Isocoria with Constricted Pupils

Argyll-Robertson Pupil

Causes: 

The precise location of the lesion is not known; presumably the dis-order is due to a lesion is in the pretectal region and the Edinger-Westphal nucleus such as tabes dorsalis (Argyll-Robertson phenomenon), encephalitis, diffuse encephalitis, syringomyelia, trauma, bleeding, tumors, and alco-holism.

Diagnostic considerations:

❖ Direct and consensual light reflexes are absent.

❖Near reflex is intact or there is overcompensation (the Edinger-Westphal nucleus is being controlled via the convergence center).

❖The pupil is not round, and constriction is not always symmetrical.

❖There is no reaction to darkness or pharmacologic stimuli.

Bilateral Pupillary Constriction due to Pharmacologic Agents

Causes:

❖ Morphine.

❖Deep general anesthesia.

❖ Pilocarpine eyedrops.

Toxic Bilateral Pupillary Constriction

Causes: 

Mushroom poisoning.

Inflammatory Bilateral Pupillary Constriction

Causes:

❖ Encephalitis.

❖ Meningitis.

Comments

Post a Comment

Popular posts from this blog

Developmental Anomalies of the Eye Lens

Image
  Developmental Anomalies of the Lens Anomalies of lens shape are very rare.  Lenticonus  is a circumscribed conical protrusion of the anterior pole (anterior lenticonus) or posterior pole (poste-rior lenticonus). A hemispherical protrusion is referred to as  lentiglobus . Symptoms include myopia and reduced visual acuity. Some patients with Alport’s syndrome (kidney disease accompanied by sensorineural hearing loss and anomalies of lens shape) have  anterior  lenticonus.  Posterior lenti-conus  may be associated with a lens opacity (Fig. 7. 6 ). Treatment is the sameas for congenital or juvenile cataract. Microphakia  refers to a lens of abnormally small diameter. Any interrup-tion of the development of the eye generally leads to microphakia. This can occur for example in Weill-Marchesani syndrome (see Table 7. 5 ).
Read more

Optic Nerve

Image
  Optic Nerve Basic Knowledge The optic nerve extends from the posterior pole of the eye to the  optic chiasm  (Fig. 13. 1 ). After this characteristic crossing, the fibers of the optic nerve travel as the  optic tract  to the  lateral geniculate body.  Depending on the shape of the skull, the optic nerve has a total length of 35 – 55 mm. The nerve consists of: An intraocular portion.  An intraorbital portion.  An intracranial portion.   Intraocular Portion of the Optic Nerve The intraocular portion of the optic nerve is visible on ophthalmoscopy as the  optic disk . All the retinal nerve fibers merge into the optic nerve here, and thecentral retinal vessels enter and leave the eye here. The complete absence of photoreceptors at this site creates a gap in the visual field known as the  blindspot . Shape and size:  The optic disk (Fig. 13. 2 ) is normally slightly vertically oval with an average area of approximately 2.7 mm...
Read more

Curative Corneal Procedures

Image
  Curative Corneal Procedures Penetrating Keratoplasty  (Fig. 5. 18a ) Principle:  This involves replacement of diseased corneal tissue with a full-thickness donor graft of corneal tissue of varying diameter. A clear, regularly refracting button of donor cornea is placed in an opacified or irregularly refracting cornea. The corneal button is sutured with a continuous single or double suture (Fig. 5. 19 ) or with interrupted sutures. (For special considera-tions in corneal transplants, see also Morphology and healing.) Penetrating keratoplasty can be performed as an  elective procedure  to improve visual acuity or as an emergency procedure ( emergency kerato-plasty ). Emergency keratoplasty is indicated to treat a perforated or nonheal-ing corneal ulcer to remove the perforation site and save the eye ( tectonic ker-atoplasty ). Indications:  Corneal diseases that affect the full thickness of the cornealstroma (corneal scars, dystrophy, or degeneration) or pr...
Read more