studies on diab retino

7/29/2019 Studies on Diab Retino

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Diabetic Retinopathy Vitrectomy Study (DRVS)

Purpose

To compare early vitrectomy versus conventional management forrecent severe vitreous hemorrhage secondary to diabeticretinopathy. To compare early vitrectomy and conventionalmanagement in eyes that have good vision but a poor prognosisbecause they are threatened with hemorrhage or retinaldetachment from very severe proliferative retinopathy.

To study the natural history of severe proliferative diabeticretinopathy.

Study pattern

Patient eligibility criteria was presence of recent severe vitreoushemorrhage (within 5 months) or very severe proliferative retinopathywith extensive active fibrovascular proliferations and useful vision inpatients with Type 1 and Type 2 diabetes mellitus. Early vitrectomy 1-6months after the onset of hemorrhage. Conventional managementincludes vitrectomy if hemorrhage fails to clear during a waiting period of12 months or if retinal detachment involving the center of the maculadevelops at any time.

Results

In the severe vitreous hemorrhage trial, 2-year results showed thatrecovery of good vision (10/20 or better) was more frequent in theearly vitrectomy group (25 percent versus 15 percent in theconventional management group) and the advantage was moreapparent in Type 1 diabetics who were younger and had moresevere fibrovascular proliferations (36 percent with visual acuity of10/20 or better in the early vitrectomy group versus 12 percent

with conventional management). In Type 1 diabetics, the risk ofloss of light perception was the same in two groups (28 percent and26 percent, respectively) but in Type 2 diabetics, there was a trendtoward more frequent loss of light perception in the early group (25percent versus 19 percent).

Conclusion

For eyes with recent severe vitreous hemorrhage, early vitrectomyprovided a greater chance of prompt recovery of visual acuity


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although greater early risk of visual acuity of no light perceptionmust be kept in mind. The benefit is more pronounced for patientswith Type 1 diabetes, particularly for those in whom severe vitreoushemorrhage occurred after a shorter duration of diabetes. Thisbenefit remained at least as great after 4 years of followup as it was

at 2 years. The DRVS findings support early vitrectomy in eyes known or

suspected to have very severe proliferative diabetic retinopathy as ameans of increasing the chance of restoring or maintaining goodvision.

Editors Note:At the present time, it should be noted that the results ofDRVS were obtained before the development of modern vitrectomyinstrumentation, techniques and endolaser photocoagulation. With thesetechniques, results are more favorable. Nowadays in general, the

recommended timing of vitrectomy for severe diabetic vitreoushemorrhage is before 3 months for Type 1 diabetics and 6 months forType 2 patients.

Diabetes Control and Complications Trial (DCCT)

Purpose:

To assess the effect of tight glycemic control on complications of diabetes

(nephropathy, neuropathy and diabetic retinopathy) for persons with Type1 diabetes.

Study Pattern

Patients with IDDM with no retinopathy at base line (the primary-prevention cohort) and with mild retinopathy (the secondary-interventioncohort) were randomly assigned to intensive therapy administered eitherwith an external insulin pump or by three or more daily insulin injections

and guided by frequent blood glucose monitoring or to conventionaltherapy with one or two daily insulin injections.

Results

In the primary-prevention cohort, intensive therapy (mean HbA1c7.2%) reduced the risk for the development of retinopathy by 76 percentas compared with conventional therapy (mean HbA1c 9.0%). In thesecondary-intervention cohort, intensive therapy slowed the progression

of retinopathy by 54 percent and reduced the development ofproliferative or severe nonproliferative retinopathy by 47 percent. In the


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two cohorts combined, intensive therapy reduced the occurrence ofmicroalbuminuria (urinary albumin excretion of 40 mg per 24 hours) by39 percent, that of albuminuria (urinary albumin excretion of 300 mg per24 hours) by 54 percent and that of clinical neuropathy by 60 percent.The chief adverse event associated with intensive therapy was a two-to-

threefold increase in severe hypoglycemia. Because of this risk, DCCTresearchers do not recommend intensive therapy for children under age13, people with heart disease or advanced complications, older adults,and people with a history of frequent severe hypoglycemia. Persons in theintensive management group also gained a modest amount of weight,suggesting that intensive treatment may not be appropriate for peoplewith diabetes who are overweight. DCCT researchers estimate thatintensive management doubles the cost of managing diabetes because ofincreased visits to a health care professional and the need for morefrequent blood testing at home. However, this cost is offset by the

reduction in medical expenses related to long-term complications and bythe improved quality of life of people with diabetes.

