The Differential of Decrease in Vision
By Mays Dairi, MD

PAINFUL DECREASE IN VISION

Painful Red Eye

Keratitis:

Bacterial ulcer (contact lens wearer), Herpes simplex ophthalmicus
Symptoms: foreign body sensation, epiphora, purulent discharge,
Exam: corneal epithelial defect, uptake by fluorescein
Management: gram stain, culture, and antibiotics or antivirals  (for herpes)

Acute angle closure glaucoma

Risk factors: narrow anterior chamber, hyperopia, Eskimos and Asians
Symptoms: very painful red eye, haloes around light (due to corneal edema), nausea, vomiting
Exam: Fixed mid-dialated pupil, high intraocular pressure (>45), narrow anterior chamber, dialated conjunctival, episcleral and iris vessels, might see glaucomafleckens (not seen acutely, but if seen, indicate a previous episode of angle closure).
Management: miotics, carbonic anhydrase inhibitors, mannitol, laser iridotomy

Uveitis (see the Red Eye chapter)

Risk factors: reiter's, ankylosing spondylitis, collagen vascular disease, sarcoidosis, granulomatous infections, juvenile rheumatoid arthritis, syphilis
Symptoms: red eye, decreased vision (variable), tearing, photophobia
PE:keratic precipitates, cells in the anterior chamber, iris nodules, hypopyon
Management: rheumatological and infectious work up, topical steroids and cycloplegics for mild cases, oral steroids and immune suppressants if severe.

Non Red Eye

Optic neuritis

Risk factors: multiple sclerosis, syphilis, sarcoidosis, lyme disease, collagen vascular disease (SLE, Wegener's)
Symptoms: pain around the eye, exacerbated by eye movement, subacute visual deterioration, a decrease in contrast sensitivity, color vision and visual field defect (central scotoma)
Exam: decreased contrast sensitivity, relative APD if unilateral
Management: rheumatologic work up, IV steroids

PAINLESS DECREASE IN VISION

Sudden decrease in vision

Retinal detachment

Risk factors: high myopia, glaucoma, family history, previous surgery, and trauma
Symptoms: flashing lights (photopsia), floaters, and shadow across visual field
Signs on Exam: APD, retinal folds
Treatment: pneumatic retinopexy, scleral buckle, pars plana vitrectomy

Retinal vascular disease

Amaurosis fugax

Unilateral tansient visual loss
Cholesterol and/or fibrin platelet emboli
Exam: may be normal, may show Hollen-Horst plaques
Management: evaluate for cardiac or carotid disease. Aspirin therapy

Retinal Artery occlusion

Symptoms: sudden loss of vision in the visual field that corresponds to the territory of the obstructed artery

Branch retinal artery occlusion:
      90 % are due to emboli, cardiac or carotid in origin.
Exam: ischemic whitening of the retina in the territory of the obstructed artery, retinal arteries distal to the blockage are attenuated, might see embolic material

Central retinal artery occlusion
      In central retinal artery obstruction, the blockage is within the optic nerve itself and the site of obstruction could not visualized.  It is believed however that most cases are due to thrombus formation. It could also be due to extrinsic nerve compression due to orbital or optic nerve tumors, inflammation or trauma.
Exam: cherry red spot in the macular area
Management: There is no proven treatment for retinal artery occlusion.  If caught within 72 hours trials of dislodging the emboli (by massaging, paracentesis, and lowering the intraocular pressure), or thrombus dissolution, or increasing oxygenation to the retina, have been tried.

Retinal vein occlusion

Risk factors: hypertension, diabetes mellitus, and hyperviscosity syndromes
Symptoms: rapid unilateral painless loss of vision
Exam: dilated tortuous veins, cotton wool spots, and retinal hemorrhages
Management: panretinal photocoagulation for neovascularization

Cataract

Acute metabolic changes or trauma can cause a cataract

Neurologic disease

Lesion involving the neuronal visual pathways: optic tract, chiasm, Lateral geniculate nucleus, cortex
Symptoms: painless decrease in the visual field
Exam: ophthalmologic exam is usually normal, might find some associated neurologic findings
Management: LP, CT, MRI and manage accordingly
 

Arteritic Ischemic optic neuropathy

Weight loss, anorexia, fever, jaw claudications, headache, scalp tenderness, proximal joint and muscle pain
Exam: altitudinal visual field defects, pale swollen optic nerve
High ESR
Management: start high dose steroids therapy, schedule for a temporal artery biopsy within a few days (pathology results are the same up till 1 week after treatment)
 

Gradual decrease in vision

Cataract

Risk factors: trauma, metabolic disease (diabetes, some inborn errors of metabolism), medications, old age
Symptoms: painless decrease in vision, myopic shift, glares
Exam: lens opacity
Management: surgical extraction and replacement with an intraocular lens

Open Angle Glaucoma

Risk factors: elevated intraocular pressure, genetic predisposition, African origin, myopia, exfoliation syndrome, pigment dispersion syndrome, history of trauma to the eye, severe anemia...
Symptoms: patients don’t notice the damage until late in the disease where by they notice a decrease in the peripheral visual field
Exam: high intraocular pressure, large cup to disc ratio, visual filed defect
Management: decrease intraocular pressure by medications (beta blockers, prostagandins, adrenergics, carbonic anhydrase inhibitors, hyperosmotic agents, miotics), and surgery in refractive cases.

Retinopathies

Diabetic Retinopathy, hereditary retinopathies, Age-related Macular Degeneration.
Risk factors: endocrine disease, genetic factors, old age, medications...
Management: prevention is the key term, the only thing current management does is prevent the progression of the disease.

Corneal Dystrophies and Ectasias

Hereditary, non-inflammatory, commonly progressive changes in the cornea interfering with clarity of vision
Risk factors: family history
Symptoms: progressive refractive error, recurrent erosions
Exam: changes in the corneal clarity (dystrophy), or change in the curvature (ectasia)
Management: spectacle correction, penetrating keratoplasty

Non-Arteritic Ischemic Optic Neuropathy

No systemic symptoms, associated with cardivascular disease, diabetes and hypertension
Normal ESR (see retinal artery occlusion)