Visionstar JS-266B1

Low vision clinics are the setting where a full aperture matters most. Patients with macular degeneration and other central field loss often view eccentrically, and a trial frame with 36.5 mm lenses lets them adopt their preferred viewing position while the practitioner refines the correction. Published work on new low-vision patients found that refraction improved acuity by two lines or more in about one in nine, which makes a careful trial frame refraction worth the time.

Hospital eye services use trial frame refraction for patients who cannot sit comfortably at a phoropter, including wheelchair users, patients with limited neck movement and those recovering from surgery. A wide clear zone helps them keep a usable view while seated in an unusual posture.

Community optometry practices use a full-aperture set for final checks in a trial frame, and for letting a patient walk around, read a page and look at a distant sign in the proposed correction before it is dispensed. Paired sphere and cylinder powers let both eyes carry identical lenses during binocular balancing.

Orthoptic and binocular vision clinics draw on the whole-value prism ladder from 1 to 10 and the paired white Maddox rods. Engraved prism base marks keep orientation readable through repeated handling.

Teaching clinics can use the set to show students how aperture and posture affect a patient's responses.

Two situations suit it less well: domiciliary rounds on foot, given the listed 7.5 kg, and practitioners who rely on ±0.12 D lenses. Institutional buyers commonly ask for evidence of conformity. The conformity documentation those procurement routes require is issued by the manufacturer and provided by the seller.

A Natural View Through Every Lens

A 36.5 mm clear zone lets patients look around the room, down at a card or toward a window while comparing lenses. Their responses come from something close to everyday viewing.

Room for Eccentric Viewing

Patients with central field loss can use an off-centre part of the lens without reaching its edge. That supports the trial frame refraction approach recommended for low vision.

Prism Base Marks That Stay Put

Each prism's base mark is engraved into the optic surface, so the mark and the prism's orientation cannot separate.

Metal Rings With Chromium Plating

The rings are metal with chromium electroplating. Plating durability is not published, and the seller should confirm it.

Whole-Value Prism Ladder to 10

A prism at every whole value from 1 to 10, plus a pair at 0.50, measures most moderate deviations with one prism in one cell.

Six Accessory Types in Pairs

Plane lenses, white Maddox rods, slits, cross-line pieces, pinholes and cross cylinders each come twice, supporting bilateral testing and covering a lost piece.

Cylinders Without Gaps to 4.00 D

Cylinders run in quarter steps to 4.00 D, including 3.25 and 3.75 D, then in half steps to 6.00 D.

No Electrical Upkeep

The set has no electrical parts, needs no mains supply and never enters a portable appliance testing schedule.

Convex Spheres

Forty powers, two of each: 0.25 D to 6.00 D in 0.25 D steps; 6.50 D to 10.00 D in 0.50 D steps; 11.00 D to 16.00 D in 1.00 D steps; then 18.00 and 20.00 D.

Concave Spheres

Forty powers, two of each, at the same values as the convex spheres.

Convex Cylinders

Twenty powers, two of each: 0.25 D to 4.00 D in 0.25 D steps, then 4.50, 5.00, 5.50 and 6.00 D.

Concave Cylinders

Twenty powers, two of each, at the same values as the convex cylinders.

Prisms

Twelve prisms: 0.50 in a pair, then 1.00 to 10.00 in whole steps, one of each. No unit is printed.

Engraved Prism Base Marks

The axial mark of each prism is engraved directly on the optic surface, which the manufacturer states keeps it from changing position.

Accessory Row

Sixteen pieces: red filter, green filter, a lens listed as black, plane lens (2), white Maddox rod (2), slit (2), cross line (2), frosted lens, pinhole (2) and cross cylinder (2).

Cross Cylinders

Two cross cylinders for refining cylinder axis and power. Their powers are not published.

36.5 mm Full Aperture

Every lens has a 36.5 mm clear aperture. Ring outer diameter is not published.

Chromium-Plated Metal Rings

Lenses are mounted in metal rings finished by chromium electroplating.

Integral Welding Process

The manufacturer describes an integral welding process. What it joins is not specified.

Single-Side Handle Lettering

Powers are lettered on one side of each handle, which the manufacturer states is convenient for use and inspection.

Tray and Case

The datasheet gives no dimensions. The manufacturer's online listing gives a 530 × 310 × 35 mm tray in a 560 × 340 × 90 mm case at 7.5 kg. The photograph shows a dark case with a carry handle and a light-coloured tray.

The JS-266B1 is a set built around the patient's view: 36.5 mm full apertures in chromium-plated metal rings, prism base marks engraved into the optic, paired spheres to 20.00 D, cylinders to 6.00 D without gaps and a whole-value prism ladder to 10. It suits low vision and trial frame work where natural viewing posture matters, at the cost of more weight. Medigear.uk lists the JS-266B1 for business buyers worldwide and can arrange delivery, familiarisation and service cover. Request confirmed dimensions and weight, the packing list, ring outer diameter, lens material, sign-marking convention and the declaration of conformity from the seller at quotation.