Kuwait MOH Optometrist key terms

A refractive state in which parallel light from a distant object does not focus on the retina when accommodation is relaxed, covering myopia, hyperopia and astigmatism. It is corrected with spectacles, contact lenses or refractive surgery.

The refractive condition in which parallel rays from a distant object focus sharply on the retina with accommodation relaxed, giving clear distance vision without correction. It is the reference point against which ametropia is measured.

The increase in crystalline lens power produced by ciliary muscle contraction, allowing the eye to focus on near objects. Amplitude declines with age, and its accuracy is measured as the accommodative response versus the stimulus.

The age-related loss of accommodative amplitude that makes near work difficult, usually noticed after age 40. It is managed with reading additions, progressive lenses, multifocal contact lenses or surgical options.

A single number summarising a spherocylindrical refraction, calculated as sphere plus half the cylinder. It is used for screening, epidemiological reporting and estimating the overall defocus of an eye.

A refractive error in which power varies across meridians because the cornea or lens is toroidal, so light forms two focal lines instead of one point. Regular forms are corrected with cylindrical lenses.

The separation in millimetres between the back surface of a spectacle lens and the corneal apex. It must be accounted for when converting prescriptions above about four dioptres between spectacles and contact lenses.

The refractive power of a lens measured from its posterior surface, which is the value used in ophthalmic dispensing and in focimetry. It differs from front vertex power in plus lenses of significant thickness.

A unit of prismatic deviation equal to one centimetre of displacement at one metre. It quantifies the prism in spectacles used for heterophoria, convergence excess or decompensating strabismus.

A measure of visual resolution expressed as the distance at which the test is performed over the distance at which a standard letter subtends five minutes of arc. It is recorded separately for each eye with and without correction.

A visual acuity scale in which each line is scored as the logarithm of the minimum angle of resolution, giving evenly spaced steps and better statistical behaviour. It is preferred in research and low-vision monitoring.

A quick test in which the patient views through a small aperture that blocks peripheral rays. Improvement in acuity suggests an uncorrected refractive cause, while no improvement suggests media, retinal or neural disease.

An objective technique in which a streak of light is swept across the eye and the movement of the reflex is neutralised with lenses to estimate refractive error. It is especially useful in children and non-communicative patients.

Refraction performed after paralysing the ciliary muscle with a cycloplegic drug, removing accommodative influence. It is essential in young children and in suspected accommodative esotropia or latent hyperopia.

Measurement of corneal curvature and astigmatism, usually by measuring the size of reflected mires over a known chord. Values guide contact lens fitting and detection of irregular astigmatism such as keratoconus.

Computerised mapping of corneal shape and power across the whole surface using Placido rings or elevation data. It detects keratoconus, pellucid degeneration and contact lens warpage that slit-lamp inspection may miss.

A progressive non-inflammatory ectasia in which the cornea thins and steepens, producing irregular astigmatism and reduced best-corrected acuity. Management includes rigid or scleral lenses and corneal collagen cross-linking.

Opacification of the crystalline lens that scatters light and reduces acuity, contrast and glare tolerance. Surgery with intraocular lens implantation is the definitive treatment once function is impaired.

A group of optic neuropathies characterised by progressive retinal ganglion cell loss and characteristic field defects, with raised intraocular pressure as the main modifiable risk factor. Diagnosis combines disc assessment, fields and tonometry.

Measurement of intraocular pressure, most commonly by Goldmann applanation at the slit lamp or by non-contact air-puff devices. Central corneal thickness and corneal biomechanics influence the reading.

Examination of the anterior chamber angle using a mirrored contact lens after topical anaesthesia. It distinguishes open-angle from angle-closure mechanisms and is essential before dilating a narrow-angle patient.

Perimetric mapping of the patient's sensitivity across the visual field, commonly by automated static threshold testing. It detects glaucomatous defects and neurological field loss and monitors progression over time.

A non-invasive imaging method using low-coherence light to produce cross-sectional images of the retina, optic nerve and anterior segment. It quantifies macular oedema, retinal layers and ganglion cell loss.

Documentation of the retina, optic disc and macula with a specialised camera, often after pupil dilation. Images support screening for diabetic retinopathy and provide a baseline for monitoring change.

