Clinical applications of the MicroPulse diode laser

PURPOSE

To evaluate the efficacy of the Iris Oculight MicroPulse 810 nm diode laser in the treatment of macular oedema secondary to either branch retinal vein occlusion (BRVO) or diabetic maculopathy and in the treatment of proliferative diabetic retinopathy. The specific advantages of this type of laser delivery are greater retinal pigment epithelial specificity and less damage to the inner retina, thus preserving visual field and colour contrast sensitivity.

METHODS

Fifty-two eyes of 33 consecutive patients were treated over a 6-month period. Thirteen eyes had proliferative diabetic retinopathy and 39 had macular oedema secondary to BRVO or diabetic maculopathy. Panretinal and grid pattern photocoagulation were performed using the micropulse mode with the laser on for 100-300 microseconds and off for between 1900 and 1700 microseconds repeatedly in a pulse envelope of 0.1-0.3 s duration. Microaneurysms were not treated directly. Patients were assessed clinically and angiographically at 3 and 6 months.

RESULTS

Ten eyes (77%) with proliferative disease showed some regression of new vessels at 6 months. Twenty-two eyes (57%) showed resolution of macular oedema at 6 months. Visual acuity was maintained in 27 eyes (69%) and improved in 11 eyes (28%).

CONCLUSION

Diode laser in micropulse mode is effective in the management of diabetic and occlusive macular oedema and proliferative diabetic disease.

Vitrectomy results in diabetic macular oedema without evident vitreomacular traction

PURPOSE

To determine the effectiveness of vitrectomy in eyes with diabetic macular oedema without evident traction from a thickened vitreous membrane.

METHODS

Twenty-one consecutive eyes from 19 patients with diabetic macular oedema that had undergone vitrectomy were analysed retrospectively. All eyes had an attached posterior hyaloid membrane in the macular region, but without thickening and without evident traction on the macula. A standard pars plana vitrectomy with the creation of a posterior vitreous detachment was performed.

RESULTS

Median duration of macular oedema at the time of vitrectomy was approximately 11.0 months (range 2-36 months). The median preoperative best-corrected visual acuity of 0.08 (range hand motions/0.003 to 0.4), improved by 5 lines to a median final postoperative best-corrected visual acuity of 0.25 (range 0.025-0.5) (P = 0.001). Seven eyes without preoperative macular photocoagulation had a median visual acuity improvement of 77%, range 32-400%, while 12 eyes with preoperative macular laser treatment had a median visual acuity improvement of 14.8%, range 0-66.1% (P = 0.02, CI 95%, after multivariate regression analysis). In all 21 eyes, macular oedema was no longer visible on microscopic examination after a median period of 3.0 months (range 1-9 months) after vitrectomy.

CONCLUSIONS

In eyes with diabetic macular oedema without evident macular traction from a thickened vitreous membrane, vitrectomy resulted in the resolution of macular oedema, with an improvement in visual acuity in the majority of cases. Eyes without preoperative macular photocoagulation had a significantly higher percentage visual improvement than eyes without preoperative macular laser treatment. A randomised controlled prospective trial of primary vitrectomy versus macular photocoagulation is needed to determine the role of vitrectomy as treatment modality for diabetic macular oedema.

Characteristics of Type 1 diabetes of over 50 years duration (the Golden Years Cohort)

BACKGROUND

Type 1 diabetes mellitus is associated with high levels of premature morbidity and mortality. Prolonged survival is possible, however, and some patients appear to be protected from the long-term complications of this condition.

METHODS

Diabetes UK awards medals to patients who have had Type 1 diabetes for 50 years or more. By examining medal-holders, we have established the clinical and biochemical features of a group of 400 subjects (54% male) with Type 1 diabetes of long duration.

RESULTS

Mean age of the subjects was 68.9 years and mean age-at-onset of diabetes 13.7 years. Features of long duration diabetes in this cohort include normal body mass (mean BMI 25.0 kg m-2), low insulin dose (mean 0.52 units kg-2) and greatly elevated HDL-cholesterol (mean 1.84 mmol/l). Mean HbA1c was 7.6% (normal range 3.8-5.0%) and no patient had a normal HbA1c at the time of venesection. As a group, they have long-lived parents and consume moderate amounts of alcohol. Medical contact has often been sporadic. A significant proportion (29%) were taking anti-hypertensive medication. Screening for micro- and macroalbuminuria was positive in 35.7%.

CONCLUSIONS

Patients with long-duration (> 50 years) Type 1 diabetes are relatively protected from clinical diabetic nephropathy and large vessel disease; our data are consistent with protection possibly being genetically determined in part via elevated HDL-cholesterol levels. An abnormal urinary albumin/creatinine ratio is common in these patients, despite their low risk of significant renal deterioration; this may have implications for microalbuminuria screening programmes.

