Cataract is a common complication of diabetes indeed it has been estimated 

that up to fifteen per cent of cataract surgery is performed on diabetics57. 

The main indications for surgery are the same as for non-diabetic patients. 

In addition, surgery is indicated if the lens opacity prevents an adequate 

examination of the fundus or produces excessive scatter of light during laser 

therapy. Standard surgical techniques are applicable eg. extracapsular 

cataract extraction or phacoemulsification. with posterior chamber intraocular 

flexible or non-flexible lens implantation. If phacoemulsification is performed, 

it is advisable to perform a large capsulorrhexis with a 7mm optic lens, thus 

allowing the better visualization of the fundus for PRP if required. Following 

surgery, the incidence of capsular opacification is greater in diabetics than in 

non-diabetics. Therefore, a large YAG capsulotomy to improve vision or 

improve visualization of the retina may become necessary. The results of 

surgery  best in those eyes with no retinopathy and worst in those eyes with 

active proliferative retinopathy58.

10.2 Complications of surgery

All forms of DR may become more severe following cataract surgery. In addition, 

surgery may be followed by a stormy post-operative course, particularly in those 

with active retinal disease. Complications include:

.

• severe uveitis with or without a ‘fibrin response’ in the anterior chamber..

.
• the development or progression of rubeosis iridis. In patients with 

existing rubeosis, this should be treated pre-operatively with panretinal 
photocoagulation. If this is not possible, laser therapy should be 
performed peroperatively or in the immediate postoperative period.
..
• vitreous haemorrhage in patients with active new vessels. If preoperative 

laser is inadequate or impossible due to poor visualization through the lens
opacity, peroperative laser therapy should be considered as for rubeosis.
If peroperative laser is not possible, then evaluation of the retina and 
adequate laser treatment should be performed in the immediate 
postoperative period.
.
• the development or worsening of active maculopathy. Evaluation and 

treatment of the maculopathy should be carried out at an early stage in 
the postoperative period. Patients with diabetes are at slightly greater 
risk of cystoid macular oedema which may be difficult to differentiate 
from true diabetic maculopathy. In cystoid macular oedema there is 
normally leakage of dye from the disc on fluorescein angiography which 
helps to differentiate the two conditions.

.

Cataract in  patients with severe PDR or who require vitrectomy presents 

special therapeutic problems. The use of red or infra-red wavelengths allows

laser photocoagulation to be delivered through many nuclear sclerotic cataracts. 

Use of the laser indirect ophthalmoscope allows panretinal laser photocoagulation 

to be delivered at the time of cataract surgery (see above for indications for 

preoperative laser therapy). Post-operative laser photocoagulation can readily 

be delivered either using the hand held 90D or 78D lens at the slit-lamp or with 

contact lens after small incision (phacoemulsification) cataract extraction 

techniques. It is worth re-iterating that patients with significant ischaemic 

retinopathy or proliferative retinopathy may frequently require additional 

panretinal laser photocoagulation preoperatively or in the immediate post-

operative period to prevent rapidly progressive neovascular glaucoma and 

blindness.

.

10.3 Lensectomy and vitrectomy
Patient with cataract and severe proliferative retinopathy (vitreous haemorrhage, 

widespread proliferative retinopathy, traction retinal detachment) requiring 

vitrectomy may undergo combined lens-vitreous surgery59. Cataract extraction 

with intra-ocular lens implant is performed (either manual expression extracapsular 

surgery or phacoemulsification cataract surgery), followed by a 3 port pars plana 

vitrectomy with delivery of full panretinal laser photocoagulation using the endolaser. 

Membrane dissection may be performed if needed60. In general, phacoemulsification 

is the preferred procedure in lensectomy/vitrectomy when they are performed as 

sequential procedures. 

.

Alternatively combined pars plan vitrectomy and lensectomy, with preservation of 

the anterior capsule, may be performed with pars plana delivery of endolaser. 

Insertion of a posterior chamber sulcus-fixated intra-ocular lens anterior to the 

anterior lens capsular, either a central anterior capsulotomy may be performed at 

the same surgical session or at a later date.

.
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