Conclusion

Intensive therapy effectively delays the onset and slows the progressionof diabetic retinopathy, nephropathy, and neuropathy in patients withIDDM.

Early Treatment Diabetic Retinopathy Study(ETDRS)

Purpose

To evaluate the effectiveness of both argon laser photocoagulationand aspirin therapy in delaying or preventing progression of earlydiabetic retinopathy to more severe stages of visual loss andblindness.

To help determine the best time to initiate photocoagulationtreatment in diabetic retinopathy.

To monitor closely the effects of diabetes mellitus and ofphotocoagulation on visual function.

To produce natural history data that can be used to identify riskfactors and test etiologic hypotheses in diabetic retinopathy.

Study Pattern

Patient eligibility criteria was presence of mild to very severe NPDR


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and/or non high risk PDR with or without macular oedema in both eyes.One eye of each patient was assigned randomly to immediatephotocoagulation and the other eye to deferral of photocoagulation(careful follow up) until high-risk PDR developed. Eyes with diabeticmacular edema were assigned to immediate or deferred focal

photocoagulation (direct laser for focal leaks and grid laser for diffuseleaks). Patients were assigned randomly to aspirin or placebo. The term"clinically significant macular oedema" was coined to designate this levelof severity.

Results

Focal photocoagulation reduced the risk of moderate vision loss(defined as doubling of visual angle) by 50% or more and increased

the chance of a small improvement in visual acuity. Both early scatter and deferral were followed by low rates of severe

visual loss (5 year rates in deferral subgroups were 2-10%; in earlyphotocoagulation groups these rates were 2-6%.groupsstatisticallysignificant reduction in severe visual loss for those eyes with earlytreatment, especially for those patients with non-insulin-dependentdiabetes mellitus (NIDDM). However, the reduction was small andthe risk was low in the deferral group.

Aspirin use did not affect the progression of retinopathy to the high-risk proliferative stage but aspirin also did not increase the risk of

vitreous hemorrhage, did not affect vision, and was associated witha decreased risk of cardiovascular disease.

Conclusion

Focal photocoagulation should be considered for eyes with CSME. Scatter treatment is not indicated for eyes with mild to moderate

non proliferative diabetic retinopathy. As the retinopathy progressesto the severe non proliferative or early proliferative stage, scattertreatment should be considered, especially for patients with Type 2

diabetes and it should be performed without delay for virtually alleyes with high-risk proliferative retinopathy. Aspirin has no clinically important beneficial effect on the

progression of retinopathy. However, since aspirin also has noclinically important harmful effects for diabetic patients withretinopathy therefore there is no ocular contraindications to aspirinuse when required for cardiovascular disease or other medicalindications.



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Purpose

To compare early vitrectomy versus conventional management forrecent severe vitreous hemorrhage secondary to diabeticretinopathy. To compare early vitrectomy and conventional

management in eyes that have good vision but a poor prognosisbecause they are threatened with hemorrhage or retinaldetachment from very severe proliferative retinopathy.


Study pattern

Patient eligibility criteria was presence of recent severe vitreous

hemorrhage (within 5 months) or very severe proliferative retinopathywith extensive active fibrovascular proliferations and useful vision inpatients with Type 1 and Type 2 diabetes mellitus. Early vitrectomy 1-6months after the onset of hemorrhage. Conventional managementincludes vitrectomy if hemorrhage fails to clear during a waiting period of12 months or if retinal detachment involving the center of the maculadevelops at any time.

Results

In the severe vitreous hemorrhage trial, 2-year results showed thatrecovery of good vision (10/20 or better) was more frequent in theearly vitrectomy group (25 percent versus 15 percent in theconventional management group) and the advantage was moreapparent in Type 1 diabetics who were younger and had moresevere fibrovascular proliferations (36 percent with visual acuity of10/20 or better in the early vitrectomy group versus 12 percentwith conventional management). In Type 1 diabetics, the risk ofloss of light perception was the same in two groups (28 percent and26 percent, respectively) but in Type 2 diabetics, there was a trendtoward more frequent loss of light perception in the early group (25percent versus 19 percent).

Conclusion

For eyes with recent severe vitreous hemorrhage, early vitrectomyprovided a greater chance of prompt recovery of visual acuityalthough greater early risk of visual acuity of no light perceptionmust be kept in mind. The benefit is more pronounced for patients

with Type 1 diabetes, particularly for those in whom severe vitreoushemorrhage occurred after a shorter duration of diabetes. This


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benefit remained at least as great after 4 years of followup as it wasat 2 years.

