Retinal fixation impairment in diabetic macular edema.
OBJECTIVE
To evaluate the characteristics of retinal fixation in patients with diabetic macular edema using microperimetry.


METHODS
One hundred seventy nine eyes (98 patients) with untreated diabetic macular edema underwent best corrected visual acuity determination (Early Treatment Diabetic Retinopathy Study charts), digital color stereoscopic fundus photos, fluorescein angiography and Optical Coherence Tomography assessment of macula. Fixation and retinal thresholds were determined with an automatic microperimeter.


RESULTS
Best corrected visual acuity (approximate Snellen equivalent) was: 20/25 or better in 90 (52%) eyes, 20/50 to 20/32 in 39 (22.5%) eyes, 20/200 to 20/62.5 in 35 (20.2%) eyes and inferior to 20/200 in 9 (5.2%) eyes. Fixation was central in 128 (71.51%), poor central in 26 (14.53%) and predominantly eccentric in 25 (13.97%) eyes; stable in 133 (74.3%), relatively unstable in 42 (23.46%) and unstable in 4 (2.23%) eyes. Both fixation location and stability were not significantly influenced by edema characteristics (diffuse, focal, cystoid, spongelike, with or without subfoveal neuroretinal detachment), (P > 0.05), whereas they were significantly influenced by the presence of subfoveal hard exudates, (P = 0.004 and P = 0.0046, respectively). Site and stability of fixation were significantly associated, (P < 0.0001). Retinal pseudofovea would have been covered by laser photocoagulation in 24 (47%) eyes with poorly central and predominantly eccentric fixation and in 29 (63%) eyes with relatively unstable and unstable fixation.


CONCLUSIONS
Microperimetry shows that fixation location and stability in patients with diabetic macular edema are independent of edema characteristics, except when subfoveal hard exudates are present. Location of pseudofovea may influence treatment strategy.
Vujosevic
Stela
S
Fondazione G. B Bietti per l'Oftalmologia, IRCCS, Roma, Italy.
Pilotto
Elisabetta
E
Bottega
Elisa
E
Benetti
Elisa
E
Cavarzeran
Fabiano
F
Midena
Edoardo
E
D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D005451:Fluorescein Angiography; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D008269:Macular Edema / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012160:Retina / Q000502:physiology*; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology
D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human