title: The effect of corneal light scatter on vision after penetrating keratoplasty.
abstract: OBJECTIVE
  To determine the effect of corneal light scatter on vision after penetrating keratoplasty (PK).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  setting: Cornea service at Mayo Clinic, Rochester, Minnesota. study population: Sixty-one eyes with clear grafts at 14.6 +/- 10.5 years after PK; 12 eyes with late endothelial failure (LEF) at 19.7 +/- 6.4 years after PK; 41 normal eyes. observation procedures: PK. main outcome measures: Backscatter from different depths of the cornea was measured by a custom scatterometer; intraocular forward light scatter was measured with a stray light meter; high-contrast visual acuity (HCVA) was measured by Early Treatment Diabetic Retinopathy Study (ETDRS) or Snellen chart; mesopic and photopic low-contrast visual acuity (LCVA) were measured with a 10% contrast chart.
  
  
  RESULTS
  Backscatter from the anterior, middle (stroma), and posterior thirds of the cornea was higher in clear grafts compared with normal (P < .001), and higher in grafts with LEF compared with clear grafts (P < .001). Corneal stromal backscatter from clear grafts correlated with time after keratoplasty (r = 0.21; P = .006; n = 61). Forward light scatter was higher in eyes with clear grafts compared with normal (P < or = .006), and higher in eyes with LEF compared with clear grafts (P < or = .01). Corneal stromal backscatter from clear grafts correlated with HCVA (r = 0.34; P = .02; n = 52), mesopic LCVA (r = 0.36; P = .01; n = 28), and photopic LCVA (r = 0.57; P < .001; n = 28). Forward scatter in eyes with clear grafts correlated with photopic LCVA (r = 0.38; P = .04; n = 26).
  
  
  CONCLUSIONS
  Light scattered from the cornea increases with time after PK and is associated with decreased high- and low-contrast vision.
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota 55905, USA. patel.sanjay@mayo.edu
authors.forename: Sanjay V
authors.initials: SV
authors.lastname: Patel
authors.forename: Jay W
authors.initials: JW
authors.lastname: McLaren
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.forename: William M
authors.initials: WM
authors.lastname: Bourne
mesh_terms: D002452:Cell Count; D015350:Contrast Sensitivity / Q000502:physiology; D003316:Corneal Diseases / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D004728:Endothelium, Corneal; D005500:Follow-Up Studies; D006801:Humans; D015948:Keratoplasty, Penetrating; D008027:Light; D012542:Scattering, Radiation; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology
references.citation: Biometrics. 1986 Mar;42(1):121-30
references.pmid: 3719049
references.citation: Ophthalmology. 2005 Sep;112(9):1541-8
references.pmid: 16005975
references.citation: Refract Corneal Surg. 1992 Mar-Apr;8(2):114-21
references.pmid: 1591203
references.citation: Curr Opin Ophthalmol. 1998 Aug;9(4):15-28
references.pmid: 10387463
references.citation: Am J Ophthalmol. 2005 Feb;139(2):311-9
references.pmid: 15733993
references.citation: Ophthalmology. 1999 Oct;106(10):1962-5
references.pmid: 10519593
references.citation: J Refract Surg. 2006 Nov;22(9):926-31
references.pmid: 17124891
references.citation: J Microsc. 2008 Jan;229(Pt 1):21-31
references.pmid: 18173641
references.citation: Am J Ophthalmol. 2008 Jan;145(1):97-105
references.pmid: 17996211
references.citation: Invest Ophthalmol Vis Sci. 1999 Jun;40(7):1593-8
references.pmid: 10359343
references.citation: Appl Opt. 1992 Jul 1;31(19):3694-6
references.pmid: 20725342
references.citation: Invest Ophthalmol Vis Sci. 2001 Feb;42(2):333-9
references.pmid: 11157863
references.citation: J Opt Soc Am A. 1986 Nov;3(11):1970-82
references.pmid: 3783292
references.citation: Invest Ophthalmol. 1971 Apr;10(4):294-9
references.pmid: 5549595
references.citation: Cornea. 2000 Jan;19(1):40-6
references.pmid: 10632007
references.citation: Cornea. 2005 Jul;24(5):509-22
references.pmid: 15968154
references.citation: Cornea. 2006 Sep;25(8):895-9
references.pmid: 17102663
references.citation: Doc Ophthalmol. 1986 Jan 15;61(3-4):327-33
references.pmid: 3948666
references.citation: Ophthalmology. 2003 Jul;110(7):1396-402
references.pmid: 12867398
references.citation: Invest Ophthalmol Vis Sci. 2007 Jan;48(1):166-72
references.pmid: 17197529
references.citation: Am J Ophthalmol. 1983 Sep;96(3):362-7
references.pmid: 6351624
references.citation: Ophthalmology. 1989 Mar;96(3):299-305
references.pmid: 2652028
references.citation: Arch Ophthalmol. 2007 Dec;125(12):1693-8
references.pmid: 18071124
references.citation: Aust N Z J Ophthalmol. 1996 May;24(2 Suppl):5-9
references.pmid: 8811231
references.citation: Ophthalmology. 1986 Jun;93(6):817-24
references.pmid: 3526228
references.citation: J Cataract Refract Surg. 2006 Mar;32(3):411-8
references.pmid: 16631048
references.citation: Ophthalmology. 2007 Aug;114(8):1482-90
references.pmid: 17350688
references.citation: Am J Ophthalmol. 2003 Feb;135(2):194-205
references.pmid: 12566024
references.citation: Appl Opt. 1986 Aug 15;25(16):2739
references.pmid: 18231553
references.citation: Br J Ophthalmol. 2004 May;88(5):653-7
references.pmid: 15090418
references.citation: Eur J Ophthalmol. 1991 Oct-Dec;1(4):173-80
references.pmid: 1821211
references.citation: Cornea. 2005 Nov;24(8):980-4
references.pmid: 16227846