Ophthalmologic

Question 1

Refractive Errors

Answer 1

• Main types of refractive errors are myopia (nearsightedness), hyperopia (farsightedness), presbyopia (loss of near vision with age), and astigmatism
• Myopia (nearsightedness) = objects up close appear clearly, while objects far away appear blurry
• Hyperopia (farsightedness) = distant objects may be seen more clearly than objects that are near
• Astigmatism = eye does not focus light evenly onto the retina, causes images to appear blurry and stretched out
• Presbyopia = age-related condition in which the ability to focus up close becomes more difficult

Question 2

Glaucoma

Answer 2

• Second MCC of legal blindness in US, leading cause of blindness in AA
• Destroys peripheral vision (ARMD destroys central vision)
• RF: increased intraocular pressure, age, enlarged optic nerve cup (≥ 0.5 cup-to-disk ratio)
• Dx: intraocular pressure measurement
• Tx: BB = 1^st line med tx, prostaglandin analogs, 2^nd line agents = topical carbonic anhydrase inhibs, alpha-2 agonists
• Open-angle -> more common; affects people >40y
  
  • Chronic, asymptomatic until late in dz, potentially blinding dz
  • Increased IOP, defects in the peripheral visual field and increased cup-to-disc ratio
  • Management
    
    • Ophth referral
    • Beta blockers, Acetazolamide, cholinergic agents, brimonidine
• Angle-closure -> painful eye and loss of vision
  
  • Steamy cornea, fixed mid-dilated pupil, decreased visual acuity, tearing, N/V
  • Anterior chamber is narrowed; IOP acutely elevated
  • Management
    
    • Refer to ophth
    • IV acetazolamide, topical beta blocker, osmotic diuresis (mannitol)

Question 3

Cataract

Answer 3

• Any opacity in the lens that causes lens to lose transparency
• 50% of ppl ≥ 80yo
• Three varieties: nuclear sclerosis, posterior subcapsular, cortical spoking
• RF: inc hours of sunlight exposure, smoking, heavy alc consumption, low educational level, diabetics, AA females
• Dx: slit lamp
• Tx: surgical – 20/50 visual acuity or worse with glare testing is considered surgical level of dysfunction
• Lens opacification (thickening); usually bilateral
• Risk factors = aging (>60y), cigarette smoking, corticosteroids
• Clinical manifestations
  
  • Blurred/loss of vision over months-years
  • Absent red reflex, opaque lens
• Management
  
  • Surgical

Question 4

Retinal Detachment

Answer 4

• Retinal tear à retinal inner sensory layer detaches from choroid plexus
• Clinical manifestations
  
  • Photopsia (flashing lights) w/ detachment à floaters à progressive unilateral vision loss (curtain coming down) in peripheral initially à loss of central visual field
• Diagnosis
  
  • Fundoscopy
    
    • Shafer’s sign = clumping of brown-colored pigment cells in the anterior vitreous humor resembling tobacco dust
  • ULS
• Management
  
  • Ophtho emergency = keep pt supine while awaiting consult
  • DON’T USE MIOTIC DROPS
  • Laser, cryotherapy, ocular surgery

Question 5

Macular degeneration

Answer 5

• Leading cause of severe vision loss in pts 75yrs of age and older
• MCC new visual impairment in pts >65
• M = F
• Older white americans affected 2x more than older blacks
• RF are similar to CAD (i.e. HTN, smoking, atherosclerosis)
• Dx: dilated fundus exam, slit lamp, optical coherence ttomography (OCT) has become standard for monitoring ARMD
• Tx: no medical management available for dry ARMD
  
  • Pharmaceuticals to inhibit vascular endothelial growth factor (VEGF) are used to tx wet ARMD
• Risk factors – age >50y, Caucasians, smokers
• MC cause of permanent legal blindness & visual loss in the elderly
  
  • Macula is responsible for central vision as well as detail & color vision
• 2 types
  
  • Dry (atrophic)
    
    • Drusen = small, round, yellow-white spots on the outer retina
  • Wet (neovascular or exudative)
    
    • New, abnormal vessels grown under the central retina, while leak and bleed à retinal scarring
• Clinical manifestations
  
  • Bilateral blurred or loss of central vision (including detailed & colored vision)
  • Scotomas (blind spots), metamorphopsia (straight lines appear bent)
• Diagnosis of wet
  
  • Fluorescein angiography
• Management
  
  • Dry = Amsler grid @ home
    
    • Zinc, vitamin A, C, E may slow progression
  • Wet
    
    • Intravitreal anti-angiogenics ex – Bevacizumab (reduces neovascularization)