Extensive argon laser photocoagulation in the treatment of proliferative diabetic retinopathy

Photocoagulation Up to Ora Serrata in Diabetic Vitrectomy to Prevent Recurrent Vitreous Hemorrhage

PURPOSE

To evaluate the role of performing photocoagulation up to ora serrata during vitrectomy in preventing recurrent vitreous hemorrhage (VH) in patients undergoing pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR).

METHODS

This retrospective, nonrandomized study included 60 eyes from 60 patients who had undergone PPV for VH due to PDR. These patients were divided into two groups: group 1, those who underwent photocoagulation up to ora serrata using the scleral indentation technique during surgery; and group 2, those who did not undergo scleral indentation when photocoagulation and underwent photocoagulation up to vortex veins. Their hospital records were analyzed to investigate the recurrence rate of VH, the time until recurrence of VH after surgery, logarithm of the minimal angle of resolution (logMAR) best-corrected visual acuity (BCVA) measured before surgery and at 1, 2, and 3 years after surgery, and the occurrence of complications such as neovascular glaucoma (NVG) during follow-up.

RESULTS

Group 1 exhibited lower recurrence rate of VH (2 of 30 [6.7%] vs. 10 of 30 [33.3%], p = 0.01) and lower occurrence of postoperative NVG (2 of 30 [6.7%] vs. 8 of 30 [26.7%], p = 0.038) compared with group 2. There were no statistically significant differences in logMAR BCVA measured at 1, 2, and 3 years between the two groups (at 1 year: 0.54 ± 0.43 vs. 0.54 ± 0.44, p = 0.954; at 2 years: 0.48 ± 0.47 vs. 0.55 ± 0.64, p = 0.235; at 3 years: 0.51 ± 0.50 vs. 0.61 ± 0.77, p = 0.200). Logistic regression analysis showed that among several factors that could affect recurrence rate of VH, only range of photocoagulation performed was a statistically significant factor (odds ratio, 0.119; 95% confidence interval, 0.022-0.659; p = 0.015).

CONCLUSIONS

Photocoagulation treatment over a wider range with scleral indentation could be a beneficial adjunct procedure for preventing postoperative recurrent VH following diabetic vitrectomy.

INTRAVITREAL BEVACIZUMAB FOR PROLIFERATIVE DIABETIC RETINOPATHY: Results From the Pan-American Collaborative Retina Study Group (PACORES) at 24 Months of Follow-up

PURPOSE

To evaluate the effects of intravitreal bevacizumab (IVB) on retinal neovascularization in patients with proliferative diabetic retinopathy (PDR).

METHODS

Retrospective multicenter interventional case series. A chart review was performed of 81 consecutive patients (97 eyes) with retinal neovascularization due to PDR, who received at least 1 IVB injection.

RESULTS

The mean age of the patients was 55.6 ± 11.6 years. The mean number of IVB injections was 4 ± 2.5 injections (range, 1-8 injections) per eye. The mean interval between IVB applications was 3 ± 7 months. The mean duration of follow-up was 29.6 ± 2 months (range, 24-30 months). Best-corrected visual acuity and optical coherence tomography improved statistically significantly (P < 0.0001, both comparisons). Three eyes without previous panretinal photocoagulation ("naive" eyes) and with vitreous hemorrhage did not require vitreoretinal surgery. Five (5.2%) eyes with PDR progressed to tractional retinal detachment requiring vitrectomy. No systemic adverse events were noted.

CONCLUSION

Intravitreal bevacizumab resulted in marked regression of retinal neovascularization in patients with PDR and previous panretinal photocoagulation. Intravitreal bevacizumab in naive eyes resulted in control or regression of 42.1% of eyes without adjunctive laser or vitrectomy during 24 months of follow-up. There were no safety concerns during the 2 years of follow-up of IVB for PDR.

Pascal panretinal laser ablation and regression analysis in proliferative diabetic retinopathy: Manchester Pascal Study Report 4

AIMS

To quantify the 20-ms Pattern Scan Laser (Pascal) panretinal laser photocoagulation (PRP) ablation dosage required for regression of proliferative diabetic retinopathy (PDR), and to explore factors related to long-term regression.

