Influence of Corneal Opacity on Visual Acuity After Cataract Surgery

Santaro NoguchiSyunji Yokokura

Megumi UemastuAkiraKubotaKoji 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

high-order aberration(HOA) (KR-9000-PW TM TOPCON)

high order irregularity(HOI)(TMS-4TM TOMY CORPORATION)

Dencitometry(PentacamTM OCULUS)

METHODS March,2006 ～ Jun,2009 17cases 22eyes

(5males 　 12females) 70 ～ 86years 　 76 ． 88±4 ． 8

6※ 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

Unknown,11

Avellinocorneal

dystrophy, 1

Bandkeratopathy, 1

Pterygium(post

operated), 5Syphilis(congenital), 4

FC(1

Projection by indirect illumination

Projection by direct illumination

Good visualization of iris

Not good visualization of iris Bad visualization of iris

Grade 0.5　

Grade 2　

Grade 4

Grade 1　

Grade 3

Grade 0 normal

CCD(central corneal densitometry) were defined on the basis of average value of 25 densitometry values.

475nm blue slit light rotate with Sheimpflug camera.

25shots are took in 1second.

Apex of cornea is Automatically recognized and captured.

Corneal Densitometry value

The Pentacam

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　　　　 male 　 23.01±1.814 　　　　　 female 　 23.51±1.439 no sex difference(**p=0.1532)

Age correlate with CCD

r=0.423

**Mann-Whitney's U test

*p=0.0132

*Spearman's rank correlation coefficient matrix

0

5

10

15

20

25

30

0 20 40 60 80 100yeas old

CCD

Y=0.0352x+21.863R=0.4233*p＜ 0.02

Reproducibility

CaseFirst day 2nd day 3rd day

Variance(%) Case

First day 2nd day 3rd day

Variance(%)

1 23.61 24.46 23.45 2.265 14 22.28 23.82 22.99 3.347

2 21.74 24.43 22.33 6.195 15 21.00 22.36 21.99 3.224

3 22.42 22.43 22.43 0.008 16 25.30 24.43 22.76 5.327

4 23.19 21.02 22.56 5.027 17 23.62 23.71 23.41 0.654

5 25.42 25.12 24.77 1.315 18 23.81 22.28 23.18 3.325

6 22.59 23.01 24.51 4.319 19 22.15 21.31 21.61 1.961

7 24.45 24.99 24.56 1.155 20 21.96 20.97 21.79 2.444

8 22.28 23.82 22.99 3.347 21 24.70 27.14 26.05 4.715

9 22.67 23.83 23.90 2.946 22 24.84 25.31 23.69 3.387

10 22.18 22.01 22.41 0.903 23 25.08 24.28 24.71 1.628

11 22.86 23.39 23.42 1.363 24 24.55 25.18 24.22 1.981

12 22.48 23.68 23.86 3.204 25 23.76 24.41 26.50 5.769

13 24.44 24.99 24.56 1.155 26 23.88 23.42 22.74 2.441

Variance is less than 10%.CCD is reproducible method.

Volunteers without eye disease, but ametropia 12cases,24eyes(man 2 、 woman 10) 21 ～ 60years(28.20±9.850)

0

0.2

0.4

0.6

0.8

0 0.2 0.4 0.6 0.8 1HOI(D)

Log

MA

R

0

0.5

1

1.5

2

0 0.5 1 1.5 2HOA-RMS（μm）

Log

MA

R

No correlation with VA. it is difficult to calculate VA accurately

y=-0.6539x+0.0309r=0.6494*p=0,0794

φ4mm corneal HOA and VA

φ3mm HOI and VA

0

0.5

1

1.5

2

0 1 2 3 4 5FC

Lo

gM

AR

FC and VA y=0.0698x+0.3518r=0.2197

y=-0.447x+0.1553r=0.4965*p=0.0502

CCD and VA

CCD correlated with VA strongly. It suggest that we can calculate VA by CCD

y = 0.0182x - 0.5933r2 = 0.6795r=0.8243※p=0.000

-0.5

0

0.5

1

1.5

2

0 20 40 60 80 100 120

Densitometry

Log

MA

R

*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.