LINK VT-25

Base direction all the way round the circle

The LINK VT-25 is an optometry phoropter with prism base direction across a full 360 degrees and both angular scales readable to a single degree by estimation. Sphere runs from minus 19.00 to plus 16.75 in 0.25D steps, at a net weight of 4.75kg.

Sections

Phoropters

Oblique Base Prism Prescribing

Prism base direction across the full 360 degrees means an oblique base can be set as prescribed rather than rounded toward whatever the instrument permits. Patients with vertical or combined deviations frequently need prism at a base direction that does not fall neatly horizontal or vertical, and approximating that orientation degrades the correction in a way the patient experiences even when the magnitude is right.

Precise Astigmatic Axis Determination

Being able to estimate the axis to 1 degree between 5 degree markings matters most with higher cylinders, where the penalty for an axis error grows with the power involved. The printed steps set the coarse position and judgement between them refines it, which gives the practitioner more resolution than the scale alone implies without pretending to a precision the instrument does not have.

Consistent Vertex Geometry Across Patients

A fixed vertex corneal distance of 13.75mm means every refraction is conducted at the same working distance. Effective power at the eye becomes predictable, and comparisons between one examination and the next are not confounded by a positional variable that changed between visits. For practices wanting reproducible records, a known constant has real advantages over an adjustable range set differently each time.

Binocular Vision Assessment

Rotary prism to 20 prism dioptres in single steps, combined with full circle base direction, supports phoria measurement and vergence testing in the same sitting as the refraction. Where a patient reports headaches or reading difficulty without an obvious refractive cause, the instrument carries what is needed to pursue the binocular question immediately. Pursuing the question immediately is what makes it likely to be pursued at all.

Prescribing What Was Measured

The value of full circle base direction is that the prescription written matches the deviation measured. Every rounding toward an available orientation introduces a small error the patient eventually notices, and those errors are hardest to trace afterwards precisely because the magnitude looks correct on paper. Being able to set what was found removes an approximation that most heads quietly require. Small approximations accumulate into complaints nobody can trace.

Resolution Beyond the Printed Scale

Estimating to 1 degree between 5 degree markings is a modest sounding capability with real consequence at higher cylinders, where axis error and cylinder power compound. The manufacturer is also being honest in describing it as estimation rather than claiming 1 degree detents, which tells you what the instrument actually offers rather than what would sound better in a specification. Honest specification is worth something in itself.

A Known Working Distance

Fixing vertex corneal distance at 13.75mm trades adjustability for consistency. Every patient is refracted at the same geometry, so effective power at the eye is predictable and results compare cleanly across visits. Whether that trade suits a given practice depends on how often unusual fitting geometries arise, which is worth thinking about before choosing. Consistency and adjustability pull in opposite directions here. It is a genuine choice rather than a shortcoming.

Prism Base Across 360 Degrees

Base direction covers the complete circle in 5 degree steps. Oblique base prescriptions can be set directly rather than approximated toward the nearest available orientation.

Angle Readable to One Degree

Both the prism axis and the base direction scales are marked at 5 degrees but can be estimated to 1 degree between markings, giving finer working resolution than the printed steps suggest.

Fixed Vertex Corneal Distance

Vertex corneal distance is stated at 13.75mm. A known and consistent working distance means the effective power reaching the eye is predictable from one patient to the next.

Quarter Dioptre Sphere Steps

Spherical power runs from minus 19.00 to plus 16.75 in 0.25D steps, with cylindrical power from 0 to minus 6.00, matching the resolution at which prescriptions are ordinarily written.

Rotary Prism to Twenty Dioptres

Rotary prism covers 0 to 20 prism dioptres in single prism dioptre steps, supporting phoria measurement and vergence assessment alongside the refraction itself.

Butterfly Housing Form

The manufacturer describes an unusual butterfly form for the housing. At 320mm by 305mm by 100mm the head stays compact on the mounting arm despite the distinctive shape.

Coated Optical Lenses

Coated optical lenses are specified by the manufacturer. Coatings reduce internal reflection within a lens assembly, which matters where a patient is viewing a chart through several elements at once.

Light Net Weight

Net weight is 4.75kg, with a gross weight of 6.55kg. The modest head weight keeps demands on the mounting arm and on daily handling within comfortable limits.

The LINK VT-25 optometry phoropter handles angle more thoroughly than most heads of its type. Prism base direction covers a full 360 degrees and prism axis covers 0 to 180 degrees, both marked at 5 degrees and readable to 1 degree by estimation between the markings. That combination lets oblique base prism be prescribed as measured rather than rounded toward the nearest available setting.

Spherical power runs from minus 19.00 to plus 16.75 in 0.25D steps with cylindrical power to minus 6.00, the cross cylinder is plus or minus 0.25D, and rotary prism reaches 20 prism dioptres in single steps. Vertex corneal distance is fixed at 13.75mm, pupillary adjustment spans 50mm to 75mm in 1mm steps, and the forehead rest offers 16mm of travel. The head measures 320mm by 305mm by 100mm at 4.75kg net and 6.55kg gross. Because convergence arrangements and effective field of view are not stated, those warrant confirming alongside mounting arrangements, compatible stands, certification status, condition and reseller and listing rights for the manufacturer trademark. A refracting head stays in service for many years, so establishing the specification before purchase is worth the time. Speak to Medigear.uk, a verified medical equipment supplier, and we will set out precisely what a given head includes.

FAQ

Frequently Asked Questions

Everything buyers need to know about sourcing medical equipment through MediGear.

Base direction covers a complete 360 degrees, marked in 5 degree steps. That full circle coverage means an oblique base can be set as it was measured, instead of being rounded toward whichever orientation the instrument happens to permit. Prism axis separately covers 0 to 180 degrees.

The manufacturer states that both angular scales, marked at 5 degrees, can be estimated to read 1 degree. The printed markings set the coarse position and judgement between them refines it. Describing this as estimation rather than as 1 degree detents is an honest account of what the instrument provides. Knowing the real resolution helps you judge the instrument fairly.

It is fixed at 13.75mm rather than offered as an adjustable range. Every refraction is therefore conducted at the same working distance, which makes effective power at the eye predictable and results comparable between visits. It also means the distance cannot be altered for an unusual fitting geometry. Whether that trade suits your practice depends on how often unusual geometries arise.

Spherical power runs from minus 19.00 to plus 16.75 in 0.25D steps, and cylindrical power from 0 to minus 6.00. The cross cylinder is specified at plus or minus 0.25D, which is the standard step for astigmatic refinement work. Those spans cover the great majority of prescriptions met in ordinary practice.

Rotary prism covers 0 to 20 prism dioptres in single prism dioptre steps. Combined with base direction across the full circle, that supports phoria measurement and vergence assessment during the same appointment as the refraction itself. Vergence findings are ordinarily recorded at exactly that resolution.

Pupillary adjustment runs from 50mm to 75mm in 1mm steps, and the forehead rest offers 16mm of travel. The upper pupillary figure sits below what some refracting heads reach, so it is worth measuring against the spread of patients your practice sees.

Product size is 320mm by 305mm by 100mm at a net weight of 4.75kg. Gross weight is 6.55kg and the carton measures 485mm by 485mm by 245mm. The manufacturer describes an unusual butterfly form for the housing, which the product photographs show clearly. Both product and carton dimensions being given is useful when planning where the head will sit.

It does not. Convergence arrangements and effective field of view are both absent from the manufacturer sheet for this model. Rather than supply figures taken from a related product, we would ask you to have those points confirmed by Medigear.uk before committing.