The Influence of Binocular Refraction on Horizontal Heterophoria
Abdessamad Khaldoun*
*Correspondence to: Abdessamad Khaldoun, Morocco.
Copyright
© 2023 Abdessamad Khaldoun This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Received: 02 January 2024
Published: 10 January 2024
DOI:https://doi.org/10.5281/zenodo.10477383
Abstract
The aim of this study is to investigate the relationship between binocular refraction and its effect on horizontal heterophoria . A total of 11 participants took part in the experiment , where we measured heterophoria measurements using multiple tests to confirm the measurements and gain a deeper understanding of the visual system we examined the changes in heterophoria during monocular refraction , Binocular refraction , And with and without wearing glasess to observe their effects . Our results revealed that participants with horizontal heterophoria displayed differents results between monocular and binocular refraction. In conclusion, Our findings establish a relationship between binocular refraction and horizontal heterophoria.
Introduction
Heterophoria refersto the tendency of the two visual axes of the eyes not to being directed towards the point of fixation in the absence of an adequate stimulus for fusion . Exophoria and esophoria , on the other hand, refer to the outward and inward turning of the eye, respectively from the active position when fusion is suspended .
Fusion and heterophoria are linked to each other .that's why when we wear glasses , the measurement of heterophoria decreases . regardless of the type of optical glass , it affects the clarity and the size of the image,resulting in a lawer value of Heterophoria .The purpose of this study was to investigate the changes in the degree of the heterophoria with binocular refraction and monocular refraction .
Materials and Methods
Design
An analytical, observation, clinical study was conducted at the Institute of optometry and orthoptics in agadir (ISOOA).
The equipment :
-The equipment that we used in the first session included a phoropter , an auto refractometer , and a digital screen for far vision.
-The equipment that we used in the second session is a follows : maddox rod , cover test , horizontal prism bar set , lang fixation cube.
Subjects
The sample was composed of 11 subjects (6 women and 5 men). The participants' mean age was (18-24) years. The selected population comprised students from the Institute of optometry and orthoptics in agadir (ISOOA). All of the subjects had at least 20/20 best-corrected visual acuity and the absence of ocular motility defects, strabismus, nystagmus, amblyopia, or any ocular or systemic disease that could affect the results. Subjects who had undergone some type of ocular surgery ,or anything that can effect the study resultat.
We divided the study into two sessions because we noticed that irrational results appeared due to participants fatigue , so we divided it into two sessions . The first session is in which we do monocular refraction and binocular refraction. In the second session , we take measurements of heterophoria by wearing glasses that contain correction of monocular refraction and the orther glasses that contain correction of binocular refraction.
During the first session, we measure mono refraction , and then we perform bino refraction . And the end of the first session we begin by asking the participants several questions, such as whether you prefer the first or second measurement ( mono-refraction or bino-refraction ), or do you feel headache or dizziness.....
During the second session , we take the measurement of the Horizontal Heterophoria without wearing any glasses by using cover test and then we use maddox rod to study the results well and thoroughly . And then we give them glasses that containing monocular correction and others containing binocular correction, and we repeat the same methode by taking the measurement of cover test and then measurement of maddox rod in both glasses to compare the results and study them in depth .
Results
During the first session , we measure mono refraction and then we perform bino refraction .what we notice that bino refraction gives us a different resultat compared to mono refraction results . And when we asked all the participants whch is batter and which measurement are you most comfortable with they all gave one answer that they were comfortable and preferred the bino refraction correction.
In the second session , we noticed that the deviation of Horizontal Heterophoria decreases when wearing the glasses that containing monocular correction , and it decreases more or disiappers total in some cases when they wear the glasses that containing binocular correction.
Conclusions
The role of binocular refraction is to make the two images that centered on the retina appear the same carity when received by the brain , and thus the process of fusion is done better and not only that , we have understood and noticed that most of the deviations are due to sa defect in fusion . therefore , if we treat the main problem , which is fusion, we can treat most of binocular vision abnormalities.
Not only that , but we discovered that we must completely get rid of monocular refraction correction which many of eye specialists adopt . Instead , we should rely on the binocular refraction correction to give better comfort to the patient and maintain the health of his visual system , especially for those who suffer from a high Heterophoria.