Oculomotor Dysfunction - Causes, Diagnosis, and Treatment

Introduction:

In oculomotor dysfunction (OMD), specific visual skill deficiency occurs, including eyeball fixation and saccadic and pursuit eye movements. Due to dysfunction, reading efficiency decreases, and reading comprehension ability also decreases. 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 decreases because of developmental delay or some adverse neurologic event. Many aspects of daily life are affected by 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 - The ability of the eye to jump from one spot to another spot accurately.

What Is the Cause of Oculomotor Dysfunction?

Six extraocular muscles are present in the eye. 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 vessels 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 (human immunodeficiency virus) and Lyme disease (a bacterial infection caused by the bite of black-legged ticks).

• Migraine (headache type).

What Are the Symptoms of OMD?

Individuals suffering from oculomotor dysfunction find difficulty in eye movement. So, patients face eye problems. This results in several issues. 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 (learning disability in writing and reading). Because there are lots of similarities in symptoms of OMD. However, in OMD, there is an anomaly in the eye's visual system.

• Comprehensive Examination: 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.

• Visual Acuity Test: The test is performed to check the vision sharpness at various distances.

• Eye Movement Examination: For the oculomotor system, various aspects, such as fixations, pursuits (checks the ability to smoothly follow a moving target), and saccades (the ability of the eye to quickly shift from one target to another), should be evaluated carefully.

• Binocular Vision Assessment: The convergence and divergence test measures the ability to align both eyes on near and distant objects.

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 the visual muscles. It improves saccadic and pursuit eye movements and can improve information processing skills.

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 to strengthen each eye. 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.

• Rotatory Peg Board Exercise: This exercise is performed to improve pursuit movement. In this monocular activity is done. 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. The eye specialist should track eye movement for track improvement.

• 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.

• 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 (brain's ability to interpret information that is seen through the eyes).

• Eye-hand coordination development (hand-eye coordination develops as the child grows and is required for performing daily activities, such as grasping and manipulating).

• Binocular vision therapy (physical therapy for the eyes to improve vision issues).

• Visual imagery therapy (by creating images, the person can reduce pain and other symptoms associated with the condition).

• Visual-motor integration development (the ability to correctly perceive visual information).

Conclusion:

After treatment, patients' visible improvements include improved reading speed, fluency, attention, and concentration power. Motion sickness is reduced, and visual-spatial awareness increases. Eye-hand coordination is also improved. If the child is facing any issues in reading, writing, head movement, or vision, they should contact an eye specialist for personalized treatment.