Pars plana vitrectomy with removal of the internal limiting membrane in the treatment of persistent diabetic macular edema

PURPOSE

To evaluate the benefit of pars plana vitrectomy (PPV) and removal of the internal limiting membrane (ILM) in eyes with diffuse diabetic macular edema refractory to laser photocoagulation.

DESIGN

Prospective, consecutive, interventional case series.

METHODS

Diabetic patients with biomicroscopic, angiographic, and tomographic evidence of diabetic macular edema persisting for at least 3 months after numerous sessions of macular photocoagulation were evaluated for inclusion. Patients with biomicroscopic evidence of epiretinal membrane or taut posterior hyaloid, previous vitreoretinal surgery, or active proliferative diabetic retinopathy were excluded. The main outcome measures were macular thickness, as measured by optical coherence tomography (OCT) and visual acuity (VA).

RESULTS

PPV with ILM removal was performed in 11 eyes of 10 patients (four men, six women; mean age = 58.2 years). Six-month follow-up data were available for 10 eyes (91%). At 6 months postoperatively, central macular thickness had improved by at least 20% in eight of 11 eyes (mean preoperative thickness of 421 mum compared with mean postoperative thickness of 188 mum; P = .007). Mean VA improved from 20/352 to 20/94 at 6 months (P = .002). By the most recent visit (range = 6-20 months postoperatively), VA had improved by at least 2 Snellen lines in 6 of 10 eyes treated with surgery alone.

CONCLUSIONS

The early results of this ongoing study suggest that PPV with ILM removal may provide anatomic and visual benefit in some eyes with chronic diabetic macular edema unresponsive or unamenable to additional laser photocoagulation.

Factors associated with visual acuity outcomes after vitrectomy for diabetic macular edema: diabetic retinopathy clinical research network

PURPOSE

To evaluate factors ¶associated with favorable outcomes after vitrectomy for diabetic macular edema.

METHODS

Data were collected prospectively on 241 eyes undergoing vitrectomy for diabetic macular edema. Multivariate models were used to evaluate associations of 20 preoperative and intraoperative factors with 6-month outcomes of visual acuity and retinal thickness.

RESULTS

Median central subfield thickness decreased from 412 μm to 278 μm at 6 months, but median visual acuity remained unchanged (20/80, Snellen equivalent). Greater visual acuity improvement occurred in eyes with worse baseline acuity (P < 0.001) and in eyes in which an epiretinal membrane was removed (P = 0.006). Greater reduction in central subfield thickness occurred with worse baseline visual acuity (P < 0.001), greater preoperative retinal thickness (P = 0.001), removal of internal limiting membrane (P = 0.003), and optical coherence tomography evidence of vitreoretinal abnormalities (P = 0.006). No associations with clinician's preoperative assessments of the posterior vitreous were identified.

CONCLUSION

These results suggest that the removal of epiretinal membranes may favorably affect visual outcome after vitrectomy. Preoperative presence of vitreoretinal abnormalities appeared to be associated with somewhat greater reductions in retinal thickness but not with visual acuity outcome. These results may be useful for future studies evaluating vitrectomy for diabetic macular edema.

The lens and pars plana vitrectomy for diabetic retinopathy complications

Major cataracts developed in 28 of 168 eyes during the six months after pars plana vitrectomy for complications of diabetic retinopathy. In only ten of these cases did the cataract influence the visual results. The visual acuities of the phakic and aphakic eyes six months after vitrectomy were almost identical. Rubeosis iridis occurred in 23% of the phakic eyes and 45% of the aphakic eyes, with the difference being related to the loss in the aphakic eyes of a protective barrier lens quality. However, this same barrier quality increased the incidence of postoperative opaque vitreous hemorrhage from 8% of the aphakic eyes to 21% of the phakic eyes. Corneal epithelial edema at surgery occurred in 55% of those eyes that had lens removal combined with vitrectomy, but in only 36% of those that retained their lenses, and the difference was caused by the increase in operative time and procedure.

Randomized trial of peribulbar triamcinolone acetonide with and without focal photocoagulation for mild diabetic macular edema: a pilot study

OBJECTIVE

To provide pilot data on the safety and efficacy of anterior and posterior sub-Tenon injections of triamcinolone either alone or in combination with focal photocoagulation in the treatment of mild diabetic macular edema (DME).

DESIGN

Prospective, phase II, multicenter, randomized clinical trial.

PARTICIPANTS

One hundred nine patients (129 eyes) with mild DME and visual acuity 20/40 or better.

