Immediate sequential bilateral cataract surgery (ISBCS): A single-site experience of 41 patients during the COVID-19 pandemic.

Background: The practice of immediate sequential bilateral cataract surgery (ISBCS) was more widely adopted in the UK during the COVID-19 pandemic, in response to limited surgical capacity and the risk of nosocomial infection. This study reports on a single site experience of ISBCS in Northern Ireland. Methods: Data was collected prospectively between 17th November 2020 and 30th November 2021. The ISBCS surgical protocol, recommended by RCOphth and UKISCRS, was followed. Primary outcomes measures were: postoperative visual acuity (VA), refractive prediction accuracy, intraoperative and postoperative complications. Results: Of 41 patients scheduled, 39 patients completed ISBCS and two patients underwent unilateral surgery (n=80 eyes). Mean age at the time of surgery was 71.6 years (standard deviation (SD) ±11.8 years). Median preoperative VA was 0.8 logMAR (range: PL to 0.2 logMAR). Seventeen (20.9%) eyes were highly myopic and 9 (11.1%) eyes were highly hypermetropic. Median cumulative dissipated phacoemulsification energy was 15.7 sec (range: 1.8 sec to 83.4 sec). Median case time was 10.4 min (range: 4.3 min to 37.1 min).One eye (1.3%) developed iritis secondary to a retained tiny cortical fragment. Four eyes (5.0%, n=3 patients) developed cystoid macular oedema, with full resolution. On wide field imaging, an asymptomatic unilateral peripheral suprachoroidal haemorrhage was noted in two highly myopic patients (axial lengths of 27.01mm and 25.05mm respectively). The posterior pole was spared, and both resolved spontaneously without any visual impairment. Conclusions: In our initial experience, ISBCS was found to be a safe approach to cataract surgery. Our patient cohort included eyes with dense cataracts and high ametropia. Further studies are required to assess patient reported outcome measures and the possible economic benefits of ISBCS in our local population.

Accuracy of Toric Intraocular Lens Formulas With Measured Posterior Corneal Astigmatism of Different Orientations.

PURPOSE: To assess whether the use of measured posterior corneal astigmatism (PCA) values improves the prediction accuracy of toric intraocular lens power formulas, compared to predicted PCA values, when the orientation of the steep axis of PCA is non-vertical. DESIGN: Retrospective observational cohort study. METHODS: Four hundred eighteen eyes of 344 patients were included in the study. Prediction errors (PE) for postoperative refractive astigmatism at 4 weeks postoperatively were determined using vector analysis and compared for the following toric intraocular lens power formulas: Barrett Toric with predicted posterior corneal astigmatism (PPCA); Barrett Toric with measured posterior corneal astigmatism (MPCA); EVO Toric PPCA; EVO Toric MPCA; Holladay I with Abulafia-Koch regression. Subgroup analysis compared PEs for eyes with a vertically orientated steep axis of PCA (60-120°) to eyes with a non-vertically orientated steep axis of PCA. SETTING: Cathedral Eye Clinic, Belfast, United Kingdom and Tan Tock Seng Hospital, Singapore. RESULTS: Standard keratometry was with-the-rule in 48% of eyes, while the steep PCA axis was vertically orientated in 91% of eyes. For all eyes, EVO-PPCA had a smaller mean absolute error than Barrett-MPCA, Barrett-PPCA, and Abulafia-Koch (P < .01 for all). EVO-PPCA had the highest percentage of eyes within 0.50D of predicted postoperative astigmatism for eyes with vertical PCA (61%), while EVO-MPCA had the highest percentage for eyes with non-vertical PCA (54%). EVO-MPCA had the smallest centroid error for all eyes, and the subgroups (P < .01 for all). Eyes with non-vertical PCA had a lower percentage within 0.50D than eyes with vertical PCA when using PPCA (43% vs 61%, P = .034), but there was no significant difference between these groups when MPCA is used for eyes with non-vertical PCA (54% vs 61%, P = .40). CONCLUSIONS: When the steep axis of posterior corneal astigmatism is not vertically orientated, the use of measured posterior keratometry values improves prediction accuracy.