Microvascular retinal disease caused by chronic hyperglycaemia, showing microaneurysms, haemorrhages, exudates and in advanced stages neovascularisation. Screening intervals and referral thresholds depend on graded severity.

A latent deviation of the eyes held in check by fusion when both eyes are open, becoming manifest when fusion is broken. It is measured with cover tests and prism bars and treated with prism or exercises.

A dissociation test in which one eye is occluded while the other fixates, revealing manifest deviation, and then the cover is moved across to reveal latent deviation. It is the core clinical measure of strabismus.

A manifest misalignment of the visual axes in which the eyes do not point at the same object, classified by direction, comitance and age of onset. Childhood forms risk amblyopia and loss of binocularity.

Reduced best-corrected acuity in one or both eyes caused by abnormal visual experience during the sensitive period, without structural cause. Treatment relies on correcting refractive error, occlusion or atropine penalisation.

A significant difference in refractive error between the two eyes, which can cause aniseikonia and amblyopia in children. It is managed with balanced spectacle correction, contact lenses or refractive surgery.

A perceived difference in image size between the two eyes, usually from unequal spectacle magnification in anisometropia. Symptoms include asthenopia, headache and disturbed depth perception.

A large rigid gas-permeable lens that rests on the sclera and vaults the cornea, creating a fluid reservoir. It is used for keratoconus, irregular corneas, ocular surface disease and post-surgical eyes.

A rigid contact lens made of oxygen-permeable polymer that maintains its own shape on the eye and corrects irregular astigmatism. Its fitting depends on fluorescein pattern assessment of alignment and edge clearance.

Dry eye disease caused by reduced tear production or excessive evaporation, producing burning, grittiness, fluctuating vision and surface staining. Management includes lubricants, lid hygiene and punctal occlusion.

The interval in seconds between a complete blink and the first dry spot appearing in the fluorescein-stained tear film. Values under ten seconds suggest an unstable tear film and evaporative dry eye.

A short-acting antimuscarinic drop that dilates the pupil and paralyses accommodation within about thirty to sixty minutes. It is the standard cycloplegic for paediatric refraction, with caution for angle closure risk.

A short-acting antimuscarinic mydriatic with weak cycloplegia, used for fundus examination and anterior segment assessment. Effects last a few hours and patients should be warned about glare and driving.

Damage from acid or, more severely, alkali exposure to the ocular surface, requiring immediate copious irrigation before any examination. Alkali penetrates and can cause limbal ischaemia and permanent visual loss.

Magnified illuminated examination of the anterior segment including lids, conjunctiva, cornea, anterior chamber and lens. With additional lenses it also permits fundus and angle assessment.

A patient's voluntary agreement to an examination or procedure after receiving understandable information about purpose, risks, alternatives and consequences of refusal. It must be documented and can be withdrawn at any time.

The systematic, legible and contemporaneous documentation of findings, advice, referrals and consent in a patient's clinical record. Accurate records support continuity of care, audit and medico-legal defence.

The agreed route by which a patient is sent from community optometry to an appropriate ophthalmology or hospital service, with documented urgency and findings. Clear pathways reduce delay in sight-threatening disease.

The routine cleaning of hands with soap and water or alcohol-based rub at defined clinical moments to prevent transmission of pathogens. It is the single most effective infection control measure in eye care settings.

Infection control measures applied to every patient regardless of known status, including hand hygiene, gloves, protective eyewear and safe sharps handling. They assume all blood and body fluids are potentially infectious.

Cleaning and chemical disinfection of reusable trial lenses and occluders between patients to prevent transfer of organisms such as adenovirus and Pseudomonas. Contact time must follow the manufacturer's instructions.

A custom-made artificial eye or shell worn in the socket after enucleation, evisceration or for a phthisical eye. Fitting requires socket assessment, regular polishing and monitoring for discharge or socket contracture.

The orbit and conjunctival cavity remaining after removal of the globe, which may develop volume deficit, deep superior sulcus or contracture. Management includes implants, conformers and planned prosthetic fitting.

A population-level test of distance or near acuity used to detect uncorrected refractive error and suspected eye disease in schools or communities. Positive screens require confirmatory optometric assessment.

Any optical defect in which the eye fails to focus light accurately on the retina, including myopia, hyperopia and astigmatism. It is the leading cause of correctable visual impairment worldwide.