***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 evaluate the safety and efficacy of limbal relaxing incisions for the correction of corneal astigmatism during phacoemulsification . METHODS Fifty eyes of 37 patients ( mean age 66.5 years , range : 45 to 80 years ) with cataract and coexisting topographic astigmatism were included in the study . Eyes were r and omly divided into two groups : eyes that underwent cataract surgery with limbal relaxing incisions ( cataract LRI group ) and eyes that underwent cataract surgery only ( control group ) . All limbal relaxing incisions were performed during phacoemulsification . Best spectacle-corrected visual acuity ( BSCVA ) , uncorrected visual acuity ( UCVA ) , and corneal topography were recorded preoperatively and 1 , 3 , and 6 months postoperatively . RESULTS A statistically significant improvement in BSCVA was seen in the cataract LRI eyes from 0.9 + /- 0.7 preoperatively to 0.1 + /- 0.1 at 1 , 3 , and 6 months postoperatively ( P < .01 ) . A statistically significant improvement in BSCVA was seen in control eyes from 0.8 + /- 0.6 before surgery to 0.2 + /- 0.2 at 1 , 3 , and 6 months after surgery ( P < .01 ) . No difference in postoperative BSCVA was noted between the groups . A statistically significant reduction in the mean topographic astigmatism was seen in the cataract LRI eyes from 1.93 + /- 0.58 diopters ( D ) preoperatively to 1.02 + /- 0.60 D 6 months postoperatively ( P < .05 ) . The control eyes did not show a statistically significant change in topographic astigmatism . CONCLUSIONS Limbal relaxing incisions performed during phacoemulsification surgery appear to be a safe , effective , and stable procedure to reduce pre-existing corneal astigmatism PURPOSE To compare the effectiveness of limbal relaxing incisions ( LRI ) with that of toric intraocular lens ( IOL ) implantation for the treatment of astigmatism during phacoemulsification using nonvectorial ( predictability , safety , and efficacy ) and vectorial analyses . METHODS This longitudinal observational case series assessed 62 eyes of 31 consecutive cataract patients with preoperative corneal astigmatism of 0.75 - 2.50 diopters ( D ) in both eyes . Patients were r and omly assigned to 2 groups : a toric IOL group , which received toric IOLs in both eyes , and an LRI group , which received spherical IOLs associated with LRI placement in both eyes . All patients were evaluated at 1 , 3 , and 6 months after surgery , when refractive astigmatism analysis was performed using both nonvectorial and Alpins vectorial methods . Outcomes were assessed within each group and compared between groups . RESULTS The proportion of eyes within ±0.50 D of the intended correction at 3 and 6 months after surgery was 75 % and 71.88 % , respectively , in the LRI group and 40 % and 66.67 % , respectively , in the toric IOL group . In the remaining period , the proportion was greater in the toric IOL group . The safety index showed no difference at any time point . The efficacy index at 1 and 3 months after surgery was significantly higher in the toric IOL group ( 0.43 and 0.44 , respectively ) than in the LRI group ( 0.31 and 0.36 , respectively ) . At 6 months after surgery , the status of eyes in the LRI group was as follows : 53.13 % were undercorrected , 43.74 % achieved the intended correction , and 3.13 % were overcorrected . In the toric IOL group , 16.76 % eyes were undercorrected , 76.67 % achieved the intended correction , and 6.67 % were overcorrected . The success rates for astigmatic surgery , astigmatism reduction at the intended axis , and astigmatism corrected were 43 % , 62 % , and 64 % , respectively , in the LRI group and 57 % , 81 % , and 94 % , respectively , in the toric IOL group . CONCLUSIONS Our results suggest that the use of toric IOLs may be advantageous over the use of LRIs for the treatment of astigmatism during phacoemulsification . Although such advantages seem subtle in nonvectorial analyses , they