| Objective:To analyze the correlation of anterior chamber depth. Thisstudy uses Sirius Scheimpflug tomography measurements cornea, anteriorchamber parameters before and after myopic excimer laser refractivesurgery.Corneal8mm area is bounded to the anterior chamber is dividedinto two sections (Anterior chamber depth of cornea4mm radius areasagittal height section,Sag4mmACD;and residual anterior chamber depthsection,RACD). On this basis, further use A-scan US pachymetrymeasurements each segment of eye axial to explore the dynamic changes ofthe anterior segment.Methods:(1)A retrospective analysis of fifty-nine myopic eyes ofthirty-one consecutive patients were include in the study.Collect data ofcentral corneal thickness (CCT),corneal volume(CV),posterior cornealcurvature(PCC),anterior chamber depth (ACD), anterior chambervolume(ACV), anterior chamber angle(ACA) from Sirius Scheimpflugtomography.Using SPSS17.0statistical analyze the anterior segmentparameters, and using the Pearson correlation analyze the correlation between corneal parameters and anterior chamber parameters separatelydiscussed with ACD.(2)Collect data of CCT,ACD,lens thickness(LT),vitreous length(VL) and axial length(AL) from A-scan US pachymetryto analyze changes of preoperative and postoperative.And further explorethe correlation between ACD.Results:1.In both Sirius Scheimpflug tomography and A-scan pachymetry twomeasurement metods,showed CCT as (549.42±31.55)mm at pre-op、(427.69±45.80mm at1mo、(433.07±43.72)mm at3mo、(441.27±39.90)mmat6mo of Sirius and (551.19±30.49)μm at pre-op、(432.63±37.33)μm at1mo、(438.33±39.51)μm at3mo、(447.29±38.48)μm at6mo ofA-scan.1,3,6months postoperative compared with preoperation werereduced statistically significant(P <0.001).Sirius measurement CV showedas (59.03±2.71)mm3at pre-op、(56.35±2.38)mm3at1mo、(56.46±2.42)mm3at3mo、(57.29±2.24)mm3at6mo.1,3,6months postoperative were lowerthan preoperation statistically significant(P <0.001).And PCC (cornealcenter of3mm diameter) showed as （-6.21±0.21）D at pre-op、（-6.36±0.28）D at1mo、（-6.37±0.24）D at3mo、（-6.41±0.19）D at6mo;1,3,6months postoperative compared with the preoperative difference wasdecreased statistically significant (P <0.001).2.In both Sirius Scheimpflug tomography and A-scan pachymetry twomeasurement methods,showed ACD as (3.29±0.30)mm at pre-op、 (3.14±0.27)mm at1mo、(3.14±0.24)mm at3mo、(3.13±0.22)mm at6moofSirius and (3.16±0.26)mm at pre-op、(3.02±0.24)mm at1mo、(3.01±0.23)mm at3mo、(3.01±0.22)mm at6mo of A-scan;1,3,6monthspostoperative compared with preoperation actual ACD were reducedstatistically significant(P <0.001). There was no statistically significancebetween1,3,6months(P>0.05).Sirius measurement ACV showed as(170.39±20.59)mm3at pre-op、(161.42±21.22)mm3at1mo、（162.49±18.07）mm3at3mo、(161.36±14.77)mm3at6mo.1,3,6months post-operative were lower than preoperation statistically significant(P<0.05).ACA showed as (43.73±5.40)°at pre-op、(41.38±5.51)°at1mo、(42.12±4.69)°at3mo、(42.55±3.88)°at6mo.1,3,6months postoperative werereduced, the difference was statistically significant (P <0.05).Sag4mm-ACDshowed as (1.99±0.30)mm at pre-op、(1.85±0.32)mm at1mo、(1.83±0.27)mm at3mo、(1.81±0.21)mm at6mo;1month compared with the pre-operative decreased, the difference was statistically significant (P <0.05);in3,6months the difference was not statistically significant (P>0.05).RACDshowed as (1.99±0.30) mm at pre-op、(1.85±0.32)mm at1mo、(1.83±0.27)mm at3mo、(1.81±0.21)mm at6mo;1,3,6months postoperative weredecreased, the difference was statistically significant (P <0.05).3.A-scan pachymetry measurement LT showed as (3.70±0.28)mm atpre-op、(3.86±0.24) mm at1mo、(3.80±0.25)mm at3mo、(3.85±0.23)mmat6mo;1,3,6months postoperative were increased significantly(P <0.001).VL showed as (18.21±1.36)mm at pre-op、(18.33±1.16)mm at1mo、(18.34±1.06)mm at3mo、(18.43±1.21)mm6mo;1,3months post-operative the difference was not statistically significant (P>0.05)；and in6months were increased significantly(P <0.05). Axial length (AL) showedas (25.62±1.49)mm、(25.64±1.21)mm、(25.58±1.14)mm、(25.74±1.29)mm;1,3,6months postoperative were increases, the difference was notstatistically significant (P>0.05).Conclusion:The corneal thickness, corneal volume were decreased after excimerlaser refractive surgery for myopia.Posterior corneal curvature(3mmdiameter area) increased in early postoperative,and increased graduallywith time.The anterior chamber depth, anterior chamber volume, anteriorchamber angle decreases postoperative.The lens thickness increasedpostoperative,the axial length was not significant changes. Vitreous lengthwas not significant change in in early postoperative,there are differences ingrowth in6months postoperatively;This difference may be related tomeasurement error.2.The anterior chamber depth’s change in postoperative have nosignificant correlation with central corneal thickness,posterior cornealelevation(3mm diameter area) and vitreous length change in post-operative.There’s negative correlation between anterior chamber depth withthe lens thickness,and low correlation coefficients with statistically significant (P <0.05).3.Sag4mmACD preoperative and postoperative was not statisticallysignificant(P>0.05).RACD preoperative and postoperative was differentstatistically significant(P<0.05).To analyze A-scan pachymetry measur-ement axial parameter of each segment,we analyzed that the RACD is themajor change state of total ACD decrease,which due to myopic refractivesurgery in the early postoperative accommodation increased lead to lensthickness increased, and forward shifting of the lens. |
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