METHODS

We retrospectively studied a cohort of patients who participated in a randomised clinical trial, the Manchester Pascal Study. In all, 36 eyes of 22 patients were investigated over a follow-up period of 18 months. Primary outcome measures included visual acuity (VA) and complete PDR regression. Secondary outcomes included laser burn dosimetry, calculation of retinal PRP ablation areas, and effect of patient-related factors on disease regression. A PDR subgroup analysis was undertaken to assess all factors related to PDR regression according to disease severity.

RESULTS

There were no significant changes in logMAR VA for any group over time. In total, 10 eyes (28%) regressed after a single PRP. Following top-up PRP treatment, regression rates varied according to severity: 75% for mild PDR (n=6), 67% for moderate PDR (n=14), and 43% in severe PDR (n=3). To achieve complete disease regression, mild PDR required a mean of 2187 PRP burns and 264 mm(2) ablation area, moderate PDR required 3998 PRP burns and area 456 mm(2), and severe PDR needed 6924 PRP laser burns (836 mm(2); P<0.05).

CONCLUSIONS

Multiple 20-ms PRP treatments applied over time does not adversely affect visual outcomes, with favourable PDR regression rates and minimal laser burn expansion over 18 months. The average laser dosimetry and retinal ablation areas to achieve complete regression increased significantly with worsening PDR.

Intravitreal Bevacizumab (Avastin) for Diabetic Retinopathy: The 2010 GLADAOF Lecture

This paper demonstrates multiple benefits of intravitreal bevacizumab (IVB) on diabetic retinopathy (DR) including diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) at 24 months of followup. This is a retrospective multicenter interventional comparative case series of intravitreal injections of 1.25 or 2.5 mg of bevacizumab for DME, PDR without tractional retinal detachment (TRD), and patients who experienced the development or progression of TRD after an intravitreal injection of 1.25 or 2.5 mg of bevacizumab before vitrectomy for the management of PDR. The results indicate that IVB injections may have a beneficial effect on macular thickness and visual acuity (VA) in diffuse DME. Therefore, in the future this new therapy could complement focal/grid laser photocoagulation in DME. In PDR, this new option could be an adjuvant agent to panretina photocoagulation so that more selective therapy may be applied. Finally, TRD in PDR may occur or progress after IVB used as an adjuvant to vitrectomy. Surgery should be performed 4 days after IVB. Most patients had poorly controlled diabetes mellitus associated with elevated HbA1c, insulin administration, PDR refractory to panretinal photocoagulation, and longer time between IVB and vitrectomy.

Intracameral bevacizumab and mitomycin C Trabeculectomy for eyes with neovascular glaucoma: a case series

The purpose of this study was to describe the surgical outcomes and safety of intracameral bevacizumab during trabeculectomy in eyes with neovascular glaucoma. Pilot study included four eyes (four patients) with refractory neovascular glaucoma submitted to fornix-based trabeculectomy with adjunctive use of bevacizumab in the anterior chamber during the procedure. Patients were previously treated with panretinal photocoagulation as standard therapy. Variables evaluated were intraocular pressure, bleb appearance, iris neovascularization, intraoperative/postoperative complications, and visual outcomes. No intraoperative complication was observed. The mean follow-up period was 12.75 (range, 12–15 months). All eyes showed significant intraocular pressure control postoperatively. Iris neovascularization reduced significantly within 1 month after surgery. Mild anterior chamber inflammation was observed during follow-up in all eyes. No significant postoperative complication was observed, and no patient presented visual acuity deterioration. Intracameral bevacizumab may be used as an adjunctive therapy during trabeculectomy in eyes with neovascular glaucoma.

A proposed new classification for diabetic retinopathy: the concept of primary and secondary vitreopathy

BACKGROUND

Many eyes with proliferative diabetic retinopathy (PDR) require vitreous surgery despite complete regression of new vessels with pan retinal laser photocoagulation (PRP). Changes in the vitreous caused by diabetes mellitus and diabetic retinopathy may continue to progress independent of laser regressed status of retinopathy. Diabetic vitreopathy can be an independent manifestation of the disease process.

