Your FREE COT Flashcards 2026 – 250+ Cards

COT Flashcards

Three layers (tunics) of the eye?

Outer fibrous (cornea + sclera), middle vascular uvea (iris, ciliary body, choroid), inner neural (retina).

Five layers of the cornea (anterior → posterior)?

Epithelium, Bowman's layer, stroma, Descemet's membrane, endothelium.

Which corneal layer pumps fluid out to keep the cornea clear?

The endothelium — a non-regenerating single cell layer that maintains corneal deturgescence (dehydration).

What gives the cornea most of the eye's refractive (focusing) power?

The cornea provides ~⅔ of the eye's total power (~43 D of ~60 D); the crystalline lens supplies the rest.

Three layers of the tear film?

Lipid (outer, from meibomian glands), aqueous (middle, lacrimal gland), and mucin (inner, goblet cells).

Path of aqueous humor outflow?

Ciliary body → posterior chamber → through the pupil → anterior chamber → trabecular meshwork → Schlemm's canal → episcleral veins.

Where is aqueous humor produced?

By the ciliary body (ciliary processes / epithelium) in the posterior chamber.

What is the macula and the fovea?

The macula is the central retina responsible for sharp central vision; the fovea is its center, packed with cones, giving the best acuity.

Rods vs. cones?

Rods: night/peripheral, motion, no color, very light-sensitive. Cones: central, color (red/green/blue), high detail, need bright light.

What is the optic disc (blind spot)?

Where retinal ganglion axons exit as the optic nerve — it has no photoreceptors, creating the physiologic blind spot ~15° temporal to fixation.

What does the lacrimal drainage system route, in order?

Puncta → canaliculi → lacrimal sac → nasolacrimal duct → inferior meatus of the nose.

Function of the iris and pupil?

The iris is the colored diaphragm; the pupil is its central aperture that controls light entering the eye (constricts in light, dilates in dark).

Which muscle constricts the pupil, and which dilates it?

Sphincter pupillae (parasympathetic) constricts (miosis); dilator pupillae (sympathetic) dilates (mydriasis).

Emmetropia vs. ametropia?

Emmetropia = light focuses exactly on the retina (no refractive error). Ametropia = a refractive error (myopia, hyperopia, astigmatism).

Myopia (nearsightedness)?

The eye is too long or too powerful, so light focuses in front of the retina; distance is blurry. Corrected with a minus (concave) lens.

Hyperopia (farsightedness)?

The eye is too short or too weak, so light focuses behind the retina; near is blurry first. Corrected with a plus (convex) lens.

Astigmatism?

The cornea/lens has unequal curvatures (toric), so light focuses at two points instead of one. Corrected with a cylindrical lens.

Presbyopia?

Age-related loss of accommodation (the lens stiffens), making near focus difficult, typically after ~40. Corrected with a reading add.

Accommodation?

The eye's ability to increase its focusing power for near objects — the ciliary muscle contracts, zonules relax, and the lens becomes more convex.

Normal blood pressure and what defines hypertension?

Normal is <120/80 mmHg; stage 1 hypertension is 130–139/80–89, stage 2 is ≥140/90 (current ACC/AHA categories).

Normal adult resting heart rate and respiratory rate?

Heart rate ~60–100 beats/min; respiratory rate ~12–20 breaths/min.

Vasovagal (syncope) response — recognition and action?

Pale, sweaty, lightheaded, slow pulse. Stop the procedure, recline the patient, elevate the legs, monitor, and call for help.

Anaphylaxis signs and first-line emergency drug?

Hives, swelling, wheeze, hypotension after an allergen. First-line is intramuscular epinephrine; activate emergency response.

What are the six cardinal positions of gaze used to test the EOMs?

Right, left, up-right, up-left, down-right, down-left — each isolates a pair of yoke (agonist) muscles.

Diabetes and the eye — the main retinal complication?

Diabetic retinopathy — microaneurysms, hemorrhages, exudates, and neovascularization; a leading cause of blindness. Control of glucose/BP is key.

Cranial nerves controlling the extraocular muscles?

CN III (oculomotor — most muscles), CN IV (trochlear — superior oblique), CN VI (abducens — lateral rectus). Mnemonic: LR6 SO4, rest 3.

What is the limbus?

The transition zone where the clear cornea meets the white sclera; it contains corneal stem cells and is a surgical landmark.

What is the conjunctiva?

The clear mucous membrane covering the white of the eye (bulbar) and the inner eyelids (palpebral); it produces mucin and tears.

What is the chief complaint (CC)?

The patient's main reason for the visit, recorded in their own words — the foundation of the ophthalmic history.

What does the mnemonic OLD CARTS capture for a symptom history?

Onset, Location, Duration, Character, Aggravating, Relieving, Timing, Severity — a structured way to document the chief complaint.

What does HPI stand for?

History of Present Illness — the detailed chronological account of the chief complaint and its associated symptoms.

Key elements of an ocular history?

Glasses/contact lens use, prior eye surgery or injury, glaucoma, amblyopia, eye drops, family eye history (glaucoma, macular degeneration).

Why ask about systemic medications during an eye history?

