|Year : 2015 | Volume
| Issue : 2 | Page : 92-95
Effect of cataract surgery on diabetic retinopathy
Khalid G Ali1, Tarek T Soliman1, Asmaa A Mohammed2
1 Department of Ophthalmology, Faculty of Medicine, Benha University, Benha, Egypt
2 Department of Ophthalmology, Ministry of Health, Menofeya, Egypt
|Date of Submission||17-Aug-2015|
|Date of Acceptance||02-Nov-2015|
|Date of Web Publication||14-Apr-2016|
Asmaa A Mohammed
MBBCh, Quesna, El-Monofeya, 12 Azab Al-Leithy street, Quesna, Menofeya, 32631
Source of Support: None, Conflict of Interest: None
The aim of this study was to review articles on the effect of cataract surgery on diabetic retinopathy (DR). Of the reviewed publications, it was found that diabetic patients with mild-to-moderate DR are less likely to show progression of DR after phacoemulsification. Patients with severe nonproliferative diabetic retinopathy and proliferative diabetic retinopathy have high risk of progression. Elevated hemoglobin A1c (HbA1c) at the time of cataract surgery increases the risk for DR progression after surgery.
Currently, early surgery is favored before the development of significant DR rather than waiting for the cataract to become denser. All efforts should be made to stabilize DR before cataract surgery.
Keywords: Cataract surgery, diabetic retinopathy, macular edema, phacoemulsification
|How to cite this article:|
Ali KG, Soliman TT, Mohammed AA. Effect of cataract surgery on diabetic retinopathy. Benha Med J 2015;32:92-5
| Background|| |
Diabetes mellitus (DM) is a growing major health concern worldwide. In industrialized countries, ∼1% of the population is diabetic, and at least another 1% comprises undiagnosed diabetic patients . Diabetic retinopathy (DR), a well-known consequence of long-standing and poorly controlled DM, causes significant vision loss and blindness in the human population . Diabetic macular edema (DME) is the major vision-threatening complication of DR. The Wisconsin Epidemiologic Study has reported that the prevalence of DME in diabetic patients of 15-year duration is ∼20% in patients with type I DM and 25% in patients with type II DM who are on treatment .
Studies have demonstrated that patients with DM are two to five times more likely to develop cataract compared with their nondiabetic counterparts . Although advances in cataract surgery have generally resulted in favorable surgical outcomes, individuals with DM have not always shared the same benefits as their nondiabetic counterparts. Pre-existent diabetic eye disease and prior laser surgery have limited the visual potential for patients with DM .
| Materials and methods|| |
A search was performed in several databases. It included Medline, articles in Medscape, and PubMed. The search included all articles published, with no language restriction.
All studies were independently assessed for inclusion. They were included if they fulfilled the following criteria:
- Published in English language.
- Published in peer-reviewed journals.
- Discussed the effect of cataract surgery on DR progression, effect of phacoemulsification on macular edema (ME), risk factors for progression of DR after phacoemulsification, and adjuvant modalities to control ME for diabetic patients undergoing cataract surgery.
Data from each eligible study were independently abstracted in duplicate using a data collection form to capture information on study characteristics, interventions, and results reported for each outcome of interest. It was not possible to perform meta-analysis. Significant data were collected.
The quality of all studies was assessed. Important factors included study design, attainment of ethical approval, evidence of a powerful calculation, specified eligibility criteria, appropriate controls, adequate information, and specified assessment measures. It was expected that confounding factors be reported and appropriate data analysis be made in addition to an explanation of the missing data.
A structured review was performed.
| Results|| |
Five studies that fulfilled the inclusion criteria were considered eligible.
| Discussion|| |
Gupta and Gupta  showed that, although more than 90% of the patients who have no pre-existing DR carry a good visual prognosis and eventually have 20/40 or better visual acuity (VA), nearly one-third of patients with pre-existing retinopathy may show retinopathy progression.
