Corneal responses to intraocular pressure elevations in keratoconus.

Area of Science:

• Ophthalmology
• Corneal Biomechanics
• Ocular Physiology

Background:

• Keratoconus (KC) is a progressive thinning disorder of the cornea.
• Understanding corneal response to intraocular pressure (IOP) is crucial for KC management.
• Previous studies have not fully elucidated the dynamic topographical changes in KC corneas under elevated IOP.

Purpose of the Study:

• To investigate corneal topographical alterations in response to induced elevated intraocular pressure (IOP).
• To compare the responses between healthy individuals and those with keratoconus (KC).
• To assess the influence of age on these corneal responses.

Main Methods:

• Induced IOP elevation using a standardized ophthalmodynamometer (ODM) force in 10 normal subjects and 10 KC patients.
• Measured IOP using noncontact tonometry during scleral indentation.
• Assessed corneal topography using the same ODM force before and during IOP elevation.

Main Results:

• Elevated IOP induced significant topographical changes in KC patients, including increased steepest point of curvature and simulated keratometry values.
• These changes were more pronounced in KC subjects under 30 years of age.
• No significant topographical changes were observed in control subjects or in either group after IOP normalization.

Conclusions:

• The findings suggest reduced corneal rigidity and increased distensibility in some keratoconus (KC) corneas.
• Abnormal distending responses to elevated IOP in KC may be exacerbated by higher, longer, or more frequent IOP elevations.
• The study indicates that these abnormal responses in KC corneas might diminish with increasing age.