Manipal Journal of Medical Sciences


Background: Cataract is an ageing process and surgery is the only mode of restoring vision. Patients who undergo surgery have only one aim in mind, which is improvement in their visual acuity (VA). However, some patients do not achieve this aim for improved vision after having undergone the surgery. Reasons for worsening vision after cataract surgery should be identified to counsel the patients on the possibility of poorer outcomes so that patients are prepared for such eventualities should they happen. Objective: While cataract surgery restores vision in most, a subset of patients experience worsening vision post-operatively. We investigated various reasons which might explain this phenomenon. We aim to begin a discussion, which we hope will culminate in evidenceinformed guidelines for patients and surgeons. We hope it will be used for the appropriate screening process for surgical candidate selection to choose the patients who may benefit from surgery and also for counselling patients on likely outcomes after surgery. Materials and Methods: We performed a retrospective secondary data analysis using the National Eye Database (NED) of Melaka Hospital from 2007 to 2014. Phacoemulsification and extracapsular cataract extraction were done. Other techniques were lens aspiration, intracapsular cataract extraction and phaco converted to extracapsular cataract extraction. Patients were followed up till 12 weeks and the best-corrected VA was recorded. We classified patients as having good (6/6-6/12), impaired (6/18-6/36), or poor vision (6/60 and worse) and recorded whether they improved, worsened, or remained unchanged postoperatively. We identified possible causes for worsening vision after surgery among the patients who presented to us with good VA. We included only patients who had a worse vision after the cataract surgery. Results: Among 603 patients who initially came with good vision, 34 had impaired and three had a poor vision while 44 (7.2%) had no change in vision post-operatively. Subluxated/dislocated lenses had worse outcomes. Other ocular comorbidities, all systemic comorbidities, age, and gender did not affect outcomes. Combined filtering/ vitrectomy with cataract surgery, posterior capsule rupture, vitreous loss, and zonular dehiscence cause worse outcomes. Poor outcomes were caused by astigmatism, posterior capsule opacity (PCO), and cystoid macular oedema (CMO). Conclusion: Patients who have pre-existing subluxated/dislocated lenses and those at risk for complications such as posterior capsule rupture, vitreous loss, and zonular dehiscence should be screened and counselled regarding poorer outcomes. Attempts must be made to reduce astigmatism, PCO, and CMO. We recommend a meta-analysis of epidemiological studies on specific factors which determine the post-operative visual outcome in cataract surgery patients, to inform the development of screening guidelines for surgical candidates.