METHODS

The participants were assigned randomly to receive either focal photocoagulation (n = 38), a 20-mg anterior sub-Tenon injection of triamcinolone (n = 23), a 20-mg anterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 25), a 40-mg posterior sub-Tenon injection of triamcinolone (n = 21), or a 40-mg posterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 22). Follow-up visits were performed at 4, 8, 17, and 34 weeks.

MAIN OUTCOME MEASURES

Change in visual acuity and retinal thickness measured with optical coherence tomography (OCT).

RESULTS

At baseline, mean visual acuity in the study eyes was 20/25 and mean OCT central subfield thickness was 328 mum. Changes in retinal thickening and in visual acuity were not significantly different among the 5 groups at 34 weeks (P = 0.46 and P = 0.94, respectively). There was a suggestion of a greater proportion of eyes having a central subfield thickness less than 250 mum at 17 weeks when the peribulbar triamcinolone was combined with focal photocoagulation. Elevated intraocular pressure and ptosis were adverse effects attributable to the injections.

CONCLUSIONS

In cases of DME with good visual acuity, peribulbar triamcinolone, with or without focal photocoagulation, is unlikely to be of substantial benefit. Based on these results, a phase III trial to evaluate the benefit of these treatments for mild DME is not warranted.

Vitrectomy for cystoid macular oedema with attached posterior hyaloid membrane in patients with diabetes

AIM

To report the success of vitrectomy in eliminating cystoid macular oedema and improving vision in three eyes of two patients with diabetic cystoid macular oedema. In all of the eyes there was no ophthalmoscopic evidence of traction from a posterior hyaloid membrane or from proliferative tissue.

METHODS

Pars plana vitrectomy was performed on three eyes of two patients with diabetic cystoid macular oedema who did not show traction upon examination with a slit lamp biomicroscope and a scanning laser ophthalmoscope.

RESULTS

Cystoid changes disappeared 1, 3, and 5 days, postoperatively, and diffuse macular oedema resolved within 2 weeks. The visual acuity was improved and maintained.

CONCLUSION

Vitrectomy can be effective in some patients with diabetic cystoid macular oedema even in patients who lack evidence of traction by ophthalmoscopy.

Laser photocoagulation for proliferative diabetic retinopathy

BACKGROUND

Diabetic retinopathy is a complication of diabetes in which high blood sugar levels damage the blood vessels in the retina. Sometimes new blood vessels grow in the retina, and these can have harmful effects; this is known as proliferative diabetic retinopathy. Laser photocoagulation is an intervention that is commonly used to treat diabetic retinopathy, in which light energy is applied to the retina with the aim of stopping the growth and development of new blood vessels, and thereby preserving vision.

OBJECTIVES

To assess the effects of laser photocoagulation for diabetic retinopathy compared to no treatment or deferred treatment.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2014), EMBASE (January 1980 to June 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 3 June 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) where people (or eyes) with diabetic retinopathy were randomly allocated to laser photocoagulation or no treatment or deferred treatment. We excluded trials of lasers that are no longer in routine use. Our primary outcome was the proportion of people who lost 15 or more letters (3 lines) of best-corrected visual acuity (BCVA) as measured on a logMAR chart at 12 months. We also looked at longer-term follow-up of the primary outcome at two to five years. Secondary outcomes included mean best corrected distance visual acuity, severe visual loss, mean near visual acuity, progression of diabetic retinopathy, quality of life, pain, loss of driving licence, vitreous haemorrhage and retinal detachment.

DATA COLLECTION AND ANALYSIS

We used standard methods as expected by the Cochrane Collaboration. Two review authors selected studies and extracted data.

MAIN RESULTS

We identified a large number of trials of laser photocoagulation of diabetic retinopathy (n = 83) but only five of these studies were eligible for inclusion in the review, i.e. they compared laser photocoagulation with currently available lasers to no (or deferred) treatment. Three studies were conducted in the USA, one study in the UK and one study in Japan. A total of 4786 people (9503 eyes) were included in these studies. The majority of participants in four of these trials were people with proliferative diabetic retinopathy; one trial recruited mainly people with non-proliferative retinopathy. Four of the studies evaluated panretinal photocoagulation with argon laser and one study investigated selective photocoagulation of non-perfusion areas. Three studies compared laser treatment to no treatment and two studies compared laser treatment to deferred laser treatment. All studies were at risk of performance bias because the treatment and control were different and no study attempted to produce a sham treatment. Three studies were considered to be at risk of attrition bias.At 12 months there was little difference between eyes that received laser photocoagulation and those allocated to no treatment (or deferred treatment), in terms of loss of 15 or more letters of visual acuity (risk ratio (RR) 0.99, 95% confidence interval (CI) 0.89 to 1.11; 8926 eyes; 2 RCTs, low quality evidence). Longer term follow-up did not show a consistent pattern, but one study found a 20% reduction in risk of loss of 15 or more letters of visual acuity at five years with laser treatment. Treatment with laser reduced the risk of severe visual loss by over 50% at 12 months (RR 0.46, 95% CI 0.24 to 0.86; 9276 eyes; 4 RCTs, moderate quality evidence). There was a beneficial effect on progression of diabetic retinopathy with treated eyes experiencing a 50% reduction in risk of progression of diabetic retinopathy (RR 0.49, 95% CI 0.37 to 0.64; 8331 eyes; 4 RCTs, low quality evidence) and a similar reduction in risk of vitreous haemorrhage (RR 0.56, 95% CI 0.37 to 0.85; 224 eyes; 2 RCTs, low quality evidence).None of the studies reported near visual acuity or patient-relevant outcomes such as quality of life, pain, loss of driving licence or adverse effects such as retinal detachment.We did not plan any subgroup analyses, but there was a difference in baseline risk in participants with non-proliferative retinopathy compared to those with proliferative retinopathy. With the small number of included studies we could not do a formal subgroup analysis comparing effect in proliferative and non-proliferative retinopathy.

