Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Ms Lucy Brooks


Contact details

162 City Road
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title


BOLT (Bevacizumab Or Laser Treatment)

Study hypothesis

Intravitreal injections of Avastin® are better at improving and stabilising vision than laser therapy in clinically significant macula oedema secondary to diabetes mellitus.

Ethics approval

Approved by the Moorfields and Whittington Ethics Committee on the 11th May 2007 (ref: 07/Q0504/28).

Study design

Randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Diabetes mellitus


Intervention group: 40 patients for intravitreal avastin every six weeks
Control group: 40 patients for focal laser as ETDRS criteria

Intervention type



Not Specified

Drug names

Bevacizumab (Avastin®)

Primary outcome measure

Visual acuity.

Secondary outcome measures

OCT thickness.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Patients of either sex aged 18 years or over
2. Diagnosis of diabetes mellitus (type one or type two). Any one of the following will be considered to be sufficient evidence that diabetes is present:
2.1. Current regular use of insulin for the treatment of diabetes
2.2. Current regular use of oral anti-hyperglycaemic agents for the treatment of diabetes
2.3. Documented diabetes by American Diabetes Association (ADA) and/or World Health Organisation (WHO) criteria
3. Best corrected visual acuity in the study eye between 35 and 69 Early Treatment Diabetic Retinopathy Study (ETDRS) letters at 4 metres (Snellen equivalent of 6/60 or better and less than 6/12) within 14 days of randomisation
4. On clinical examimation, definite retinal thickening due to diabetic macular oedema involving the centre of the macula: Optical Coherence Tomography (OCT) central subfield greater than or equal to 270 microns within 14 days of randomisation
5. Media clarity, pupillary dilation, and subject cooperation sufficient for adequate fundus photographs
6. At least one prior macular laser therapy
7. Intraocular pressure less than 30 mmHg
8. Written informed consent
9. Ability to return for study visits
10. Vision in fellow eye of 3/60 or better
11. Fellow eye has no anti-Vascular Endothelial Growth Factor (anti-VEGF) treatment within the past three months and no expectation of such treatment in next three months

Participant type


Age group




Target number of participants


Participant exclusion criteria

The following exclusions apply to the study eye only (i.e., they may be present for the non-study eye):
1. Macular ischaemia (Foveal Avascular Zone [FAZ] greater than 1000 um in diameter or severe perifoveal intercapillary loss in Intravenous Fluorescein Angiography [IVFA])
2. Macular oedema is considered to be due to a cause other than diabetic macular oedema. An eye should not be considered eligible if:
2.1. The macular oedema is considered to be related to cataract extraction, or
2.2. Clinical examination and/or OCT suggest that vitreoretinal interface abnormalities disease (e.g., a taut posterior hyaloid or epiretinal membrane) is the primary cause of the macular oedema
3. Co-existent ocular disease:
3.1. An ocular condition is present such that, in the opinion of the investigator, visual acuity would not improve from resolution of macular oedema (e.g., foveal atrophy, pigmentary changes, dense subfoveal hard exudates, non-retinal conditions, such as amblyopia)
3.2. An ocular condition is present (other than diabetes) that, in the opinion of the investigator, might affect macular oedema or alter visual acuity during the course of the study (e.g., vein occlusion, uveitis or other ocular inflammatory disease, neovascular glaucoma, Irvine-Gass Syndrome, etc.)
3.3. A substantial cataract that, in the opinion of the investigator, is likely to be decreasing visual acuity by three lines or more (i.e., cataract would be reducing acuity to 20/40 or worse if eye was otherwise normal)
4. History of treatment for Diabetic Macula Oedema (DMO) at any time in the past three months (such as focal/grid macular photocoagulation, intravitreal or peribulbar corticosteroids, anti-VEGF drugs, or any other treatment)
5. History of Panretinal scatter Photocoagulation (PRP) within three months prior to randomisation
6. Anticipated need for PRP in the six months following randomisation
7. Proliferative diabetic retinopathy in the study eye except for tufts of new vessels less than one disc in area with no vitreous haemorrhage
8. A condition that, in the opinion of the investigator, would preclude participation in the study:
8.1. HbA1c greater than 11.0 mmol
8.2. A past medical history of significant renal disease, defined as a history of chronic renal failure requiring dialysis or kidney transplant
8.3. Blood pressure greater than 170/100 mmHg (i.e. systolic above 170 mmHg OR diastolic above 110 mmHg). If blood pressure is brought below 170/100 mmHg by anti-hypertensive treatment, subject can become eligible
8.4. Myocardial infarction, other cardiac event requiring hospitalisation, stroke, transient ischaemic attack, or treatment for acute congestive heart failure within six months prior to randomisation
8.5. Major surgery within 28 days prior to randomisation or major surgery planned during the next 12 months. Major surgery is defined as a surgical procedure that is more extensive than fine needle biopsy/aspiration, placement of a central venous access device, removal/biopsy of a skin lesion, or placement of a peripheral venous catheter
9. Participation in an investigational trial within 30 days of randomisation that involved treatment with any drug that has not received regulatory approval at the time of study entry. Note: subjects cannot receive another investigational drug while participating in the study
10. Systemic anti-VEGF or pro-VEGF treatment within three months prior to randomisation
11. Pregnant or lactating women or women intending to become pregnant within the study period including three months after study cessation
12. History of major ocular surgery (including cataract extraction, scleral buckle, any intraocular surgery, etc.) within prior three months or anticipated within the next six months following randomisation
13. Aphakia
14. Uncontrolled glaucoma (in investigator’s judgment)
15. Exam evidence of external ocular infection, including conjunctivitis, chalazion, or severe blepharitis. If treated these patients can be included
16. Known allergy to fluorescein dye or to any component of the study drug

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

162 City Road
United Kingdom

Sponsor information


Moorfields Eye Hospital NHS Foundation Trust (UK)

Sponsor details

162 City Road
United Kingdom

Sponsor type




Funder type


Funder name

Moorfield Eye Hospital Special Trustees (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

1. 2010 results in

Publication citations

  1. Results

    Michaelides M, Kaines A, Hamilton RD, Fraser-Bell S, Rajendram R, Quhill F, Boos CJ, Xing W, Egan C, Peto T, Bunce C, Leslie RD, Hykin PG, A prospective randomized trial of intravitreal bevacizumab or laser therapy in the management of diabetic macular edema (BOLT study) 12-month data: report 2., Ophthalmology, 2010, 117, 6, 1078-1086.e2, doi: 10.1016/j.ophtha.2010.03.045.

Additional files

Editorial Notes