Effects and Prognosis of Cataract Surgery in Patients with Retinitis Pigmentosa

Author: He H, Song H, Meng X, Cao K, Liu YX, Wang J, Wan X, Jin ZB. 

Geographical coverage: Not reported

Sector: Cataract surgery

Sub-sector: Effects and prognosis

Equity focus: Not reported

Study population: Patients with cataracts

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background

Retinitis pigmentosa (RP) is the most common inherited eye disorder and a leading global cause of blindness. It involves progressive degeneration of rod and cone photoreceptors, typically resulting in night blindness followed by central vision loss. Prevalence ranges from 1 in 13,000 in Spain to 1 in 750 in rural India. Cataract and cystoid macular oedema are frequent co-morbidities; cataracts occur in about 23 % of patients and further diminish visual acuity (VA). While cataract surgery is performed to restore vision, there is concern that increased retinal light exposure might accelerate degeneration.

Objective

To assess changes in VA before and after cataract surgery in RP and to determine whether the pre-operative macular ellipsoid zone (EZ) on optical coherence tomography (OCT) predicts postoperative VA.

Main findings

Authors included 16 retrospective observational studies (12 English, 4 Chinese) involving 796 patients (1,133 eyes); follow-up 1 day–60 months. All scored ≥ 7 on the Newcastle–Ottawa Scale.

• Visual acuity: Significant postoperative improvement across all time-points. Greatest gain within 1 month (mean difference [MD] 0.57 logMAR, 95 % CI 0.45–0.69), persisting, though attenuated, up to 1–5 years (MD 0.26, 95 % CI 0.09–0.43).
• Predictive role of EZ:
  • Invisible EZ – no significant improvement (MD 0.27, 95 % CI –0.17 to 0.70).
  • Abnormal EZ – significant gain (MD 0.56, 95 % CI 0.27–0.85).
  • Normal EZ – significant gain (MD 0.46, 95 % CI 0.27–0.65).
    Presence of a discernible (normal or abnormal) EZ is thus a positive prognostic indicator.
• Complications: Posterior capsule opacification was most frequent (42.6 % of eyes). Other events included cystoid macular oedema (28 eyes), zonular dialysis (20), capsular contraction syndrome (12) and transient intra-ocular pressure elevation (5). Rare events such as posterior capsule rupture, foveal thinning and macular hole were documented.

The authors concluded that cataract surgery offers sustained VA improvement for patients with RP, especially when the pre-operative EZ is intact or only mildly disrupted. An invisible EZ predicts limited benefit.

Methodology

Comprehensive searches (PubMed, Web of Science, MEDLINE, CNKI, Wanfang, VIP) from 1 January 2000 to 31 May 2022 identified English- and Chinese-language studies of RP patients undergoing cataract extraction (phacoemulsification ± intra-ocular lens implantation or extracapsular extraction). Two reviewers independently screened, extracted data and appraised study quality (Newcastle–Ottawa). Fixed- or random-effects models were applied according to heterogeneity (I² threshold 50 %). Publication bias was assessed with Egger’s test.

Applicability / external validity

Generalisability is limited by retrospective designs, small cohorts and heterogeneous follow-up. High postoperative PCO rates and concerns regarding light toxicity warrant further study.

Geographic focus

No geographical limits were imposed, but study locations were not specified.

Summary of quality assessment

Overall confidence in review’s conclusion is medium. Searches were thorough, criteria explicit, and dual review processes employed. Study characteristics and meta-analytic methods were clearly reported, and heterogeneity explored. Limitations include language restriction (English/Chinese), absence of an excluded-study list and lack of reference-list hand-searching.