Sir,

We read with interest the article by Kim et al1 investigating intraocular pressure (IOP) elevation following resident-performed cataract surgery. High-volume extracapsular cataract extraction (ECCE) is routinely performed in sub-Saharan Africa, where access to phacoemulsification is scarce. However, knowledge of post-operative changes in IOP post-ECCE in African eyes is limited.

Therefore, following ethical approval (Malawi College of Health Sciences), we prospectively studied 145 consecutive sutureless ECCE operations for senile cataract at Nkhoma Eye Hospital, Malawi, in 2010. IOP was assessed using a Reichert AT555 non-contact tonometer (Reichert, Depew, NY, USA). Length of operation was determined starting from superior rectus suture to speculum removal, and time of irrigation/aspiration (IA) was determined by duration of removal of viscoelastic after IOL implantation.

Mean age of patients was 67.7±9.1 years, and 55.7% were female. Five people had pseudo exfoliation, and one had open-angle glaucoma. No one was currently taking IOP-lowering medication, or corticosteroids. Mean operative length was 550±144 s, and mean IA time was 53±22 s. Three cases (2.1%) involved posterior capsule tear with vitreous loss.

Mean IOP pre-operatively was 15.4±4.9 mm Hg, rising by a mean of 9.8 mm Hg at 6 h post-operatively (paired t-test, P<0.001), and was also significantly elevated at 24 h compared with baseline (P=0.02; Table 1). There was a statistically significant difference in IOP across all groups (ANOVA, P<0.001). Over half (53.0%) had IOP ≥23 mm Hg and 34.7% had IOP>30 mm Hg 6 h post-operatively. Pre-operative IOP was a significant predictor of post-operative IOP at 6 h (P<0.001). However, length of IA was not associated with IOP at 6 h post-operatively (P=0.316).

Table 1 Pre and post-operative intraocular pressure (IOP) in 145 Malawians undergoing sutureless extra-capsular cataract extraction (ECCE) for senile cataract
Full size table

In this African population, a post-operative rise in IOP after ECCE is common, and higher than recently reported.1 IOP was significantly raised at 6 and 24 h post-operatively, but reduced almost to baseline at 48 h. Nonetheless, a long-term decrease in IOP of up to 4.4 mm Hg at 6 months following ECCE has been shown.2 Viscoat is used at Nkhoma, and has also been shown to cause significantly higher IOP increase than Ocucoat.3 Additional research is planned to further elucidate risk factors for IOP rise following ECCE in our African population.