AIM

To examine this concept by studying the long-term behavior of the vitreous in cases of PDR regressed with PRP.

MATERIALS AND METHODS

Seventy-four eyes with pure PDR (without clinically evident vitreous traction) showing fundus fluorescein angiography (FFA) proven regression of new vessels following PRP were retrospectively studied out of a total of 1380 eyes photocoagulated between March 2001 and September 2006 for PDR of varying severity. Follow-up was available from one to four years.

RESULTS

Twenty-three percent of eyes showing FFA-proven regression of new vessels with laser required to undergo surgery for indications produced by vitreous traction such as recurrent vitreous hemorrhage, tractional retinal detachment, secondary rhegmatogenous retinal detachment and tractional macular edema within one to four years.

CONCLUSION

Vitreous changes continued to progress despite regression of PDR in many diabetics. We identifies this as "clinical diabetic vitreopathy" and propose an expanded classification for diabetic retinopathy to signify these changes and to redefine the indications for surgery.

Intravitreal bevacizumab (Avastin) for proliferative diabetic retinopathy: 6-months follow-up

AIMS

To study the effects of intravitreal bevacizumab (Avastin) on retinal neovascularization (RN) in patients with proliferative diabetic retinopathy (PDR).

METHODS

Retrospective study of patients with RN due to PDR who were treated with at least one intravitreal injection of 1.25 or 2.5 mg of bevacizumab. Patients underwent ETDRS best-corrected visual acuity (BCVA) testing, ophthalmoscopic examination, optical coherence tomography (OCT), and fluorescein angiography (FA) at baseline and follow-up visits.

RESULTS

Forty-four eyes of 33 patients with PDR and a mean age of 57.2-years (range: 23-82 years) participated in the study. Thirty-three eyes (75%) had previous panretinal photocoagulation (PRP). Twenty-seven eyes (61.4%) showed total regression of RN on fundus examination with absence of fluorescein leakage, 15 eyes (34.1%) demonstrated partial regression of RN on fundus examination and FA. Follow-up had a mean of 28.4 weeks (range from 24 to 40 weeks). BCVA and OCT demonstrated improvement (P<0.0001). Three eyes without previous PRP ('naive' eyes) and with vitreous haemorrhage have avoided vitreo-retinal surgery. One eye (2.2%) had PDR progression to tractional retinal detachment requiring vitrectomy, and one eye (2.2%) had vitreous haemorrhage with increased intraocular pressure (ghost cell glaucoma). No systemic adverse events were observed.

CONCLUSIONS

Intravitreal bevacizumab resulted in marked regression of RN in patients with PDR and previous PRP, and rapid resolution of vitreous haemorrhage in three naive eyes. Six-months results of intravitreal bevacizumab at doses of 1.25 or 2.5 mg in patients with PDR do not reveal any safety concerns.

The National Diabetic Retinopathy Laser Treatment Audit. III. Clinical outcomes

PURPOSE

To describe the short-term clinical outcomes for a cohort of patients undergoing first photocoagulation treatment for proliferative retinopathy or maculopathy in the United Kingdom.

METHOD

Nine-month follow-up of the Royal College of Ophthalmologists' national audit of laser treatment for diabetic retinopathy.

RESULTS

For eyes with maculopathy, 9.2% had had a deterioration in visual acuity equivalent to a doubling of the visual angle and 3.3% of eyes had a visual acuity of less than 6/60 at follow-up. There had been an improvement in the macular oedema or exudate in 64.6% and 77.3% respectively. Prognostic factors for a poorer visual acuity at follow-up were worse visual acuity at baseline, the presence of diffuse (vs focal) oedema and grid (vs focal) treatment. For eyes with proliferative retinopathy, the retinal neovascularisation had regressed fully in 50.8% of cases, whilst there had been no change or a deterioration in 10.3%. A visual acuity of less than 6/60 at follow-up was present in 8.6% of eyes. There was a poor morphological outcome at follow-up (as defined by rubeosis, new tractional detachment or having had a vitrectomy) in 7.2%. Risk factors for poor morphological outcome were the presence of 'high-risk characteristics', female sex and the presence of concurrent maculopathy at baseline. Regression of neovascularisation was associated with greater areas of retinal ablation at the initial treatment session. Although some eyes with proliferative retinopathy appeared to be undertreated initially compared with DRS and ETDRS protocols, some of these eyes did respond to lower amounts of treatment.

