The Clinical Applications Of IOLMaster In Certain Conditions

Objective:1,To evaluate the clinical feasibility of IOLMaster compared with contact A-Scan in cataract patients with high myopia and posterior scleral staphyloma, then to compare the accuracy of different IOL power calculation formulas.2,To compare axial length (AL) measurements obtained with IOLMaster and contact A-Scan in eyes with macular edema (ME) and to examine the correlation between measurement difference and foveal thickness.3,To evaluate the accuracy of AL measurement by IOLMaster in eyes with silicone oil tamponade.Methods:1,This is a prospective case control clinical research.2,41 eyes with age-related cataract of 28 patients underwent phacoemulsification with monofocal foldable IOLs implantation were involved,who were all high myopia with posterior scleral staphyloma. Preoperative measurement was measured with IOLMaster as well as with Contact A-scan and manual keratometry (MK). IOL power was calculated according to the SRK-II,SRK-T,Haigis,Hoffer Q,Holladay 1 formulas. The refractive outcome was followed-up 3 months after operation.3,67 eyes with ME of 42 patients and 40 healthy eyes of 30 participants were included. Foveal thickness was measured with TOPCON 3D OCT-1000, The AL was prospectively measured using IOLMaster and Contact A-scan.4,26 eyes of 30 patients, vitrectomized with silicone oil tamponade were enrolled. IOLMaster was performed 1day before and 1 month after surgery in order to assess change in AL measurements.5,Statistical method:SPSS software version 16.0 was used.The difference between 2 methods and formulas was assessed using paired-samples t test,one-way ANOVA,McNemar test; The correlation was assessed using Pearson coefficients.Results:1,The difference was significant between the 2 methods in AL and ACD measurement (P=0.005,0.000);In corneal curvature measurement, there was no significant difference between them (P=0.398). When MAE was Divided by±1.00 D, IOLMaster performed better than Contact A-scan (χ2=3.953,P=0.047) only in Haigis formula. The SRK/T and Haigis formula performed better than other formulas measured by IOLMaster; The Holladay 1,Hoffer Q and Haigis formula performed better than other formulas measured by Contact A-scan combined with MK, respectively.2,Mean foveal thickness of ME eyes was (377.85±119.84)μm. Mean AL by IOLMaster and Contact A-scan in ME eyes were (22.95±0.97) mm and (22.82±1.04) mm, respectively (P=0.003). Correlation between AL difference and foveal thickness was poor in ME eyes (r=-0.097; P=0.447).3,Mean AL in presence vs absence of silicone oil tamponade was (24.38±3.18)mm and (24.23±2.91) mm, respectively, there was no statistically difference (P=0.261). Conclusion:1,For those cataract patients with high myopia and posterior scleral staphyloma, IOLMaster is more accurate than Contact A-scan in IOL power calculation only in Haigis formula. SRK/T and Haigis formula were recommended when employing IOLMaster; whereas when using Contact A-scan combined with MK, we prefer Holladay 1,Hoffer Q or Haigis formula.2,AL measurements using Contact A-scan and IOLMaster in eyes with ME differ statistically and clinically significantly. However, the correlation between AL difference and foveal thickness was poor.3,Presence vs absence of silicone oil tamponade did not influence the AL measurements by means of IOLMaster.