DRAFT: clinical wording pending Dr van der Westhuizen review
Dr Dean van der Westhuizen
Ophthalmologist · Mbombela

Central Distortion Screen

A clinic screening aid for metamorphopsia, inspired by published dot-chart (D-chart) methods. It maps where in the central field the patient sees distortion, and how coarse a pattern still looks distorted.

1. Set-up (once per laptop)

Hold a bank card (85.6 mm wide) against the screen and drag the slider until the green bar is exactly the card's width. This sets true size on this screen.

Room lights on, screen brightness high, glare-free. Patient wears near correction. Nothing entered here is stored or sent.

2. Choose eye

Click or tap a segment to mark it as wavy, bent, missing or faint. Click again to unmark. Press Enter when the patient has finished with this pattern.

Results

Please note

This is an independent educational and clinic screening aid. It approximates published D-chart methods on a general-purpose screen. It is not equivalent to licensed D-chart software or a regulated home monitoring device, and it is not a diagnosis. Results depend on screen size calibration, viewing distance, fixation and lighting. Interpret alongside clinical examination and imaging (e.g. OCT).

How scoring works: each ring is split into 8 segments. Patterns run from fine (densely packed squares) to coarse. For each segment we record the coarsest spacing (in degrees) still marked as distorted. The total score is the sum across all segments; higher means more widespread or more marked distortion. Zero means no distortion was reported.