The effect of corneal light scatter on vision after penetrating keratoplasty.
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.
Patel
Sanjay V
SV
Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota 55905, USA. patel.sanjay@mayo.edu
McLaren
Jay W
JW
Hodge
David O
DO
Bourne
William M
WM
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
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