Many drugs affect the eye — steroids (cataract/glaucoma), tamsulosin (floppy iris), hydroxychloroquine (retinal toxicity), amiodarone (corneal deposits).

What is the difference between OD, OS, and OU?

OD = right eye (oculus dexter), OS = left eye (oculus sinister), OU = both eyes (oculus uterque).

Drug allergy documentation — what must be recorded?

The drug name and the specific reaction (e.g., hives vs. anaphylaxis vs. nausea); distinguish a true allergy from a side effect.

What is an NKDA notation?

No Known Drug Allergies — documented when a patient reports no medication allergies.

What is the difference between subjective and objective data?

Subjective = what the patient reports (symptoms, history). Objective = measurable findings (acuity, IOP, exam). Both belong in the chart.

What is scope of practice for an ophthalmic technician?

Perform delegated testing and assist; do NOT diagnose, prescribe, or interpret results for the patient — that is the physician's role.

What does ROS stand for?

Review of Systems — a checklist of body systems screened for relevant symptoms beyond the chief complaint.

Photophobia, diplopia, and metamorphopsia — define each.

Photophobia = light sensitivity; diplopia = double vision; metamorphopsia = distorted/wavy vision (often macular).

What is the proper way to correct a charting error on paper?

Draw a single line through it, write 'error,' add the correct entry, then date and initial — never erase, scribble out, or use white-out.

What does a Snellen 20/40 acuity mean?

At 20 feet the patient reads what a normal eye reads at 40 feet — worse than normal. The bottom number is the test distance for a normal eye.

What is logMAR and why is it used?

Logarithm of the Minimum Angle of Resolution — a uniform-step acuity scale (each line = 0.1 log unit, 5 letters) used in research (e.g., ETDRS charts).

What does the pinhole test do?

It blocks unfocused peripheral rays, so improvement with a pinhole indicates uncorrected refractive error; no improvement suggests a media or retinal cause.

Standard chart distance and how to record fewer-than-full lines?

20 feet (6 m). If a patient misses letters, record e.g. 20/30 -2 (read the 20/30 line missing two letters).

Order of low-vision acuity notation when letters can't be read?

Counting Fingers (CF), Hand Motion (HM), Light Perception (LP), then No Light Perception (NLP), with the test distance.

What is the purpose of lensometry (focimetry)?

To measure the power of an existing spectacle lens — sphere, cylinder, axis, add, and prism — by neutralizing it.

How is a bifocal add measured on a lensometer?

Read the distance power, then move to the segment and read the near power; the add = near power minus distance power (always plus).

What is retinoscopy?

An objective refraction technique: a streak of light is swept across the pupil and the reflex movement is neutralized with lenses to find the refractive error.

'With' vs. 'against' motion in retinoscopy?

'With' motion (reflex moves same direction) needs plus lenses; 'against' motion needs minus lenses; neutralization = no movement.

What is the spherical equivalent and how is it calculated?

The single sphere that best represents a sphero-cylindrical lens: spherical equivalent = sphere + ½ × cylinder.

What is the Jackson Cross Cylinder used for?

Refining the cylinder axis and power during subjective refraction by flipping the cross cylinder and asking 'which is clearer, one or two?'

Plus-cylinder to minus-cylinder transposition — the three steps?

1) New sphere = sphere + cylinder; 2) change the cylinder sign; 3) rotate the axis 90°.

Transpose +2.00 +1.00 × 090 to minus-cylinder form.

+3.00 −1.00 × 180. (Sphere 2+1=3; flip cyl sign; axis 90+90=180.)

What is the vertex distance and when must you adjust for it?

The distance from the back of the lens to the cornea (~12–14 mm). Adjust for high powers (>±4.00 D) because effective lens power changes with distance.

What is the duochrome (red-green) test?

A subjective check of refractive endpoint: a slightly under-minused eye sees red letters clearer; over-minused sees green clearer. 'Make red and green equal.'

What is pupillary distance (PD) and why measure it?

The distance between the pupil centers; it aligns the optical centers of the lenses with the visual axes so the patient isn't induced into prism.

What is a prism diopter (Δ)?

A unit of prism deviation: 1Δ displaces an image 1 cm at 1 meter. The base direction (BU, BD, BI, BO) names where the prism's base points.

Prentice's rule?

Induced prism (Δ) = lens power (D) × decentration (cm). It quantifies prism created when looking away from a lens's optical center.

What is a base curve in spectacle lenses?

The front surface curvature of a lens; it affects fit, magnification, and how the lens looks, and is matched when remaking a lens.

What does a 'plus' lens do and how do you identify it?

A convex (converging) lens magnifies and corrects hyperopia/presbyopia. Moving it shows 'against' motion; objects appear larger.

What does a 'minus' lens do and how do you identify it?

A concave (diverging) lens minifies and corrects myopia. Moving it shows 'with' motion; objects appear smaller.

Photochromic, polycarbonate, and high-index lenses — one use each.

Photochromic: darken in UV. Polycarbonate: impact-resistant (safety/children). High-index: thinner lenses for strong prescriptions.

What are the parts of a contact-lens fit measurement?

Base curve (mm), diameter (mm), and power (D); soft lenses also consider water content and material; the fit is checked for centration and movement.

Keratoconus and the typical contact lens used?

