DYNAMIC CONTOUR TONOMETRY AND GOLDMAN APPLANATION TONOMETRY IN EYES WITH KERATOCONUS

The dynamic contour tonometer is a nonapplanation contact tonometer designed to be largely independent of the structural properties of the cornea. Theoretically, it may measure intraocular pressure most accurately in abnormally thinner corneas. This study compares intraocular pressure measurements by dynamic contour tonometry with Goldman applanation tonometry in eyes with normal corneas and eyes with advanced keratoconus. A comparative case series. Subjects underwent intraocular pressure measurements by dynamic contour tonometry, Goldman applanation tonometry, ultrasonic pachymetry, and slit scanning topography. Exclusion criteria: any ocular pathology other than keratoconus, previous corneal or refractive surgery, stromal scarring due to acute hydrops, or any other corneal opacities. Ten patients with keratoconus were included in Group A, and 12 normal patients composed Group B according to the pre-established criteria. The mean Goldman tonometry measurement in group A was 10.3 ± 1.8 mm Hg and group B was 14.3 ± 0.75 mm Hg. (P = 0.024). In group A, the mean measurement with the dynamic contour tonometer was 14.6 ± 2.09 mm Hg, and in group B, it was 17.4 ± 3.1 mm Hg (P = 0.026). The difference between both methods of measurement in group A was statistically significant (P < 0.0002). Intraocular pressure readings with dynamic contour tonometry in the keratoconus group were significantly higher than Goldman measurements and lower when compared to the control group. As there are no published manometric studies in eyes with keratoconus, these lower intra-ocular readings with the dynamic contour tonometry could be related to the discrepancy between the radius of corneal curvature and its tip, the significant thinning of the cornea, or other corneal biomechanical abnormalities related to advanced keratoconus. O tonômetro de contorno dinâmico é um aparelho de contato e não-aplanação projetado para ser independente das propriedades estruturais da córnea. Teoricamente, ele mede de forma mais precisa a pressão intra-ocular em córneas muito finas. Este estudo compara as medidas de pressão intra-ocular pelo tonômetro de contorno dinâmico com a tonometria de aplanação de Goldman em olhos normais e em olhos com ceratocone avançado. uma série comparativa de casos. Pacientes foram submetidos às medidas de pressão intra-ocular por ambos os métodos mencionados, paquimetria ultrassônica e topografia corneana de varredura. Critérios de exclusão: qualquer patologia ocular exc