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Clinical evaluation of Q-value guided LASIK

Poster Details

First Author: N.Takhchidi RUSSIA

Co Author(s):    N. Maichyk              

Abstract Details


То investigate the visual quality after Q-value guided FemtoLASIK.


: S. Fyodorov Eye Microsurgery Institution, Moscow


64 myopic patients who underwent FemtoLASIK were divided in 2 equal groups: the group of investigation - after Q-value guided FemtoLASIK and he control group – after conventional myopic FemtoLASIK. All patients were followed-up for 1 year after surgery. Postoperative assessments of uncorrected visual acuity (UCVA) was performed. Aberrometry was assessed using OPD-Scan ARK-10000 (Nidek, Japan). The following parameters were evaluated: RMS HO 6 mm, spherical aberration (Z12), Q-value. The quality of vision assessment was performed pre- and postoperatively in both groups using Optec 6500 (Stereo Optical company, USA) and included measurement of BCVA visual acuity in photopic (85 cd/m ) and mesopic ( 30 cd/m) conditions with and without glare. Spatial contrast sensitivity (CS) was assessed using FACT (functional acuity contrast test) in photopic and mesopic conditions. Femtosecond laser Femto LDV (Ziemmer, Switzerland) was used for flap creation. The intended flap thickness was 90 mkm. Ablation was performed using MicroScan Visum excimer laser (Optosystems, Troitsk, Russia).


Pre op. data: Group of investigation: SE -4.29± 0.27 D, UCVA 0.05 ± 0.03; RMS HO 0.44 ± 0.21 mkm, Z12 0,03 ± 0,06, Q -0.37± 0.11. Control group: SE - 4.11 ± 0.32 D, UCVA 0.04 ± 0.02; RMS HO 0.43 ± 0.11 mkm, Z12 0,03 ± 0,12, Q -0.35 ± 0.06 (р <0.05). Post-op. data: group of investigation - SE was close to “0 D”: 0.12 ± 0.04 D, comparing to control group 0.26 ± 0.11 D (р <0.05). UCVA 1.1 ± 0.02 was higher comparing to control group 0.87 ± 0.08. In the group of investigation RMS HO 0.48 ± 0.18 mkm, Z12 0,06±0,08 and Q value (-0.33±0.09) stayed in preoperative ranges, while in control group these values increased in 2 times: RMS HO was 0.74 ± 0.24 mkm, Z12 0,09±0,10, Q: 0.023± 0.10 (р<0.05). In the control group VA under mesopic light conditions was slightly higher than accustomed-correction VA. In the group of investigation - was higher in two times. CS increased in 2 times in mesopic conditions in all spatial frequencies, comparing to pre op. data in the group of investigation. In control group CS slightly increased mostly in low and moderate spatial frequencies. .


After Q-value guided FemtoLASIK visual functions was higher than visual functions before the surgery and also higher than visual functions after conventional Femto-Lasik. After Q-value guided FemtoLASIK the ablation depth was considerably. It limits the use of this technology in patients with initial thin cornea and high degree of ametropia.

Financial Disclosure:


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