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BACKGROUND: Secondary ocular hypertension and glaucoma are severe complications after penetrating keratoplasty (PKP), which increase the risk of graft failure and irreversible loss of vision. PURPOSE: Analysis of intraocular pressure (IOP) elevation in relation to the changes of anterior chamber geometry comparing elective and PKPs à chaud. METHODS: This retrospective study at the Department of Ophthalmology, Saarland University Medical Center in Homburg/Saar included 148 eyes after PKP (123 elective and 25 PKPs à chaud). Between 2014 and 2021 treatment data were documented preoperatively and postoperatively after 6-8 weeks, after partial (18 ± 3 months) and after complete (31 ± 6 months) suture removal. The study analyzed visual acuity, IOP, Pentacam® HR (OCULUS GmbH, Wetzlar, Germany) measurements with central and peripheral corneal pachymetry (CCT, PCT), anterior chamber angle (ACA), anterior chamber depth (ACD) and anterior chamber volume (ACV). RESULTS: The anterior chamber geometry of all eyes changed significantly after PKP: early postoperatively (6-8 weeks) the pachymetry increased (p < 0.001), while ACA, ACD and ACV (p < 0.001) decreased. The average increase of IOP (p < 0.001) showed a positive correlation with CCT and a negative correlation with ACD. In contrast to elective keratoplasty, PKP à chaud revealed significantly lower ACDs and ACVs (p < 0.001) and higher PCTs (nasal p < 0.033, temporal p = 0.042). In contrast, significant differences were not observed for IOP, CCT and ACA. Increases in IOP ≥ 25 mm Hg (n = 21) were more frequent in eyes with keratoconus (n = 14) with a high proportion of these cases showing a steroid response (n = 10). CONCLUSION: After PKP the anterior chamber geometry changes postoperatively; however, anterior chamber changes do not necessarily correlate with an increase in IOP. It is possible that a steroid response has a greater influence on postoperative increases in IOP because no significant anterior chamber flattening occurred postoperatively in eyes with keratoconus. In future prospective studies it is expected that further factors with a potential influence will be identified in the complex system of regulation of postoperative IOP.
Universität des Saarlandes (UdS), Klinik für Augenheilkunde, Universitätsklinikum des Saarlandes (UKS), Kirrbergerstr. 100, 66421, Homburg/Saar, Deutschland. robe.schir@gmx.de.
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