Effects of conventional argon panretinal laser photocoagulation on retinal nerve fibre layer and driving visual fields in diabetic retinopathy

• Published in: Eye (London) Vol. 24; no. 7; pp. 1136 - 1142
• Main Authors: Muqit, M M K, Wakely, L, Stanga, P E, Henson, D B, Ghanchi, F D
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-07-2010; Nature Publishing Group
• Subjects: Adult; Argon - therapeutic use; Biological and medical sciences; clinical-study; Diabetes. Impaired glucose tolerance; Diabetic Retinopathy - physiopathology; Diabetic Retinopathy - surgery; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Humans; Laboratory Medicine; Lasers, Gas - therapeutic use; Light Coagulation - instrumentation; Male; Medical sciences; Medicine; Medicine & Public Health; Middle Aged; Miscellaneous; Nerve Fibers - pathology; Nerve Fibers - radiation effects; Ophthalmology; Pharmaceutical Sciences/Technology; Pilot Projects; Prospective Studies; Retina - pathology; Retina - radiation effects; Retina - surgery; Retinopathies; Surgery; Surgical Oncology; Tomography, Optical Coherence; Visual Fields - physiology; nerve fibre layer; laser photocoagulation; driving visual fields; diabetic retinopathy; Endocrinopathy; Retinopathy; Visual field; Diabetes mellitus; Retina; Photocoagulation; Eye disease; Treatment; Surgery; Laser; Ophthalmology; Argon; Nerve fiber
• ISSN: 0950-222X; 1476-5454
• DOI: 10.1038/eye.2009.308

Aims
To determine the effects of argon green panretinal laser photocoagulation on retinal nerve fibre layer thickness, threshold visual fields, and Estermann full-binocular visual fields over time in diabetic retinopathy.
Method
Prospective, pilot clinical study. Time-domain optical coherence tomography (TD-OCT) of the optic nerve head and 24-2 SITA-Fast Humphrey/Estermann visual fields (HVF, EVFs) recorded at baseline, 10 weeks, and 6 months post laser. Quantitative field analysis of central 10°, 24°, and binocular visual fields.
Results
A total of 10 eye samples were subjected to uncomplicated multiple-session 100 ms panretinal laser using 2000 burns, 300-
μ
m spot, and mean power of 136 mW (SD ±39.3). TD-OCT detected and quantified an increase in mean retinal nerve fibre layer thickness at 10 weeks (+8 
μ
m;
P
<0.05) and progressive thinning at 6 months (−4 
μ
m;
P
<0.05) compared with baseline. Mean threshold sensitivities, and 10° and 24° HVF improved at both time points in the majority (9 of 10 and 8 of 10) of patients. EVFs showed no significant change with treatment.
Conclusions
This pilot study shows that conventional argon laser panretinal photocoagulation may increase the retinal nerve fibre layer thickness in the short term, presumably related to laser-induced axonal injury, with progressive thinning of nerve fibre layer over the long term. The 10° and 24° visual fields improved significantly after laser with no adverse effects on the UK standard driving fields.