Ocular Biometric and Corneal Biomechanical Changes Following Ahmed Glaucoma Valve Implantation in Neovascular Glaucoma

Background: To evaluate the impact of Ahmed glaucoma valve (AGV) implantation on ocular biometric and corneal biomechanical parameters in neovascular glaucoma (NVG) patients. Methods: This prospective study included 18 eyes of 18 NVG patients undergoing AGV implantation. Biometrical parameters, including anterior chamber depth(ACD), axial lenghth(AL) and keratometric values in addition to corneal biomechanical indices(deformation amplitude, peak distance, applanation lenghths and velocities) , were assessed preoperatively and three months postoperatively. Statistical analysis evaluated changes and correlations between parameters. Results: The mean age of the subjects was 57.44 (±10.325). The mean preoperative IOP was 36.65(±12.3) mmHg, which was reduced to 15.5(±2.64) mmHg post-operatively (p value <0.001). Axial length (AL) decreases from 23.42±0.76 to 23.21±0.76 (P<0.001). Postoperatively, although corneal Keratometry and central corneal thickness significantly decreased (p value<.001), anterior chamber depth showed an increase in amount, which was significant (p value=.037). The Peak distance increased from 3.33±0.72 mm preoperatively to 3.66±0.78 mm, postoperatively, (p =0.004) and deformation amplitude also increased from 0.58±0.18 mm to 0.72±0.22 mm (P =0.001). No significant change in preoperative measures of applanation length 1, applanation length 2, applanation velocity 1, and applanation velocity 2 with the amount of these variables postoperatively (All P-values>0.05). Conclusion: AGV implantation induces significant ocular biometric and corneal biomechanical changes in NVG patients. Understanding these alterations is vital for optimizing treatment strategies and clinical outcomes in NVG management.