EFFECTS OF REFRACTIVE SURGERY ON BINOCULAR VISION : PRE- AND POST- - - PowerPoint PPT Presentation

EFFECTS OF REFRACTIVE SURGERY ON BINOCULAR VISION : PRE- AND POST- LASIK BINOCULAR VISION : PRE- AND POST- LASIK VALUES

JOSÉ DE JESÚS ESPINOSA GALAVIZ, OD, MSc, FCOVD ELIZABETH CASILLAS CASILLAS, OD, MSc JAIME BERNAL ESCALANTE OD MSc JAIME BERNAL ESCALANTE, OD, MSc SERGIO RAMÍREZ GONZALEZ, OD MSc

VI INTERNATIONAL CONGRESS OF BEHAVIORAL OPTOMETRY APRIL 2010

Introduction

 More than a million of refractive surgery procedures

were done in USA in 2002

 Some reports about complications after surgery on

binocular vision as a result of the procedure have appeared

 R

dl f th t i b t ith th

 Regardless of the controversy is about with the

procedure with the refractive amblyopia patient, thousands could have the procedure without a comprehensive binocular vision evaluation

Binocular Vision Values

GENERAL OBJECTIVE

 Determine the effects of refractive surgery (LASIK

procedure) on binocular vision by comparing binocular vision pre surgery values against post binocular vision pre‐surgery values against post‐ surgery values.

SPECIFIC OBJECTIVES

 Determine binocular

vision values in patients who decided to have a refractive surgery, specifically a LASIK procedure before surgery LASIK procedure before surgery

 Determine binocular vision values in the same patients  Determine binocular vision values in the same patients

after surgical procedure

 Compare both results and analyze the changes in

binocular vision values

Methods

 The research was done in “Visual Láser Ocular” in

Ciudad Victoria, México from May 30th 2007 until July 31th of 2008. 31th of 2008.

 The study was done in patients who decided to have

LASIK for either myopia, hyperopia, with or without i i All l d

• astigmatism. All were selected.

 Sample: 15 patients; 10 women and 5 men. Age range

from 24 to 39. from 24 to 39.

 All were selected by the ophthalmologist who had only

done: refractive studies, corneal topography, ultrasonic h t f d l ti d l t ti pachymetry, fundus evaluation, and corneal testing.

Hypothesis

 HYPOTHESIS  Refractive surgery DOES change the binocular vision

values

 ALTERNATE HYPOTHESIS:  Refractive surgery DOES NOT change binocular vision

values values

Statistical Analysis Statistical Analysis

 Statistical analysis was done using a “T” paired test using SPSS

Version Soft are ith the data grouped using the OEP model Version 17 Software with the data grouped using the OEP model:

a)

Habitual phoria for far (#3)

b)

Habitual phoria for near (#13A)

)

I d d h i (#8)

c)

Induced phoria (#8)

d)

True adduction (first blur) (#9)

e)

Convergence (break and recovery) (#10 break and #10 rec)

f)

Abd i (b k d ( b k d )

f)

Abduction (break and recovery (#11 break and #11 rec )

g)

Base out to blur‐out (#16A)

h)

Base out break (#16B/B) ( )

i)

Base out to recovery (#16B/R)

j)

Base in to blur‐out (#17A)

k)

Base in break (#17B/B)

l)

Base in to recovery (#17B/R)

Expectative Expectative

Prueba Morgan (1944ª, Saladin y Sheedy Jackson y Goss (1991) Expectativas OEP (1944 , 1944b) Sheedy (1978) Goss (1991) OEP #3 Habitual phoria far .5 exo #13A Habitual phoria near 6 exo #8 Induced phoria far 1 exo 1 exo 1 exo .5 exo #9 BO blur far 9 15 14 7 a 9 #9 BO, blur far 9 15 14 7 a 9 #10 BO break/recovery 19/10 28/20 23/6 19/10 #11 BI break/recovery 7/4 8/5 12/4 9/5 #12 Vertical phoria far Orto #13 3 3 6 #13B Induced phoria near 3 exo 0.5 exo 3 exo 6 exo #16ª BO blur near 17 22 21 15 #16B BO break/recovery 21/11 30/23 27/10 21/15 #17ª BI blur near 14 14 15 14 #17B BI break/recovery 21/13 19/13 21/9 22/18 #17B BI break/recovery 21/13 19/13 21/9 22/18 #18 Vertical phoria near Orto #19 Amplitud lente negativo 5.00 D #20 (PRA)