A progressive corneal thinning/cone causing irregular astigmatism; rigid gas-permeable (RGP) or scleral lenses give the best vision.

What is fluorescein used for in RGP contact-lens fitting?

It pools under the lens to show the tear film pattern — apical clearance vs. touch — so the fitter can judge the fit relationship.

Why must patients remove soft contact lenses before keratometry/topography?

Lenses mold the cornea (corneal warpage); readings are inaccurate until the cornea recovers (often hours to days for RGP).

What is the major risk of overnight/extended contact-lens wear?

Microbial keratitis (corneal infection/ulcer), especially Pseudomonas and Acanthamoeba — a sight-threatening emergency.

What is a confrontation visual field test?

A gross bedside screening: the examiner compares the patient's peripheral field to their own, presenting fingers in each quadrant, one eye at a time.

Automated (e.g., Humphrey) vs. Goldmann perimetry?

Automated = static threshold perimetry (computer presents stationary lights of varying brightness). Goldmann = kinetic (a moving target maps isopters).

What is a scotoma?

An area of reduced or absent vision within the visual field (e.g., the physiologic blind spot, or a pathologic defect in glaucoma).

Glaucoma's classic early visual field defects?

Nasal step, arcuate (Bjerrum) scotoma, and paracentral defects, reflecting nerve-fiber-layer loss; central vision is spared until late.

Bitemporal hemianopia points to a lesion where?

The optic chiasm (e.g., pituitary tumor) — crossing nasal fibers are affected, so both temporal fields are lost.

A homonymous hemianopia localizes the lesion where?

Posterior to the chiasm (optic tract, radiations, or occipital cortex) on the side opposite the field loss.

What is a reliable visual field — three indices to watch?

Fixation losses, false positives, and false negatives; high rates make the field unreliable and may need a repeat.

What is the direct pupillary light reflex?

Shining light in one eye constricts that same eye's pupil. The consensual reflex constricts the fellow (unstimulated) eye.

What is an RAPD (Marcus Gunn pupil) and how is it found?

A relative afferent pupillary defect — the swinging-flashlight test shows the affected pupil dilate when light swings to it; it signals optic nerve/retinal disease.

What is anisocoria?

Unequal pupil sizes. Note whether the difference is greater in light (parasympathetic/CN III problem) or dark (sympathetic/Horner's).

Components recorded for the pupil exam — PERRLA?

Pupils Equal, Round, Reactive to Light and Accommodation; also note size in mm in light and dark, and shape.

What is the cover-uncover test?

A test for tropias (manifest deviation): cover one eye and watch the OTHER for a shift to take up fixation, revealing a strabismus.

What is the alternate cover test?

Rapidly switching the cover between eyes to dissociate them and reveal the total deviation (tropia + phoria); measured with prisms.

Esotropia vs. exotropia vs. hypertropia?

Eso = inward turn, exo = outward turn, hyper = upward turn (of the deviating eye). A '-phoria' is the latent (controlled) version.

What does the corneal light reflex (Hirschberg) test estimate?

Ocular alignment by where a penlight reflects on each cornea; each mm of decentration ≈ 7° (≈15Δ) of deviation.

What is amblyopia ('lazy eye')?

Reduced vision in an eye that developed poorly in childhood (from strabismus, anisometropia, or deprivation) despite a healthy eye — best treated early.

What is stereopsis and a test for it?

Depth perception from binocular vision; tested with the Titmus (fly) or Randot stereo tests, scored in seconds of arc.

What is the near point of convergence (NPC)?

The closest point both eyes can converge on a target before one breaks outward; a receded NPC suggests convergence insufficiency.

What is nystagmus?

Involuntary rhythmic eye oscillation (jerk or pendular); it can be congenital or acquired (neurologic, vestibular, drug-related).

What does tonometry measure?

Intraocular pressure (IOP) — the fluid pressure inside the eye, a key screening value for glaucoma.

What is the normal range of intraocular pressure?

About 10–21 mmHg; pressures consistently above 21 raise concern for glaucoma, though glaucoma can occur at normal pressures.

What is the gold-standard method of measuring IOP?

Goldmann applanation tonometry — it flattens a fixed corneal area; the force needed equals the pressure (Imbert-Fick principle).

What two things are instilled before Goldmann applanation?

A topical anesthetic (e.g., proparacaine) and fluorescein dye, so the examiner can see the mires (semicircles) to align.

How does central corneal thickness (CCT) affect applanation IOP?

Thick corneas read falsely high; thin corneas read falsely low. Pachymetry helps interpret the IOP.

Name two non-contact / portable tonometers.

Non-contact 'air-puff' tonometer (no anesthetic needed) and the Tono-Pen / iCare rebound tonometer (handheld).

How are Goldmann tonometer tips disinfected between patients?

Wipe and disinfect per protocol (e.g., diluted bleach or hydrogen peroxide soak, then rinse/dry) or use disposable tips/covers to prevent infection transmission.

What does keratometry measure?

The curvature (in mm or diopters) of the central cornea along its two principal meridians — the 'K readings' — and corneal astigmatism.

What are keratometry readings used for?

Contact-lens base-curve fitting, IOL power calculation for cataract surgery, and detecting/monitoring corneal astigmatism and keratoconus.