are highlighted in vectorial analyses PURPOSE To evaluate the clinical utility of spherocylindrical automated refraction ( AR ) based on time-based wavefront technology compared with subjective manifest refraction ( MR ) for the purpose of prescribing eyeglasses . DESIGN Prospect i ve observational case series . PARTICIPANTS A convenience sample of 105 eyes of 53 patients ( ages 19 to 87 ) with corrected acuity no worse than 20/40(-2 ) . METHODS Manifest refraction was performed on all subjects followed by three consecutive wavefront measurements at both a 4-mm and 6-mm optical zone using the 3D Wave OPD Scan ARK 10,000 aberrometer . MAIN OUTCOME MEASURES Repeatability of multiple consecutive ARs ; difference in the sphere , cylinder , and axis of AR compared with MR ; difference between the corrected visual acuity based on AR- and MR-derived acuity . RESULTS Repeatability analysis showed that the initial wavefront refraction was not significantly different from the mean of the three refractions . At the 4-mm zone , the absolute value ( + /- st and ard deviation ) of the difference between the initial AR compared with the MR was 0.34+/-0.28 diopters ( D ) for sphere , 0.22+/-0.21 D for cylinder , and 12.5+/-15.8 degrees for axis . At the 6-mm zone , these values were 0.32+/-0.29 D for sphere , 0.25+/-0.24 D for cylinder , and 11.8+/-14.6 degrees for axis . When 4-mm AR visual acuity was superior to MR acuity ( 19.0 % of eyes ) it was 0.28+/-0.24 Snellen lines better , and when inferior ( 53.3 % of eyes ) it was 0.47+/-0.37 lines worse . When 6-mm AR acuity was superior to MR acuity ( 16.2 % of eyes ) it was 0.32+/-0.22 Snellen lines better , and when inferior ( 60.0 % of eyes ) it was 0.48+/-0.48 lines worse . The absolute value of the difference in spherical equivalent of the first AR measurement at the 4-mm zone compared with the MR value was 0.33+/-0.23 D , and at the 6-mm zone it was 0.30+/-0.27 D. CONCLUSIONS The wavefront-derived AR values reflect the physical optical system , but not necessarily subjectively derived values , and the impact of this disagreement on patient satisfaction is unknown . Future studies evaluating this technology and its role in clinical ophthalmology are warranted PURPOSE To compare the outcomes of phacoemulsification with toric intraocular lens implantation vs phacoemulsification with monofocal intraocular lens implantation followed by photorefractive keratectomy ( PRK ) for correction of pre-existing astigmatism . DESIGN R and omized controlled trial , 6-month study . METHODS setting : Institutional . STUDY POPULATION Sixty eyes of 52 patients with age-related senile cataract and regular corneal astigmatism ranging from 1.50 to 3.00 diopters , enrolled and r and omly allocated in 2 groups based on computer-generated r and om number table . INTERVENTION Group 1 patients underwent phacoemulsification with toric intraocular lens ( IOL ) implantation and Group 2 patients underwent phacoemulsification with monofocal IOL implantation followed by PRK 3 months later . MAIN OUTCOME MEASURES The main outcome measures were uncorrected distance visual acuity ( UDVA ) , corrected distance visual acuity ( CDVA ) , residual cylinder , contrast sensitivity , glare acuity , pain score , and higher-order aberrations . RESULTS At 6 months 53.3 % of eyes in the toric IOL and 60 % eyes in the monofocal IOL with PRK group attained UDVA of 20/20 . Median residual refractive cylinder value was higher in the toric IOL group ( toric IOL = -0.5 , monofocal IOL with PRK = 0 ; P = .02 ) . Mean root mean square value of total aberrations ( 5 mm pupil ) was higher in monofocal IOL with PRK eyes ( toric IOL= 1.02 ± 0.44 , monofocal IOL with PRK = 1.28 ± 0.5 ; P = .04 ) . Mean contrast sensitivity values were comparable . Mean toric IOL rotation was 1.3 ± 2.1 degrees . Mean glare acuity was better in toric IOL eyes ( toric IOL = 0.46 ± 0.16 , monofocal IOL with PRK = 0.73 ± 0.12 ; P < .001 ) . Median postoperative pain