Clinical Evaluation Of Ocular Anterior Segment Changes After Phacoemulsification Cataract Extraction With IOL Implantation

After cataract surgery, there are always some doubts about the followup schedule and spectacle prescription time because of unknown about theanterior segment changes of the eyes. A great deal of data from the cornea,anterior chamber and lenses are able to be acquired and analyzed withPentacam. Firstly, this study carries on the test of the Pentacamreliability and stability. Secondly, the study makes use of Pentacam toobserve the cornea and the anterior chamber differences before and aftersurgery. Finally, the changes in each part of the eyes are explained inintegration and suggestions are given.Methods:In this study, 48 eyes of 30 patients who underwent 3.2mm clearcorneal incision phacoemulsification cataract extraction with IOLimplantation were analyzed. 22 eyes of 18 patients entered the follow upresearch. All the patients were examined by Pentacam preoperatively andpostoperatively at 1 week, 1 month, and 3 months. The items included thecorneal thickness, the anterior and posterior corneal surface curvature,the anterior chamber depth and angle, KPD, and simultaneously withmanifest refraction and visual acuity. All the data were analyzed by theSPSS 11.5 statistical software package.Results:1. The values of central and midperipheral corneal thickness,anterior and posterior corneal curvature, anterior chamber depth, anterior chamber angle among the three tests have no significantdifferences.2. The refractive power derived from the anterior surface curvatureishigher than the true net power, while the true net power hasno statistic differences compared to the manual keratometerpower.3. The thickness of some lenses is not able to be measuredpreoperatively because the lenses can not be seen wholly. SomeIOLs can be identified clearly postoperatively.4. The anterior surface curvature radii increased in 1 weekpostoperatively while the posterior surface curvature radiidecreased in 1 week and 1 month postoperatively. KPD increasedpostoperatively and was highest in 1 week. Ecc was lower in 1 week,and even became minus. The astigmatism of anterior and posteriorsurface increased 1 week postoperatively and decreased to thepreoperative level in 1 month.5. The anterior surface around the incision became more flat whileposterior surface became more steep in 1 week. The surfacerecovered in 1 month.6. The anterior chamber depth and anterior chamber angle increasedpostoperatively. The differences among the follow up time had nostatistic significance. The central corneal thickness increasedin 1 week and 1 month while the corneal volume increased all thefollow up time.7. The visual acuity did not change among the follow up time. Thebest corrected visual acuity became stable in 1 month. The sphere,cylinder and sphere equivalence of manifest refractionstabilized in 1 week after surgery. 8. The postoperative anterior chamber depth was positive linealcorrelation with the preoperative anterior chamber depth andocular axial length, also negative with anterior surfacecurvature radii.Conclusion:1. Pentacam is reliable and stable when measuring corneal thickness,corneal curvature, anterior chamber depth and anterior chamberangle.2. The IOL is able to be detected by Pentacam. The density can bemeasured in the clear, slight to moderate cloudy lens.3. After 3.2mm clear corneal incision phacoemulsification cataractextraction with IOL implantation, the anterior corneal surfacebecomes more flat, while posterior surface more steep. The changeof posterior surface is more significant than that of anteriorsurface. The posterior surface has more influence on the wholecorneal refractive power postoperatively. The shape of the corneaaround the incision recovers 1 week after surgery.4. The IOL gains stability 1 week postoperatively. The anteriorchamber angle increases after surgery and gets stable in 1 month.5. The injury of corneal endothelium is not limited in center. Thecorneal volume can reflect endothelium function morecomprehensively. The function of the central endotheliumrecovers 3 months after surgery while the whole endothelium hasnot yet.6. The refraction changes are the result of co-function from everyaspect. Some parts of the eye are still changing though therefraction is already stable. We suggest the time of spectacleprescription should be 3 months after surgery. 7. The postoperative anterior chamber depth is positive linealcorrelation with the preoperative anterior chamber depth, ocularaxial length and keratometer power, which is important to thediopter selection of IOL.