Cataracts — master index¶
Last curated: 2026-10-31 · status: 8 curated, 14 draft after the literature sweep
The condition in five sentences. Cataract is loss of crystalline-lens transparency — nuclear, cortical or posterior subcapsular, often mixed — and its molecular core is oxidation of crystallin protein once a transport barrier isolates the lens nucleus in middle age (Truscott 2005, PMID 15862178; Chylack 1993, PMID 8512486). It is the single largest cause of blindness in the world: 15.2 million blind and 78.8 million with moderate-or-severe vision impairment among adults aged ≥50 in 2020, and 17.0 million blind (39.6% of all blindness) on the all-ages cataract-specific model, 60% of them women (GBD Vision Loss Expert Group 2021, PMID 33275949; Vision Loss Expert Group 2024, PMID 38461217). Surgery is the only established treatment and among the most cost-effective operations in medicine, yet age-standardised cataract blindness fell 27.5% between 1990 and 2020 while the absolute cataract-blind count rose 29.7%, because ageing and population growth outran surgical capacity (PMID 38461217; Lansingh 2007, PMID 17383730). The World Health Assembly's replacement target — a 30-percentage-point rise in effective cataract surgical coverage by 2030 — is not on track, with a modelled rise of 8.4 points (95% CI 8.1–8.6) between 2020 and 2030 (McCormick 2026, PMID 41687671). The field's two recurring intellectual problems are therefore that visual acuity is a poor measure of what cataract takes away, and that rare surgical harms need denominators no trial can supply.
Start here: overview.md. Research frontier: OPEN-QUESTIONS.md. Growth history: LOG.md.
At a glance¶
| Layer | Built content |
|---|---|
| Canonical wiki pages | 22/22 written; 8 curated, 14 draft |
| Distinct PMIDs cited across wiki | 465 |
| Citations per page | 26–57 (median 40) |
| Landmark paper notes | 6 |
| Tiered open questions | 23, plus a 12-row "dots not yet connected" table |
| ClinicalTrials.gov records verified and displayed | 27 |
Reading paths¶
| Reader goal | Path |
|---|---|
| Understand the condition | overview → classification and grading → lens biology and pathogenesis → risk factors |
| Plan adult surgery | diagnosis and preoperative assessment → IOL power calculation → intraocular lenses → anaesthesia and perioperative care → surgical technique → complications |
| Compare lenses | intraocular lenses → IOL power calculation → posterior capsule opacification → outcomes and quality of life |
| Operate on a difficult eye | surgery with coexisting eye disease → secondary and traumatic cataract → complications |
| Study global delivery | epidemiology and global burden → access, equity and service delivery → patient experience and advocacy |
| Review safety | complications → red flags and safety concerns → guidelines |
| Understand children's disease | congenital and paediatric cataract → IOL power calculation → posterior capsule opacification |
| Find research gaps | clinical trials landscape → non-surgical and preventive approaches → open questions |
Pages¶
| File | Scope | Refs | Status |
|---|---|---|---|
| overview.md | What cataract is, the burden, what surgery does and does not fix, map of the knowledge base | 40 | curated |
| classification-and-grading.md | Nuclear/cortical/PSC phenotypes, LOCS III and its predecessors, WHO simplified system, objective and deep-learning grading | 27 | draft |
| epidemiology-and-global-burden.md | Definitions that control the numbers, global counts, the rate-versus-count paradox, incidence, regional concentration, the 2030 target | 27 | curated |
| lens-biology-and-pathogenesis.md | Crystallin packing and chaperones, the glutathione barrier hypothesis, oxidative markers, aggregation reversal, lens epithelial cells | 26 | draft |
| risk-factors.md | Age, sex, smoking, corticosteroids, diabetes, UV, drugs, alcohol, nutrition — with effect sizes and their confounding | 31 | draft |
| congenital-and-paediatric-cataract.md | Prevalence, genetics, detection and timing, IATS and TAPS, glaucoma risk, myopic shift, optical correction, cost | 41 | draft |
| secondary-and-traumatic-cataract.md | Trauma, uveitis, post-vitrectomy and post-injection cataract, drugs, radiation, retinitis pigmentosa | 32 | curated |
| diagnosis-and-preoperative-assessment.md | The indication problem, the negative preoperative-testing evidence, medications that matter, the ocular examination, biometry, consent | 44 | draft |
| iol-power-calculation.md | Prediction error as endpoint, biometry inputs, formula generations, short and long eyes, post-refractive and irregular corneas, paediatric eyes | 41 | curated |
| intraocular-lenses.md | Optical classes, comparative evidence, toric correction, dysphotopsia, material and edge design, selection and economics | 35 | curated |
| anaesthesia-and-perioperative-care.md | Anaesthetic options and their complication associations, systemic risk, antithrombotics, perioperative drugs, ISBCS, process safety | 50 | curated |
| surgical-technique.md | Phacoemulsification, MSICS, ECCE, femtosecond assistance, difficult eyes, learning curve, setting and cost | 36 | draft |