AUTHORS' CONCLUSIONS

This review provides evidence that laser photocoagulation is beneficial in treating proliferative diabetic retinopathy. We judged the evidence to be moderate or low, depending on the outcome. This is partly related to reporting of trials conducted many years ago, after which panretinal photocoagulation has become the mainstay of treatment of proliferative diabetic retinopathy.Future Cochrane Reviews on variations in the laser treatment protocol are planned. Future research on laser photocoagulation should investigate the combination of laser photocoagulation with newer treatments such as anti-vascular endothelial growth factors (anti-VEGFs).

Vitreous levels of vascular endothelial growth factor are not influenced by its serum concentrations in diabetic retinopathy

Vascular endothelial growth factor (VEGF) plays a major role in the development of neovascularization in proliferative diabetic retinopathy (PDR). The source of intravitreous VEGF is presumably ischaemic retina, but increased levels derived from serum cannot be excluded. The aim of the study is to determine the intravitreous concentrations of VEGF in diabetic patients with PDR and to investigate whether serum VEGF could contribute to the intravitreous concentration. For this purpose, we studied 20 diabetic patients (5 IDDM and 15 NIDDM) with PDR in whom a vitrectomy was performed (group A). Non-diabetic patients (n = 13) with other conditions requiring vitrectomy served as a control group (group B). In both groups, VEGF was determined in serum and undiluted vitreous samples obtained simultaneously. Furthermore, serum VEGF was determined in 69 healthy control subjects (group C) and 39 diabetic patients without microvascular complications (group D). Vitreous and serum VEGF was determined by ELISA (R & D Systems, Abingdon, UK); intra-assay CV 3.8%, interassay CV 5.1%. Intravitreous concentrations of VEGF were strikingly higher in group A (median 1.75 ng/ ml, range 0.33-6.66) in comparison with group B (median 0.009 ng/ml, range 0.009-0.038); p < 0.0001. This difference remained significant after adjusting for intravitreous protein concentration (p < 0.05). Differences in serum VEGF among the groups included in the study were not found. We conclude that the high vitreous levels of VEGF observed in diabetic patients with PDR cannot be attributed to serum diffusion across the blood-retinal barrier. Therefore, intraocular synthesis is the main contributing factor for the high vitreous VEGF concentrations observed in PDR.

Detecting and treating retinopathy in patients with type I diabetes mellitus. A health policy model

Diabetic retinopathy is the major cause of new cases of blindness among working-age Americans. The authors analyzed the medical and economic implications of alternative screening strategies for detecting retinopathy in a diabetic population. The approaches compared included dilated fundus examination at 6-, 12-, and 24-month intervals with and without fundus photography. Potential savings from screening and treatment are based on amounts paid by the federal government for blindness-related disability. Screening for and treating retinopathy in patients with type I diabetes mellitus was cost-effective using all screening strategies. Between 71,474 and 85,315 person years of sight and 76,886 and 94,705 person years of reading vision can be saved for each annual cohort of patients with type I diabetes mellitus when proper laser photocoagulation is administered. This results in a cost savings of $62.1 to $108.6 million. Annual examination of all diabetic patients and semi-annual examination of those with retinopathy was more effective than annual examination with fundus photography. This screening strategy is consistent with the Preferred Practice Pattern for Diabetic Retinopathy of the American Academy of Ophthalmology.

The impact of diabetic retinopathy on health-related quality of life

PURPOSE OF REVIEW

To review recent evidence evaluating the effect of diabetic retinopathy and diabetic macular edema on health-related quality of life.

