to recommend the use of one type of medication over another .