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@#AIM: To explore the dynamic distribution of pupil size and center, the eccentricity distribution of corneal light reflection, and its correlation analysis about suitable for femtosecond laser combined with excimer laser <i>in situ</i> keratomileusis.<p>METHODS: Randomly selected 225 patients(407 eyes)who underwent femtosecond laser combined with excimer laser <i>in situ</i> keratomileusis at Yanbian University Hospital in 2019 from January to May, preoperative use of Wavelight Allegro Topolyzer Corneal Topography to measure the pupil size and center position, the German Wavelight EX500 excimer Laser(500Hz)records the deviation between the pupil center and the coaxially sighted corneal light reflex when the patient is supine. <p>RESULTS:The average displacement distribution between the center of the cornea and the center of the pupil is 0.322±0.194mm, and 64% of the eyes are ≤0.40mm. The average displacement distribution of P-Dist(the eccentricity between the pupil center and the coaxially sighted corneal light reflex point)is 0.225±0.102mm, and 80% of the eyes are ≤0.30mm. The coaxially sighted corneal light reflex point is mainly deviated to the superior temporal side of the corneal center(34%). The X-axis of the left eye in low light conditions: -0.061±0.084mm, and the X-axis of the right eye: -0.016±0.059mm(<i>P</i>=0.002)(the left eye shifted to the temporal side in the dark light). The corneal transverse diameter(WTW)was positively correlated with changes in pupil diameter(dark pupil diameter-bright pupil diameter)(<i>r</i>=0.270, <i>P</i><0.001).<p>CONCLUSION: The left eye should be adjusted to a position of the machining center within 0.061mm. If the cornea is too large, try to maintain a dark light environment during the operation to improve the efficiency of pupil matching. This study further confirms the necessity of rationally positioning the cutting center under different angle kappa states.
ABSTRACT
PURPOSE: To analyze the positional relationships of various centers in patients undergoing femtosecond laser-assisted cataract surgery (FLACS). METHODS: The locations of the pupil center (PC), limbal center (LC) and lens center were analyzed in each patient using optical coherence tomography during FLACS in 35 eyes of 35 patients. Using the preoperative corneal aberrometry device, angle kappa and the location of the visual axis (VA) were calculated. After acquiring the relative horizontal and vertical coordinates of each center, the distance and location among each center were compared. The relative location and distance of each center were statistically evaluated. RESULTS: The distance from the PC to the lens center was 0.147 ± 0.103 mm, that from the LC to the lens center was 0.205 ± 0.104 mm, and that from the VA to the lens center was 0.296 ± 0.198 mm. The distance from the PC to the VA was 0.283 ± 0.161 mm, that from the LC to the VA was 0.362 ± 0.153 mm, and that from the lens center to the VA was 0.296 ± 0.198 mm. Among the various centers, the PC was the closest to the lens center, whereas the LC and VA were the farthest. Based on the location of the lens center, the PC, LC, and VA exhibited differences in the X and Y coordinate positions (vertical p = 0.004, horizontal p < 0.001). Among them, the LC was significantly inferior and temporal compared to the PC (vertical p = 0.026, horizontal p = 0.023). Based on the location of the VA, the respective locations of the PC, LC and lens center in two dimensions did not significantly differ (vertical p = 0.310, horizontal p = 0.926). CONCLUSIONS: This study demonstrated the positional and locational relationships between the centers regarding FLACS. The locations of the PC, LC, and VA were different from the lens center with the PC being the closest. Surgeons should be aware of these positional relationships, especially in FLACS.
Subject(s)
Humans , Aberrometry , Cataract , Pupil , Surgeons , Tomography, Optical CoherenceABSTRACT
AIM:To investigate the effect of different cutting centers on the visual acuity, refractive diopter and visual quality of patients undergoing laser assisted in situ keratomileusis (LASIK).METHODS: A total of 80 patients (160 eyes) with myopia treated by elective LASIK were divided into two groups.Thirty-six cases (72 eyes) with visual axis corneal reflection point (VACRP) as the cutting center were included into the VACRP group while 44 cases (88 eyes) with pupil center (PC) as the cutting center were included into the PC group.The uncorrected visual acuity (UCVA), the best corrected visual acuity (BCVA), refractive diopter, corneal aberration [total corneal and anterior corneal surface higher-order aberrations (HOA), spherical aberration (Z40), vertical coma (Z3-1), horizontal coma (totZ31) and offset of cutting centers were determined before surgery and 1mo after surgery.RESULTS: There was no difference in the probability of UCVA ≥ 0.1, BCVA and refractive diopter between the two groups at 1mo after surgery (P>0.05).The astigmatism and cutting center deviation of VACRP group were lower than those of PC group (P<0.05).The totHOA, totZ40, totZ3-1, totZ31, froHOA, froZ3-1、froZ31 and froZ40 were lower in VACRP group than PC group at 1mo after surgery (P<0.05).CONCLUSION: The UCVA of patients treated with both cutting centers for LASIK is good but VACRP has more advantages in reducing the offset of cutting center and improving postoperative visual quality.