BOCP cheat sheet

Corneal ulcer pattern rule: dendritic branching lesions suggest herpes simplex; marginal infiltrates with an intact overlying epithelium suggest staphylococcal hypersensitivity.

Keratoconus triad: inferior steepening on topography, scissoring retinoscopic reflex, and Vogt striae; Munson sign appears only in advanced disease.

Cataract grading by LOCS-style criteria uses nuclear color/opalescence, cortical spoke extent, and posterior subcapsular area as separate scales.

Diabetic retinopathy severity steps: microaneurysms only (mild NPDR), hemorrhages in 2-3 quadrants or IRMA (moderate-severe), neovascularization (PDR).

Macular degeneration: drusen plus pigmentary change defines early AMD; geographic atrophy or choroidal neovascularization defines late AMD.

Papilledema is bilateral, spares initial visual acuity, and enlarges the blind spot; unilateral disc edema with acuity loss favors optic neuritis.

Anterior uveitis signs: cells and flare in the anterior chamber, ciliary flush, photophobia, and consensual photophobia from the fellow eye.

Retinal detachment: pigment cells in the anterior vitreous (Shafer sign) plus a tobacco-dust appearance suggest a retinal tear.

Spherical equivalent = sphere + (cylinder / 2); use for keratometry comparison and contact lens power estimation.

Vertex distance conversion: Fc = F / (1 - dF), where d is the change in vertex distance in meters; effect grows with high plus power.

Prentice rule: prism diopters = decentration in centimeters x lens power in diopters.

Minimum blank size = frame PD difference plus effective diameter plus 2 mm; frame PD = A + bridge.

Snellen to logMAR conversion: logMAR = log10(denominator / numerator); 20/20 equals 0.0, 20/40 equals 0.3.

Toric transposition: new sphere = sphere + cylinder; new cylinder = opposite sign of original cylinder; new axis = axis +/- 90 degrees.

Jackson cross-cylinder at axis 90 measures cylinder power; at the correcting axis it refines cylinder axis.

Pantoscopic tilt increases effective plus power at the optical center line and requires compensation above roughly 10 degrees of tilt.

Base curve rule of thumb: steeper (smaller) base curve tightens fit; flatter (larger) base curve loosens fit on a soft lens.

Soft lens fit targets 0.5-1.0 mm of limbal coverage, centration within 0.5 mm, and 0.2-0.4 mm post-lens movement on blink.

Rigid lens fluorescein pattern: apical bearing means too flat; central pooling with mid-peripheral bearing means too steep.

Sagittal depth determines rigid lens fit more reliably than keratometry alone; larger diameter increases sagittal depth.

Oxygen permeability: Dk/t of at least 24 is the classic daily-wear threshold; extended wear requires substantially higher Dk/t.

Orthokeratology requires corneal topography at baseline and follow-up; reverse-geometry design flattens the central cornea.

Giant papillary conjunctivitis is associated with lens protein deposits, poor replacement schedules, and mechanical lid friction.

Solution-related corneal staining suggests preservative toxicity (for example, polyhexamethylene biguanide or benzalkonium chloride).

Prostaglandin analogs (latanoprost, bimatoprost, travoprost) lower intraocular pressure most effectively, typically 25-33%, by increasing uveoscleral outflow.

Timolol, a nonselective beta-blocker, reduces aqueous production; contraindicated in asthma and second-degree or worse heart block.

Pilocarpine, a direct muscarinic agonist, increases trabecular outflow but causes miosis, induced myopia, and dim vision.

Atropine 0.01% slows myopia progression with fewer side effects than higher concentrations; cycloplegia and photophobia remain risks.

Topical corticosteroids carry risks of ocular hypertension, cataract, and infection; potency rises with fluorination and acetate/alcohol forms.

Fluorescein angiography uses excitation near 465-490 nm and detects emission above 520 nm; sodium fluorescein is excreted renally.

Mydriatic combination of tropicamide 1% and phenylephrine 2.5% gives mydriasis without cycloplegia; phenylephrine is a direct alpha-1 agonist.

Antibiotic prophylaxis for bacterial keratitis typically uses fluoroquinolones; fungal ulcers require natamycin or voriconazole, not antibacterials.

Diabetes: retinopathy screening intervals depend on severity; no retinopathy in type 2 warrants annual or biennial follow-up per guideline.

Hypertension: grade III-IV retinopathy (hemorrhages, cotton-wool spots, papilledema) signals malignant hypertension and urgent referral.

Graves disease: lid retraction, proptosis, and restrictive myopathy; optic neuropathy risk rises with apical crowding on imaging.

Giant cell arteritis: age over 50, headache, jaw claudication, elevated ESR/CRP; anterior ischemic optic neuropathy may cause permanent loss.

Marfan syndrome: ectopia lentis is typically superotemporal and bilateral; homocystinuria causes inferonasal subluxation.