RECENT FINDINGS

A search of PubMed was conducted according to a strategy that combined the text words 'diabetic retinopathy' and 'quality of life' (n = 91; November 11, 2004) and 'diabetic macular edema' and 'quality of life' (n = 6; November 22, 2004). The Methods sections of all abstracts were reviewed for valid generic or disease-specific instruments used to evaluate health-related quality of life. In addition, abstracts were reviewed to ensure that the study sample was made up predominantly of diabetic individuals. Recent data suggest that persons with diabetic retinopathy are willing to trade off significant time to eliminate their ocular condition (mean time tradeoff score = 0.77-0.8) and that laser photocoagulation can improve health-related quality of life (significant improvement noted in 8 of 11 domains in the National Eye Institute Visual Function Questionnaire). In addition, recent research has noted that health-related quality of life can become affected in persons with diabetic retinopathy prior to visual loss, primarily because of anxiety about the future and emotional reaction to diagnosis and treatment.

SUMMARY

From a search of the literature, several recent articles could be identified that demonstrated both a qualitative and a quantitative reduction in health-related quality of life in persons with diabetic retinopathy. With many novel treatments being explored for the management of diabetic retinopathy and diabetic macular edema, measuring health-related quality of life will likely play an important role both in the decision to offer treatment and in monitoring relevant health gains that may be derived from intervention.

Intravitreal triamcinolone plus sequential grid laser versus triamcinolone or laser alone for treating diabetic macular edema: six-month outcomes

OBJECTIVE

To evaluate the efficacy of sequential intravitreal triamcinolone acetonide (TA) injection followed by grid laser photocoagulation for treating diabetic macular edema (DME).

DESIGN

Prospective, 3-armed, randomized clinical trial.

PARTICIPANTS

One hundred eleven eyes of 111 patients with DME involving the fovea.

INTERVENTION

Patients were randomized to grid laser photocoagulation (37 eyes), 4 mg of intravitreal TA (38 eyes), or 4 mg of intravitreal TA combined with sequential grid laser about 1 month later (36 eyes).

MAIN OUTCOME MEASURES

Central foveal thickness (CFT) as measured by optical coherence tomography, logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA), and side effect profiles. The 6-month results are reported.

RESULTS

All patients completed 6 months' follow-up. Baseline mean (+/- standard deviation) CFTs were 385+/-100 microm, 396+/-91 microm, and 424+/-108 microm for the laser, intravitreal TA, and combined groups, respectively (P = 0.24). After treatment, significant CFT reductions were noted in both the intravitreal TA and combined groups at all follow-up visits (P<0.01) but not in the laser group. Mean CFT improved significantly to minimums of 267+/-75 microm and 256+/-73 microm for the intravitreal TA and combined groups, respectively, but the difference between the 3 groups was not significant at 6 months. The standardized change in macular thickening at 17 weeks was significantly greater in the combined group versus the intravitreal TA group (P = 0.007), suggesting that combined treatment might prolong the effects of intravitreal TA. Mean baseline logMAR BCVAs were 0.64+/-0.37, 0.72+/-0.34, and 0.69+/-0.34 in the laser, intravitreal TA, and combined groups, respectively (P = 0.67). Best-corrected visual acuity improved significantly at 4 and 9 weeks for the intravitreal TA group but did not change significantly in the other 2 groups. No significant difference in BCVA was observed between the 3 groups at any time point.

CONCLUSIONS

Contrary to the results of a recent study, combined treatment of intravitreal TA plus grid laser did not yield better CFT reduction or BCVA improvement at 6 months than intravitreal TA alone. Grid laser alone was significantly worse than the 2 other treatment modalities.

Long-term stability and visual outcome after favorable initial response of proliferative diabetic retinopathy to panretinal photocoagulation

The authors assessed the relationship between early objective response to panretinal photocoagulation (PRP) and the subsequent long-term visual outcome in 59 eyes of 59 consecutive patients who developed proliferative diabetic retinopathy while under the care of a retinal specialist. Thirty five eyes (59%) had regression of high-risk retinopathy characteristics within 3 months of treatment. Eighteen of these eyes (52%) had a final visual acuity of 20/20 or better with a mean follow-up of more than 4 years. Only 2 of the 24 nonresponder eyes (8%) had visual acuity of 20/20 or better. Thirteen of the responder eyes (37%) sustained a delayed vitreous hemorrhage, which was usually self-limited. Three responders underwent vitrectomy with excellent visual results. The authors conclude that the beneficial effect of PRP on visual outcome is directly related to the regression of retinopathy risk factors and that the long-term visual prognosis in high-risk eyes manifesting a favorable initial response to PRP is excellent.

