Myopic LASIK Visual Outcomes of Wavefront-Guided Ablation with Iris Registration

Mouhab Aljajeh, M.D., Engy Mohamed, M.D., Wayne Bowman, M.D., Dwight Cavanagh, M.D., PhD., Steven Verity, M.D., James McCulley M.D.,FRCOphth (UK)

Dr. McCulley is a consultant of Alcon Inc. No financial interest of any of the other authorsSupported in part by an unrestricted research grant from Research to Prevent Blindness, Inc., New York, New York.

Financial Disclosure:

BackgroundWavefront-guided refractive surgery is designed to

correct High-order Aberration (HOA) as well as sphere and cylinder.

The position of the pupil center shifts as the pupils size changes.1-3 A static decentration of wavefront-guided ablation may occur due to pupil centroid shift as laser refractive surgeries are usually performed under photopic conditions whereas, wavefront measurements are often performed under mesopic condition1 Yang y, Thompson K, Burns SA: Pupil location under mesopic, photopic, pharmacologically dilated conditions. Invest Ophthalmol Vis Sci 2002;43:2508-25122 Walsh G: The effect of mydraiasis on pupilary centration of human eye. Ophthalmic physiol 1988;178-1823 Wilson MA, Campbell MCW,Simonet P: Change of pupil centration with change of illumination and pupils size; the Julius F. Neumueller Award in optics, 1989 Optom Vis SCI 1992;69:129-136

Purpose

In this study, our purpose was to evaluate visual and clinical outcomes of wavefront-guided laser in situ keratomileusis (LASIK) with iris registration platform (VISX CustomVue, VISX Inc., Santa Clara, CA) in myopic correction.

Methods

Prospective analysis was used to evaluate wavefront-guided myopic LASIK with iris registration in a consecutive cohort of 123 eyes (66 patients; 38 males) with no history of ocular inflammation, trauma, or systemic disease affecting vision

Methods

The primary outcome variables assessed pre-operatively and postoperatively at 1 and 3 months were:

Uncorrected visual acuity (UCVA)Best spectacle-corrected visual acuity (BSCVA) Manifest refraction, High order aberrations, using VISX aberrometer. Contrast sensitivity using the CSV-1000HGT charts

ResultsMean age was 39.2±10 years (21 to 61 years). Mean pre-treatment spherical equivalent (SE) was

reduced from -3.4±2.0 D to -0.2±0.3D (range -1.25 to 0.5) (p <0.001) at 3 months.

At 3 months, UCVA was 20/25 or better in 89% (95% of eyes after retreatment of nine eyes).

10% of eyes gained one line of BSCVA and 86% were within ±0.50D at 3 months.

Predictability

Attempted Spherical Equivalent (D)-12 -10 -8 -6 -4 -2 0 2 4

Achi

eved

Sph

eric

al E

quiv

alen

t (D

)

-10

-8

-6

-4

-2

0

2

4

Spherical equivalent at 3 months postoperative

Attempted vs achieved spherical equivalent

0%

20%

40%

60%

80%

100%

±0.5D ±1D ±1.5D

% of eyes

Safety

Lost > 2 Lost 2 Lost 1 Unchanged Gained 1 Gained 2 Gained >20%

20%

40%

60%

80%

100%

Loss or Gain in BSCVA

20/15 or better

20/20 or better

20/25 or better

20/30 or better

20/40 or better

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Post 1 wPOM 1POM 3

UCVA at 1 week, 1 month and 3 month follow-up

Efficacy

0%20%40%60%80%

100%

20/ 15 orbetter

20/ 20 orbetter

20/ 25 orbetter

20/ 30 orbetter

20/ 40 orbetter

Preoprative BCVA POM 3 UCVA

Total HOA increased significantly from (0.38±0.15µm) to (0.45±0.22µm) (p<0.001).

Spherical aberrations increased (p=0.001) while Coma increased (p=0.4).

Trefoil decreased (p<0.002) at 3 months.

High Order Aberrations Total HOA Coma SA Trefoil

RM

S (u

m)

0.0

0.2

0.4

0.6

0.8 PreoperativePost-operative 3 m

Contrast sensitivity improved under glare conditions (p <0.001) at 3 months.

Mesopic with Glare

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 5 10 15

frequency (cpd)

Log c

ontra

st sen

sitivi

tyPreoperative Postoperative

Conclusion

Wavefront-guided LASIK with iris registration using VISX S4 IR platform is an effective, predictable, and safe procedure for treating refractive errors.