***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: PURPOSE To investigate the effect of hinge position on corneal sensation and dry eye syndrome after laser in situ keratomileusis ( LASIK ) .  DESIGN Prospect i ve , r and omized , self-controlled trial . PARTICIPANTS Fifty-two patients > /=18 years of age undergoing bilateral LASIK .  INTERVENTION Patients underwent  bilateral LASIK with the superior-hinge Hansatome microkeratome in one eye and the nasal-hinge Amadeus microkeratome in the other eye . In all eyes , the flaps were 160 micro m thick , with a diameter of 9.5 mm . MAIN OUTCOME MEASURES Masked Cochet-Bonnet esthesiometry was performed central ly before surgery and at 1 week , 1 month , 3 months , and 6 months after surgery . Dry eye was evaluated at the same time intervals with lissamine green corneal and conjunctival staining , Schirmer testing with anesthesia , and tear-film breakup time . Subjective evaluation of dry eye sensation was performed at 3 and 6 months after surgery . RESULTS Corneal sensation was reduced in eyes with either superior- or nasal-hinge corneal flaps at 1 week , 1 month , and 3 months after surgery ( P < 0.001 ) . Compared with preoperative values , a significant reduction in corneal sensation remained at 6 months in corneas with superior-hinge flaps ( P < 0.001 ) but not in corneas with nasal-hinge flaps ( P = 0.263 ) . Mean corneal sensation was greater in corneas with a nasal-hinge flap compared with corneas with a superior-hinge flap at all postoperative visits ( P < 0.001 ) . The loss of sensation was greatest at 1 week and showed improvement at each subsequent time interval up to 6 months . Overall , dry eye signs and symptoms were greatest during the immediate postoperative period and improved at all subsequent time intervals . Dry eye signs and symptoms were generally greatest in the eyes with a superior-hinge flap and milder in eyes with a nasal-hinge flap . CONCLUSIONS The long posterior corneal nerves , which innervate the cornea , enter the eye at 3- and 9-o'clock . A superior-hinge flap transects both arms of the neuroplexus , whereas a nasal hinge transects only the temporal arm . LASIK results in a significant reduction in corneal sensation . Corneal sensation and dry eye signs and symptoms decreased immediately after LASIK and improved at all time periods between 1 week and 6 months in eyes with both a nasal-hinge flap and a superior-hinge flap . However , the loss of corneal sensation and presence of dry eye syndrome were greater in eyes with a superior-hinge flap than in eyes with a nasal-hinge flap PURPOSE To compare the differences in the clinical results of  LASIK  with a nasal corneal flap and with a superior corneal flap . SETTING Department of Ophthalmology , Kangnam St. Mary 's Hospital , Seoul , Korea . METHODS This r and omized prospect i ve study comprised 30 patients whose age and degrees of myopia were similar . In 1 group ( 25 eyes ) , a superior hinge was made and in the other group ( 25 eyes ) , a nasal hinge was made .  Uncorrected visual acuity ( UCVA ) , spherical equivalent ( SE ) , astigmatism , and corneal topographical change before surgery and 1 week and 2 and 6 months after surgery were compared . The tear breakup time ( BUT ) and the Schirmer test before surgery and 2 months postoperatively were also compared . RESULTS At 6 months , there were no significant between-group differences in UCVA , SE , astigmatism , and corneal ablation decentration ( P > .05 ) . At 2 months , the results of BUT and the Schirmer tests were 6.80 seconds and 9.54 mm , respectively , in the nasal hinge group ( P > .05 ) and 5.08 seconds and 6.05 mm , respectively , in the superior hinge group ( P < .05 ) . CONCLUSIONS There were no between-group differences in UCVA , SE , astigmatism , and corneal ablation decentration at 6 months , but the BUT and Schirmer test results were aggravated after LASIK in the superior hinge group PURPOSE To determine the incidence of dry eye and its risk factors after myopic laser-assisted in situ keratomileusis ( LASIK ) .  DESIGN Single-center , prospect i ve r and omized clinical trial of 35 adult patients , aged 24 to 54 years , with myopia undergoing LASIK .  