The Effect of Corneal Light Scatter on Vision After Penetrating Keratoplasty
Accepted 9 July 2008. published online 09 September 2008.
Purpose
To determine the effect of corneal light scatter on vision after penetrating keratoplasty (PK).
Design
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 ≤ .006), and higher in eyes with LEF compared with clear grafts (P ≤ .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.
aDepartment of Ophthalmology, Mayo Clinic, Rochester, Minnesota
bDepartment of Health Sciences Research, Mayo Clinic, Rochester, Minnesota
Inquiries to Sanjay V. Patel, Mayo Clinic, 200 First Street SW, Rochester, MN 55905
ABSTRACT