15. Ophthalmology




“Cataract is an easily treatable condition, but, unfortunately, it is the most common cause of blindness in the world because of decreased availability of healthcare. In developed countries, the three leading causes of blindness are glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy.”



15.1 Eye Infections



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15.1.1 Conjunctivitis



Etiology



  • • Infectious—viruses, bacteria, fungi, and parasites (amoeba)



  • Noninfectious—allergic or chemical conjunctivitis



Physical examination

Red conjunctiva (conjunctival injection) plus discharge.



1 Conjunctivitis alone does not cause visual impairment. Presence of decreased visual acuity in a patient with apparent conjunctivitis indicates involvement of cornea (keratoconjunctivitis).











































Viral


Bacterial


Allergic


Clues


Flu-like symptoms may be present

Other sites may also be infected (e.g., coexistent otitis media)

Coexistent allergic rhinitis, atopic dermatitis, asthma, etc.


Discharge


Mostly clear, but can be yellow

Mucopurulent discharge (yellow to white)

Watery, clear discharge (never mucopurulent)


Laterality


Unilateral or bilateral

Almost always bilateral


Managementa


Supportive:




  • Use combination of topical antihistamine plus vasoconstrictor-decongestant (e.g., naphazoline + pheniramine)



  • Use warm or cold compresses, as needed

Topical antibiotic options are:




  • macrolides (erythromycin, azithromycin, etc.)



  • trimethoprim + polymyxin



  • bacitracin + polymyxin



  • sulfacetamide, etc.b


Acute (< 2-week duration):
Use combination of topical antihistamine plus vasoconstrictor-decongestant eye drop (e.g., naphazoline + pheniramine)
Frequent episodes (> 2 days/ month) or lasting longer than 2 weeks:
Use topical antihistamine with mast cell stabilizing properties (Ketotifen, epinastine, azelastine, olopatadine, alcaftadine, etc.)c


aDrops are generally preferred in adults, as ointments may blur vision. Ointments are preferred in children and noncompliant patients, as they typically remain in contact longer.


bUse quinolone eye drops to cover pseudomonas in patients using contact lenses (e.g., ofloxacin, ciprofloxacin). It is very important to rule out keratitis in such patients.


cOral antihistamines can worsen dry eyes and should be avoided.



Conjunctivitis in newborns






























Etiology


Usual time of appearance


Rx


Chemical conjunctivitis (reaction to silver nitrate eye drops)a


Within the first 24 hours

Symptomatic treatment with eye lubricants as needed


Gonococcal conjunctivitis


1-5 days

Single dose of intramuscular ceftriaxoneb


Chlamydial conjunctivitis


> 5 days

Oral erythromycinb


aAll newborn babies routinely get erythromycin ointment (or silver nitrate) within the first few hours of birth to prevent gonococcal conjunctivitis.


bTopical treatment is not necessary when systemic is given. One can use saline irrigation until the discharge clears up.



Trachoma

Microbial cause: certain subtypes of Chlamydia Trachomatis, which is the bacteria commonly known to cause sexually transmitted infections


Background: it is easily treatable with run-of-the-mill antibiotics, but unfortunately it is one of the leading causes of preventable blindness in developing countries, due to decreased availability of health care.


Disease features: persistent follicular conjunctivitis (usually accompanied by nasal discharge) followed by corneal neovascularization and opacification.


Rx: single-dose oral azithromycin or topical tetracycline.



15.1.2 Corneal Injury



Etiology

Infectious keratitis, ulcer, abrasion, foreign body, direct trauma, etc.



Common Presentation to All Forms of Corneal Injury





















Eye pain (may be severe) and foreign body sensation in the cornea


Miosis


In corneal injury, sensory trigeminal nerve gets irritated, which initiates a miotic reaction


Photophobia




  • Exposure to light dilates irritated miotic pupil, which results in pain and photophobia



  • Cycloplegics (M blockers such as atropine, homatropine, and scopolamine) help alleviate the pain by paralyzing pupillary muscle


Blurred vision


Corneal involvement will result in vision abnormalities


Reactive conjunctival injection


Red conjunctiva



Eye Examination



  • Start with the gross penlight examination first.



  • The next step is a full eye examination. If a patient is uncomfortable or uncooperative, a topical anesthetic like tetracaine can be used to perform the examination.



    2 Use topical anesthetic only when necessary, as its use have been associated with local complications.




  • Full eye examination includes visual acuity test and fundoscopic examination, followed by fluorescein dye examination (this dye stains only the exposed basement membrane of the cornea).