The DRVS findings support early vitrectomy in eyes known orsuspected to have very severe proliferative diabetic retinopathy as ameans of increasing the chance of restoring or maintaining good

vision.

Editors Note:At the present time, it should be noted that the results ofDRVS were obtained before the development of modern vitrectomyinstrumentation, techniques and endolaser photocoagulation. With thesetechniques, results are more favorable. Nowadays in general, therecommended timing of vitrectomy for severe diabetic vitreoushemorrhage is before 3 months for Type 1 diabetics and 6 months forType 2 patients.


Purpose:

To assess the effect of tight glycemic control on complications of diabetes(nephropathy, neuropathy and diabetic retinopathy) for persons with Type1 diabetes.

Study Pattern

Patients with IDDM with no retinopathy at base line (the primary-prevention cohort) and with mild retinopathy (the secondary-interventioncohort) were randomly assigned to intensive therapy administered eitherwith an external insulin pump or by three or more daily insulin injectionsand guided by frequent blood glucose monitoring or to conventionaltherapy with one or two daily insulin injections.

Results

In the primary-prevention cohort, intensive therapy (mean HbA1c7.2%) reduced the risk for the development of retinopathy by 76 percentas compared with conventional therapy (mean HbA1c 9.0%). In thesecondary-intervention cohort, intensive therapy slowed the progressionof retinopathy by 54 percent and reduced the development ofproliferative or severe nonproliferative retinopathy by 47 percent. In thetwo cohorts combined, intensive therapy reduced the occurrence ofmicroalbuminuria (urinary albumin excretion of 40 mg per 24 hours) by

39 percent, that of albuminuria (urinary albumin excretion of 300 mg per24 hours) by 54 percent and that of clinical neuropathy by 60 percent.


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The chief adverse event associated with intensive therapy was a two-to-threefold increase in severe hypoglycemia. Because of this risk, DCCTresearchers do not recommend intensive therapy for children under age13, people with heart disease or advanced complications, older adults,and people with a history of frequent severe hypoglycemia. Persons in the

intensive management group also gained a modest amount of weight,suggesting that intensive treatment may not be appropriate for peoplewith diabetes who are overweight. DCCT researchers estimate thatintensive management doubles the cost of managing diabetes because ofincreased visits to a health care professional and the need for morefrequent blood testing at home. However, this cost is offset by thereduction in medical expenses related to long-term complications and bythe improved quality of life of people with diabetes.

Conclusion


Diabetic Retinopathy Study (DRS)

Purpose

To determine whether laser photocoagulation helps to preventsevere visual loss from proliferative diabetic retinopathy.

To determine whether a difference exists in the efficacy and safetyof argon versus xenon photocoagulation for proliferative diabeticretinopathy

Study Pattern

Patient eligibility criteria was presence of proliferative diabetic retinopathy

in at least one eye or severe non proliferative retinopathy in both eyes.One eye of each patient was assigned randomly to immediatephotocoagulation (scatter panretinal treatment, direct local treatment tonew vessels and focal treatment for macular edema). The other eye wasassigned to follow up without photocoagulation. The eye chosen fortreatment was then randomly assigned to either argon laser or xenon arcphotocoagulation.

Results

Both argon and xenon photocoagulation reduced the risk of severevisual loss by 50 percent or more compared with no treatment


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(Severe vision loss was defined as visual acuity


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Results

Focal photocoagulation reduced the risk of moderate vision loss(defined as doubling of visual angle) by 50% or more and increasedthe chance of a small improvement in visual acuity.

Both early scatter and deferral were followed by low rates of severevisual loss (5 year rates in deferral subgroups were 2-10%; in earlyphotocoagulation groups these rates were 2-6%.groupsstatisticallysignificant reduction in severe visual loss for those eyes with earlytreatment, especially for those patients with non-insulin-dependentdiabetes mellitus (NIDDM). However, the reduction was small andthe risk was low in the deferral group.

Aspirin use did not affect the progression of retinopathy to the high-risk proliferative stage but aspirin also did not increase the risk ofvitreous hemorrhage, did not affect vision, and was associated with

a decreased risk of cardiovascular disease.

Conclusion

Focal photocoagulation should be considered for eyes with CSME. Scatter treatment is not indicated for eyes with mild to moderate

non proliferative diabetic retinopathy. As the retinopathy progressesto the severe non proliferative or early proliferative stage, scattertreatment should be considered, especially for patients with Type 2diabetes and it should be performed without delay for virtually all

eyes with high-risk proliferative retinopathy. Aspirin has no clinically important beneficial effect on the

progression of retinopathy. However, since aspirin also has noclinically important harmful effects for diabetic patients withretinopathy therefore there is no ocular contraindications to aspirinuse when required for cardiovascular disease or other medicalindications.