Retinal vasoconstriction after laser treatment for diabetic macular edema

The diameter of retinal arterioles, venules, and their macular branches was measured before and after macular laser photocoagulation in one eye each of six men and eight women with diabetic macular edema. The macular arteriolar branches constricted 20.2% (P < .001) and the venular branches constricted 13.8% (P < .001). This autoregulatory vasoconstriction results from the improved retinal oxygenation caused by the laser treatment. By extrapolating the principles of tissue edema formation in general, we hypothesized how macular laser treatment affects diabetic macular edema. Starling's law predicts that (laser-induced) vasoconstriction and reduced intravascular hydrostatic pressure should reduce edema formation in any tissue, including the retina.

Vitrectomy with silicone oil infusion in severe diabetic retinopathy

AIMS

To determine the results of pars plana vitrectomy (PPV) and silicone oil infusion (SOI) in severe proliferative diabetic retinopathy (PDR).

METHODS

The records of 23 eyes (21 patients: 12 males, nine females) with PDR who had undergone PPV and SOI were reviewed retrospectively.

RESULTS

Average follow up was 5.4 months (range 1-25). Surgical indications were tractional retinal detachment (TRD) (17.4%), traction-rhegmatogenous retinal detachment (TRRD) (8.7%), TRD with vitreous haemorrhage (VH) (48%), TRD with neovascular glaucoma (NVG) (8.6%), TRD with fibrinoid syndrome (FS) (17.3%). With one operation, the retinal reattachment rate was 17/23 (74%). Among these 23 eyes, 11 (48%) had previously failed vitrectomy, and the retina was attached in 8/11 (73%) with a single procedure. With additional surgery employing PPV and SOI, the final reattachment rate was 20/23 (87%). The only cases with intraocular pressure <5 mm Hg had retinal detachment. Postoperative visual acuity (VA) improved in 10 eyes (44%), was unchanged in three (12%), and decreased in 10 eyes (44%).

CONCLUSION

SO tamponade is useful in severely diseased eyes with PDR, even in the presence of rubeosis iridis (RI) and NVG, FS, or in cases with previously failed vitrectomy, especially in the presence of RI.

Angiopoietin concentrations in diabetic retinopathy

BACKGROUND/AIM

Angiopoietin 1 and 2 interact with vascular endothelial growth factor (VEGF) to promote angiogenesis in animal and in vitro models. Although VEGF concentrations are elevated, there is little information regarding angiopoietin concentration in the vitreous of patients with diabetic retinopathy.

METHODS

Angiopoietin concentrations were measured by luminescence immunoassay in vitreous samples from 17 patients with non-proliferative diabetic retinopathy (NPDR) and clinically significant diabetic macular oedema (CSMO), 10 patients with proliferative diabetic retinopathy (PDR), and five patients with macular hole (controls) obtained at pars plana vitrectomy.

RESULTS

Angiopoietin 1 concentrations were low in patients with macular hole (median 17 pg/ml) while in NPDR with CSMO they were 2002 pg/ml (range 289-5820 pg/ml) and in PDR 186 pg/ml (range 26-2292 pg/ml). Angiopoietin 2 concentrations in NPDR with CSMO were a median of 4000 pg/ml (range 1341-14 329 pg/ml). For both macular hole and PDR patients angiopoietin 2 was below the limit of detection.

CONCLUSIONS

Angiopoietin 2 concentration was twice that of angiopoietin 1 in NPDR with CSMO. Angiopoietin 2 is the natural antagonist of angiopoietin 1 which is thought to act as an anti-permeability agent. The predominance of angiopoietin 2 may allow VEGF induced retinal vascular permeability in patients with CSMO. The relatively low concentration of both angiopoietin 1 and 2 in patients with proliferative diabetic retinopathy may reflect the established nature of the neovascularisation in cases proceeding to vitrectomy.

Progressive enlargement of scattered photocoagulation scars in diabetic retinopathy

PURPOSE

To clarify the evolution of laser scars and factors that possibly affect progression of laser-induced chorioretinal atrophy.

METHODS

The authors quantified 191 areas of laser scarring from panretinal photocoagulation in 19 eyes with diabetic retinopathy and calculated the expansion rate of the laser scars. They also analyzed factors affecting expansion, including location, laser wavelength, and follow-up period. The follow-up period ranged from 36 to 122 months (mean, 62 months).

RESULTS

Most (89.5%) laser scars gradually increased in size. The mean annual expansion rates were 12.7% in the posterior pole and 7.0% in the midperiphery. The annual expansion rate (16.5%) more than 4 years (late period) after treatment was higher than that (8.8%) within 4 years of treatment (early period). The expansion rate was minimal (1.2%) after argon laser treatment, whereas it was 11.7% after treatment with a 590-nm wavelength laser and 15.8% after treatment with a 610-nm wavelength laser.

