We in ophthalmology are fortunate to be able to measure quantitatively many aspects of ocular morphology and visual function. These measurements are either objective (e. g. electroretinography, tonometry, electromyography, visually evoked responses, etc.) or subjective and psychophysical (e. g. visual acuity, visual fields, color vision, etc.). One aspect of corneal physiology and pathology which has so far escaped careful and reliable measurements is corneal sensitivity. Previous attempts have been rather crude and can be compared to measuring intraocular pressure by digital compression. Professor Draeger has for the last decade and a half directed his attention to the question of esthesiometry of the cornea. He has a gift for constructing and devising new ingenious ocular instruments. His handheld tonometer is a splendid example. He has now applied the principle of this instrument to the new electronic optical esthesiometer. In many publications he has reported on his first results using this modern technique to study corneal physiology and evaluate certain pathologic conditions. In this monograph Professor Draeger has collected all of his material and reports on his long experience. The usefulness of this instrument is just beginning to be appreciated. It is obvious that this new measuring device will help us in the fitting of contact lenses, evaluating herpes simplex infections of the cornea, follow the postoperative course of patients with a penetrating keratoplasty, etc.

1. Introduction.- 2. Anatomy and Physiology of the Cornea.- 2.1 Anatomy.- 2.1.1 The Layers of the Cornea.- 2.1.2 Innervation of the Cornea.- 2.2 Corneal Sensitivity.- 3. Development of the Various Methods of Esthesiometry.- 3.1 Early Investigations.- 3.2 Newer Attempts for a Technical Solution.- 3.2.1 The Application of Modern Technology.- 3.3 Electronic-Optic Esthesiometer.- 3.3.1 Producing and Measuring the Stimulus Force.- 3.3.2 The Optical Device for the Observation.- 3.3.3 The Use of the Instrument.- 3.3.4 Technical Data of the Esthesiometer.- 4. How to Use the Esthesiometer.- 5. Comparison Between Static and Dynamic Esthesiometry.- 6. Topography of Corneal Sensitivity.- 7. The Receptor Field of Corneal Sensitivity.- 8. Stimulus-Sensation - Relationship in the Cornea.- 8.1 Results.- 8.1.1 Quality of Sensation.- 8.1.2 Graduation of Sensation.- 8.2 Discussion.- 9. The Sensitivity of the Conjunctiva.- 10. The Localization of a Stimulus on Cornea and Conjunctiva.- 11. The Lid Reflex as an Indicator of Corneal and Conjunctival Sensitivity.- 12. The Age Dependency of the Corneal Sensitivity.- 13. Metabolie Influences on the Corneal Sensitivity.- 13.1 Corneal Sensitivity in Patients with Diabetes mellitus.- 13.2 Corneal Sensitivity After Light Coagulation.- 13.3 Changes in Corneal Sensitivity Düring Pregnancy.- 14. The Effect of Surface Anesthetics.- 14.1 Discussion of Our Results.- 15. Local Anesthetic Effects of Beta Blockers.- 15.1 Methodology.- 15.2 Results.- 15.3 Discussion.- 16. Examinations on Pharmacogenetics.- 17. The Influence of Contact Lenses on Corneal Sensitivity.- 17.1 Retrospective Study.- 17.1.1 PMMA Contact Lenses.- 17.1.2 HEMA Contact Lenses.- 17.2 Prospective Study.- 17.2.1 PMMA Contact Lenses.- 17.2.2 HEMA Contact Lenses.- 18. Corneal Sensitivity as an Indicator for the Reinnervation of the Cornea After a Cataract Incision or After a Perforating Keratoplasty.- 18.1 Corneal Sensitivity After Cataract Extraction.- 18.2 Corneal Sensitivity After Penetrating Keratoplasty.- 18.3 Comparison Between Fresh and Stored Donor Corneas.- 18.4 Reinnervation After Keratoplasty with HLA-Typed Donor Material.- 19. The Influence of the Type of Anesthesia on Corneal Sensitivity.- 20. Corneal Sensitivity After a Bückling or Encircling Operation for a Retinal Detachment.- 21. Corneal Sensitivity and Intraocular Pressure.- 22. Differential Diagnosis and Monitoring of Herpetic Keratitis.- 23. Corneal Sensitivity After Trigeminal Block.- 23.1 Discussion.- 24. Conclusion.- References.