**12. Pediatric eye deviations**

Under normal physiological conditions, the image of an object falls simultaneously on the fovea of each. This is possible if the eyes are properly aligned. This straight position of the eyes is called orthophoria. Any misalignment of the either eye is called strabismus or eye deviation in other words. There are 2 benefits of treating strabismus. The initial one is functional gain including the improvement of visual acuity and stereopsis. The second one is the cosmetic improvement.

#### **12.1 Types of eye deviations**

Tropia defines manifest deviation of eyes and phoria implies latent deviation. Phoria is detected by the simple cover-uncover test. The test is performed while the patient fixates a distant object. The physician covers one eye for 2-3 seconds and then the other eye. If orthophoria is present, no movement is detected. If latent deviation exists movement of eyes towards the opposite of the deviation is observed. For example in a patient with inward latent deviation, the uncovered eye move from inwards to outwards. Latent deviations may become manifest temporarily, when the child is tired or ill. It can also become permanently manifest during the follow-up.

Horizontal deviations are the most commonly observed types of strabismus. Esotropia is the manifest inward deviation of eyes, while esophoria is the latent inward deviation of eyes. Exotropia is the manifest outward deviation of eyes, while exophoria is the latent outward deviation of eyes. Esotropia is by far the most common form of strabismus. Infantile esotropia constitutes almost half of all cases of esotropia. Infantile esotropia is the inward deviation of eyes, which is diagnosed at 6 months of age. The angle of deviation is usually large and surgery is usually indicated. Pseudo-strabismus is the illusion of deviation in a child with orthophoria. It is most commonly in the form of pseudo-esotropia. The most common reason for this false appearance of inward deviation is broad nasal bridge with prominent epicanthal folds. This appearance usually resolves spontaneously and requires no treatment (Fredrick, & Asbury, 2004).

Paralytic strabismus in children may be in form of third, fourth or sixth cranial nerve palsy.

Pediatric Ophthalmology / Eye and Disorders 17

Chalazion (Chronic inflammation of the meibomian glands), blepharitis (effects base of the eyelashes) and acute infection of the eye lash follicle (stye) are very frequent infections of the eyelids in children. The infections are mostly innocent and respond well to conservative

The bacterial infections of the soft tissue anterior or posterior to the orbital septum are the most common diseases of the orbit in the pediatric age group. The infections occur in two clinical forms; preseptal cellulitis or orbital cellulitis. Orbital cellulitis is the most common cause of protrusion of the eyeball in children. It is a life-threatening disease of the tissues behind the orbital septum. On the other hand, preseptal cellulits involves tissues anterior to the orbital septum. Preseptal cellulitis usually responds to ampiric antibiotic treatment, whereas orbital cellulitis may be associated with serious complications requiring longer

Protrusion of the eyeball, limitations of the eye movements and decreased visual acuity are signs of orbital cellulitis. Skin trauma, sinusitis, lacrimal sac infections and rarely remote infections may be the source of preseptal or orbital cellulitis. Preseptal cellulitis rarely

Subperiosteal and orbital abscesses, intracranial complications (meningitis, brain abscess) and ocular complications such as optic neuropathy and endophthalmitis may complicate orbital cellulitis. Hospitalization and aggressive medical treatment to prevent lifethreatening complications is indicated in orbital cellulitis (Sullivan, 2004). Any painful periorbital edema or pain associated with eye movements should raise the suspicion of

Ophthalmia neonataurum means, conjunctivitis occurring in the first month of life. It is still a significant cause of blindness in underdeveloped countries. It can be bacterial, viral and chemical. The most serious form is caused by *Neisseria gonorrhoeae*. Onset is typically within the first 3-4 days of life. It causes a severe purulent discharge. Treatment includes systemic

serious orbital cellulitis and referral to an ophthalmologist is indicated.

periods of treatment and surgical interventions (Kanski, 2011).

therapies (Hughes, 2000).

**13.1 Orbital infections** 

progresses to orbital cellulitis.

Fig. 6. Left orbital cellulitis

**14. Conjunctival diseases in children** 

**14.1 Ophthalmia neonatarum** 

The most common one is the sixth cranial nerve palsy (abducens palsy), which is characterized by loss of abduction. Cranial imaging must be ordered in all forms of acquired paralytic strabismus to exclude cranial masses (Harley, 1980).

The angle of deviation in eyes with all types of deviations is measured objectively by using special prisms. The prism cover test is preferred if the child cooperates. In severe amblyopia and in very young children prism reflex test (Krimsky test) is performed. The patient fixates a light and the prism is placed in front of the deviating or bad eye to center the corneal reflex.
