NZ Optometry Registration key terms

The recess between the posterior corneal surface and the anterior iris, bounded peripherally by the trabecular meshwork. Its width and pigmentation determine whether the drainage pathway is open, narrow, or closed.

A sieve-like band of connective tissue in the anterior chamber angle through which aqueous humour passes before entering Schlemm canal. Resistance here is the main determinant of outflow facility and intraocular pressure.

The balance of aqueous production by the ciliary epithelium and drainage via trabecular and uveoscleral routes. Reduced outflow raises intraocular pressure, the principal modifiable risk factor for glaucomatous optic neuropathy.

Estimation of the pressure within the globe, most often by Goldmann applanation tonometry. Corneal thickness, curvature, and rigidity bias readings, so results must be interpreted alongside pachymetry and optic disc assessment.

A contact method that measures the force needed to flatten a fixed area of cornea, calibrated for an average corneal thickness. It is the reference standard in clinic but requires a quiet, cooperative patient and intact corneal surface.

The distance between corneal epithelium and endothelium at the corneal apex, typically around 540 micrometres. Thicker corneas overestimate and thinner corneas underestimate applanation readings, and thin values independently predict glaucoma progression.

Examination of the anterior chamber angle using a mirrored or prismatic contact lens that overcomes total internal reflection at the cornea. It distinguishes open, narrow, and closed angles and identifies abnormal vessels or pigment.

Glaucomatous optic neuropathy caused by obstruction of the trabecular meshwork by the iris root, usually in eyes with a crowded anterior segment. Acute attacks present with pain, haloes, and a mid-dilated pupil and require urgent referral.

A laser-created opening in the peripheral iris that equalises pressure between the anterior and posterior chambers, relieving pupillary block. It is the definitive prophylactic and therapeutic procedure for angle closure.

A condition in which apposition between the iris and crystalline lens impedes aqueous flow from the posterior to the anterior chamber. Pressure builds behind the iris, bowing it forward and narrowing the angle.

A topical ocular hypotensive agent, such as latanoprost, that increases uveoscleral outflow. Common adverse effects include iris darkening, eyelash lengthening, and periorbital skin pigmentation.

Enlargement and excavation of the central optic nerve head, reflecting loss of retinal ganglion cell axons. Progressive thinning of the neuroretinal rim and disc haemorrhage are key signs of glaucomatous damage.

A non-invasive imaging technique using low-coherence light to produce cross-sectional images of ocular tissue. It quantifies retinal nerve fibre layer and ganglion cell layers, and images the macula and anterior segment.

Measurement of the area of vision perceived by a steady fixating eye, commonly by automated static perimetry. It detects and monitors functional loss in glaucoma and neurological disease, and requires reliable fixation and patient effort.

A reproducible pattern of visual loss characteristic of glaucoma, beginning with nasal steps and arcuate scotomas and respecting the horizontal meridian. Defects usually emerge after substantial retinal ganglion cell loss.

The innermost retinal layer containing unmyelinated axons of ganglion cells travelling toward the optic disc. Its thickness, measured by optical coherence tomography, falls early in glaucoma and other optic neuropathies.

Classification of retinal changes from diabetes into non-proliferative and proliferative stages, noting microaneurysms, haemorrhages, exudates, and neovascularisation. Grading guides screening intervals and referral urgency.

Fluid accumulation within the macula due to leaking retinal capillaries in diabetes, causing central visual loss. It may occur at any retinopathy grade and is detected by clinical examination and optical coherence tomography.

Growth of new, fragile blood vessels in response to retinal ischaemia, seen at the disc, elsewhere on the retina, or on the iris. It risks vitreous haemorrhage, tractional detachment, and neovascular glaucoma, and warrants urgent referral.

An intravitreally injected drug, such as ranibizumab or aflibercept, that suppresses abnormal vessel growth and permeability. It is used for neovascular age-related macular degeneration, diabetic macular oedema, and retinal vein occlusion.

Degeneration of the macula in older adults, classified as dry (drusen and geographic atrophy) or wet (choroidal neovascularisation). Wet disease causes rapid central loss and requires urgent referral for anti-VEGF treatment.

A grid chart used for monocular home monitoring of central vision. New distortion, missing areas, or wavy lines may signal choroidal neovascularisation and prompt urgent assessment.

Distortion of shape or straight lines in the visual field, typically caused by macular oedema, epiretinal membrane, or choroidal neovascularisation. Patients often report bent doorframes or wavy text.