Krepler and colleagues investigated 42 patients with DM and mild-to-moderate nonproliferative diabetic retinopathy (NPDR) in both eyes who underwent cataract surgery, but no patients with advanced stages of retinopathy, clinically significant macular edema (CSME), or previous laser treatment were included. Moreover, diabetic patients without DR were excluded and they reported a progression of DR in 12% of operated versus 10.8% of nonoperated eyes during the follow-up of 12 months. In the 42 operated eyes, DR improved in none of the eyes, it was unchanged in 37 (88%) eyes, and progressed to moderate-to-severe nonproliferative retinopathy in five (12%) eyes during the first postoperative year. None of the eyes progressed to proliferative retinopathy. Five of the 42 nonoperated fellow eyes were excluded from analysis, four underwent cataract surgery because of progressive cataract between 3 and 5 months after cataract surgery of the first eye, and one developed ischemic central retinal vein occlusion and was treated. Of the remaining 37 nonoperated fellow eyes, four (10.8%) had a progression of retinopathy, one of which progressed to proliferative retinopathy. There was no statistically significant difference in the progression rates between operated eyes and nonoperated fellow eyes .
During the same follow-up period of 12 months, Squirrell and colleagues showed that, of the 50 patients (28 patients with mild or moderate NPDR) undergoing unilateral phacoemulsification surgery, 20% of the operated eyes and 16% of the nonoperated eyes had a progression of DR. In seven patients, the retinopathy progressed in both eyes. In three patients, it progressed in the operated eye alone. In one patient, it progressed in the fellow eye alone .
Studies by Krepler et al.  and Squirrell et al.  suggest that patients with no DR, or mild-to-moderate NPDR preoperatively have no increased risk of progression owing to phacoemulsification, and progression simply represents natural course of the disease.
In the study by Flesner et al., they evaluated the effect of phacoemulsification on DR. Thirty-nine diabetic patients completed 6 months of follow-up after phacoemulsification. In each patient, one eye underwent phacoemulsification and the other eye was considered a control. At baseline, 50% of the patients had no retinopathy, 23% had background retinopathy, 2.5% had preproliferative retinopathy, 16% were previously photocoagulated, and 10% had quiescent proliferative retinopathy. At the final follow-up, seven patients who underwent phacoemulsification showed progression and two patients showed progression in the control eye. They concluded that when DR is not in a proliferative phase it should not be regarded as a contraindication to phacoemulsification .
Mittra and colleagues in their retrospective review evaluated 150 eyes of 119 diabetic patients who underwent phacoemulsification surgery. Preoperative laser therapy was performed on 53 eyes. Eight eyes underwent focal/grid laser therapy for DME, 32 eyes underwent panretinal photocoagulation (PRP) for proliferative retinopathy, and 13 additional eyes underwent both procedures. They reported 25% progression rate of DR after phacoemulsification . Another 1-year prospective follow-up study of 32 patients [50% with severe NPDR and proliferative diabetic retinopathy (PDR)] showed a significantly higher rate of DR progression in eyes with severe retinopathy. Progression rate was 50% in eyes with severe NPDR or PDR and only 12.5% in eyes with no DR or only mild-to-moderate NPDR .
The study by Fong et al.  showed that patients with diabetes and those with a history of preoperative laser treatment for prior CSME or PDR had no or less improvement in their VA compared with patients with DR but with no history of previous laser treatment. Patients without previous laser treatment gained an average 2 logMAR lines 1 year after phacoemulsification cataract surgery.
Prospective studies with good controls suggest that there is no increased risk of progression of DR in diabetic patients with no DR, or only mild-to-moderate NPDR. However, the risk of worsening with severe NPDR or PDR has been reported .
DME has been shown to worsen after cataract surgery, although controversy remains as to the incidence of this worsening. Studies have shown that there are two types of worsening of ME after surgery, transient pseudophakic edema that spontaneously resolves (Irvine-Gass syndrome) and actual progression of diabetic maculopathy. Distinguishing transient edema from substantial progression of maculopathy is important to the timing of treatment for the ME, including laser photocoagulation, vitrectomy, and triamcinolone injection .
Gupta and Gupta have shown that postoperative angiographic ME is more common in patients with diabetes, but resolves spontaneously in patients with no or minimal DR. In patients with moderate-to-severe NPDR or more, CSME tends to persist, may arise de novo, or even worsen after cataract surgery .
Dowler and colleagues demonstrated that CSME arising after surgery commonly resolved, particularly if retinopathy was mild. CSME occurred in half of the eyes in which CSME was absent at the time of surgery, with a peak incidence at 6 weeks. It resolved spontaneously by 6 months in half of the eyes affected and by 1 year in three-quarters of the affected eyes. Moreover, they reported that CSME present in diabetic eyes at the time of cataract surgery is unlikely to resolve spontaneously .
