NBEO Part II cheat sheet

Red-flag triad for same-day referral: sudden painless monocular vision loss, new flashes/floaters with a curtain, and monocular transient visual loss (amaurosis fugax).

Duration rule: acute onset over minutes to hours suggests vascular or retinal event; gradual over months suggests refractive, cataract, or chronic glaucoma.

Pain vs. no pain: painful vision loss points to acute angle closure, uveitis, keratitis, or optic neuritis; painless points to retinal vascular occlusion, detachment, or cataract.

Metamorphopsia (distorted lines on Amsler grid) localizes to macula; glare and halos around lights suggest cataract or corneal edema.

Family history positivity raises risk: primary open-angle glaucoma ~9x with first-degree relative; keratoconus, high myopia, and age-related macular degeneration also cluster.

Medication review: hydroxychloroquine (retinal toxicity at >5 mg/kg/day), ethambutol (optic neuropathy), amiodarone (corneal verticillata, optic neuropathy), topiramate (acute angle closure).

Systemic risk: diabetes (retinopathy, cataract, cranial nerve palsy), hypertension (retinal vascular disease), autoimmune disease (dry eye, scleritis, uveitis).

Occupational and driving history determines whether acuity meets legal standards (typically 20/40 or better in most US states for unrestricted license).

Spherical equivalent = sphere + ½ cylinder; used for contact lens conversion when cylinder ≤ 0.75 D.

Vertex distance conversion: F_new = F_old / (1 − d·F_old), where d is vertex distance change in meters; needed when power exceeds ±4.00 D.

Jackson cross-cylinder: flip test to refine cylinder axis, then power; add minus cylinder at 90° to axis of the correcting cylinder.

Duochrome test: red-green balance at end of refraction; red clearer = under-minus, green clearer = over-minus.

Amplitude of accommodation: push-up or minus-lens method; Hofstetter formula minimum = 15 − 0.25(age), average = 18.5 − 0.3(age).

Near point of convergence normal ≤ 5 cm; receded NPC plus exophoria at near suggests convergence insufficiency.

AC/A ratio (calculated) = IPD(cm) + (near phoria − distance phoria)/accommodative demand; normal 4-6 Δ/D.

Cover test interpretation: esophoria = eye moves outward when uncovered; exophoria = eye moves inward when uncovered.

Bacterial keratitis: contact lens wear is the leading risk; hypopyon or stromal infiltrate requires same-day ophthalmology referral and fluoroquinolone.

Herpes simplex keratitis: dendritic ulcer with terminal bulbs; topical steroid contraindicated without antiviral coverage.

Herpes zoster ophthalmicus: Hutchinson sign (tip of nose) predicts ocular involvement; treat within 72 hours with oral antiviral.

Acute anterior uveitis: cells and flare in anterior chamber, consensual photophobia, ciliary flush; HLA-B27, sarcoidosis, and trauma are common associations.

Anterior blepharitis vs. posterior: posterior involves meibomian gland dysfunction with capped or inspissated glands; treat with warm compresses and lid hygiene.

Pterygium vs. pinguecula: pterygium crosses limbus onto cornea; pinguecula is confined to conjunctiva.

Hyphema grading: grade I < 1/3 of anterior chamber, grade II 1/3-1/2, grade III 1/2 to total, grade IV total (8-ball).

Corneal ulcer differential: bacterial (purulent, acute), fungal (feathery margins, agricultural trauma), Acanthamoeba (contact lens, ring infiltrate, severe pain).

Central retinal artery occlusion: cherry-red spot, pale retina, sudden painless loss; emergent workup for embolic source (carotid, cardiac).

Central retinal vein occlusion: blood-and-thunder fundus, flame hemorrhages; associated with hypertension, diabetes, glaucoma.

Retinal detachment: flashes, floaters, visual field defect; pigment in anterior vitreous (Shafer sign) is a red flag.

Diabetic retinopathy grading: mild, moderate, severe NPDR (4-2-1 rule), and PDR; refer for panretinal photocoagulation in PDR.

Age-related macular degeneration: dry (drusen, geographic atrophy) vs. wet (choroidal neovascularization, metamorphopsia); wet warrants urgent anti-VEGF.

Optic neuritis: pain with eye movement, relative afferent pupillary defect, decreased color vision, disc may be normal (retrobulbar).

Papilledema: bilateral disc edema from elevated intracranial pressure; spares central vision early, enlarges blind spot.

Horner syndrome: ptosis, miosis, anhidrosis; postganglionic lesions do not cause anhidrosis (sweat glands of face spared).

Open-angle glaucoma: optic nerve cupping, RNFL thinning, visual field defects (nasal step, arcuate, paracentral); IOP is a risk factor, not a diagnostic criterion.

Acute angle closure: mid-dilated fixed pupil, corneal edema, IOP often >40 mmHg, nausea/vomiting; emergent IOP lowering and laser peripheral iridotomy.

Normal-tension glaucoma: glaucomatous damage with IOP consistently ≤21 mmHg; consider sleep apnea, hypotension, and vascular risk.

Target IOP is individualized: typically 20-30% reduction from baseline for mild disease; more aggressive for advanced.

Visual field testing: 24-2 or 30-2 SITA; pattern deviation removes overall depression from cataract.

Optic disc hemorrhage is a strong risk factor for progression in glaucoma.

Optic neuritis vs. ischemic optic neuropathy: pain with movement and younger age favor neuritis; altitudinal defect and older age favor NAION.

Gonioscopy grading: Shaffer system; grade 0 closed, grade 4 wide open (≥35°).

Diabetes: retinopathy, cataract, cranial nerve palsy (CN III with pupil sparing), and increased infection risk.