A progressive non-inflammatory thinning and conical protrusion of the cornea that produces irregular astigmatism and reduced best-corrected acuity. Corneal topography is diagnostic and cross-linking may be required.

Mapping of corneal curvature and elevation across the surface using reflected rings or scanning techniques. It detects irregular astigmatism, keratoconus, and contact lens-induced warpage.

A rigid contact lens made of oxygen-permeable polymer that maintains its own shape on the eye. It masks irregular corneal astigmatism and is often the optical correction of choice in keratoconus.

The pattern of lens-cornea bearing, clearance, and edge lift observed with fluorescein. An acceptable fit shows central alignment, mid-peripheral clearance, and adequate peripheral edge lift without limbal impingement.

Ingrowth of blood vessels into the normally avascular cornea, usually from hypoxia or chronic inflammation. It can reduce transparency and is a recognised complication of extended contact lens wear.

Infection of the cornea by bacteria, fungi, or protozoa, presenting with pain, photophobia, discharge, and a corneal infiltrate. It is a sight-threatening emergency, particularly with contact lens wear, and requires same-day referral.

Instillation of fluorescein dye, viewed under cobalt blue light, to reveal corneal and conjunctival epithelial defects and to assess tear film and lens fit. Punctate or geographic uptake indicates surface damage.

Retinoscopy or subjective refraction performed after paralysing the ciliary muscle with a cycloplegic drug. It reveals latent hyperopia and is essential in children and in suspected accommodative spasm.

A topical antimuscarinic drug, such as cyclopentolate or atropine, that relaxes the ciliary muscle and dilates the pupil. Effects include blurred near vision and photophobia, and patients must be warned about driving.

Dilation of the pupil produced by an adrenergic agonist or by blocking the parasympathetic supply to the iris sphincter. It facilitates fundus examination but may precipitate angle closure in predisposed eyes.

The ratio of convergence induced per unit of accommodation, expressed in prism dioptres per dioptre. An abnormal ratio helps distinguish accommodative esotropia from other forms of strabismus and guides treatment.

An inward deviation of the eyes triggered by the accommodation reflex in uncorrected hyperopia. Full hyperopic correction, sometimes with bifocals or surgery, is used to restore alignment and prevent amblyopia.

A latent misalignment of the eyes held in check by fusion and revealed when fusion is disrupted, as in the cover test. It is measured in prism dioptres and may cause asthenopia if compensation is inadequate.

A dissociation test in which one eye is occluded while the other fixates, revealing manifest and latent deviations. Alternate and uncover phases distinguish tropia from phoria and quantify the deviation.

The cortical integration of slightly disparate images from the two eyes into one percept with depth. It depends on motor alignment, clear images, and intact visual pathways, and underlies stereopsis.

Reduced best-corrected acuity in one or both eyes caused by abnormal visual experience during development, not by structural disease. Treatment aims to correct refractive error and force use of the amblyopic eye.

Loss of the temporal half of each visual field, caused by damage to the optic chiasm, most often by a pituitary adenoma. It is a neurological red flag requiring imaging and referral.

Bilateral optic disc swelling due to raised intracranial pressure, with preserved acuity until late. Headache, transient visual obscurations, and absent spontaneous venous pulsation are typical, and urgent referral is required.

The extent to which a patient follows an agreed treatment plan, such as instilling glaucoma drops or wearing lenses as prescribed. It is improved by simplified regimens, education, and shared decision-making.

A patient's voluntary agreement to an examination or procedure after receiving and understanding information about its purpose, risks, alternatives, and consequences of declining. It must be documented and revisited as circumstances change.

Practice in which the clinician examines their own culture and power, and delivers care that respects the patient's cultural identity and worldview. In Aotearoa New Zealand it is grounded in the Treaty of Waitangi.

The absence of avoidable, unfair differences in health status between groups. Achieving it requires identifying barriers such as cost, transport, language, and racism, then adapting services to remove them.

Including the patient's family and wider support network in decisions and care planning, consistent with Māori values of collective wellbeing. It improves engagement, understanding, and follow-through with treatment and appointments.

The defined activities a registered optometrist is competent and authorised to perform, including prescribing rights and the use of diagnostic drugs. Practising outside it may breach professional standards and insurance cover.

The agreed route by which a patient is sent to another clinician, including urgency, clinical information, and expected response. Clear pathways ensure timely care and continuity, especially for sight-threatening conditions.