CONCLUSION

For maculopathy, poorer outcome was related to worse visual acuity at baseline, diffuse (vs focal) maculopathy, and grid treatment. For proliferative retinopathy, poorer outcome was related to 'high-risk characteristics' and coexistence of maculopathy at baseline, and improvement was related to larger areas of ablation. The relationship of poor outcome with worse initial disease argues for earlier detection of retinopathy.

The National Diabetic Retinopathy Laser Treatment Audit. II. Proliferative retinopathy

The National Diabetic Retinopathy Laser Treatment Audit is a prospective survey of laser treatment for diabetic retinopathy throughout the United Kingdom. This paper presents data on 284 patients who were undergoing their first panretinal photocoagulation for proliferative retinopathy during a 2 month period in 1995, describing the demographic features, the level of systematic screening, the sources of referral, and the waiting times. For those cases where proliferative retinopathy was present at the first ophthalmology outpatient visit, the retinopathy was detected as a result of systematic screening in 46.8%, whilst 28.7% presented symptomatically. Of these patients 28.4% waited for more than 12 weeks from referral to the time of laser treatment, but once the patient had been listed for laser treatment this was performed within 8 weeks in 95.3%. The retinopathy features and the type of treatment given are also described. Compared with the DRS and ETDRS recommendations, at least 32.5-40.2% of eyes may be undertreated initially, and for those with high-risk characteristics these figures were at least 30.8-38.5%.

Relationship of diabetic microvascular complications to outcome in panretinal photocoagulation treatment of proliferative diabetic retinopathy

Argon laser panretinal photocoagulation for proliferative diabetic retinopathy was shown in the Diabetic Retinopathy Study and Early Treatment Diabetic Retinopathy Study to reduce the incidence of blindness by 50% with relatively small amounts of treatment. However, some diabetics require much more extensive photocoagulation for control of proliferative disease. We attempted to determine risk factors for poor response to treatment with panretinal photocoagulation (PRP) by studying outcome in relation to the argon laser burn count and the presence of diabetic vascular complications. Sixty-six consecutively treated eyes undergoing PRP were studied, of which 57% showed resolution of new vessels 6 weeks after treatment. This was significantly related to the total amount of laser treatment given (mean no. in regressed eyes 5800 burns, non-regressed 3510 burns; p < 0.05). Renal disease and age (< 50 years) were identified as risk factors for non-regression (p < 0.05); hypertension, neuropathy, duration of disease and insulin dependence had no significant effect on outcome. We conclude that regression of proliferative disease is significantly related to the cumulative total number of laser burns applied and that successful laser photocoagulation in patients with diabetic renal disease requires considerably more treatment than that suggested by earlier studies.

Quantitation of retinal ablation in proliferative diabetic retinopathy

PURPOSE

We studied 294 eyes of 182 patients, to quantitate the amount of retinal ablation required for regression of proliferative diabetic retinopathy.

METHODS

Eyes included in the study had two or more proliferative diabetic retinopathy risk factors, received panretinal photocoagulation, and had a minimum follow-up of one year. Laser photocoagulation or cryotherapy was given to eyes that failed to regress or had progression of retinopathy. Eyes treated by other physicians, treated with xenon arc photocoagulation, or undergoing laser treatment or vitrectomy for other retinal conditions were excluded. The total area of retina ablated was calculated and used as a quantitative measure of treatment.