Manual keratometer alignment — what do you do with the mires?

Focus the eyepiece, then align and superimpose the plus and minus mires along each meridian; the lack of doubling gives the reading.

What is corneal topography?

A color map of the entire corneal surface curvature (not just the center), used to detect irregular astigmatism, keratoconus, and to plan refractive surgery.

What is biometry in ophthalmology?

Measuring ocular dimensions — chiefly axial length and keratometry — to calculate the intraocular lens (IOL) power for cataract surgery.

Optical (IOLMaster) vs. ultrasound (A-scan) biometry?

Optical biometry is non-contact and very precise (preferred). Ultrasound A-scan touches the eye (or uses immersion) and is used when media are too dense for optics.

Applanation vs. immersion A-scan — the difference?

Applanation touches the cornea and can compress (shortening axial length, error). Immersion uses a saline standoff for more accurate, non-compressing readings.

What is the most important measurement that affects IOL power accuracy?

Axial length — a 1 mm error produces roughly 2.5–3 diopters of postoperative refractive error.

What is pachymetry?

Measurement of corneal thickness (CCT), important for glaucoma IOP interpretation, refractive surgery screening, and corneal disease.

What is the major safety check before contact tonometry/biometry?

Confirm no active corneal infection/abrasion, instill anesthetic, use clean/disposable tips, and avoid pressure on the globe.

What is OCT (optical coherence tomography)?

A non-invasive cross-sectional scan of the retina and optic nerve using light interferometry — it measures retinal/RNFL thickness for glaucoma and macular disease.

What does OCT of the optic nerve measure for glaucoma?

The retinal nerve fiber layer (RNFL) thickness and the ganglion cell complex; thinning indicates glaucomatous damage.

What is fundus photography?

Photographing the retina, optic disc, macula, and vessels to document and monitor disease (diabetic retinopathy, glaucoma, AMD).

What is fluorescein angiography (FA)?

IV sodium fluorescein is injected and timed retinal photos show blood flow, leakage, and ischemia — used in diabetic retinopathy and AMD.

Most serious adverse reaction to IV fluorescein, and the benign expected effects?

Rare anaphylaxis (have emergency drugs ready). Expected: transient nausea and yellow-orange discoloration of skin and urine.

Indocyanine green (ICG) angiography is better for imaging what?

The choroidal circulation (deeper than the retina), useful in occult choroidal neovascularization and choroidal disorders.

What is a B-scan ultrasound used for?

A 2-D ultrasound image of the posterior eye/orbit when the view is blocked (dense cataract, vitreous hemorrhage) — to detect retinal detachment, tumors, foreign bodies.

What is specular microscopy?

Imaging and counting the corneal endothelial cells (cell density, morphology) — important before cataract surgery and in corneal disease.

What is a potential acuity meter (PAM) used for?

Estimating the best possible vision behind a cataract (projects an acuity chart through clearer media) to predict post-surgery acuity.

What does color vision testing (Ishihara) screen for?

Red-green color deficiency (congenital), and acquired defects from optic nerve disease; pseudoisochromatic plates hide a number from the color-deficient.

What is the Amsler grid used for?

Detecting and monitoring central (macular) field distortion (metamorphopsia) or scotomas, as in macular degeneration; patients self-monitor at home.

What is exophthalmometry (Hertel)?

Measuring the forward protrusion of the globe (proptosis), used in thyroid eye disease and orbital masses.

What is a Schirmer test?

A measure of aqueous tear production: a paper strip in the lower fornix wets a length in 5 minutes; <5–10 mm suggests dry eye.

What is the tear breakup time (TBUT)?

The seconds from a blink to the first dry spot in the fluorescein-stained tear film; <10 seconds indicates tear-film instability (dry eye).

What is the gold standard quality of a clinical photograph?

Sharp focus, correct exposure, proper field/centration of the pathology, and accurate labeling of eye (OD/OS) and date.

What class of drug dilates the pupil by stimulating the dilator muscle?

A sympathomimetic (adrenergic) mydriatic such as phenylephrine — it dilates without affecting accommodation (no cycloplegia).

What is a cycloplegic and name an example?

An anticholinergic that paralyzes accommodation (and dilates) — e.g., tropicamide (short), cyclopentolate, atropine (longest). Used for cycloplegic refraction.

Which mydriatic should be used cautiously due to risk of acute angle-closure?

Any dilating drop in a patient with narrow/occludable angles can precipitate angle-closure glaucoma — screen and counsel for red eye/pain after dilation.

What does a miotic do, and name one?

Constricts the pupil (and lowers IOP by opening the angle), e.g., pilocarpine — historically for glaucoma and angle-closure.

Name two common topical anesthetics used in the clinic.

Proparacaine and tetracaine — used before tonometry, foreign-body removal, and biometry. Never dispense for home use (delays healing).

Beta-blocker glaucoma drops (e.g., timolol) — mechanism and key caution?

They lower IOP by reducing aqueous production. Caution in asthma/COPD, bradycardia, and heart block (systemic absorption).

Prostaglandin analogs (e.g., latanoprost) — mechanism and side effects?