    3 Early dye examination can interfere with visual acuity and fundoscopic examination; hence it is done at the end.

    Use Wood’s lamp (or slit lamp + cobalt-blue filter or ophthalmoscope + cobalt-blue filter) for better visualization.









































Etiology of corneal injury


Additional information


Management (urgent ophthalmologic referral is recommended)

Corneal abrasion, ulcer, or presence of foreign body


Can occur as a result of blast injury or abrasion in contact lens wearers


  • Foreign body removal, if present



  • Topical antibiotic to prevent secondary infection. For contact lens-related abrasions, give topical antibiotics that are effective against pseudomonas (e.g., moxifloxacin, ciprofloxacin)



  • Large abrasions and ulcers may require cycloplegics and an eye patch


Bacterial keratitis


Contact lens is the most common risk factor
Examination: red eye + round white spot in cornea (corneal infiltrate)

Do Gram stain and culture of corneal scrapings before initiating topical antibiotics (e.g., topical quinolones)


Amebic keratitis




  • Occurs in contact lens wearers



  • Causative organism is Acanthamoeba


Staining of corneal scraping can reveal the organism
Rx: antiprotozoal eye drops


HSV keratitis


This can be recurrent (akin to recurrent herpes labialis). Episodes can cause corneal scarring, opacification and corneal blindness.
Examination: vesicles can be seen. Fluorescein staining can reveal dendritic ulcers.

Rx: oral and topical acyclovir or valacyclovir. Chronic suppressive therapy may be indicated in patients with recurrent episodes


Epidemic adenoviral keratoconjunctivitis


Membranes and pseudomembranes can occur


  • Self-limiting disease



  • Supportive treatment


Fungal keratitis




  • Causative organism is Fusarium spp.



  • This typically occurs after a corneal injury involving plant material (e.g., palm branch hitting the eye); hence, it is more likely to occur in agricultural workers



  • Can also occur in contact lens wearers

Use topical voriconazole or natamycin. In immunocompromised patients or severe infections, add systemic voriconazole.

Abbreviation: HSV, herpes simplex virus.



Keratoconjunctivitis Sicca (Dry Eye Disease)

Risk factors: advanced age, lacrimal gland inflammation associated with autoimmune syndrome (Sjögren syndrome, systemic lupus erythematosus, rheumatoid arthritis, etc.).


Pathophysiology: decreased lubricating effect of tears may lead to conjunctival and corneal irritation, with subsequent development of conjunctival injection, sensation of foreign body in eye, and mild photophobia. Complications may include corneal abrasion, scar, and corneal blindness.


Rx: use artificial tears. For refractory ocular Sjogren’s syndrome, use topical immunosuppressive (e.g., cyclosporine).



15.1.3 Uveitis














































Definition


Anterior uveitis: inflammation limited to iris and ciliary body (iridocyclitis)— mostly anterior chamber
Posterior uveitis: inflammation of the choroid (choroiditis) and other adjacent structures (commonly involved structures are retina and/or optic nerve head)
Panuveitis: anterior + posterior uveitis


Type


Granulomatous


Nongranulomatous


Differentiating feature (slit-lamp examination)




  • Large and greasy-looking keratic precipitatesa



  • Presence of iris nodules

No iris nodules


Etiologyb


It can be a part of systemic granulomatous disease, such as Lyme disease, tuberculosis, syphilis, or autoimmune (sarcoidosis)

Associated with autoimmune conditions related to HLA-B27 (e.g., seronegative spondyloarthropathy, ulcerative colitis)


Presentation




  • Anterior uveitis: eye pain, photophobia, miosis, and conjunctival injection (presentation is similar to corneal injury)



  • Posterior uveitis: floaters and/or visual impairment (in contrast to anterior uveitis, it is less likely to have red eye or eye pain)


Work up




  • NSiM is immediate referral to ophthalmologist for slit-lamp and fundoscopic examination



  • Anterior uveitis: pus or leukocytes in the anterior chamber (hypopyon) makes the dx of uveitis and differentiates it from keratitis



  • Posterior uveitis: direct visualization of choroiditis + leukocytes in vitreous humor


Management


Infectious cause: treatment is directed against underlying microbial cause


Noninfectious uveitis:




  • Anterior uveitis—topical steroidsc



  • Posterior uveitis or panuveitis—observation (in mild cases), or periocular and/or sometimes intraocular steroidsd


For refractory cases, give oral steroids


Use cycloplegics for severe pain

aKeratic precipitates are clusters of inflammatory cellular deposit on cornea, seen as white spots when examined with a slit lamp.