METHODS setting and study population : Participants were r and omized to undergo LASIK with a superior or a nasal hinge flap . They were evaluated at 1 week and 1 , 3 , and 6 months after surgery . intervention : Bilateral LASIK with either a superior-hinge Hansatome microkeratome ( n = 17 ) or a nasal-hinge Amadeus microkeratome ( n = 18 ) . main outcome measures : The criterion for dry eye was a total corneal fluorescein staining score > or =3 . Visual acuity , ocular surface parameters , and corneal sensitivity were also analyzed . Cox proportional-hazard regression was used to assess rate ratios ( RRs ) with 95 % confidence intervals . RESULTS The incidence of dry eye in the nasal- and superior-hinge group was eight ( 47.06 % ) of 17 and nine ( 52.94 % ) of 17 at 1 week , seven ( 38.89 % ) of 18 and seven ( 41.18 % ) of 17 at 1 month , four ( 25 % ) of 16 and three ( 17.65 % ) of 17 at 3 months , and two ( 12.50 % ) of 16 and six ( 35.29 % ) of 17 at 6 months , respectively . Dry eye was associated with level of preoperative myopia ( RR 0.88/each diopter , P = .04 ) , laser-calculated ablation depth ( RR 1.01/microm , P = 0.01 ) , and combined ablation depth and flap thickness ( RR 1.01/microm , P = 0.01 ) . CONCLUSIONS Dry eye occurs commonly after  LASIK surgery in patients with no history of dry eye . The risk of developing dry eye is correlated with the degree of preoperative myopia and the depth of laser treatment PURPOSE : To compare the incidence of  laser in situ keratomileusis (LASIK)–associated dry eye and the need for postoperative cyclosporine A treatment after flap creation with a femtosecond laser and a mechanical microkeratome . SETTING : Cole Eye Institute , Clevel and , Ohio , USA . METHODS : Eyes were r and omized to flap creation with an IntraLase femtosecond laser ( 30 or 60 kHz ) or a Hansatome microkeratome . No patient had signs , symptoms , or treatment of dry eye preoperatively . Flap thickness was determined by intraoperative ultrasonic pachymetry . Slitlamp assessment s of the cornea and need for postoperative dry‐eye treatment were evaluated preoperatively and 1 month postoperatively . RESULTS : The flap was created with the  femtosecond laser in 113 eyes and with the  microkeratome in 70 eyes . The difference in mean central flap thickness between the femtosecond group ( 111 μm ± 14 [ SD ] ) and the microkeratome group ( 131 ± 25 μm ) was statistically significant ( P<.001 ) . The incidence of LASIK‐associated dry eye was statistically significantly higher in the microkeratome group ( 46 % ) than in the femtosecond group ( 8 % ) ( P<.0001 ) , as was the need for postoperative cyclosporine A treatment ( 24 % and 7 % , respectively ) ( P<.01 ) . In the microkeratome group , there was no correlation between thick flaps and a higher incidence of LASIK‐induced dry eye . CONCLUSIONS : Eyes with femtosecond flaps had a lower incidence of LASIK‐associated dry eye and required less treatment for the disorder . In addition to neurotrophic effects from corneal nerve cutting , other factors may be important because no correlation was found between flap thickness ( or ablation depth ) and the incidence of LASIK‐induced dry eye PURPOSE To compare clinical outcomes between the IntraLase femtosecond laser and the mechanical microkeratome for creating flaps during laser in situ keratomileusis . DESIGN Nonr and omized clinical trial . METHODS The study involved a total of 55 eyes of 30 patients , with 27 eyes of 16 patients comprising the microkeratome group and 28 eyes of 14 patients comprising the IntraLase group .  Refractive errors , visual acuity , higher-order aberrations , contrast sensitivity , and corneal sensitivity were compared between the two groups . RESULTS There were no statistically significant differences between the two groups in terms of refractive errors and postoperative uncorrected visual acuity . There was no loss of best-corrected visual acuity in either group . The higher-order aberrations were similar in both groups ( P > .05 ) , except for spherical aberration , which was greater in the microkeratome group ( P < .05 ) . In the IntraLase group , the contrast sensitivity value at 12 and 18 cycles per degree under mesopic conditions was