Increase uveoscleral outflow (first-line, once daily). Side effects: iris/lash darkening, lengthened lashes, periocular pigmentation, conjunctival hyperemia.

How do carbonic anhydrase inhibitors lower IOP?

They decrease aqueous humor production (e.g., topical dorzolamide/brinzolamide, oral acetazolamide).

What is punctal occlusion and why teach it?

Pressing the inner corner after instilling drops blocks nasolacrimal drainage, increasing ocular absorption and reducing systemic side effects.

How long should you wait between two different eye drops?

About 5 minutes, so the second drop doesn't wash out the first.

What is the difference between a suspension and a solution drop, in handling?

A suspension (e.g., some steroids) must be shaken before use so the drug is evenly dispersed; a solution does not.

What is the most common cause of bacterial conjunctivitis vs. viral signs?

Bacterial: purulent discharge, often Staph/Strep/Haemophilus. Viral (often adenovirus): watery discharge, very contagious, preauricular node.

What organisms most threaten contact-lens wearers' corneas?

Pseudomonas aeruginosa (rapid bacterial ulcer) and Acanthamoeba (linked to water/poor hygiene) — both can cause vision loss.

What are Standard Precautions?

Treat all blood and body fluids as potentially infectious: hand hygiene, gloves/PPE as needed, safe sharps handling, and equipment disinfection between patients.

Single most important measure to prevent infection spread in the clinic?

Hand hygiene before and after every patient contact (and between exams), plus disinfecting shared instruments and chin/forehead rests.

Spaulding classification — critical, semicritical, noncritical?

Critical (enters sterile tissue) = sterilize; semicritical (touches mucosa, e.g., tonometer tip) = high-level disinfection; noncritical (intact skin) = low-level.

What does an autoclave do, and the typical parameters?

Steam sterilization under pressure — commonly 121°C at 15 psi for ~15–30 min (or 132°C flash cycles); kills all microorganisms including spores.

How is autoclave sterilization verified?

Chemical indicators (tape/strips that change color) confirm exposure; biological indicators (spore tests) confirm actual sterilization, run periodically.

What is high-level disinfection appropriate for?

Semicritical items that touch mucous membranes but aren't easily sterilized (e.g., applanation tips) — using agents like glutaraldehyde or hydrogen peroxide per protocol.

Slit-lamp routine maintenance includes what?

Cleaning optics, replacing bulbs, disinfecting chin/forehead rests between patients, and checking alignment and illumination.

Why must instrument calibration be checked (e.g., Goldmann tonometer)?

Drift causes inaccurate readings; the Goldmann tonometer is checked with a calibration bar/weight at set positions, and other devices per manufacturer schedule.

What is a cataract?

A clouding of the eye's natural crystalline lens, causing blurred vision and glare; treated by surgical removal and IOL implantation.

What is phacoemulsification?

The standard cataract surgery: an ultrasonic probe emulsifies and aspirates the cloudy lens through a small incision, then an IOL is implanted.

What is the role of the technician in surgical assisting?

Prepare/sterilize instruments, position and drape the patient, hand instruments, maintain the sterile field, and document — never exceeding delegated tasks.

What defines the sterile field rules?

Only sterile items touch sterile items; keep within view and above waist level; consider edges/borders non-sterile; never reach over the field or turn your back on it.

What is informed consent and the technician's role?

The physician explains the procedure, risks, benefits, and alternatives; the technician may witness/document the signature but does not obtain the consent itself.

What is the 'time-out' before surgery?

A team pause to verify correct patient, correct procedure, and correct site/eye (and IOL) — a Universal Protocol safety step to prevent wrong-site surgery.

What is LASIK?

Laser refractive surgery that reshapes the corneal stroma under a flap to correct refractive error (myopia, hyperopia, astigmatism).

What is a YAG capsulotomy?

A laser procedure that opens a cloudy posterior capsule ('secondary cataract') that can form months to years after cataract surgery, restoring vision.

What is the difference between a monofocal and a multifocal IOL?

A monofocal IOL focuses at one distance (usually far). A multifocal/EDOF IOL provides multiple focal points to reduce glasses dependence.

How should ophthalmic surgical instruments be handled to prevent TASS?

Thoroughly clean and rinse to remove detergent/debris (Toxic Anterior Segment Syndrome is caused by retained residues), then sterilize properly.

What is glaucoma in one sentence?

A progressive optic neuropathy (cupping + visual field loss), often associated with elevated IOP, that causes irreversible vision loss if untreated.

Open-angle vs. angle-closure glaucoma — key contrast?

Open-angle: chronic, painless, gradual field loss (most common). Angle-closure: can be acute — pain, red eye, halos, nausea, fixed mid-dilated pupil — an emergency.

What is age-related macular degeneration (AMD)?

Central retinal (macular) degeneration causing loss of central vision; dry (drusen, atrophy) and wet (neovascular, treated with anti-VEGF injections) forms.

What is a retinal detachment and a key warning symptom?

The retina separates from the underlying tissue — an emergency. Warning signs: sudden flashes, a shower of floaters, and a curtain/shadow over the field.

What is the technician's role in patient education?

Reinforce the physician's instructions (drops, follow-up, postoperative care), confirm understanding, and answer general questions within scope — not diagnosing.

