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Influence of Corneal Opacity on Visual Acuity After Cataract Surgery. Santaro Noguchi Syunji Yokokura Megumi Uemastu AkiraKubota Koji Nishida Department of Ophtalmology,University of Tohoku Graduate School of Medicine. Foreword.
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Influence of Corneal Opacity on Visual Acuity After Cataract Surgery Santaro Noguchi Syunji Yokokura Megumi Uemastu AkiraKubota Koji Nishida Department of Ophtalmology,University of Tohoku Graduate School of Medicine
Foreword • Safely phacoemulsification and ijnect intraocular lens(PEA IOL) with hazy cornea has be done. • we cannot exactly make prognostication post operative visual acuity(VA),because nobody knows how much impact opacified cornea makes to VA. • Fantes categorized the degree of corneal haze to 5steps by slit lamp eximination.(Fantes classification FC)(1 • After years, the quantity of corneal haze by slit was treid to determine.(2(4(5 • Seiya and Mastuda tried to quantify corneal opacification(3(7 (1Fantes FE,Hanna KD,et al:Wound healing after excimer laser keratomileusis in monkeys.Arch Ophthalmol 108:665-675,1990 (2LIn N,Yee SB et al:Prediction of corneal haze using an ablation depth/corneal thickness ratio after laser epithelial keratomilersis .J Refract Surg 20:797-802,2004 (3Koichi Seiya et al:Ringan49:1524-1528、1995 (4Tanabe T et al:Influence of wave front aberration and corneal subepithelial hee on low contrast visual acuity after photorefractive keratectomy.Am J Ophthalmol 138:620-624,2004 (5Kazutaka Kamiya et al::Ringan:529-532、1996 (6Mstuda et al:Nichigan kaishi :111:447-453,2007
PURPOSE • How mach impact a hazy cornea make to VA. • To quantify corneal opacification • To study how corneal opacification and shape affect VA Dencitometry (PentacamTM OCULUS) high-order aberration(HOA) (KR-9000-PW TM TOPCON) high order irregularity(HOI) (TMS-4TM TOMY CORPORATION)
METHODS • March,2006~Jun,2009 • 17cases 22eyes (5males 12females) • 70~86years76.88±4.86※ • Patients who were operated(PEA IOL) at Tohoku Uni Hospital and more than 3months followed. • The correlation of HOA,HOI,densitometry and FC was analyzed. ※average±standard deviation
FC(1 Grade 0 normal Grade 0.5 Projection by indirect illumination Grade 1 Grade 2 Projection by direct illumination Good visualization of iris Grade 4 Grade 3 Not good visualization of iris Bad visualization of iris
The Pentacam 475nm blue slit light rotate with Sheimpflug camera. 25shots are took in 1second. Corneal Densitometry value CCD(central corneal densitometry) were defined on the basis of average value of 25 densitometry values. Apex of cornea is Automatically recognized and captured.
Normal value of clear cornea • Volunteers without eye disease, but ametropia • 24cases,44eyes (12 males,12females) • 11~82yeas old (43.30±20.00 ) • 23.25±1.597 male23.01±1.814 female23.51±1.439 • no sex difference(**p=0.1532) • Age correlate with CCD r=0.423 *p=0.0132 Y=0.0352x+21.863 R=0.4233 *p<0.02 *Spearman's rank correlation coefficient matrix **Mann-Whitney's U test
Reproducibility • Volunteers without eye disease, but ametropia • 12cases,24eyes(man 2、woman 10) • 21~60years(28.20±9.850) Variance is less than 10%.CCD is reproducible method.
FC and VA y=0.0698x+0.3518 r=0.2197 φ3mm HOI and VA y=-0.447x+0.1553 r=0.4965 *p=0.0502 φ4mm corneal HOA and VA No correlation with VA. it is difficult to calculate VA accurately y=-0.6539x+0.0309 r=0.6494 *p=0,0794
CCD and VA CCD correlated with VA strongly. It suggest that we can calculate VA by CCD *Spearman's rank correlation coefficient matrix
RESULT • CCD reference value is 23.5 • CCD is reproducible method. • CCD correlate with VA stronger than FC. • φ4mm corneal HOA ,φ3mm corneal HOI and FC did not correlate with VA. • It suggest that we may previously calculate VA by CCD in advance PEA IOL.
Discussion Conclusion • For all I know,vision-limiting factor in corneal moderate haze may be scatter . • CCD may calculate postoperative VA, so CCD can be information for making a decision that only PEA IOL should be done or keratoplasty too. • The Densitometry value is limited 0 to 100.So it often run up 100 with haze. • The Pentacam measurement process takes less than two seconds and minute eye movements are captured and corrected simultaneously,but in blink furiously and bad face fixation Pentacam data get poor.