Sir,

We thank Dr Raj for his interest in our paper. Cataract surgery in diabetic patients can indeed be associated with an increased risk of macular oedema and lead to a poor visual outcome. Dowler et al1 carried out intraoperative and postoperative fundus fluorescein angiograms in diabetic patients undergoing cataract surgery. They found that the presence or absence of pre-existing macular oedema was the single most significant predictor of postoperative visual outcome. In all, 56% of their patients developed new macular oedema after cataract surgery. 50% of these, had resolved after 6 months and 75% after 1 year. In patients who had pre-existing macular oedema, only 25% achieved a final acuity of 6/12 or better, compared with 85% in patients who had no pre-existing macular oedema.

We agree that hydrodissection can be hazardous in the vitrectomised eye. In our experience, hydrodelineation is a safer technique, especially in vitrectomised eyes that have posterior capsular plaques. It is well recognised that cataracts can develop as a result of lens touch from vitrectomy instruments. We have also seen instances of chips or defects in the posterior capsule or zonules caused by vitreous cutters. We advise that all eyes with postvitrectomy cataracts undergo a careful preoperative slit-lamp assessment to determine the possible presence of capsular defects. In these eyes, hydrodissection should be avoided. Instead, hydrodelineation should be performed with care to prevent capsular blow-out, and phacoemulsification carried out with minimal cracking, with the epinucleus acting as a protective shell.

However, it is worth noting that in many presbyopic patients, pars plana vitrectomy is now increasingly being combined with phacoemulsification and intraocular implant to reduce the need for further surgery.