Oculomotor Dysfunction - Causes, Diagnosis, and Treatment

Introduction

In oculomotor dysfunction (OMD), deficiency of specific visual skills occurs, including fixation of the eyeball and saccadic and pursuit eye movements. Due to dysfunction, reading efficiency decreases, and reading comprehension ability is also limited or decreased. OMD is also known as ocular motility dysfunction or eye tracking problem. In OMD, the brain's ability to coordinate the eye movement to follow, fixate and move the eye from one spot to another decrease because of developmental delay or some adverse neurologic event. Many aspects of daily life are affected due to OMD, such as attention, reading, handwriting, and performance in athletics.

Explanation of some terms:

• Fixation – On target objects, maintain steady directing vision.

• Smooth Pursuits – Eye ability to follow a moving object steadily.

• Saccades – Jumping ability of the eye from one spot to another spot accurately.

What Is the Cause of Oculomotor Dysfunction?

In the eye, there is the presence of six extraocular muscles. These muscles are coordinated together for proper and accurate eye movement. When coordination between these muscles is affected, several visual changes and problems can occur.

The following conditions may lead to oculomotor dysfunction:

• Certain brain tumors.

• A brain aneurysm (weakness in the blood vessel in the brain).

• Previous head injuries.

• Multiple sclerosis (a disease in which the covering of the nerve is removed).

• Some microvascular diseases, such as diabetes and high blood pressure.

• Infections such as HIV and Lyme disease.

• Migraine.

What Are the Symptoms of OMD?

Individuals suffering from oculomotor dysfunction find difficulty in the movement of their eyes. So patients face eye problems. This results in a plethora of issues in this regard. Individuals who have oculomotor dysfunction often have symptoms such as:

• Movement of the head while reading.

• Skip lines or lose words quickly during reading.

• Decrease the speed of reading.

• Decreased reading comprehension.

• Difficulty copying any information (from a book or a blackboard in the classroom, etc.).

• Athletic abilities become poor because the patient's tracking ability decreases.

• Depth perception becomes poor.

• Headaches become frequent.

• Regular eye fatigue and strain.

• Pain in the eye or tense feeling during close work.

• The patient starts to whisper during silent reading.

• Writing becomes poorly spaced or crooked.

• A closer look at the objects tires the patient.

• The patient begins forgetting numbers, letters, or words.

• Feels confused by similar terms.

• Completion of assignments in the allotted time becomes difficult.

• Visual motor coordination becomes poor.

• Confusion on the right and left appears.

• Difficulty following sequence of directions.

What Is the Diagnosis of Oculomotor Dysfunction?

OMD is a type of condition that can improve by itself if left untreated. Patients start to rely on compensatory mechanisms. These include fingers used as markers for reading, and patients start head tilting while reading. Diagnosis in children with OMD is often misdiagnosed with dyslexia. Because in OMD, there are lots of similarities in symptoms. But in OMD, there is an anomaly in the eye's visual system.

For diagnosis of oculomotor dysfunction, a comprehensive eye exam should be made that should include a binocular vision examination to help identify and diagnose the condition. Diagnosis of oculomotor dysfunction generally includes various tests, which are sometimes very tricky to detect. Sometimes, it can be misdiagnosed.

So specialized neuro-optometrists or some specialists in binocular vision disorders are required to make the correct diagnosis and treatment.

For the oculomotor system, various aspects, such as fixations, pursuits, and saccades, should be evaluated carefully.

What Is the Treatment for Oculomotor Dysfunction?

A form of vision therapy used in OMD treatment involves specific neuro-optometry activity that improves eye problems such as fixation. It can strengthen your visual muscles. It improves saccadic and pursuit eye movements and can improve information processing skills also.

Other treatments include lenses, prisms, and special tints for symptomatic relief. The duration of therapy varies depending on the patient's complexity. After that, regular follow-up is done. If vision therapy is the next step to relieve symptoms due to oculomotor dysfunction, these exercises should be done.

Hart Chart Saccades Exercise: Saccadic eye movement efficiency and accuracy can be improved through this exercise. Individual eyes are treated separately before being trained together so that each eye can strengthen together. This exercise uses a particular eye chart called the hart chart. It should be held five feet away from the patient. First, tell the patient to read the top row, then jump to the last row of the chart. Repeat the same until the patient can read the complete set within 15 seconds without error.

1. Rotatory Peg Board Exercise: This exercise is performed to improve pursuit movement. In this also, monocular activity is done. In this, on a large rotary board, there are several holes. Tell the patient to hold the golf stick and push the golf tee in one of the holes of the rotating board. Activity is repeated with alternating eyes. Track eye movement also to track improvement.

2. Symbol Tracking: This is similar to tasks used in school. To the patient, a worksheet is given on which some numbers, letters, or characters are present on top. On the rest of the sheet, a paragraph is written in which a similar sequence is present. Ask the patient to look at the whole sheet from right to left and top to bottom. The patient is then asked to scan from right to left and make a circle in a sequence similar to the top of the sheet.

3. Visual Tracing: It is a “connect the line” worksheet. Difficulty ranges from easy to difficult. The patient is told to follow the line from the start to the end point through the eyes and suggest where the line ends. Fingers cannot be used.

In some cases, advanced treatment given includes:

• Visual processing development.

• Eye-hand coordination development.

• Binocular vision therapy.

• Visual imagery therapy.

• Visual-motor integration development.

• Visual-vestibular integration development.

Conclusion

After treatment, an improvement that is visible in patients includes that there is improvement in reading speed. The fluency of patients is improved. Attention and concentration power is restored. Reduction of motion sickness and visual-spatial awareness increases. Eye-hand coordination is also improved.