Non-Strabismic Binocular Vision Abnormalities

Special Article - Optometry

J Ophthalmol & Vis Sci. 2016; 1(1): 1006.

Non-Strabismic Binocular Vision Abnormalities

Chandra P¹* and Akon M²

¹Department of Optometry, University of Buraimi, Oman

²Department of Optometry, Chitakara University, India

*Corresponding author: Pablo Chandra, Department of Optometry, University of Buraimi, Oman

Received: April 27, 2016; Accepted: July 06, 2016; Published: July 07, 2016

Abstract

Non Strabismic Binocular Vision Anomalies are highly significant and prevalent condition among young generation people who spend most of their time in electronic gazette this condition is often associated with headache, eyestrain and blurred vision. These symptoms are often misunderstood with other binocular vision anomalies unless complete binocular and orthoptic examination is done. Proper diagnosis and treatment can be done with vision therapy exercises which improve quality of life of the patient. This article motivates and provides useful information to detect, diagnose and treat these anomalies.

Introduction

Today in our changing environment and working pattern, the near and intermediate visual task have increased dramatically; consisting of work on computer and related gazettes, reading books, watching television. This needs lots of work to our external eye muscles which leads to eye fatigue. These also give rise to number of binocular anomalies in accommodation & convergence. On cursory examination, we may diagnose it as “computer vision syndrome” [1,2] but on a careful examination, we may realize patient is having other non-strabismic vergence anomalies. Failing to diagnose & treat these symptoms & signs give rise to strabismic problem [3]. In this article we will discuss about various Non-strabismus binocular vision abnormalities and its diagnosis and management. We will enumerate a case which will tell us how orthoptic work up help us in diagnosis a latent squint and how eye exercise help us to overcome this problem of the patient.

A 22 year old male patient came to the Binocular vision department of Hospital with a complaint of intermittent squinting of eyes (eyes deviating outward). He was a software engineer with near and intermittent work on computer and related gazettes for 12- 14 hours a day. He did not have any other subjective complain of asthenopia. On evaluation his refractive error was found to be -1.50 Dsph in the right eye and -1.50 Dsph /-0.50 Dcyl 50 in the left eye which was confirmed with cyloplegic refraction and his best corrected visual acuity was found to be 6/6 on both eyes with N6 vision for his near. On cover -uncover test he did not have any obvious tropia but alternate cover test showed exophoria.

On Binocular Vision evaluation his sensory status was found well within normal limits as his fusion was present on worth four dot test and steropsis was found to be 40 secs of arcs on titmus fly test. His near point of accommodation was found to be within the normal limits checking with RAF rule. His near point of convergence was found to be till tip of the nose on checking on ten occasions with RAF rule.

His phoria value was 10 prism diopter base in for distance and 9 prism diopter base in for near. His Accommodative Convergence/ Accommodation values (AC/A) was 4:1 checked by gradient method. His accommodation amplitude was checked by minus lens method and was -10.00 Dsph unioccularly and was confirmed by push up method test. His accommodative dynamic was also checked by accommodative facility and was 14 cycles per minute and his accommodative response which was check by Monocular Estimation Method (MEM) was +0.75 Dsph. His Negative Relative Accommodation (NRA) and Positive Relative Accommodation (PRA) values were +4.50 Dsph & -6.50 Dsph. His Positive Fusional Vergence (PFV) was 10 prism diopters blurs, 15 prism diopters break & 16 prism diopter recovery for distance. For near his, Positive Fusional Vergence (PFV) was 15 prism diopter blur, 20 diopter break, 20 prism recovery. His Negative Fusional Vergence (NFV) was 6 prism diopters blur for distance, 10 prism diopter break, 8 prism diopter for recovery. For near, his Negative Fusional Vergence (NFV) was 10 prism diopter blur, 14 prism diopter break, 12 prism diopter recovery.

This Binocular findings were compared to those with Morgan table of expected values & optometric extension program values [4,5]. Based on our findings, we diagnosed him as “high exophoria for distance and near with reduced positive fusional vergence”.

The patient was called for exercise and his exercise was planned in three different phase. Phase 1, he was given exercise with brock string and cat card in the orthoptic department to increase his voluntary convergence. In Phase 2 of the exercise, the exercise of phase 1 was given as home exercise and variable tranaglyphs to increase his Positive Fusional Vergence (PFV) with voluntary convergence. In the Phase 3 patient was given eccentric circles with variable tranaglyphs to increase his positive fusional vergence for near.

After 2 weeks of phase I exercise, the patient was reevaluated and his phoria values decreased from 10 prism diopter to 7 prism diopter and his Positive Fusional Vergence (PFV) increased from 20 prism diopter break to 25 prism diopter break and his accommodative remains the same which was within the normal limits.

In Phase 2 of the exercise, the phase 1 exercise was given as home exercise and variable tranaglyphs to increase his positive fusional vergence with voluntary convergence which will decrease his squinting of eyes and increase his binocular vision. In the Phase 3 patient was given eccentric circles with variable tranaglyphs to increase his Positive Fusional Vergence (PFV) for near as it was not decreasing for near. Patient was evaluated for orthoptic values after completing his exercises and he was orthophoric for distant and near.

This case shows problem of our current life style, its problem on the eye and more importantly appropriate work up and its management.

We will briefly describe various binocular vision problems and its management.

According to the wick [6,7] there is a nine possible classification of binocular vision problem based on AC/A ratio. The three categories are low AC/A ratio, high AC/A ratio, normal AC/A ratio, within which three subdivision are found (Table 1).

Citation: Chandra P and Akon M. Non-Strabismic Binocular Vision Abnormalities. J Ophthalmol & Vis Sci. 2016; 1(1): 1006.