Some studies suggest that, in diabetic patients who underwent uneventful phacoemulsification, postoperative ME probably represents natural disease progression rather than being a direct effect of surgery. In the study by Krepler et al. , ME occurred in 31% of the operated eyes, which was not significantly different from the fellow eyes. Similarly, in the study by Romero-Aroca et al. , of the 132 diabetic patients who underwent cataract surgery, ME occurred in the operated eye in eight patients (6.1%) and in the fellow eye in six patients (4.5%). However, patient population in both of these studies consisted of patients with mild-to-moderate retinopathy ,.
Squirrell et al.  have shown an increased risk of DR progression following cataract surgery in patients with elevated hemoglobin A1c (HgbA1c). Moreover, longer surgical duration and surgical inexperience resulted in an increased rate of retinopathy progression . The Early Treatment Diabetic Retinopathy Study (ETDRS) identified that patients with moderate-to-severe NPDR had a significantly higher risk of poor visual results when compared with patients with mild NPDR after lens extraction. In this study, 53% of the eyes with mild NPDR had VA of 20/40 or better and only 1% of eyes had VA 5/200 or worse at 1-year follow-up. In contrast, only 25% of eyes with severe DR had 20/40 or better vision and 22% had vision worse than 5/200 . The longer duration of diabetes had a significant adverse influence on the surgical visual outcome, after considering DR status .
The presence of maculopathy at the time of surgery has been suggested to be a risk factor for poorer visual outcome. If CSME is identified before surgery, the Royal College of Ophthalmologists' guidelines for cataract surgery in diabetic patients state that it should be treated at least 12 weeks before surgery. However, it is not uncommon to see patients with significant cataract that impedes the treatment or even diagnosis of CSME. It has also been recommended that pre-existing CSME identified after surgery should be treated promptly but the results are usually poor .
In a prospective study, 42 diabetic patients with ME were randomly assigned to receive either cataract surgery with phacoemulsification only or combined with 1.25 mg of intravitreal bevacizumab. Macular thickness (MT) measured by means of optical coherence tomography was over 300 μm in all patients. The eyes that had been subjected to laser treatment within 12 months before surgery or with PDR were excluded. At the first and third month after surgery, MT significantly decreased in the intravitreal bevacizumab group, whereas it significantly increased in the control group. At the third month after surgery, VA significantly improved in both groups, but VA was significantly higher in the bevacizumab group than in the control group. The authors concluded that further improvement of VA in the bevacizumab group may be related to the reduction in MT .
In a prospective and noncomparative study, 17 eyes with DME underwent phacoemulsification with intravitreal injection of 4 mg of triamcinolone acetonide. All patients had a central MT of at least 250 μm. Patients who had undergone laser treatment less than 3 months before surgery and/or PDR were excluded from the study. VA significantly improved with 2.4 lines (Snellen) in 58.8% of the patients, with a peak at month 4. ME gradually recurred during 6 months in all eyes but one. However, the mean central MT was significantly lower than that at baseline at all visits (with the minimum at the second month) until the sixth month at which it was not significantly different from the baseline. Of the 17 eyes, four developed transient intraocular pressure increase, which returned to normal by 6 months in all but one patient .
Chae and colleagues evaluated as to whether intravitreal ranibizumab injection at cataract surgery prevents postoperative diabetic macular edema (PME) in patients with stable DR without significant ME. Eighty patients with cataract, stable DR, and no significant ME were randomized to a sham group (cataract surgery only), or a group undergoing cataract surgery plus intraoperative ranibizumab injection. Best-corrected visual acuities, central subfield thickness, and total macular volume were assessed at baseline and 1 week, 1, 3, and 6 months postoperatively by means of optical coherence tomography. Clinically meaningful PME (central subfield thickness increase>60 μm relative to baseline) was computed. The results showed that the groups did not differ in baseline best-corrected visual acuity, central subfield thickness, and total macular volume. Postoperatively, the sham group had significantly larger central subfield thickness increases relative to baseline at 1 week and 1 month, larger total macular volume increases at all time points (P = 0.012, P = 0.005, P<0.001, P < 0.001, P = 0.005, and P = 0.017, respectively), higher PME occurrence at 1 month (P = 0.019), and poorer best-corrected visual acuity improvement from baseline to 6 months after surgery (P = 0.046). They concluded that, in patients with stable DR without significant ME, intravitreal ranibizumab injection at cataract surgery may prevent the postoperative worsening of ME and may improve the final visual outcome .
