In young persons, the cortical layer of the vitreous body is in close contact with the internal limiting membrane of the retina. In advanced age, the vitreous body collapses. The gel, which contains hyaluronic acid, gradually liquefies. The collagen framework of the vitreous stroma condenses and forms prominent vitreous strands. Patients often perceive fine punctate figures that appear to dance in front of a bright background. They are known as floaters. They are attributable to small vitreous densities that often go undetected by slit lamp biomicroscopy (see also p. 171).

Treatment: none.

Unilateral Visual Impairment in Children-Amblyopia

This decrease in visual acuity occurs in childhood in unilateral concomitant strabismus. It is due to chronic suppression of images perceived with the fovea of the deviating eye (strabismic amblyopia), as a sensory adaptation of the visual system to the strabismic deviation. This means the disorder is a developmental anomaly of the central nervous system. Strabismic amblyopia can vary greatly in its severity. Congenital strabismus or strabismus in early childhood is often associated with severely impaired vision of the strabismic eye, and often patients are only able to perceive hand motions. However, one encounters the full spectrum of reduced visual acuity. The amblyopia may be so slight that it only becomes apparent when the patient slowly and haltingly reads rows of numbers during visual acuity testing.

This sort of amblyopia due to functional impairments is reversible with early treatment, provided the development of the central nervous system is not yet complete.

The fundus in sensory strabismus is completely normal. However, in a few cases of strabismus organic changes in the macula or optic nerve are found. In these cases, the reduced visual acuity is caused by the disease in the fundus, and strabismus is a secondary disorder. To rule out fundus disease in strabismic patients, careful examination is required, before initiating the classic occlusion therapy for strabismus.

Organic causes of childhood amblyopia that involve the fundus:

Retrobulbar Optic Neuritis

The diagnostic situation in retrobulbar optic neuritis is best summed up by the catchphrase: “The patient doesn’t see anything, and neither does the doctor.” The optic disc initially appears perfectly normal. At the onset of retrobulbar optic neuritis, the functional impairments are the most striking features of the disorder. They also play a crucial role in the diagnostic workup. The temporal pallor indicative of incipient, partial atrophy only appears after six to eight weeks.

Fig. 7.1 Temporal pallor of the optic disc in a 27-year-old-man indicative of partial optic nerve atrophy secondary to retrobulbar optic neuritis.

Fig. 7.2 Retrobulbar optic neuritis in the left eye. VECP (above) in the right eye (R) shows normal latencies and amplitudes, whereas in the left eye (L) the latency in the VECP is prolonged and the amplitude reduced. Below: normal pattern ERG.