NZ Optometry Registration flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Corneal endothelial function

The endothelium actively pumps fluid out of the stroma to maintain corneal deturgescence. Endothelial cells do not regenerate; loss leads to corneal oedema and reduced transparency.

Aqueous outflow pathways

Conventional outflow passes through trabecular meshwork into Schlemm's canal and episcleral veins, accounting for most aqueous drainage. Uveoscleral outflow is the minor alternative route.

Foveal avascular zone

The central fovea lacks inner retinal layers and relies on choroidal circulation. This gives high acuity but makes it vulnerable to vascular and toxic injury.

Spherical equivalent formula

Spherical equivalent equals sphere plus half the cylinder power. It provides a single refractive estimate used for comparison and pre-operative planning.

Duochrome test principle

Red and green targets exploit longitudinal chromatic aberration. In myopia the red is clearer; in hyperopia the green is clearer. It refines spherical endpoint.

Jackson cross-cylinder use

With the handle aligned to the axis, it identifies astigmatism axis. With the handle at 45 degrees to the axis, it refines cylinder power.

AC/A ratio calculation

The heterophoria method divides the difference between near and distance deviation by the accommodative demand in dioptres. Normal is about 4-6 prism dioptres per dioptre.

Convergence insufficiency features

Exophoria greater at near than distance, reduced positive fusional vergence, receded near point of convergence, and symptoms with near work define convergence insufficiency.

Hofstetter amplitude formula

Minimum amplitude equals 15 minus 0.25 times age. Average amplitude equals 18.5 minus 0.3 times age. These give expected accommodative amplitude norms.

Acute angle closure signs

Mid-dilated fixed pupil, corneal oedema, shallow anterior chamber, and very high intraocular pressure. It requires urgent pressure lowering and referral for iridotomy.

Bacterial keratitis management

Contact lens wear is a major risk. Corneal infiltrate with epithelial defect needs culture if severe and fluoroquinolone treatment with prompt referral.

Wet AMD referral

Choroidal neovascularisation causes subretinal fluid or haemorrhage and sudden distortion. Urgent referral is needed for anti-VEGF treatment to limit vision loss.

Dk/t oxygen benchmarks

Dk/t measures oxygen transmissibility. Common minimum benchmarks are 24 for daily wear and 87 for extended wear in standard units.

Scleral lens fitting

The lens vaults the cornea and lands on the sclera with a fluid reservoir. Assess vault and landing zone with slit lamp or OCT and check for conjunctival compression.

Orthokeratology risks

Overnight rigid lenses reshape the corneal epithelium to reduce myopia. Baseline topography and follow-up are required, with vigilance for microbial keratitis.

Topical anaesthetic use

Proparacaine and oxybuprocaine act rapidly and briefly. They are used for tonometry and foreign body removal, not for chronic pain management.

Timolol contraindications

Topical beta-blockers reduce aqueous production but are contraindicated in asthma, heart block, and bradycardia. They can also cause ocular surface dryness.

Prostaglandin analogue effects

Latanoprost increases uveoscleral outflow to lower intraocular pressure. Side effects include iris darkening, eyelash growth, and periorbital fat atrophy.

Leukocoria differential

A white pupillary reflex may indicate retinoblastoma, congenital cataract, Coats disease, or persistent fetal vasculature. All require urgent referral.

Cycloplegic retinoscopy

Cyclopentolate relaxes accommodation in children. Retinoscopy under cycloplegia is the primary objective refraction method for paediatric patients.

Low vision magnification

Required magnification equals reference acuity divided by the patient's acuity. This guides selection of magnifiers, telescopes, and electronic video magnifiers.

Giant cell arteritis red flags

Age over 50 with headache, jaw claudication, and visual loss suggests giant cell arteritis. Urgent ESR and CRP testing plus high-dose steroids prevent bilateral blindness.

Optic neuritis features

Pain on eye movement, relative afferent pupillary defect, and colour desaturation suggest demyelinating optic neuritis. MRI and neurology referral are indicated.

Diabetic retinopathy screening

Annual retinal screening detects microaneurysms, haemorrhages, and neovascularisation. Good glycaemic control reduces progression, and refer for laser or anti-VEGF when indicated.

Goldmann tonometry principle

A 3.06 mm applanated area balances the force applied. Central corneal thickness affects readings; thin corneas underestimate and thick corneas overestimate pressure.

Gonioscopy Shaffer grading

Shaffer grades 0 to 4 describe angle width. Structures include Schwalbe's line, trabecular meshwork, scleral spur, and ciliary body band.

Humphrey field reliability

Fixation losses, false positives, and false negatives indicate test reliability. Unreliable fields should be repeated before clinical interpretation.

HPCA Act regulation

The Health Practitioners Competence Assurance Act 2003 regulates optometrists. The Optometrists and Dispensing Opticians Board sets standards and recertification requirements.

Informed consent elements

Consent requires understanding of the procedure, risks, benefits, and alternatives. Document consent, especially for invasive or research procedures.

Privacy Act 2020

The Health Information Privacy Code governs patient records. Disclosure requires consent or a legal obligation, and records must be accurate and secure.

Cultural safety in practice

Practitioners recognise their own culture and bias and their impact on care. Te Tiriti principles of partnership, participation, and protection guide equitable engagement.

Teach-back technique

The clinician asks the patient to explain the plan in their own words. This confirms health literacy and corrects misunderstandings before the patient leaves.