Hypertension: arteriovenous nicking, copper/silver wiring, flame hemorrhages, cotton wool spots (malignant hypertension).

Thyroid eye disease: lid retraction, proptosis, restrictive strabismus (inferior rectus most common), optic neuropathy risk.

Sarcoidosis: granulomatous uveitis, conjunctival nodules, lacrimal gland enlargement, optic neuropathy.

Rheumatoid arthritis: dry eye, scleritis, peripheral ulcerative keratitis; scleritis can be a marker of systemic vasculitis.

Giant cell arteritis: age >50, headache, jaw claudication, elevated ESR/CRP; anterior ischemic optic neuropathy risk; treat with high-dose corticosteroids immediately.

Multiple sclerosis: optic neuritis (often bilateral sequential), internuclear ophthalmoplegia, nystagmus.

Syphilis: uveitis, interstitial keratitis, Argyll Robertson pupil (accommodates but does not react to light).

Prostaglandin analogs (latanoprost): increase uveoscleral outflow; side effects include iris darkening, eyelash lengthening, periorbital fat atrophy.

Beta-blockers (timolol): decrease aqueous production; contraindicated in asthma, COPD, and heart block.

Alpha-agonists (brimonidine): decrease production and increase uveoscleral outflow; risk of allergic conjunctivitis and CNS depression in children.

Carbonic anhydrase inhibitors (dorzolamide, acetazolamide): decrease aqueous production; systemic acetazolamide risks include hypokalemia and paresthesias.

Pilocarpine: increases trabecular outflow; causes miosis, brow ache, and can precipitate angle closure in susceptible eyes.

Topical steroid potency: acetate > phosphate; monitor for IOP rise and cataract with chronic use.

Antibiotic coverage: fluoroquinolones (moxifloxacin, gatifloxacin) for bacterial keratitis; avoid in pregnancy and children under 8 for tetracyclines.

Antiviral dosing: HSV keratitis treated with topical trifluridine or oral acyclovir; HZO treated with oral antiviral within 72 hours.

Base curve selection: flatter than corneal curvature (steeper K) for rigid lenses; steepening tightens lens fit.

Oxygen transmissibility: Dk/t; silicone hydrogel daily wear recommended for extended wear to reduce hypoxia.

Giant papillary conjunctivitis: contact lens wear, itching, mucus, papillae on upper tarsal conjunctiva; treat with lens discontinuation and mast cell stabilizer.

Corneal neovascularization from hypoxia: reduce wear time, increase Dk/t, consider refit.

Keratoconus fitting: rigid gas permeable lenses, apical clearance pattern; monitor for corneal thinning and scarring.

Prosthetic eye care: remove and clean daily, polish annually; monitor socket for discharge, ptosis, and orbital volume loss.

Solution compatibility: multipurpose solutions vary in preservative; hydrogen peroxide systems require neutralization time.

Overwear signs: SPK, limbal redness, corneal edema; reduce wear schedule and refit.

Amblyopia treatment: patching or atropine penalization; critical period ends around age 8-10, but treatment can still help older children.

Strabismus in children: constant esotropia after 4 months of age warrants referral; intermittent exotropia may be observed.

Leukocoria differential: retinoblastoma, congenital cataract, Coats disease, persistent fetal vasculature, toxocariasis.

Pediatric refraction: cycloplegic refraction with cyclopentolate or atropine; hyperopia is common and often normal in young children.

Geriatric considerations: polypharmacy, contrast sensitivity loss, glare sensitivity, and fall risk; low vision aids improve function.

Low vision magnification: M = F/4 (where F is the dioptric power of the magnifier); required magnification = desired acuity / current acuity.

Rehabilitation: eccentric viewing training for central scotoma; prisms and telescopes for distance; CCTV and magnifiers for near.

Driving standards: most states require 20/40 or better in at least one eye; bioptic telescopes allowed in some states.

Preoperative cataract evaluation: assess ocular surface, biometry (IOLMaster), and macular status; counsel on expectations.

Postoperative cataract: mild inflammation and dryness expected; sudden vision loss, pain, or hypopyon suggests endophthalmitis and requires emergent referral.

Endophthalmitis: pain, decreased vision, hypopyon within days of surgery; treat with intravitreal antibiotics.

Triage red flags: chemical burn (irrigate immediately), penetrating trauma, acute angle closure, retinal detachment, giant cell arteritis, and endophthalmitis.

Chemical injury: irrigate with saline for at least 30 minutes; check pH until neutral.

Postoperative refractive surprise: assess for corneal edema, IOL position, and macular edema; consider refraction after 4-6 weeks.

Urgent referral timing: same day for retinal detachment, endophthalmitis, angle closure, and GCA; within 24-48 hours for new optic neuritis or NAION.

Preoperative counseling: discuss dry eye, glare, halos, and possible need for glasses after cataract surgery.

Informed consent: document discussion of risks, benefits, alternatives, and patient questions; required before procedures.

HIPAA: protected health information may be shared for treatment, payment, and operations; minimum necessary standard applies.

Record keeping: document chief complaint, findings, assessment, and plan; legible and timely entries are legally required.

Scope of practice: defined by state law and licensure; refer when condition exceeds scope (e.g., surgical, certain retinal disease).

Mandatory reporting: suspected child abuse, certain communicable diseases, and impaired drivers in some states.

Billing and coding: ICD-10 diagnosis codes and CPT procedure codes must match documentation; upcoding is fraudulent.

Interprofessional communication: use SBAR (Situation, Background, Assessment, Recommendation) for referrals and urgent calls.

Conflict of interest: disclose financial relationships; avoid incentives that compromise patient care.