Sir,

We appreciate Drs Chaudhary and Kadyan’s interest1 in our article regarding the elevated intraocular pressure (IOP) on the first postoperative day following resident-performed cataract surgery.2

Our study was a comparative study and not a consecutive case series. Although all consecutive surgeries were considered, only 1111 cataract surgeries performed by residents between 1 July 2001 and 30 June 2006 were included in this study owing to the exclusions of some cases for the reasons listed.2

We acknowledge that the types of ophthalmic viscosurgical device (OVD) were not evenly distributed during our study period. As we commented in the Methods, sodium hyaluronate (Healon; Abbott Medical Optics Inc., Santa Ana, CA, USA) was used for all procedures from July 2001 to November 2005, and combined chondroitin sulfate and sodium hyaluronate (Duovisc; Alcon Laboratories Inc., Fort Worth, TX, USA) were used for all procedures after this time.2 Owing to the retrospective nature of the study, the type of viscoelastic could not be controlled.

The ‘GV’ in ‘Healon GV’ was an error in Tables 2 and 3. It should read ‘Healon’ instead. We are grateful to Drs Chaudhary and Kadyan for alerting us to the error. The incidence of postoperative day 1 IOP >23 mm Hg was 22.0% (244/1111) in our study.2 As we described in the discussion, comparison among studies was limited because the definitions of ‘IOP increase’ and surgeon’s experience such as resident vs non-resident were different.2 Jaycock et al3 reported that the incidence of raised postoperative IOP >21 mm Hg was 2.57% (430/16731) with a median time to postoperative review of 31 days. However, the exact time when they measured postoperative IOP was not described and trainees performed only 33.9% of operations. Browning et al4 showed that the incidence of IOP >26 mm Hg at 24 h after surgery was estimated to be 11.8% by three training surgeons. We similarly found our incidence to be 14.9% (165/1111; P=0.56, Fisher’s exact test).

We agree that the aetiology of postoperative day 1 IOP rise after cataract surgery can result from relatively more manipulations, residual OVD, and subsequent increased inflammation. A prospective study to evaluate the factors would be useful.