Corneal topography is most commonly used for the following purposes
Refractive surgery: To screen candidates for normal corneal shape, patterns and ruling out suspicious or keratoconic patterns . Post operatively , topography can help to assess the dioptric change created at corneal level ( thus the effective change in the cornea) , ruling out decentred or incomplete ablation , post excimer ectasia or other changes.
Keratoconus : Early screening of keratoconus suspects is one of the most useful roles of topography. Early keratoconus and suspects look normal on slit lamp examination ,and the central keratometry (3 mm) gives only a limited assessment. Therefore topography has become the gold standard in screening keratoconus suspects. In cases with established keratoconus, the role of topography is paramount for monitoring progression and doing a timely collagen cross linking , and in contact lens fitting.
Post surgery astigmatism : Post cataract surgery and post keratoplasty corneal astigmatism can be studied with the topographer and selective suture removal or other interventions can be planned.
Surgical planning in cases with astigmatism : Limbal relaxing incisions and other methods of topography guided incision placement are used by surgeons to reduce post operative astigmatism.
Effect of corneal and ocular surface disorders: Disorders such as pterygium , limbal dermoid, localised corneal scars can cause a change in the corneal topography and thus the monitoring is very useful.
Other uses : Contact lens fitting , incision placement and intrastromal ring placement in keratoconus , monitoring of ocular vs corneal wavefront.