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Christophe Panthier, Jean Claude Rigal-Sastourné, Corinne Roumes, Pascaline Neveu; Impact of myopic refractive surgery on the accommodative vergence cross coupling. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):3934. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
<br /> Myopic refractive surgery is one of the most performed surgical procedures worldwide. The consequences of this surgery on the oculomotor system balance are poorly known. The purpose of this study was to explore the impact of myopic refractive surgery on the accommodative-vergence cross-coupling.
<br /> This prospective study included suitable patients for refractive surgery, aged from 18 to 36 years and with myopia between -3 to -8 diopters (D) of spherical equivalent. Strabismus, eye diseases or drugs that may interfere with the oculomotor system, were exclusion criteria. Patients were divided into two groups: control or treated. The surgical technique chosen for this study was the bilateral LASIK (Laser Assisted In Situ Keratomileusis) associate with femtolaser corneal flap. Four oculomotor parameters were assessed: tonic vergence (TV), tonic accommodation (TA), accommodative vergence (response AC/A ratio) and vergence accommodation (CA/C ratio). They were assessed before the surgery (J0) and after one (M1) and three months (M3) after surgery. Measurements were conducted using a- haploscope-optometer. A correlation between changes in the parameters and symptoms of visual fatigue was investigated using a questionnaire.
<br /> 40 patients were included in the study (15 in the control group and 25 in the treated group). The mean age of participants was 27.25 ± 4 years. The initial average refractive error was -4.63 ± 1.11 D. There was one lost subject in the treated group. Groups were similar at baseline for all the clinical features and the oculomotor parameters studied. AC/A ratio was higher for eyeglass wearers than among contact lens wearers at J0 (t-test, df = 35, p = 0.04). There was no change of the oculomotor system in the control group between J0, M1 and M3. At M1, the TA increased (F(1, 18)=8.763; p<0.001). The AC/A ratio decreased (F (1, 21)=26.150; p<0.001) one month after surgery. The variation of the AC/A ratio has been correlated with symptoms of asthenopia one month after surgery (R2=0.79; p<0.001).
<br /> Myopic refractive surgery has affected the oculomotor system balance by deleting the ametropia and its correction. Changes were an increase of the TA and a decrease of the AC/A ratio whose intensity was correlated with the appearance of subjective symptoms of visual fatigue. Surgical emmetropization resulted in a transient oculomotor "emmetropization".
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