IOL Master Pf. 김만수/St. 변용수/R3 김재윤

Determination of Axial length Ultrasound biometry (A scan) Ant surface of cornea to ILM Optical biometry (IOL master) Ant surface of cornea to RPE A scan은 physical contact가 필요한데 이것이 오차를 만들어 내는 중요한 요인이 된다.

Partial coherence interferometer

IOL master autoKeratometry Measures at 2.5mm diameter 5 images automatically captured in 0.5 sec 30 data points per measurement (6 spots x 5 samples) displayed result is average of 5 captured images most manual keratometers measure 3mm

Advantages Non-contact type Minimized technician factor Signal-to-noise (SNR) Relatively short measurement time Measure along the visual axis Enable to apply on Silicone filled eye 비접촉식으로 산동이나 점안마취의 필요가 적다. 또한 이로인한 감염등의 합병증이 줄어들고 각막 함입에 따른 오차도 감소 측정자 간의 차이나 측정자의 숙련도에 따른 영향이 적다. 측정치에 대한 질의 척도가 제시되어 정확도 판단에 도움이 됨. AL, K, ACD, WTW 등을 함께 비교적 짧은 시간에 측정 가능. 주시점을 바탕으로 측정하므로 시축에 따라서 측정가능

Limitations Cannot work in the presence of axial opacity Mature or brunescent lens Dense PSCO Vitreous hemorrhage Central corneal scar Patients with tremor, retinal ablation Geographic pigment epithelial atrophy Condensed posterior hyaloid face Subretinal new vessel membrane, or PED LOCS III에서 N3이상이나 PSCO 가 심하면 잘 안찍힘. 하지만 일단 찍히면 정확 Dense media opacity along the visual axis Pathological changes in the retina

Practical application Testing time A scan+Mannual K : 3 min IOL master(AL,K,ACD) : 1 min Practical difficulties Patients who have difficulty in fixing eye 검사시간(일반적인 case 기준) -> 서울성모검사실 A scan +MK; 3분 IOL maser(AL. K, ACD) : 1분

When is most accurate ? Accurate Axial length ? Accurate Keratomtry ? Which formula to use ?

Comparison of accuracy Reported in World-wide Better Soso

88 eyes 121 eyes

ITT analysis란? 검사등의 procedure failurer를 포함시켜서 하는 분석 PCI가 심한 백내장등의 문제로 시행 못한 경우도 포함해서 분석

Accuracy in our cases

CASE 1 AL A-scan 24.17 IOL master 24.14 K Manual K K1 45.25 K2 44.25 Auto-K in IOL master K1 44.00 K2 45.49 ACD 1.69 IOL-master 3.87 Preop Rx SE +1.25Ds = -2.0Dc Ax24 +0.25D Selected IOL SN60AD1 +18.00D Post op Rx +0.25Ds = -1.0Dc Ax12 -0.12D SRK-2 Predicted Rx Difference A scan +0.16D 0.28D more myopic +0.1D 0.22D more myopic SRK-T -0.15D 0.03D more hyperopic -0.36D 0.24D more hyperopic Haigis -1.32D 1.44D more hyperopic -0.76D 0.64D more hyperopic SNR 26.5 Restor로 Ascan 기준 SRK-T 118.9로 넣음

CASE 2 AL A-scan 23.69 IOL master 23.56 K Manual K K1 43.50 K2 42.75 Auto-K in IOL master K1 42.51 K2 44.00 ACD 1.66 IOL-master 3.39 Preop Rx SE err Selected IOL SN60T4 +23.5D Post op Rx -1.0Ds = -1.5Dc Ax16 -1.75D SRK-2 Predicted Rx Difference A scan -2.00D 0.25D more hyperopic -1.70D 0.05D more myopic Haigis -1.24D 0.51D more myopic -1.30D 0.45D more myopic 반대쪽눈에 맞추어 -2.0D 근처로 넣음 Normal AL로 별 문제 없음