RESULTS

Regression was observed in 275 eyes (93%); 19 eyes (7%) failed to regress and eventually required vitrectomy. Panretinal photocoagulation alone successfully led to regression in 229 eyes (77%), whereas 46 eyes (15.6%) required both photocoagulation and peripheral anterior retinal cryotherapy. An average of 1.7 treatments per eye led to regression. Eyes were bimodally distributed by requirement for treatment, into low and high treatment groups. Low treatment eyes received an average of 510 mm2 of retinal ablation (2,600 500-microns burns), and high treatment eyes, 1,280 mm2 (6,500 500-microns burns). More extensive treatment was required with more retinopathy risk factors (P = .002 for four vs three risk factors and P = .0007 for four vs two risk factors); duration of diabetes mellitus longer than 15 years (P = .004), and onset of diabetes mellitus before 30 years of age (P = .0008).

CONCLUSION

Patients with proliferative diabetic retinopathy should be treated aggressively with panretinal photocoagulation, cryotherapy, or both. The amount of initial treatment required for regression may be considerably more than that recommended by the Diabetic Retinopathy Study.

Early vitrectomy for progressive diabetic proliferations covering the macula

The clinical course in 50 eyes was analysed after pars plana vitrectomy for progressive diabetic fibrovascular proliferations. Patients were assigned to pars plana vitrectomy if progression of proliferations occurred despite a photocoagulation treatment with a mean number of 3500 burns and additional peripheral cryoablation. All cases had visual impairment because of fibrovascular tissue covering the macula without detachment of the macula. Flat proliferations were present in all eyes without retinal elevation, vitreous detachment, or vitreous haemorrhage. The follow up intervals ranged from 13 months to 39 months (mean interval 24 months). Twelve months postoperatively, 36 eyes (72%) showed improved visual acuity, five eyes (10%) were worse, and nine eyes (18%) were unchanged. Thirty two eyes (64%) achieved a final visual acuity of 0.2 or better, and 45 eyes (90%) gained 0.05 or better. In only two eyes could reproliferation be observed. The postoperative course indicates that pars plana vitrectomy for diabetic fibrovascular proliferations covering the macula can preserve socially useful visual acuity of at least 0.05 in most cases.

Characterisation of the neovascularisation process in diabetic retinopathy by means of fractal geometry: diagnostic implications

The neovascularisation formation and regression process of the peripheral retina in diabetic retinopathy was studied by means of fractal analysis. The fractal dimension of the local retinal vessel pattern was calculated to be significantly lower before formation of relevant neovascularisations than 2.5 years later, after formation of strong preretinal neovascularisations. Another year later the new vessels had regressed partially and the fractal dimension was again significantly reduced. This behaviour is almost independent of the representation of the vessel thickness during calculation. Since the retinal vasculature is a fractal, the fractal dimension appears as the "natural" measure of proliferative retinal vessel changes. It is demonstrated that the fractal dimension can be applied to characterise proliferative diabetic retinopathy. These features offer the possibility for computer-driven ("automated") quantitative characterisation of the treatment effect in proliferative diabetic retinopathy and possibly automated detection of proliferative diabetic retinopathy in the future. The limitations of the method are discussed.

Anterior hyaloidal fibrovascular proliferation after extracapsular cataract extraction in diabetic eyes

Four patients with proliferative diabetic retinopathy developed anterior hyaloidal fibrovascular proliferation after extracapsular cataract extraction and posterior chamber lens implantation. This complication of cataract extraction has been described after vitrectomy in diabetic eyes. Risk factors for this entity after extracapsular cataract extraction include proliferative diabetic retinopathy, iris neovascularization, and anterior ischemic retina. Anterior hyaloidal fibrovascular proliferation was observed an average of 12 months postoperatively and affected vision in one of four patients. No progression was seen within an average of six months of follow-up, and no complications such as traction retinal detachment and vitreous hemorrhage developed.

Cost-effectiveness of the screening and treatment of diabetic retinopathy. What are the costs of underutilization?

Diabetic retinal disease remains a leading cause of visual disability among those of working age. Controlled trials have demonstrated that timely diagnosis and photocoagulation treatment can reduce significantly the likelihood of visual impairment in affected diabetic patients. Using a prospective simulation model, we show that an annual screening and treatment program saves thousands of years of vision and reduces medical expenditures over the lifetime of a cohort of Swedish Type I diabetic patients.