Glaucoma and corneal disorders are often associated and are of diagnostic, therapeutic and prognostic relevance for each other.
Glaucoma is already present in approximately 15% of eyes prior to
keratoplasty, whereas in addition approximately 15% of cases are diagnosed following
corneal transplantation.
Corneal opacities, surface irregularities and pachymetric deviations from the norm can have a negative impact on tonometry, perimetry and morphological
glaucoma diagnosis. Digital and intracameral tonometry as well as flash VEP to determine the visual potential can be helpful in this setting. Increased intraocular pressure (IOP), long-term application of antiglaucomatous medication or the use of
antimetabolites in
glaucoma surgery can all induce keratopathy. Therefore, intraocular pressure should be regulated prior to
corneal transplantation. Risk factors for the evolution of
glaucoma following
corneal transplantation are the specific indication and surgical technique (e. g. combined corneal and
cataract/
vitreoretinal surgery), as well as postoperative
steroid application and chamber angle synechiae. Unpreserved
glaucoma medication without pro-inflammatory effects should be preferred following
keratoplasty. In the long term surgery to control IOP is required in approximately 25% of eyes. The wider use of lamellar techniques for
corneal transplantation is likely to reduce the incidence of secondary
glaucoma.