Direct summation of fields for light scattering by fibrils with applications to normal corneas

Transparency, swelling and scarring in the corneal stroma

“…A full account of the approach, called the direct summation of fields (DSF) method, is found in the original papers. 14,15 It is a statistical technique in which the scattering from each individual fibril is computed, then the effects of interference are included and summed for the whole tissue using a method called ensemble averaging. It is worth mentioning at this stage that, in this method, transmission is computed as a function of wavelength, ignoring the lamellar structure of the stroma and also the Transparency, swelling, scarring in corneal stroma KM Meek et al 928 presence of stromal cells.…”

Structural and biochemical aspects of keratan sulphate in the cornea

“…Theories of corneal light transmission contend that collagen fibrils scatter light in such a way that destructive interference occurs in all directions other than the forward direction [22]. This transparency model has been embraced by the scientific community [23][24][25][26][27][28], and while a strict lattice of collagen fibrils is not seen as an absolute requirement for corneal transparency, some level of structural order is. Keratocytes are stromal fibroblasts which are interspersed with collagen in the cornea at an estimated density of between 4.6 9 10 4 and 6.2 9 10 4 cells/mm 3 in humans, with higher densities peripherally and in younger individuals [29,30].…”

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

“…11 Various devices have been developed in the past decades to evaluate corneal damage using objective measurements. For instance, in 1986, Freund et al 12 established the direct summation of fields approach, in which corneal transmittance was estimated by measuring light scattering through each corneal fiber. However, this method was way too complex.…”