| complications.md | Frequency table, posterior capsule rupture, dropped nucleus, endophthalmitis, CME, corneal and IOP problems, retinal detachment, risk-adjusted audit | 57 | draft |
| posterior-capsule-opacification.md | Mechanism, endpoint definitions, incidence, edge and material effects, drugs, Nd:YAG and its costs, special populations | 33 | curated |
| surgery-with-coexisting-eye-disease.md | Glaucoma, AMD, diabetic retinopathy, corneal endothelial disease, pseudoexfoliation, uveitis, previous vitrectomy | 55 | curated |
| outcomes-and-quality-of-life.md | The six outcome domains, PROMs and their minimum important differences, falls and driving, registry benchmarks and risk adjustment | 45 | draft |
| access-equity-and-service-delivery.md | CSR/CSC/eCSC, the 2030 target trajectory, affordability, workforce and technique, equity gradients, implementation | 42 | draft |
| non-surgical-and-preventive-approaches.md | Why no reversing drug exists, the negative randomised record, aggregation reversal, delivery chemistry, behavioural prevention | 35 | draft |
| guidelines.md | The main documents, where guidance converges and diverges, NICE recommendations verified live, guideline quality | 44 | draft |
| clinical-trials-landscape.md | Landmark randomised trials, what is registered now, why cataract trials are hard, trial-shaped gaps | 36 | draft |
| red-flags-and-safety-concerns.md | Postoperative emergencies, endophthalmitis vs TASS vs HORV, preoperative flags, drug safety, unvalidated products | 51 | draft |
| patient-experience-and-advocacy.md | Experience before surgery, waiting, consent and expectations, satisfaction and its exceptions, access as experience, organisations | 40 | draft |
Literature layer¶
| Resource | Contents | Status |
|---|---|---|
| BIBLIOGRAPHY.md | 467 records grouped by canonical page with cited-by lines | audit plus literature-sweep additions through 2026-10-31; two records remain literature-layer only |
| notes/ | Six landmark notes: LOCS III, the ESCRS endophthalmitis trial, FACT, the GBD cause analysis, IATS at 10.5 years, and the Study of Medical Testing for Cataract Surgery | rewritten at audit |
| guidelines/REGISTRY.md | Guideline catalogue with per-entry HTTP re-verification results; geographically incomplete by its own statement | re-verified at audit |
| statistics/STATISTICS.md | Source-specific quantitative tables; one numeric error corrected at audit | re-verified at audit |
| patient-voice/ | Method and ethics, verified organisations, aggregate themes, annotated sources | re-verified at audit |
Search and verification provenance¶
- PubMed E-utilities, 2026-08-31 (audit session): all 363 previously cited identifiers re-fetched and confirmed; ~40 additional topic searches run to fill gaps; 447 distinct records cited at that audit.
- ClinicalTrials.gov API v2, 2026-08-31: all 25 cited NCT records retrieved individually and confirmed, plus a status-filtered sweep of the "cataract" condition.
- Web endpoints, 2026-08-31: eight patient-organisation URLs re-requested (all HTTP 200); guideline endpoints re-requested with per-entry results recorded in the registry — two did not return HTTP 200 and are marked unconfirmed rather than removed.
- 2026-09-01 independent re-audit: all 22 pages were promoted to
curated; see the dated LOG entry for its scope and corrections. - 2026-10-10 literature sweep: all 452 then-cited wiki PMIDs resolved through live PubMed E-utilities; the added Nigeria review was also retrieved from PubMed, bringing the total to 453. All 27 cited NCT IDs resolved through ClinicalTrials.gov API v2. Europe PMC, Crossref, the ESCRS and Nigeria-review full texts, and the 2026 UK National Cataract Audit were checked. Six edited pages are
draftpending independent review; the other 16 retain their earlier curated status. - 2026-10-17 literature sweep: PubMed E-utilities, Europe PMC, ClinicalTrials.gov v2, Crossref, NICE/ESCRS/NOD/WHO/ISRCTN web endpoints, and OA full texts for two added papers. Eight new PMIDs entered the wiki (461 distinct). Eleven pages are
draftpending independent review. Query manifest: literature/sweeps/2026-10-17.json. - 2026-10-24 literature sweep: PubMed E-utilities (publication date and Entrez date, 2026-10-17 to 2026-10-24), PubMed-indexed CDSR, Europe PMC, ClinicalTrials.gov v2, Crossref, and guideline, audit and patient-organisation endpoints. Three new PMIDs entered the wiki (464 distinct); risk factors and congenital and paediatric cataract were demoted to
draft. Query manifest: literature/sweeps/2026-10-24.json. - 2026-10-31 literature sweep: 89 unique PubMed records screened, all 20 topic-specific CDSR queries empty in the dated window, Europe PMC searched, and all 27 tracked trials re-fetched without status/results changes. Three bibliography additions; one wiki addition (465 distinct wiki PMIDs). Classification and grading is now draft; eight pages remain curated and fourteen draft. Two earlier-2026 official guidance documents newly catalogued. Query and limitation manifest: literature/sweeps/2026-10-31.json.