CONCLUSION

Laser photocoagulation causes relentless expansion of laser scars over a long period. Laser scars enlarged more in the posterior pole. Lasers of a longer wavelength contributed to larger areas of chorioretinal atrophy.

Panretinal photocoagulation for proliferative diabetic retinopathy: pattern scan laser versus argon laser

PURPOSE

To evaluate the efficacy of the pattern scan laser (PASCAL) in treating newly diagnosed high-risk proliferative diabetic retinopathy (PDR).

DESIGN

Retrospective comparative case series.

METHODS

SETTING

Institutional.

STUDY POPULATION

Eighty-two consecutive eyes of the same number of patients with newly diagnosed high-risk PDR treated with panretinal photocoagulation (PRP) using either argon green laser (41 eyes treated before February 2007) or PASCAL (41 eyes treated February 2007 or thereafter), then followed for at least 6 months.

PROCEDURE

Retrospective chart review with attention to main outcome measures, age, sex, race, follow-up interval, insulin dependence, hemoglobin A1c, and total number of lasers spots.

MAIN OUTCOME MEASURES

Persistence or recurrence of neovascularization, incidence of vitreous hemorrhage (VH), neovascularization of the iris (NVI), neovascular glaucoma (NVG), and need for vitrectomy.

RESULTS

Patients treated with the PASCAL and argon laser received a similar number of spots (1438 vs 1386; P = .59). Patients treated with the PASCAL were more likely to experience persistence or recurrence of neovascularization within 6 months of initial treatment (73% vs 34%; P < .0008). The study was not adequately powered to detect a significant difference in incidence of vitreous hemorrhage, NVI, NVG, or need for vitrectomy.

CONCLUSIONS

When using traditional laser settings, PRP performed with the PASCAL is less effective than that performed with traditional argon laser in effecting lasting regression of retinal neovascularization in the setting of previously untreated high-risk PDR. Physicians may need to change treatment parameters when using PASCAL pattern laser therapy for high-risk PDR.

Observational study of the development of diabetic macular edema following panretinal (scatter) photocoagulation given in 1 or 4 sittings

OBJECTIVE

To compare the effects of single-sitting vs 4-sitting panretinal photocoagulation (PRP) on macular edema in subjects with severe nonproliferative or early proliferative diabetic retinopathy with relatively good visual acuity and no or mild center-involved macular edema.

METHODS

Subjects were treated with 1 sitting or 4 sittings of PRP in a nonrandomized, prospective, multicentered clinical trial. Main Outcome Measure Central subfield thickness on optical coherence tomography (OCT).

RESULTS

Central subfield thickness was slightly greater in the 1-sitting group (n = 84) than in the 4-sitting group (n = 71) at the 3-day (P = .01) and 4-week visits (P = .003). At the 34-week primary outcome visit, the slight differences had reversed, with the thickness being slightly greater in the 4-sitting group than in the 1-sitting group (P = .06). Visual acuity differences paralleled OCT differences.

CONCLUSIONS

Our results suggest that clinically meaningful differences are unlikely in OCT thickness or visual acuity following application of PRP in 1 sitting compared with 4 sittings in subjects in this cohort. More definitive results would require a large randomized trial. Application to Clinical Practice These results suggest PRP costs to some patients in terms of travel and lost productivity as well as to eye care providers could be reduced.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00687154.

Autologous serum for the treatment of corneal epithelial abrasions in diabetic patients undergoing vitrectomy

PURPOSE

To compare the effect of autologous serum versus hyaluronic acid for the treatment of epithelial corneal lesions in patients such as diabetics with reduced wound healing.

DESIGN

Prospective, randomized, masked clinical trial.

METHODS

Diabetic patients undergoing pars plana vitrectomy mostly combined with cataract extraction and intraocular lens (IOL) implantation who received corneal abrasion for better intraoperative visualization were included in this study. A standardized 8-mm diameter corneal abrasion was performed. Patients were randomized into one group treated with hourly application of autologous serum and another treated with hyaluronic acid drops (Vislube). Besides the time necessary for closure of the corneal epithelium other parameters such as patients' age, gender, duration of surgery, history of diabetes, and current HbA1C were evaluated.

RESULTS

A total of 23 patients were enrolled (15 men, eight women); the autologous serum group consisted of 13 patients, the hyaluronic acid (Vislube) group consisted of 10 patients. Patients' mean age was 64.8 years; mean duration of diabetes was 19.4 years. On average, the operation lasted 145 minutes. Mean epithelialization time was 7.1 days in the hyaluronic acid group. In the autologous serum group, epithelium healed after a mean of 4.3 days. Mann-Whitney U test for statistical analysis showed a significant difference of epithelial closure time between both groups (P < .05); therefore, the study was stopped after treatment of 23 patients.

