Evaluation Of Anterior Chamber Angle Morphology Using Swept-Source Optical Coherence Tomography In Patients Undergoing Lasik And Smile

To evaluate the anterior chamber angle morphology in the immediate and early postoperative period in patients undergoing femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE).

Dr Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi.

A prospective, interventional, comparative study recruited 40 eyes of 40 patients with mild-moderate myopia undergoing SMILE (group 1, n=20) or FS-LASIK (group 2, n=20). Anterior chamber angle (ACA) parameters comprising nasal and temporal trabecular meshwork length, angle opening distance at 500 µm (AOD500) and 750 µm (AOD750), trabecular-iris surface area at 500 µm (TISA500) and 750 µm (TISA750), angle recess area at 500 µm (ARA500) and 750 µm (ARA750), and trabecular-iris angle at 500 µm (TIA500) and 750 µm (TIA750) were assessed preoperatively, immediately post-surgery and on postoperative day1 (POD1) using swept-source optical coherence tomography.

: Mean preoperative spherical equivalent (SE) was comparable in both groups (group 1= -3.6±1.42D, group 2= -3.75±0.92D; p=0.78). No significant changes were observed in angle parameters in either group immediately after surgery. On POD1, a significant increase in AOD750 (p=0.03,0.006), ARA750 (p=0.02,p=0.03), TISA750 (p=0.03,p=0.008) and TIA750 (p=0.01,p=0.01) was observed in both groups. In addition, a significant increase in TIA500 (p=0.003), AOD500 (p<0.001), AR500 (p<0.01), TISA500(p<0.01) and TIA 500 (p=0.03) was observed in LASIK group. Significant correlation was observed between preoperative SE and change in AOD750 (r=0.64,p=0.04), ARA750 (r=0.7,p=0.02), TISA750 (r=0.69,r=0.02), TISA 500(r=0.64,p=0.04) in LASIK group.

Anterior chamber angle parameters increased after SMILE and FS-LASIK in early postoperative period and the change correlated well with preoperative spherical equivalent in LASIK group.