• 2.37
• 2.14
• 2.25 a -2.50

#21 (NRA) +2 00 +1 91 +1 75 a #21 (NRA) +2.00 +1.91 +1.75 a +2.00

Final Results Final Results

Test Media Pre Media Post Difference Habitual phoria far

• 0 73
• 0 10

+0 63 Habitual phoria far 0.73 0.10 +0.63 Dist BO Blur (first blur) 17.00 13.00

• 4.00

Dist BO Break 23.87 19.40

• 4.47

Dist BO Recovery 9.0 7.13

• 1.87

Dist BI Break 9.53 8.13

• 1.4

Dist BI Recovery 2.83 2.60

• 0.23

Habitual phoria Near

• 1.33

1.03 +2.36 Near BO Blur 22.80 17.60

• 5.20

Near BO Beak 28.66 22.53

• 6.13

Near BO Recovery 11.80 10.20

• 1.6

Near BI Blur 15.25 12.50

• 2.75

N BI B k 23 46 20 00 3 46 Near BI Break 23.46 20.00

• 3.46

Near BI Recovery 9.26 8.73

• 0.53

Graph G ap

Statystical Statyst ca

Test Media Significance level (p) Habitual phoria far .633 .482 Habitual phoria near 2.3667 .160 BO blur far 4.57143 .176 BO break far 4.667 .147 BO recovery far 1.8667 .244 BI break far 1.4000 .280 BI f 2337 811 BI recovery far .2337 .811 BO blur-out near 5.200 .395 BO break near 6.1333 .059 BO recovery near 1.600 .552 BI blur-out near 2.7500 .378 BI break near 3.4667 .319 b ea ea 3 66 3 9 BI recovery near .5333 .751

RESULTS

 On the basis of the above results, the hypothesis

is rejected. f f

 This means, from an statistic point of view

refractive surgery DOES NOT change binocular vision values vision values

 However…

Discussion

 It is well known that the prescription given to a patient

can alter phoria values. Example: an overcorrection in myopia with exophoria tends to decrease phoria value myopia with exophoria tends to decrease phoria value,

• r even in some cases, change it into esophoria.

 It is also known the most of refractive surgeons tend

It is also known, the most of refractive surgeons tend to overcorrect in myopia cases in order to anticipate future changes increasing in myopia values.

Discussion

 Nevertheless the results shown binocular vision was

i f h h i h i d

Discussion

satisfactory, there were changes in phoria and binocular vision values

 An exophoric myopic patient has never face symptoms  An exophoric myopic patient has never face symptoms

• f esophoria

 Although this is still in analysis , 85% of patients in

Although this is still in analysis , 85% of patients in this study, complained about near vision problems as accommodative asthenopia, fatigue, headache, etc.

Discusion

 We believe all of this is due to the overcorrection of

myopia. U f l f h f i h

 Unfortunately, most of the refractive surgeons have no

knowledge about binocular vision evaluation and treatment procedures treatment procedures.

Discussion

 In regard to convergence and divergence resultant

values, the was a good degree of variability. There were patients who showed minimal modifications against patients who showed minimal modifications against previous values. Some others had better values and

• thers had worse values.

 For us, this results mean the re‐organization that

current in an organism as result of a LASIK procedure

 It is result of the stress imposed on the visual system  Thus, a full binocular evaluation should be done

b f f i before refraction surgery.

Discussion

 There are reports about unstable AC/A ratios after

refractive surgery that get stabilization around 6 to 9 months after (Prakash et al; 2007) months after (Prakash et al; 2007)

 Likewise, visual therapy for patients having

symptomatic BV disorders after Lasik procedure symptomatic BV disorders after Lasik procedure (Faktorovich; 2008)

 Question is: Is the patient prepared to a new

p p p environment for near vision?

Conclusion Conclusion

 Although only one out of 15 patients shown diplopia  Although, only one out of 15 patients shown diplopia

for one day (day after surgery), we believe it is important to test binocular vision status before the i l d i i i d O l ith thi d t th surgical decision is made. Only with this data can the OMD evaluate risks about diplopia after the procedure.

 85% of patients in this study complained about near

vision problems after their surgery.

 It would be desirable for refractive surgeons to lean on  It would be desirable for refractive surgeons to lean on

functional optometry in order to evaluate binocular vision.

C l i Conclusion

E l t l th tt b t ti

 Evaluate properly the matter about overcorrection;

there are some studies proving that myopia increases slightly or not at all after LASIK treatment. s g t y o

• t at a a te

S t eat e t.

 It is necessary to have more similar research in order to

state a predictable model of binocular vision results after surgery.

Gracias

 Special Thanks to:  Dr. Paul Harris for his

i l bl h l i invaluable help in preparing the document

 Robert Williams and  Robert Williams and

OEP for all the support

 Dr. Berenice Velazquez

q for her help in lecture preparation