CONCLUSIONS

It appears that autologous serum leads to a much faster closure of corneal epithelial wounds after abrasion compared with artificial tears.

Intensive diabetes therapy and ocular surgery in type 1 diabetes

BACKGROUND

The Diabetes Control and Complications Trial (DCCT) showed a beneficial effect of 6.5 years of intensive glycemic control on retinopathy in patients with type 1 diabetes.

METHODS

Between 1983 and 1989, a total of 1441 patients with type 1 diabetes in the DCCT were randomly assigned to receive either intensive diabetes therapy or conventional therapy aimed at preventing hyperglycemic symptoms. They were treated and followed until 1993. Subsequently, 1375 of these patients were followed in the observational Epidemiology of Diabetes Interventions and Complications (EDIC) study. The self-reported history of ocular surgical procedures was obtained annually. We evaluated the effect of intensive therapy as compared with conventional therapy on the incidence and cost of ocular surgery during these two studies.

RESULTS

Over a median follow-up of 23 years, 130 ocular operations were performed in 63 of 711 patients assigned to intensive therapy (8.9%) and 189 ocular operations in 98 of 730 patients assigned to conventional therapy (13.4%) (P<0.001). After adjustment for DCCT baseline factors, intensive therapy was associated with a reduction in the risk of any diabetes-related ocular surgery by 48% (95% confidence interval [CI], 29 to 63; P<0.001) and a reduction in the risk of all such ocular procedures by 37% (95% CI, 12 to 55; P=0.01). Forty-two patients who received intensive therapy and 61 who received conventional therapy underwent cataract extraction (adjusted risk reduction with intensive therapy, 48%; 95% CI, 23 to 65; P=0.002); 29 patients who received intensive therapy and 50 who received conventional therapy underwent vitrectomy, retinal-detachment surgery, or both (adjusted risk reduction, 45%; 95% CI, 12 to 66; P=0.01). The costs of surgery were 32% lower in the intensive-therapy group. The beneficial effects of intensive therapy were fully attenuated after adjustment for mean glycated hemoglobin levels over the entire follow-up.

CONCLUSIONS

Intensive therapy in patients with type 1 diabetes was associated with a substantial reduction in the long-term risk of ocular surgery. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; DCCT/EDIC ClinicalTrials.gov numbers, NCT00360893 and NCT00360815.).

Visual fields and electroretinography following extensive photocoagulation

Twenty-four patients with proliferative or preproliferative diabetic retinopathy underwent extensive argon laser photocoagulation in one eye. Detailed central and peripheral visual-field examinations and electroretinography were performed before treatment, and at intervals after treatment. Visual field changes were as follows: (1) eight patients had only mild to moderate constriction of all isopters, (2) 11 had discrete scotomata in addition, (3) two had prominent nerve-fiber-bundle defects, (4) three had severe constriction of all isopters, save (in two) that to the largest peripheral test object. Electroretinographic b-wave amplitudes were reduced an average of 40% to white test flashes. Blue test flashes showed an even larger reduction of the rod response. This suggests the receptors in approximately 40% of the retinal area are destroyed by such extensive photocoagulation, covering predominantly that part of the retina that has the highest concentration of rods.

Is there a correlation between the severity of diabetic retinopathy and keratoconjunctivitis sicca?

PURPOSE

Patients with diabetic retinopathy (DRP) seldom report symptoms of ocular surface irritation, but evaluations of dryness are pathologic. This study was designed to evaluate the correlation between the severity of DRP and dry eyes.

METHODS

We included 144 eyes of 72 patients. Severity of retinopathy was graded according to the Early Treatment Diabetic Retinopathy Study. The examinations for dry eyes included Schirmer's test, break-up time, lipid layer thickness, fluorescein and rose bengal staining of the cornea, impression cytology, and a questionnaire. A sicca severity score was calculated using a point system of the results of these tests. Patients were divided into three groups: postpanretinal laser coagulation (PPL), postcentral laser coagulation (PCL), and those with no laser treatment (0-L). For statistics, we used the correlation coefficient to determine relationships and the unpaired Student t test for statistical difference.

RESULTS

The correlation (c) of keratoconjunctivitis sicca (KCS) and DRP after laser treatment was c = 0.24 and after central laser treatment was c = 0.22; the correlation without laser treatment was 0.54. The best correlation is 1 or -1, the worst was 0. The score of those patients with mild to moderate retinopathy was compared to that of patients with severe to proliferative disease. There was a significant statistical difference in the sicca severity score between both groups, (p < 0.006. Student t test).

CONCLUSION

KCS represents another manifestation of diabetes mellitus and its severity--measured by a many-membered score--correlates with the severity of the DRP.