Sarcoidosis: granulomatous uveitis, conjunctival nodules, and optic nerve involvement; chest imaging and biopsy support diagnosis.

Sickle cell disease: proliferative retinopathy with sea-fan neovascularization; avoid high-altitude or hypoxia-related triggers.

Thyroid eye disease and myasthenia gravis both cause diplopia, but myasthenia produces variable, fatigable ptosis without pain.

Pupil light reflex pathway: afferent via optic nerve and chiasm to pretectal nucleus, efferent via Edinger-Westphal nucleus and ciliary ganglion.

Relative afferent pupillary defect suggests asymmetric or unilateral optic nerve disease; it is tested with the swinging flashlight test.

Cover test interpretation: eso deviation moves with the cover in exotropia, against in esotropia; measure with prism neutralization.

AC/A ratio = (deviation at near - deviation at distance) / (near fixation distance in diopters).

Amblyopia treatment: refractive correction first, then occlusion or atropine penalization; earlier intervention yields better outcomes.

Convergence insufficiency signs: reduced near point of convergence, exophoria at near greater than distance, and reduced positive fusional vergence.

Cranial nerve IV palsy: vertical diplopia worst in contralateral gaze and on head tilt away from the affected side.

Visual evoked potential latency prolongation suggests demyelination; amplitude reduction suggests axonal loss.

Normal-tension glaucoma shows glaucomatous cupping and field loss with intraocular pressure in the statistically normal range.

Angle grading by gonioscopy uses structures seen: Schwalbe line, trabecular meshwork, scleral spur, ciliary body band.

Optic disc cupping: neuroretinal rim thinning follows the ISNT rule in normal eyes (inferior thickest, then superior, nasal, temporal).

Visual field defects in glaucoma respect the horizontal midline; early defects include nasal step and paracentral scotoma.

Target pressure should be individualized, typically a 20-30% reduction from baseline, and reassessed with progression analysis.

Acute angle closure presents with mid-dilated fixed pupil, corneal edema, and high intraocular pressure; treat with IOP-lowering and iridotomy.

Ocular hypertension risk factors include thin central cornea, high baseline IOP, age, and disc hemorrhage.

Argon laser trabeculoplasty and selective laser trabeculoplasty lower IOP by improving trabecular outflow.

Amblyopia prevalence is roughly 2-3% of children; screening should occur before school age because treatment response declines with age.

Red reflex testing is essential in newborns; leukocoria requires urgent evaluation for retinoblastoma and congenital cataract.

Preschool visual acuity norms: 3-year-olds about 20/40, 4-year-olds about 20/30, 5-year-olds about 20/20.

A child with esotropia after 4-6 months of age warrants referral; infantile esotropia appears before 6 months.

Myopia control options include low-dose atropine, orthokeratology, and peripheral defocus lenses, with effects typically 0.3-0.6 D per year.

Geriatric considerations: dry eye, cataract, glaucoma, and macular degeneration are leading causes of visual impairment in older adults.

Polypharmacy in older adults can cause dry eye, diplopia, and blurred vision; anticholinergics and beta-blockers are common culprits.

Falls risk increases with reduced contrast sensitivity and visual field loss; home lighting assessment is part of low-vision care.

Legal blindness in the United States: best-corrected acuity of 20/200 or worse in the better eye, or visual field of 20 degrees or less.

Magnification = (desired acuity denominator) / (present acuity denominator); a 20/200 patient needing 20/40 requires 5x.

Telescopes are for distance; microscopes (high-plus lenses) are for near; field expanders include reverse telescopes and prisms.

Contrast sensitivity is measured with grating charts (for example, Pelli-Robson) and predicts mobility performance better than acuity alone.

Eccentric viewing training teaches patients to use a preferred retinal locus outside the fovea in macular disease.

Illumination needs rise with age; glare control with filters and proper lighting improves functional performance.

Reading rehabilitation often combines magnification, increased contrast, and larger print; screen magnification software is a common aid.

Referral to vision rehabilitation services and orientation and mobility specialists supports independence and safety.

Informed consent requires disclosure of diagnosis, risks and benefits of options, and the alternative of no treatment.

Record keeping should document findings, assessment, plan, and patient education; accurate records support continuity and legal defense.

Billing rules: a comprehensive examination code requires a chief complaint and documented elements; screening visits use different codes.

HIPAA permits disclosure for treatment, payment, and operations without authorization; other uses require patient authorization.

Confidentiality exceptions include suspected abuse, certain communicable diseases, and court orders.

Conflict-of-interest standards require disclosure of financial interests in optical products or referral relationships.

Scope of practice varies by jurisdiction; delegating tasks must follow supervision rules for technicians and assistants.

Malpractice risk reduction includes appropriate referral, clear documentation of advice given, and follow-up of abnormal findings.