title: Correlation between cataract grading by Scheimpflug imaging and phaco time in phacoemulsification using peristaltic and venturi pumps.
abstract: OBJECTIVE
  To study the correlation among cataract grading system by Scheimpflug imaging (Oculus Pentacam® Nucleus Grading System [PNS]), effective phaco time (EPT), and surgical time (ST) using peristaltic and venturi pumps on the Whitestar Signature Phaco System (Abbott Medical Optics, Inc., Santa Ana, California, USA).
  
  
  METHODS
  Patients scheduled to have bimanual microincision phacoemulsification by the same surgeon (T.F.) had Pentacam® Scheimpflug assessment using PNS and were randomly distributed into  2 groups. In group 1, surgery was performed using peristaltic pump, and in group 2, using venturi pump. Parameters assessed in both groups included EPT and ST.
  
  
  RESULTS
  Sixty eyes that had uneventful clear cornea phacoemulsification with implantation of foldable intraocular lens (IOL) were evaluated, 30 in each group. The EPT was statistically superior with higher nuclear density grades for both groups 1 and 2 (group 1 Spearman R = 0.739, p<0.001; group 2 Spearman R = 0.924, p<0.001). The ST statistically increased with nucleus density for both groups 1 and 2 (group  1 Spearman R = 0.620, p<0.001; group 2 Spearman R = 0.643, p<0.001). Group 2 presented statistically significant reduction on median ST compared with group 1 for nucleus grading 2, 3, 4, and 5.
  
  
  CONCLUSIONS
  The PNS is an objective and reproducible method of grading nuclear cataract density and had a correlation with EPT. Peristaltic and venturi pumps in Signature Phaco System were similar in EPT but venturi pump reduced the median ST in nucleus with higher PNS, without repercussion on complications or anterior chamber stability.
authors: Ophthalmology Department, Centro Hospitalar de Lisboa Ocidental, Lisbon - Portugal. msarapatricio@gmail.com
authors: Maria Sara
authors: MS
authors: Patrício
authors: Ana Catarina
authors: AC
authors: Almeida
authors: Maria Picoto
authors: MP
authors: Rodrigues
authors: Marta Esteves
authors: ME
authors: Guedes
authors: Tiago Bravo
authors: TB
authors: Ferreira
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000867:Anterior Chamber; D002386:Cataract / Q000145:classification*; D003952:Diagnostic Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D007907:Lens Nucleus, Crystalline / Q000473:pathology*; D008297:Male; D061646:Operative Time; D018918:Phacoemulsification / Q000295:instrumentation* / Q000379:methods; D011446:Prospective Studies; D011897:Random Allocation; D013997:Time Factors