Cataract surgery audit: the NOD outcome measures explained
The UK National Ophthalmology Database (NOD) audits cataract surgery with six outcome measures: posterior capsule rupture (PCR), final visual acuity of 6/12 or better (overall and without ocular co-pathology), vision loss, severe vision loss, and refraction within ±0.5 D and ±1.0 D of target. In its latest report, PCR was 0.69% and 93% of eyes reached 6/12 or better.
Published . Figures: RCOphth NOD National Cataract Audit, 8th Annual Report (July 2025) (UK, 1 Apr 2023 – 31 Mar 2024).
The measures and the latest UK figures
| Measure | What counts | UK figure |
|---|---|---|
| Posterior capsule rupture | PCR with or without vitreous prolapse, or zonule rupture with vitreous prolapse. Zonular dehiscence without vitreous prolapse is not PCR. | 0.69% |
| Final VA 6/12 or better | Best measured final visual acuity of 0.30 LogMAR or better, in eyes with a recorded final VA. | 93% |
| …without ocular co-pathology | The same, in eyes with no other eye disease recorded. | 96.4% |
| Vision loss | Final VA worse than pre-operative VA by 0.30 LogMAR or more. | 0.46% |
| Severe vision loss | Worse by 0.60 LogMAR or more. | 0.17% |
| Refraction within ±0.5 D | Post-operative spherical equivalent within 0.5 D of the predicted refraction. | 55% (standard) |
| Refraction within ±1.0 D | Within 1.0 D of the predicted refraction. | 85% (standard) |
PCR, visual acuity and vision loss: RCOphth NOD National Cataract Audit, 8th Annual Report (July 2025), UK, 1 Apr 2023 – 31 Mar 2024. Refraction standards: Gale RP et al., Eye 2009;23:149-52; RCOphth Cataract Surgery Guidelines (September 2010), §8.9. UK figures are context, not targets for other countries.
How to calculate your own
- Use only cases where the measure is known. A blank complication field or a missing final VA is left out of that rate, not counted as zero. Counting blanks as "no complication" makes PCR look better than it is.
- Leave out combined procedures (with trabeculectomy, keratoplasty or vitrectomy) and posterior polar cataract from the rates, as NOD does.
- Wait for enough cases. NOD publishes a surgeon’s or centre’s rates from 50 eligible operations; below that, one case moves a rate by 2% or more.
- Check how many eyes have both VAs. NOD assesses vision loss only where at least 60% of operations have both a pre-operative and a final VA.
- Record the surgeon grade. NOD groups results by consultant, career-grade non-consultant, experienced trainee and less-experienced trainee; PCR risk differs markedly between them.
Why routine post-operative refraction matters
Refractive accuracy can only be audited when the 4-week refraction is recorded, and it often happens outside the hospital, with the patient’s own optometrist. NOD recommends routine post-operative refraction; a simple way back from the community optometrist to the operating surgeon closes that gap.
Doing it without a spreadsheet
Logbook and Audit of the Cataracts computes these measures as you record cases, with the same definitions, and shows the UK figures beside yours for UK workspaces. Community optometrists can send the 4-week result back from a code on the patient’s slip.