How do you teach proper eye-drop self-administration?

Wash hands, tilt head back, pull down the lower lid to form a pocket, instill one drop without touching the eye/tip, close gently, and use punctal occlusion.

What is HIPAA and how does it affect the technician?

Federal law protecting patient health information (PHI); share PHI only on a need-to-know basis, secure records/screens, and never discuss patients publicly.

What is the proper response to a patient who asks 'what's my diagnosis?'

Defer to the physician — interpreting findings or giving a diagnosis is outside the technician's scope of practice.

What is negligence / standard of care for a technician?

Failing to act as a reasonably prudent technician would; following protocols, documenting accurately, and staying within scope reduces liability.

How is a chemical eye burn handled first?

Immediate copious irrigation with saline/water for at least 15–30 minutes (before other steps), then check pH and seek physician care urgently.

What is a corneal abrasion and how is it detected?

A scratch of the corneal epithelium causing pain, tearing, and photophobia; fluorescein staining shows the defect under cobalt-blue light.

What is the priority when a patient reports sudden, painless vision loss?

Treat as urgent — possible retinal artery occlusion, retinal detachment, or stroke. Notify the physician immediately; do not delay.

What is proper patient positioning at the slit lamp?

Chin in the rest, forehead against the band, eyes aligned to the canthus marker, comfortable and stable — adjust table/chair height first.

What information must be on every ophthalmic photo/test printout?

Patient name/ID, date, and which eye (OD/OS) — correct labeling prevents serious errors in interpretation and treatment.

What is the credential ladder at IJCAHPO?

COA (entry/assistant) → COT (intermediate/technician) → COMT (advanced/technologist).

What is the vitreous humor?

The clear gel that fills the large posterior cavity behind the lens, helping the eye keep its shape and transmit light to the retina.

What is the function of the choroid?

The vascular middle layer between the retina and sclera; it supplies blood and nutrients to the outer retina.

What are the two chambers of the anterior eye?

Anterior chamber (between cornea and iris) and posterior chamber (between iris and lens); both are filled with aqueous humor.

What are the four recti and two oblique extraocular muscles?

Superior, inferior, medial, and lateral rectus, plus the superior and inferior oblique — six muscles per eye.

Which muscle abducts the eye, and which nerve controls it?

The lateral rectus abducts (turns the eye outward), controlled by CN VI (abducens).

What is the function of the meibomian glands?

They secrete the oily (lipid) outer layer of the tear film, which slows evaporation; their dysfunction is a common cause of dry eye.

What is the normal adult body temperature range?

About 97–99°F (≈36.1–37.2°C); ~98.6°F (37°C) is the classic average.

What is hypertensive retinopathy?

Retinal vessel changes from high blood pressure — narrowing, arteriovenous nicking, hemorrhages, and in severe cases optic-disc swelling.

What systemic disease commonly causes a sudden third-nerve palsy with a dilated pupil?

A compressive lesion such as a posterior communicating artery aneurysm — a 'pupil-involving' CN III palsy is a neurologic emergency.

What is the difference between signs and symptoms?

Symptoms are what the patient reports (subjective); signs are what the examiner observes or measures (objective).

What is the lacrimal gland's role?

It produces the watery (aqueous) middle layer of the tear film, which makes up most of the tear volume.

What does the chief complaint drive in the visit?

It focuses the history and exam; everything documented connects back to why the patient came in, in their own words.

What should you do if a patient's reported medication list conflicts with the chart?

Document the discrepancy and verify with the patient/pharmacy; flag it for the physician — never silently overwrite.

Why record a social history (smoking, alcohol, occupation)?

Lifestyle and occupation affect eye disease and safety — smoking raises AMD risk; occupation guides safety-eyewear and visual-demand counseling.

What is a pertinent negative?

A relevant symptom the patient specifically denies (e.g., 'no flashes or floaters') — documenting it shows the question was asked.

What family history is most relevant in ophthalmology?

Glaucoma, macular degeneration, retinal detachment, and strabismus/amblyopia — all have a hereditary component.

What is scribing?

Documenting the physician's exam findings and orders in real time in the medical record, at the physician's direction.

What is the difference between distance and near visual acuity?

Distance acuity is tested at 20 feet (Snellen); near acuity is tested at ~14–16 inches with a reading card (e.g., Jaeger or reduced Snellen).

What is contrast sensitivity testing?

Measures the ability to distinguish an object from its background at varying contrast levels — can reveal deficits when acuity is still 20/20.

What is the correct testing order: acuity before or after dilation?

Measure visual acuity (and IOP and pupils) BEFORE dilating, because dilating drops blur near vision and change the pupil exam.

Why test each eye separately for acuity?

To detect a difference between the eyes (a weaker eye can hide behind a stronger one); occlude one eye completely without pressing on it.

What is the purpose of a trial frame or phoropter?

To hold and quickly change trial lenses in front of the eye during refraction and refinement.

What is anisometropia?

A significant difference in refractive error between the two eyes; large amounts in childhood can cause amblyopia.

What is the difference between a bifocal and a progressive lens?

A bifocal has a visible line dividing distance and near; a progressive (PAL) blends distance to near with no visible line.

Convert: what is a +2.50 D add roughly in working distance?