Purpose

To compare early vitrectomy versus conventional management forrecent severe vitreous hemorrhage secondary to diabeticretinopathy. To compare early vitrectomy and conventionalmanagement in eyes that have good vision but a poor prognosisbecause they are threatened with hemorrhage or retinaldetachment from very severe proliferative retinopathy.



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Study pattern

Patient eligibility criteria was presence of recent severe vitreoushemorrhage (within 5 months) or very severe proliferative retinopathy

with extensive active fibrovascular proliferations and useful vision inpatients with Type 1 and Type 2 diabetes mellitus. Early vitrectomy 1-6months after the onset of hemorrhage. Conventional managementincludes vitrectomy if hemorrhage fails to clear during a waiting period of12 months or if retinal detachment involving the center of the maculadevelops at any time.

Results

In the severe vitreous hemorrhage trial, 2-year results showed thatrecovery of good vision (10/20 or better) was more frequent in theearly vitrectomy group (25 percent versus 15 percent in theconventional management group) and the advantage was moreapparent in Type 1 diabetics who were younger and had moresevere fibrovascular proliferations (36 percent with visual acuity of10/20 or better in the early vitrectomy group versus 12 percentwith conventional management). In Type 1 diabetics, the risk ofloss of light perception was the same in two groups (28 percent and26 percent, respectively) but in Type 2 diabetics, there was a trendtoward more frequent loss of light perception in the early group (25

percent versus 19 percent).

Conclusion

For eyes with recent severe vitreous hemorrhage, early vitrectomyprovided a greater chance of prompt recovery of visual acuityalthough greater early risk of visual acuity of no light perceptionmust be kept in mind. The benefit is more pronounced for patientswith Type 1 diabetes, particularly for those in whom severe vitreoushemorrhage occurred after a shorter duration of diabetes. Thisbenefit remained at least as great after 4 years of followup as it wasat 2 years.

The DRVS findings support early vitrectomy in eyes known orsuspected to have very severe proliferative diabetic retinopathy as ameans of increasing the chance of restoring or maintaining goodvision.

Editors Note:At the present time, it should be noted that the results ofDRVS were obtained before the development of modern vitrectomy

instrumentation, techniques and endolaser photocoagulation. With thesetechniques, results are more favorable. Nowadays in general, the


11/12

recommended timing of vitrectomy for severe diabetic vitreoushemorrhage is before 3 months for Type 1 diabetics and 6 months forType 2 patients.


Purpose:

To assess the effect of tight glycemic control on complications of diabetes(nephropathy, neuropathy and diabetic retinopathy) for persons with Type1 diabetes.

Study Pattern

Patients with IDDM with no retinopathy at base line (the primary-prevention cohort) and with mild retinopathy (the secondary-interventioncohort) were randomly assigned to intensive therapy administered eitherwith an external insulin pump or by three or more daily insulin injectionsand guided by frequent blood glucose monitoring or to conventionaltherapy with one or two daily insulin injections.

Results

In the primary-prevention cohort, intensive therapy (mean HbA1c7.2%) reduced the risk for the development of retinopathy by 76 percentas compared with conventional therapy (mean HbA1c 9.0%). In thesecondary-intervention cohort, intensive therapy slowed the progressionof retinopathy by 54 percent and reduced the development ofproliferative or severe nonproliferative retinopathy by 47 percent. In thetwo cohorts combined, intensive therapy reduced the occurrence ofmicroalbuminuria (urinary albumin excretion of 40 mg per 24 hours) by39 percent, that of albuminuria (urinary albumin excretion of 300 mg per

24 hours) by 54 percent and that of clinical neuropathy by 60 percent.The chief adverse event associated with intensive therapy was a two-to-threefold increase in severe hypoglycemia. Because of this risk, DCCTresearchers do not recommend intensive therapy for children under age13, people with heart disease or advanced complications, older adults,and people with a history of frequent severe hypoglycemia. Persons in theintensive management group also gained a modest amount of weight,suggesting that intensive treatment may not be appropriate for peoplewith diabetes who are overweight. DCCT researchers estimate thatintensive management doubles the cost of managing diabetes because of

increased visits to a health care professional and the need for morefrequent blood testing at home. However, this cost is offset by the


12/12

reduction in medical expenses related to long-term complications and bythe improved quality of life of people with diabetes.

Conclusion


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