Correlation between Corneal Elevation Topography and Perimetric Changes in Patients with Primary Open Angle Glaucoma

Aim: The aim of this study is to assess Scheimpflug topographic elevation maps in patients with POAG and correlate the results with their perimetric changes. Methods: This was an analytical observational cross-sectional study. The study included 130 eyes of 70 subjects which were divided into 78 eyes of 44 patients diagnosed with POAG and 52 eyes of 26 control subjects. Measurement of IOP, visual field examination in patients with POAG using Humphrey Field Analyzer (2003 Carl Zeiss Meditec), Germany were done. Subjects were scanned using TMS-5 topographer (Topographic Modeling System, version 5. Tomey Corp. Nagoya, Japan) to measure central corneal thickness, mean anterior keratometry, maximum anterior and posterior topographic elevation maps in the central 3, 5, and 7 mm. Results: 78 patients with POAG classified according to visual field deterioration using Hodapp-Anderson-Parrish grading scale into mild glaucoma 33 eyes, moderate glaucoma 19 eyes, severe glaucoma 26 eyes, and 52 eyes control were included in the study. The mean age of the patients with POAG was 57.82 ± 7.78 years; 22 eyes (50%) were male and 22 eyes (50%) were female. The average age of control subjects was 56.62 ± 8.48 years; 12 eyes (46.2%) were male and 14 eyes (53.8%) were female, average CCT was 530.3 ± 23.58 µm, average mean anterior keratometry (MAK) was 42.97 ± 1.42 D, average maximum anterior elevation (MAE) in 3,5 and 7mm zone was 5.31 ± 2.28, 12.10 ± 6.94 and 44.04 ± 21.99 µm respectively and average maximum posterior elevation (MPE) in 3,5 and 7mm zone was 8.46 ± 2.10, 19.90 ± 9.39 and 62.72 ± 28.82 µm respectively in patients with POAG, whereas average CCT was 543.0 ± 31.02µm, average MAK was 43.11 ± 1.73 D, average MAE in 3,5 and 7mm zone was 4.52 ± 1.97, 5.90 ± 2.71 and 27.19 ± 8.55 µm respectively. Conclusion: Evaluation of corneal elevation topography by scheimpflug imaging showed forward shifting of the anterior and posterior corneal surfaces in POAG.