scores were higher in monofocal IOL with PRK eyes . CONCLUSION PRK yields lesser residual cylinder compared to toric IOL . However , it causes greater postoperative pain and corneal aberrations , and poor glare acuity PURPOSE To examine the efficacy and safety of topography-based limbal relaxing incision ( LRI ) surgery . METHODS Forty-four eyes of 36 consecutive patients who underwent cataract surgery more than 1 month previously , had refractive against-the-rule astigmatism of ≥2.00 diopters ( D ) , and were scheduled to undergo LRI surgery were enrolled in the study . Patients were r and omized into two groups-a topography-based LRI group ( 19 eyes of 14 patients ) and a conventional LRI group ( 25 eyes of 22 patients ) . The topography-based LRI procedure comprised 3 steps : placing a mark on the cornea and conjunctiva , identifying this mark in the topographic image , and performing LRI based on the location of the mark . In the conventional LRI group , the horizontal meridian was marked under a slit lamp and LRIs were made based on the position of the horizontal mark . RESULTS Corneal astigmatism in the topography-based LRI group before and 1 month after surgery was 2.03±0.92 D and 1.33±0.69 D , respectively ( P=.014 ) . Corneal astigmatism in the conventional LRI group before and 1 month after surgery was 2.36±0.77 D and 0.93±0.70 D , respectively ( P<.0001 ) . Fourier harmonic analysis of the topography data demonstrated that regular astigmatism was significantly decreased in the two groups . The mean regular astigmatism was not significantly different before and after LRI between groups , whereas the variances ( mean of the deviation squared from its mean ) of regular astigmatism were significantly different between groups 1 month after LRI . CONCLUSIONS Compared with conventional LRI surgery , a topography-based procedure may reduce the deviation of the effect of LRIs PURPOSE To compare the AcrySof Toric intraocular lens ( IOL ) and an AcrySof spherical control IOL and to investigate rotational stability of the AcrySof Toric IOL ( Alcon Laboratories , Inc. , Fort Worth , TX ) in subjects with cataracts and preexisting corneal astigmatism . DESIGN R and omized , subject-masked , parallel-group , multicenter , 1-year study . PARTICIPANTS We included 517 subjects ( Toric IOL , n = 256 ; control IOL , n = 261 ) . METHODS Unilateral implantation of an AcrySof Toric or AcrySof spherical control IOL ( spherical powers , 12.00 - 25.00 diopters [ D ] ; cylinder powers 1.50 , 2.25 , or 3.00 D for corneal astigmatism correction of 0.75 to < 1.50 , ≥ 1.50 to < 2.00 , and ≥ 2.00 D with no upper limit , respectively ) . No limbal relaxing incisions were permitted . MAIN OUTCOME MEASURES Visual acuity outcomes , IOL position , patient-reported spectacle use , and safety . RESULTS One year postoperatively , best spectacle-corrected distance visual acuity of ≥ 20/20 was 77.7 % ( Toric IOL ) versus 69.2 % ( control IOL ) . Uncorrected distance visual acuity of 20/20 or better was 40.7 % ( Toric IOL ) versus 19.4 % ( control IOL ; P<0.05 ) . Mean absolute residual refractive cylinder was 0.59 D ( Toric IOL ) versus 1.22 D ( control IOL ; P<0.0001 ) . Mean rotation was < 4 ° ( range , 0 ° -20 ° ) for the Toric IOL . Six-month spectacle freedom was 61.0 % ( Toric IOL ) and 36.4 % ( control IOL ; P < 0.0001 ) . Complications in both groups were few and were as would be expected with cataract surgery . CONCLUSIONS Favorable efficacy , rotational stability , distance vision 
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AUTHORS ' CONCLUSIONS Toric IOLs probably provide a higher chance of achieving astigmatism within 0.5 D after cataract surgery compared with LRIs .
There may be a small mean difference in postoperative astigmatism , favouring toric IOLs , but this difference is likely to be clinical ly unimportant .
There was no evidence of an important difference in postoperative visual acuity or quality of life between the techniques .