Working distance (m) ≈ 1 / add power, so a +2.50 add focuses at about 1 / 2.50 = 0.40 m (≈16 inches).

What is the slab-off (bicentric) prism used for?

To correct vertical prism imbalance at near in anisometropic patients reading through bifocals.

What is a Fresnel prism?

A thin, lightweight press-on prism (a series of small prism segments) applied to a lens, often as a temporary correction for diplopia.

What is the rule for prism base direction notation?

Base-up (BU), base-down (BD), base-in (BI, toward the nose), base-out (BO, toward the ear) — name where the prism's thick base points.

What is keratoconus's effect on refraction?

It causes irregular astigmatism that spectacles correct poorly; rigid or scleral contact lenses give better vision by masking the irregular surface.

What is a toric soft contact lens for?

Correcting astigmatism in a soft lens; it has a stabilization design (e.g., prism ballast) to keep the cylinder axis oriented.

What does the 'k' reading have to do with contact-lens base curve?

The base curve is chosen relative to the flattest keratometry (K) reading so the lens aligns properly with the cornea.

What is the consensual light reflex?

Constriction of the fellow (non-stimulated) pupil when light is shone in one eye — both pupils respond together.

Where is the lesion in a Horner's syndrome and the pupil sign?

A sympathetic-pathway lesion; the affected pupil is small (miosis) with mild ptosis, and the anisocoria is greater in the dark.

What is leukocoria and why is it urgent in a child?

A white pupillary reflex (instead of red); in children it can signal retinoblastoma or cataract and must be evaluated urgently.

What is the Worth 4-Dot test?

A test of binocular fusion and suppression using red/green glasses and four lights; the number and color of dots seen reveals fusion, suppression, or diplopia.

What is the Maddox rod used for?

It dissociates the eyes to measure phorias; one eye sees a line, the other a dot, and prisms quantify the deviation.

What is the Krimsky test?

An estimate of strabismus angle by placing prism over the deviating eye until the corneal light reflexes are symmetric.

What is the most common cause of an isolated CN VI palsy's clinical sign?

An esotropia worse at distance with limited abduction of the affected eye (the lateral rectus is weak).

What are versions and ductions?

Ductions are movements of one eye; versions are conjugate movements of both eyes together (tested in the cardinal positions).

What is the difference between a central and a peripheral scotoma?

A central scotoma affects fixation/reading (macular or optic-nerve disease); a peripheral scotoma affects the side field (e.g., glaucoma, retinal disease).

What is the visual-field defect of advanced glaucoma if untreated?

Progressive constriction toward central/tunnel vision, with the central island and a temporal crescent often last to go.

What does a quadrantanopia suggest?

A loss of one quadrant of the visual field, usually from a lesion in the optic radiations (temporal or parietal lobe).

Why plot the blind spot during perimetry?

It confirms correct fixation and the eye's orientation; an enlarged or shifted blind spot can also indicate disc pathology.

What is the Imbert-Fick principle behind applanation?

For a thin sphere, pressure = force ÷ area; flattening a fixed corneal area means the force applied equals the intraocular pressure.

What happens if too much fluorescein is used in Goldmann tonometry?

The mires appear too thick and the reading is falsely high; too little makes thin mires and a falsely low reading.

What is diurnal variation of IOP?

IOP fluctuates over the day (often highest in the morning); a single reading may miss peaks, so timing is noted and sometimes repeated.

What is the most common error that falsely raises applanation IOP?

Pressing on the globe or a tight collar/breath-holding, and excess fluorescein or a wide mire; thick corneas also read high.

What units does keratometry report?

Corneal curvature in millimeters of radius and/or in diopters of power, for each of the two principal meridians.

What does a large difference between the two K readings indicate?

Significant corneal astigmatism — the difference between the steep and flat meridians is the corneal cylinder.

Why must the keratometer eyepiece be focused first?

To eliminate the examiner's own accommodation, which would otherwise introduce error into the readings.

What is the anterior chamber depth used for?

It feeds modern IOL power formulas and helps assess angle-closure risk (a shallow chamber suggests a narrow angle).

Which IOL formula inputs are most critical?

Axial length and keratometry (corneal power); errors in either translate directly into postoperative refractive surprise.

What is the target refraction in most cataract surgery?

Usually emmetropia or slight myopia for distance, chosen with the patient; the IOL power is selected to hit that target.

What does pachymetry tell you in refractive surgery screening?

Whether the cornea is thick enough to safely remove tissue; a too-thin cornea is a contraindication to LASIK.

What is glare/brightness acuity testing?

Measuring acuity under a glare source, which uncovers functional vision loss from cataract or corneal haze missed in dim conditions.

What is OCT angiography (OCT-A)?

A dye-free OCT technique that images retinal and choroidal blood flow by detecting moving red cells across repeated scans.

What is the difference between a standardized and a diagnostic A-scan?

Standardized A-scan characterizes tissue/lesions (echography); diagnostic A-scan/biometry measures axial length for IOL calculation.

What artifact appears if a patient blinks or moves during OCT?

Motion artifact — broken or doubled vessels and a distorted segmentation line; re-acquire the scan.

What does external (anterior segment) photography document?

