Role of Steroids in management of diabetic cataract
Evolution of cataract surgery and management of diabetic retinopathy has resulted in improvement of prognosis following cataract surgery in diabetic patients. However studies still report progression of macular edema following cataract surgery in 23-57% cases along with progression of diabetic retinopathy.
Advances in pharmacological therapy give us the advantage of treating cataract and diabetic eye diseases simultaneously. A patient undergoing cataract surgery is already in the sterile settings in which we administer Intravitreal injections. Combining Intravitreal steroids with Phacoemulsification seems like a reasonable choice to decrease progression of macular edema. An ideal situation would be to give an Intravitreal steroid injection 3 weeks before a planned Phacoemulsification surgery as per guidelines of Royal College of surgeons. This would decrease the edema and make the eye quieter with decreased chances of inflammation which is otherwise expected to be more in any diabetic cataract surgery. Steroids appear to be a better choice compared to anti VEGFs in such cases because they are longer acting. This would give a treatment free interval of at least 4 months to the patient. Considering that the patient already underwent the trauma of a surgery on the eye the patient would be happier to not need any intervention for next 3-4 months. Moreover if the patient decides not to go for phacoemusification as planned 2 weeks after the steroid injection, we would still have a window period of 4 months during which the surgery can be carried out. With anti VEGFs this window would be shorter (not more than 3-4 weeks). And since we are already removing the cataract the fear of inducing lenticular changes is also gone.
An unpublished study from PGI Chandigarh India shows the beneficial effect of Intravitreal Dexamethasone injection in improving macular edema in patients undergoing cataract surgery. A Korean study also demonstrated better outcomes of steroid injections in Pseudophakic patients compared to phakic patients in a subgroup analysis.
Our experience in 48 eyes revealed a favourable outcome with Intravitreal Dexamethasone injection combined with phacoemusification surgery. Following surgery the Central retinal thickness decreased by an average of 322 microns at 1 month. This was followed by an increase by 184 microns at 4 months. 1 eye had a rise of intraocular pressure to 28 and another eye to 32 mm Hg. Both responded very well to topical antiglaucoma medications.
Our results demonstrated that an Intravitreal steroid injection is a preferred modality as a pre and preoperative treatment in cataract surgery cases that have a pre-existing macular edema.