Diabetes is an increasingly common systemic malady, and many of our
patients seeking cataract surgery have co-existing diabetic eye disease. While
we can still deliver excellent results from cataract surgery, these patients
are at an increased risk of complications and subsequent limitations of vision.
With careful preoperative planning, attention to detail during
phacoemulsification and close postoperative supervision, diabetic patients can
achieve excellent vision with cataract surgery.
Diabetic patients receive the same type of preoperative evaluation as
our other cataract patients, but with more emphasis placed on the presence and
extent of diabetic eye changes. Diabetic patients tend to develop cataracts at
an earlier age and may be more prone to developing posterior subcapsular
cataracts than our other patients. Importantly, the level of cataract seen
should correspond to the patients’ visual acuity and reported visual
dysfunction. If the patient reports severe vision problems but the exam shows
mild cataracts, look carefully at the retina for further causes of visual loss.
Diabetic retinopathy can be broadly divided into two categories:
background diabetic retinopathy and proliferative diabetic retinopathy, with
one of the key differentiating factors being the presence of harmful
neovascularization. The growth of these new vessels leads to a host of
subsequent problems, including vitreous hemorrhage, tractional retinal
detachment and neovascular glaucoma. Diabetics at any stage of the spectrum of
retinopathy are susceptible to macular edema, which is one of the principle
causes of central visual loss in these patients. A detailed dilated fundus
examination can reveal many of these pathologies, but additional tests, such as
optical coherence tomography or fluorescein angiography, can reveal more subtle
Significant diabetic ocular pathology should be treated before
consideration of cataract surgery. This involves a multi-pronged approach with
argon laser panretinal photocoagulation as the primary treatment for
proliferative retinopathy and focal macular laser for clinically significant
macular edema. Additional ocular treatment often involves intravitreal
injections of anti-VEGF medications and steroids. Tight control of the systemic
blood glucose level should be achieved and reflected in the hemoglobin A1c
|Anterior segment neovascularization, such as the rubeosis
iridis pictured here, is a sign of ischemia and typically accompanies other
ocular comorbidities such as neovascular glaucoma and proliferative diabetic
|This patient has a quiescent retina with a preserved macula due
to successful and extensive panretinal photocoagulation performed nearly 2
decades prior. After her cataract surgery, she recovered excellent vision with
a central acuity of 20/20.
Images: Devgan U
The anterior segment can also be negatively affected by poorly
controlled diabetes, including neovascularization of the iris and angle, which
often leads to neovascular glaucoma. Aggressive treatment of neovascular
glaucoma must take priority over cataract treatment because the prolonged
increase in IOP can cause permanent damage to the optic nerves and severe
visual loss. Partnering with a retinal colleague is often the best approach to
these complex patients.
Surgical technique and follow-up
Once the diabetic retinopathy is quiescent and the macula is dry,
cataract surgery can be planned with preference given to the implantation of
monofocal lens implants, toric IOLs or sometimes accommodating IOLs. Multifocal
IOLs should be avoided in eyes with a history of macular lesions or a
likelihood of developing macular pathology. Acrylic IOLs are preferred for
patients who will likely have a future vitrectomy for proliferative diabetic
retinopathy, whereas silicone IOLs may be a reasonable choice in patients with
well-controlled diabetes and mild retinopathy.
The cataract surgery can be less traumatic by minimizing phaco energy,
running less fluid through the eye and avoiding contact with the iris.
Efficient surgical technique is important to achieve optimal results after
cataract surgery in diabetic patients. These complex patients do better when
surgery is performed by a more experienced surgeon rather than a novice one.
Diabetic eyes often have poor pupillary dilation, particularly when active
rubeosis iridis or even regressed neovascularization is present. Pupil
stretching should be avoided because these vessels can rupture and cause
intraocular bleeding. In some cases, intravitreal injections of triamcinolone
or anti-VEGF medications are given at the time of cataract surgery. For
diabetics with non-clearing vitreous hemorrhages or tractional retinal
detachments, cataract surgery can be combined with a pars plana vitrectomy in a
teamwork approach with a vitreoretinal colleague.
In eyes with significant diabetic retinopathy, cataract surgery may lead
to progression and worsening of the retinopathy, which may have detrimental
effects on vision. In eyes with minimal diabetic changes, cataract surgery is
not as likely to cause this progression of retinopathy. Therefore, doing
cataract surgery at an earlier stage is often beneficial for diabetic patients
because it is associated with fewer complications and better postoperative
recovery of sharp vision.
Postoperatively, topical steroids as well as NSAIDs are given because
they control inflammation and may play a role in the prevention and treatment
of macular edema. Macular thickness can be evaluated at serial postop visits
before stopping the topical medications. Patients also should aim to keep their
systemic blood glucose levels controlled during the postoperative period to aid
with healing. Development of posterior capsular opacification as well as
persistent postoperative inflammation may be more common in diabetics. Despite
a beautifully performed cataract surgery, diabetic retinopathy can become
exacerbated in the postoperative period, so patients should be monitored
closely with serial dilated funduscopic examinations and referred to retinal
colleagues as needed.
Diabetic patients with visually significant cataracts pose unique
challenges during surgery, and they may be prone to a more difficult
postoperative recovery. However, with careful pre-treatment of the diabetic
retinopathy, atraumatic surgical techniques and appropriate medications after
surgery, these patients can do very well and recover excellent vision just like
our other cataract patients.
For further reading
Results after lens extraction in patients with diabetic retinopathy:
early treatment diabetic retinopathy study report number 25. Arch
Dowler J, Hykin PG. Cataract surgery in diabetes. Curr Opin
Mittra RA, Borrillo JL, Dev S, Mieler WF, Koenig SB. Retinopathy
progression and visual outcomes after phacoemulsification in patients with
diabetes mellitus. Arch Ophthalmol. 2000;118(7):912-917.
Squirrell D, Bhola R, Bush J, Winder S, Talbot JF. A prospective, case
controlled study of the natural history of diabetic retinopathy and maculopathy
after uncomplicated phacoemulsification cataract surgery in patients with type
2 diabetes. Br J Ophthalmol. 2002;86(5):565-571.
Straatsma BR, Pettit TH, Wheeler N, Miyamasu W. Diabetes mellitus and
intraocular lens implantation. Ophthalmology. 1983;90(4):336-343.
- Uday Devgan, MD, FACS, is in private practice at Devgan Eye Surgery
in Los Angeles, Beverly Hills and Newport Beach, Calif. He is also chief of
ophthalmology at Olive View UCLA Medical Center and associate clinical
professor at the UCLA School of Medicine. Dr. Devgan can be reached at 11600
Wilshire Blvd., Suite 200, Los Angeles, CA 90025; 800-337-1969; fax
310-388-3028; email: firstname.lastname@example.org;
Web site: www.devganeye.com.