4 Slit-lamp view of anterior granulomatous uveitis in sarcoidosis, showing “mutton fat” granulomatous keratic precipitates.



bPatients with Crohn disease (granulomatous inflammation of colon) can have both granulomatous and nongranulomatous uveitis.


cTopical steroids should only be prescribed by ophthalmologists, as they can be associated with significant local side effects.


dTopical steroids do not reach posterior portions of uvea; hence they are not helpful. Abbreviation: HLA, human leukocyte antigen.



15.2 Severe Eye Infection


Risk factor: Patients with high-grade immunosuppression (HIV with low CD4 count, immunosuppressive therapy, organ transplant recipients) may develop eye infection that progresses faster or have higher risk of complications.







































Features


Diagnosis


Managementa




  • Immunosuppression + features of only retinitis (e.g., floaters,b photopsia,c visual impairment)



  • Patients may or may not have symptoms of other organ involvement (e.g., pneumonitis, diarrhea)

CMV retinitis (This usually doesn’t have conjunctivitis or keratitis).




  • In HIV patients, it occurs with CD4 count of < 50 cells/μL

If sight threatening infection—use intravitreal ganciclovir or foscarnet + systemic oral valganciclovir.
If non-sight threatening infection—use oral valganciclovir (preferred).


Immunosuppression + features of retinitis + features of encephalitis (e.g. changes in the personality, altered mental status)

Toxoplasmosis




  • In HIV patients, it occurs with CD4 count of < 100 cells/uL

Oral pyrimethamine + sulfadiazine (with folinic acid)


Infection of all internal eye structures (scleritis, choroiditis, uveitis and retinitis) including infection of vitreous and aqueous humor

Endophthalmitis
Etiology:




  • Fungal or bacterial infection due to:




    • Complication of eye surgery, intravitreal injection, penetrating eye trauma, keratitis, etc.



    • Blood-borne microbial seeding into the eye from systemic infection (e.g., from candidemia).



  • Virus (e.g., HSV, CMV) can do it but it is very rare.

Systemic and intravitreal antimicrobial treatment, directed against underlying pathogen


Hx of progression in the following manner: conjunctivitis and keratitis → uveitis→ scleritis → retinitis and acute retinal necrosis → Endophthalmitis—infection of all internal eye structures (scleritis, choroiditis, uveitis, and retinitis)




  • Fluorescein examination may reveal dendritic ulcers and vesicles.

Does the patient have vesicular rash in the distribution of ophthalmic branch of trigeminal nerve?




  • If yes, then dx is Herpes zoster ophthalmicus.



  • If no, then think of herpes simplex keratitis.




  • Topical and oral acyclovir or valacyclovir.



  • In herpes zoster ophthalmicus, consider varicella-zoster immunoglobulin.

aSpecific intravitreal therapy can be considered in all cases of severe or sight threatening infections.


bDebris in vitreous humor are seen as floaters.


cIrritation of retina can result in abrupt firing of retinal nerve cells causing photopsia (seeing flashes of light). This irritation can be due to vitreous pathology (e.g., vitreous detachment) or retinal pathology (e.g., retinitis).


Abbreviation: HSV, herpes simplex virus.



15.3 Infection Involving the Preseptal Area, Orbit, and Cavernous Sinus Thrombosis


























Preseptal cellulitis


Orbital cellulitis


Cavernous sinus thrombosis



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Pathophysiology and etiology


Mild infection involving the structures anterior to the orbital septum
Etiology: local trauma (e.g., insect bite, trauma, surgery, etc.) or contiguous site infection (e.g., facial cellulitis, sinusitis, dental abscess, etc.)

More severe infection that involves the structures posterior to the orbital septum (fat and ocular muscles)
Etiology: common underlying conditions include contiguous site infection (e.g., sinusitis), orbital trauma, local surgery, etc.




  • Etiology is similar to preseptal cellulitis


  • The cavernous sinuses receive blood from the face area (nose, tonsils, orbits, etc.)



  • Infections in these areas (e.g., sinusitis and furuncles) can spread to and involve the cavernous sinus



  • Most clinical features are due to venous obstruction/congestion and nearby cranial nerve impairment


Common features: periorbital edema, erythema, swelling, chemosis (conjunctival edema), increased warmth and/or tenderness with systemic signs of infection/fever

No ophthalmoplegia, no diplopia, and no pain with eye movements.


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