Near Vision Fixation Target for NPC & Cover Test

Near Vision Fixation Target for NPC & Cover Test

This near vision fixation paddle is designed as a clinical stimulus for Near Point of Convergence (NPC) assessment and Near Cover Test evaluation in optometry and ophthalmology settings.

It provides a stable, high-contrast fixation target optimized for precise binocular vision examination.

 Target Specifications

• Letter height: approx. 3.6 mm
• Calibrated viewing distance: 40 cm
• Approximate visual acuity equivalent: ~0.16 decimal (20/125 Snellen equivalent)
• Accommodative demand at 40 cm: 2.50 D

The optotype size provides a reliable accommodative and convergence stimulus while maintaining a stable and easily visible fixation target during near convergence testing. 

Optional Higher-Demand Optotype Version

An alternative version of the paddle is also included, featuring smaller optotypes with a letter height of approximately 2.5 mm. At a calibrated viewing distance of 40 cm, this corresponds to an approximate visual acuity demand of ~0.23 decimal (~20/85 Snellen equivalent). This version provides a slightly higher accommodative and fixation demand while still remaining practical for near binocular vision testing. From a manufacturing perspective, 2.5 mm represents the practical lower limit for clean and legible optotype printing on a Bambu Lab A1 Mini using a standard 0.4 mm nozzle, ensuring the letters remain clearly defined while increasing the visual task difficulty for the patient.

Clinical Advantages

• Near Point of Convergence (NPC) break & recovery
• Near Cover Test
• Binocular vision assessment
• Convergence insufficiency screening
• Pediatric and adult examinations

 Rear Control Feature

The back of the paddle includes subtle mirrored lettering, allowing the clinician to know exactly which optotype the patient is viewing at all times.

This improves instruction accuracy and directional guidance during convergence and fixation testing.

 Printing Instructions (Important)

This model includes:

• A programmed pause for filament change (dual-color printing recommended)
• Two small vertical columns integrated into the design

 Do NOT delete the two columns.

These columns serve as controlled micro-purge towers.
They ensure:

• Clean filament transition
• Maximum letter definition
• Elimination of initial extrusion blobs
• High-quality black optotype edges

Removing them may result in visible defects on the first printed letter.

 

Complete Optometry Tool Set

This model is part of a growing 3D printable optometry tool collection, including:

• Vision Test Occluder: https://makerworld.com/en/models/2147632-vision-test-occluder-for-optometry-ophthalmology#profileId-2326927
• Trial lens flipper: https://makerworld.com/en/models/2422463-near-vision-fixation-target-for-npc-cover-test#profileId-2656782
• Additional printable clinical tools

Check my profile to see the full set.

If you print it, feel free to share your results.