CASE 3 AL A-scan 26.00 IOL master 25.90 K Manual K K1 43.00 K2 44.50 Auto-K in IOL master K1 41.93 K2 46.23 ACD 1.61 IOL-master 3.79 Preop Rx SE -2.5Ds = -3.25Dc Ax74 -4.12D Selected IOL ADAPT-AO +14.0D Post op Rx -1.0Ds = -0.75Dc Ax42 -1.37D SRK-2 Predicted Rx Difference A scan -0.88D 0.49D more hyperopic -0.81D 0.56D more hyperopic SRK-T -1.05D 0.32D more hyperopic -0.95D 0.42D more hyperopic Haigis -1.47D 0.10D more hyperopic -1.12D 0.25D more hyperopic Long AL로 K 값의 차이가 있으나 거의 비슷..

CASE 4 AL A-scan 26.80 IOL master 26.83 K Manual K K1 42.00 K2 40.50 Auto-K in IOL master K1 40.66 K2 42.35 ACD 2.21 IOL-master 2.96 Preop Rx SE -5.5Ds = -1.0Dc Ax27 -6.0D Selected IOL YA60BBR +14.50D Post op Rx +0.25Ds = -1.25Dc Ax168 -0.37D SRK-2 Predicted Rx Difference A scan -0.73D 0.36D more hyperopic -0.60D 0.23D more hyperopic SRK-T -0.93D 0.56D more hyperopic Haigis -0.97D 0.60D more hyperopic -1.07D 0.70D more hyperopic SNR 26.5

CASE 5 AL A-scan 27.13 IOL master 27.10 K Manual K K1 38.50 K2 37.00 Pentacam K K1 34.00 K2 35.80 Auto-K in IOL master K1 35.64 K2 37.50 ACD 1.78 IOL-master 2.96 Preop Rx SE -2.25Ds = -3.25Dc Ax132 -6.50D Selected IOL ZA9003 +21.00D Post op Rx +0.25Ds = -0.75Dc Ax121 -0.12D SRK-2 Predicted Rx Difference A scan + MK -3.68D 3.56D more hyperopic Ascan + PK -1.63D 1.51D more hyperopic -2.20D 2.08D more hyperopic SRK-T A scan -3.25D 3.13D more hyperopic -0.85D 0.73D more hyperopic -1.78D 1.66D more hyperopic Haigis -2.19D 2.17D more hyperopic A scan + PK +1.02D 0.90D more myopic -0.54D 0.42D more hyperopic Haigis_L로하면 +1.11DT로 나옴. Topo는 기록이 저장되어 있지 않아 4mm zone 확인 못함.,

CASE 6 AL A-scan 27.49 IOL master 27.46 K Manual K K1 38.75 K2 36.25 Pentacam K K1 33.90 K2 35.80 Auto-K in IOL master K1 35.34 K2 37.54 ACD 1.78 IOL-master 2.96 Preop Rx SE -5.5Ds = -1.25Dc Ax26 -6.25D Selected IOL ZA9003 +21.00D Post op Rx +1.0Ds = -0.5Dc Ax53 0.75D SRK-2 Predicted Rx Difference A scan + MK -4.22D 4.97D more hyperopic Ascan + PK -2.31D 3.14D more hyperopic -2.80D 3.55D more hyperopic SRK-T -3.75D 4.50D more hyperopic -1.49D 2.24D more hyperopic -2.36D 3.11D more hyperopic Haigis -2.27D 3.02D more hyperopic A scan + PK +0.39D 0.36D more hyperopic -1.00D 1.75D more hyperopic Haigis_L로하면 +0.71DT RE : +0.04D more hyperopic

To Improve accuracy Using calibrated axial length readings Modern IOL power calculation formulas with the latest generation ACD prediction algorithm Serial modifications to the A-constant J Cataract Refract Surg 2005; 31:1345–1350 Acta Ophthalmol. Scand. 2007: 85: 84–87 Acta Ophthalmol. Scand. 2005: 83: 436–438