significantly improved at three months postoperatively ( P < .05 ) . The IntraLase group showed faster corneal sensitivity recovery compared with the microkeratome group , and corneal sensitivity in the peripheral area was nearly normalized at three months postoperatively in the IntraLase group . CONCLUSIONS The femtosecond laser may have advantages over the microkeratome in the flap-making procedure . However , the IntraLase femtosecond laser failed to have significant superiority over the mechanical microkeratome in clinical outcomes , except for faster recovery of corneal sensation , lesser degree of spherical aberration , and some contrast sensitivity value PURPOSE : To determine whether hinge position has an effect on  corneal sensation and dry‐eye symptoms after myopic laser in situ keratomileusis ( LASIK ) performed with the IntraLase femtosecond laser ( IntraLase Corp. ) . SETTING : University‐based academic practice , Ann Arbor , Michigan , USA . METHODS : Sixty‐six consecutive eyes of 33 patients were prospect ively evaluated in a r and omized contralateral‐eye study to compare the difference between superior‐hinge and temporal‐hinge locations after  bilateral myopic LASIK with the IntraLase femtosecond laser .  Central Cochet‐Bonnet esthesiometry , the Ocular Surface Disease Index ( OSDI ) question naire , Schirmer test with anesthesia , tear breakup time ( TBUT ) , corneal fluorescein , and conjunctival lissamine green staining were evaluated preoperatively as well as 1 week and 1 , 3 , 6 , and 12 months after surgery . RESULTS : Corneal sensation was reduced with both superior‐hinged and temporal‐hinged LASIK flaps 1 week and 1 , 3 , 6 , and 12 months after surgery ( P<.0001 ) . There was no difference in corneal sensation between superior‐hinged and temporal‐hinged flaps at any time point . The OSDI score was increased in 22.6 % of patients at 1 week and 21.9 % at 1 month ( P<.00001 ) , and corneal fluorescein staining was increased in 18 % at 1 week . There were no differences in the OSDI , Schirmer with anesthesia , TBUT , corneal fluorescein , or conjunctival lissamine green staining when preoperative values and hinge location were compared . CONCLUSIONS : Mild dry‐eye disease was present early after myopic LASIK  with the IntraLase laser . Hinge position had no effect on central corneal sensation or dry‐eye disease Most systematic review s rely substantially on the assessment of the method ological quality of the individual trials . The aim of this study was to obtain consensus among experts about a set of generic core items for quality assessment of r and omized clinical trials ( RCTs ) . The invited participants were experts in the field of quality assessment of RCTs . The initial item pool contained all items from existing criteria lists . Subsequently , we reduced the number of items by using the Delphi consensus technique . Each Delphi round comprised a question naire , an analysis , and a feedback report . The feedback report included staff team decisions made on the basis of the analysis and their justification . A total of 33 international experts agreed to participate , of whom 21 completed all question naires . The initial item pool of 206 items was reduced to 9 items in three Delphi rounds . The final criteria list ( the Delphi list ) was satisfactory to all participants . It is a starting point on the way to a minimum reference st and ard for RCTs on many different research topics . This list is not intended to replace , but rather to be used alongside , existing criteria lists OBJECTIVE Patients frequently experience dry eye symptoms after laser in situ keratomileusis ( LASIK ) .  The mechanisms that lead to these changes are not well understood . The purpose of this study was to investigate the effect of LASIK on tear function . DESIGN Prospect i ve , comparative , nonr and omized interventional trial . PARTICIPANTS Fifty-eight consecutive patients 
    Output:
    
Conclusions According to the available data , we suggest that hinge location may have some effect on corneal sensation and dry eye syndrome after LASIK at the early postoperative period .
However , there was no significant difference between the groups at 6 months after surgery .