KISA% index: a quantitative videokeratography algorithm embodying minimal topographic criteria for diagnosing keratoconus

Abstract

The KISA% index set at 100 was highly sensitive and specific for diagnosing keratoconus; a range of 60% to 100% may be useful for designating suspects. This index is more useful than any of the other currently available tools for classifying patients with keratoconus for computerized segregation analysis and for distinguishing eyes with keratoconus from normal eyes in topographic screening of refractive surgical candidates.

Characterization of corneal structure in keratoconus

“…These criteria established that a cornea is susceptible to be catalogued as keratoconus when the central K value is equal to or above 47.2 D, the value of the I-S index is equal to or above 1.4 D, and the keratometric difference between both eyes is above 1.0 D (sensitivity and specificity of 96% and 85%, respectively). 51,[53][54][55] The Maeda et al 52 criteria allow keratoconus screening by analysis of the keratoconus index (KCI). A KCI value above 0% is codified as "similarity to keratoconus."…”

“…53,55 The keratoconus prediction index (KPI) is another descriptor used as a clinical tool for keratoconus detection. 57 It is calculated as the combination of 7 topographic parameters characterizing the morphology of the anterior corneal surface: simulated keratometry (SimK), differential sector index (DSI), opposite sector index (OSI), center/surround index (CSI), SAI, irregular astigmatism index (IAI), and percent analyzed area (AA).…”

Keratokonus ve Subklinik Keratokonusun Tespit Edilmesi için Pentacamla Korneal Hacim Ölçümleri

“…4,5,10,11 Topographic analysis can point to characteristic clues of these diseases before the development of clinical signs or symptoms. 11,12 Up to date, a lot of indices and differentiation methods, such as the Rabinowitz-McDonnell test, 13 the Klyce-Maeda-Smolek Expert System, 14 KISA% index, 15 and the corneal navigator 16 have been developed to assist ophthalmologist with keratoconus diagnosis. Although these indices were reported to have a high degree of sensitivity and specificity to detect keratoconus, they did not have this high degree of sensitivity and specificity in discrimination between normal and subclinical keratoconus cases.…”

“…Although these indices were reported to have a high degree of sensitivity and specificity to detect keratoconus, they did not have this high degree of sensitivity and specificity in discrimination between normal and subclinical keratoconus cases. [14][15][16] In addition, false negatives could occur in cases of pellucid marginal degeneration because most of the systems were calibrated for keratoconus. 17 Corneal tomography provides 3-dimensional reconstruction of the cornea, enabling evaluation of the anterior and posterior corneal surfaces and creation of a pachymetric map.…”

Alterações topográficas da córnea em pacientes com cérato-conjuntivite vernal.

“…Ceratocone é a distrofia ectásica da córnea mais comumente encontrada (KENNEDY et al1986), com incidência anual de aproximadamente 1,5 a 2,1 por 100.000 e prevalência de 54,5 por 100.000 na população (RABINOWITZ, 1998). Apesar desses números serem considerados como importantes referências, parece lógico imaginar que a incidência do ceratocone seja subestimada, uma vez que formas subclínicas não fazem parte dos estudos de incidência da doença (KRACHMER et al1984;KENNEDY et al1986;McDonnel,1989 Os mecanismos nosogênicos dessa condição permanecem desconhecidos.…”