All efforts should be made to stabilize DR before cataract surgery. All diabetic patients need close observation for at least 6 months following surgery to intervene as and when required to prevent visual loss from diabetic maculopathy and other consequences of DR .
| Conclusion|| |
Diabetic patients with no DR or only mild-to-moderate NPDR have no increased risk of progression of DR after phacoemulsification. However, the risk of worsening with severe NPDR or PDR has been reported. There is increased risk of DR progression following cataract surgery in patients with elevated hemoglobin A1c (HgbA1c). CSME edema present in diabetic eyes at the time of phacoemulsification is unlikely to resolve spontaneously.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Viswanath K, Murray McGavin DD. Diabetic retinopathy: clinical findings and management. Community Eye Health 2003; 16
King H, Aubert RE, Herman WH. Global burden of diabetes, 1995-2025: prevalence, numerical estimates, and projections. Diabetes Care 1998; 21
Klein R, Klein BE, Moss SE, Davis MD, DeMets DL. The Wisconsin epidemiologic study of diabetic retinopathy IV. Diabetic macular edema. Ophthalmology 1984; 91
Klein BEK, Klein R, Moss SE. Incidence of cataract surgery in the WESDR. Am J Ophthalmol 1995; 119
Somaiya MD, Burns JD, Mintz R, Warren RE, Uchida T, Godley BF. Factors affecting visual outcomes after small incision phacoemulsification in diabetic patients. J Cataract Refract Surg 2002; 28
Gupta A, Gupta V. Diabetic maculopathy and cataract surgery. Ophthalmol Clin North Am 2001; 14
Krepler K, Biowski R, Schrey S, Jandrasits K, Wedrich A. Cataract surgery in patients with diabetic retinopathy: visual outcome, progression of diabetic retinopathy, and incidence of diabetic macular edema. Graefes Arch Clin Exp Ophthalmol 2002; 240
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
Flesner P, Sander B, Henning V, Parving HH, Dornonville de la Cour M, Lund-Andersen H. Cataract surgery on diabetic patients. A prospective evaluation of risk factors and complications. Acta Ophthalmol Scand 2002; 80
Mittra RA, Borillo JL, Dev S,Mieler WF,Koenig SB. Retinopathy progression and visual outcomes after phacoemulsification in patients with diabetes mellitus. Arch Ophthalmol 2000; 118
Dowler JG, Kulwant SS, Hykin PG, Hamilton PA. The natural history of macular edema after cataract surgery in diabetes. Ophthalmology 1999; 106
Fong CS, Mitchell P, Rochtchina E, Loryn T, Hong T, Wang JJ. Visual outcomes 12 months after phacoemulsification cataract surgery in patients with diabetes. Acta Ophthalmol 2012; 90
Rashid S, Young LH. Progression of diabetic retinopathy and maculopathy after phacoemulsification surgery. Int Ophthalmol Clin 2010; 50
Hayashi K, Igarashi C, Hirata A, Hayashi H. Changes in diabetic macular edema after phacoemulsification surgery. Eye 2009; 23
Romero-Aroca P, Ferna´ndez-Ballart J, Almena-Garcia M, Mendez-Marin I, Salvat-Serra M, Buil-Calvo JA. Nonproliferative diabetic retinopathy and macular edema progression after phacoemulsification: prospective study. J Cataract Refract Surg 2006; 32
Chew EY, Benson WE, Remaley NA, Lindley AA, Burton TC, Csaky K, et al
. Results after lens extraction in patients with diabetic retinopathy. Early treatment diabetic retinopathy study report number 25. Arch Ophthalmol 1999; 117
Lam DS, Chan CK, Mohamed S, Lai TY, Lee VY, Lai WW, et al
. Phacoemulsification with intravitreal triamcinolone in patients with cataract and coexisting diabetic macular oedema: a 6-month prospective pilot study. Eye (Lond) 2005; 19
Takamura Y, Kubo E, Akagi Y. Analysis of the effect of intravitreal bevacizumab injection on diabetic macular edema after cataract surgery. Ophthalmology 2009; 116
Chae JB, Joe SG, Yang SJ, Lee JY, Sung KR, Kim JY, et al
. Effect of combined cataract surgery and ranibizumab injection in postoperative macular edema in nonproliferative diabetic retinopathy. Retina 2014; 34