Lids, conjunctiva, cornea, and anterior chamber findings — useful for tracking lesions, ptosis, and pre/post-operative appearance.

Why is patient consent and a timer important in fluorescein angiography?

Consent covers the IV dye risks (rare anaphylaxis); precise timing of the photo sequence is essential to interpret the dye transit.

What does ICG angiography image that fluorescein does not?

The choroidal circulation — ICG fluoresces in the infrared and stays in vessels, showing deeper choroidal flow.

What is autofluorescence imaging used for?

It maps lipofuscin in the retinal pigment epithelium without dye, useful in macular degeneration and dystrophies.

What is the role of fixation in fundus photography?

Steady central or eccentric fixation aligns the desired field (e.g., disc-centered vs. macula-centered) for a clear, reproducible image.

What is a HRT or GDx scan?

Scanning-laser instruments that quantify the optic nerve head and nerve-fiber layer to detect and monitor glaucoma.

Why disinfect the chin/forehead rest of imaging devices?

They contact patient skin between every patient; cleaning prevents transmission of infection (a noncritical-item precaution).

What is the duration of action of atropine vs. tropicamide?

Atropine lasts up to ~1–2 weeks; tropicamide is short-acting (a few hours), making tropicamide the routine dilating drop.

Why give phenylephrine plus tropicamide for dilation?

They dilate by different mechanisms (phenylephrine stimulates the dilator; tropicamide relaxes the sphincter), giving a wider, more reliable dilation.

What is the antidote concept for an anticholinergic overdose effect on the eye?

Pilocarpine (a cholinergic miotic) can reverse pupil dilation; clinically, dilation is simply allowed to wear off.

Which patients need extra caution with phenylephrine 10%?

Patients with hypertension or cardiovascular disease, because systemic absorption can raise blood pressure; the 2.5% strength is safer.

What is the purpose of a fluorescein strip (not the IV dye)?

Topical fluorescein stains corneal/conjunctival epithelial defects (abrasions, ulcers) green under cobalt-blue light.

How are most multidose eye-drop bottles kept sterile?

A preservative (e.g., benzalkonium chloride) and not touching the tip to any surface; discard if contaminated or past the date.

What is the contact time concept in high-level disinfection?

The instrument must stay in the disinfectant for the full manufacturer-specified time/temperature to kill pathogens — shortcuts fail.

What does 'sterile' mean versus 'disinfected'?

Sterile = free of ALL microorganisms including spores; disinfected = most pathogens killed but not necessarily spores.

What is a wrapped vs. flash (immediate-use) autoclave cycle?

Wrapped items stay sterile in storage; flash/immediate-use sterilization is for an item needed right away and is used straight from the autoclave.

How do you handle a contaminated sharps?

Dispose directly into a puncture-resistant, leak-proof, labeled sharps container without recapping by hand.

What PPE is standard for a routine clinic eye exam?

Hand hygiene is universal; gloves and additional PPE are added when contacting body fluids or for infectious cases.

Why calibrate biometry and topography units regularly?

Drift produces inaccurate axial-length or curvature readings, which propagate into wrong IOL powers and contact-lens fits.

What is the surgical 'sterile field' boundary rule?

Consider table edges, anything below the waist, and the back of a gown non-sterile; only the front from chest to waist and gloved hands are sterile.

What is the difference between a refractive and non-refractive laser?

Refractive lasers (LASIK/PRK) reshape the cornea to change focus; non-refractive lasers treat disease (e.g., YAG capsulotomy, retinal photocoagulation).

What is panretinal photocoagulation (PRP) used for?

Laser treatment of the peripheral retina to reduce abnormal new-vessel growth in proliferative diabetic retinopathy.

What is an intravitreal injection commonly used to treat?

Wet macular degeneration, diabetic macular edema, and retinal vein occlusion — anti-VEGF drugs injected into the vitreous.

What laser-safety steps protect staff and patients?

Wavelength-specific protective eyewear, warning signage on the door, restricted access, and a labeled laser-safe zone.

What is the priority sign of acute angle-closure glaucoma?

Sudden severe eye pain and headache with a red eye, halos around lights, nausea/vomiting, and a fixed mid-dilated pupil — an emergency.

How do you respond to a patient reporting flashes and a curtain over their vision?

Treat as a possible retinal detachment — an urgent finding; notify the physician immediately for same-day evaluation.

What is the first action for a foreign body sensation with possible metallic FB?

Do not rub; protect the eye, ask about high-velocity exposure (grinding), and have the physician evaluate — an intraocular foreign body is sight-threatening.

What is the technician's role in obtaining vital signs before a procedure?

Accurately measure and record blood pressure, pulse, and sometimes oxygen saturation, and report abnormal values to the physician.

What is the proper response when a patient refuses a test?

Respect the refusal, document it, explain the purpose, and notify the physician — never coerce the patient.

What is informed consent's required content?

The nature of the procedure, its risks and benefits, alternatives, and the chance to ask questions — explained by the physician.

What is the main purpose of accurate medical coding?

To document services correctly for the record and billing; inaccurate coding is a compliance and legal risk.

What is appropriate when discussing test results with a patient?

Provide the measured data the physician has authorized, but defer interpretation and diagnosis to the physician (scope of practice).