Large-spot subthreshold infrared laser to treat diabetic macular edema.
OBJECTIVE
To evaluate the efficacy of a large-spot subthreshold infrared laser protocol to treat diabetic maculopathy.


METHODS
In a prospective, fellow eye, controlled case series, all patients had clinically significant diabetic macular edema (DME) treated with a single application of subthreshold infrared (810 nm) laser. If bilateral disease was present, the fellow eye was treated with conventional macular laser. The study was to include 20 patients. Visual acuity and central macular thickness (CMT) measured by optical coherence tomography (OCT) were assessed in the study and fellow eyes at baseline and 6 months, and any changes were compared.


RESULTS
The 11th patient developed a choroidal infarct with subsequent profound loss of vision immediately after treatment. The study was terminated prematurely at this point. For the remaining 10 patients, there was a trend toward improvement in visual acuity in the study eye compared with the fellow eye at the 6-month follow-up (median change: +1.5 letters for study eye vs -6.5 letters for fellow eye; P = 0.08). There was also significant improvement in OCT-measured CMT in the study eye (mean decrease, 117 microm) compared with deterioration in OCT-measured CMT in the fellow eye (mean increase, 24 microm; P = 0.02).


CONCLUSIONS
This subthreshold infrared laser protocol led to improvement in OCT-measured CMT and stabilization of vision in most subjects. The current protocol is however unpredictable and should not be used in the treatment of DME without further modification.
Squirrell
David M
DM
Department of Ophthalmology, Royal Hallamshire Hospital, Sheffield, United Kingdom. David.Squirrell@sth.nhs.uk
Stewart
Alistair W
AW
Joondeph
Brian C
BC
Danesh-Meyer
Helen V
HV
McGhee
Charles N J
CN
Donaldson
Mark L
ML
D000368:Aged; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000532:radiotherapy*; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D007259:Infrared Rays; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy; D008269:Macular Edema / Q000175:diagnosis / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011379:Prognosis; D011446:Prospective Studies; D012160:Retina / Q000473:pathology; D041623:Tomography, Optical Coherence; D014792:Visual Acuity