SHORT-WAVELENGTH SENSITIVE VISUAL-FIELD LOSS IN PATIENTS WITH CLINICALLY SIGNIFICANT DIABETIC MACULAR EDEMA

The aim of the study was to compare the sensitivity of short-wavelengt h and conventional automated static threshold perimetry for the psycho physical detection of abnormality in patients with clinically signific ant diabetic macular oedema. The sample comprised 24 patients with cli nically significant diabetic macular oedema (mean age 59.75 years, ran ge 45-75 years). One eye of each patient was selected. Exclusion crite ria included the presence of lenticular opacity. The sensitivity of th e macular visual field of each patient was determined with programme 1 0-2 of the Humphrey Field Analyser on two occasions, using both short- wavelength and conventional stimulus parameters; the results of the se cond session were analysed to minimise learning effects. A pointwise h orizontal hemifield asymmetry analysis was derived for short-wavelengt h perimetry (thereby negating the influence of pre-receptoral absorpti on); the pointwise pattern deviation probability plot was analysed for conventional perimetry. Abnormality was defined as 3 or more contiguo us stimulus locations with negative asymmetries (short-wavelength) or reduced sensitivity values (conventional) that resulted in a statistic al probability level of p less than 0.05. The fields of 8 patients wer e abnormal as assessed by conventional perimetry while all were classi fied as abnormal using short-wavelength perimetry. In the 8 patients w ho exhibited both abnormal conventional and abnormal short-wavelength perimetry results, the extent of field loss was generally greater usin g short-wavelength perimetry. The position of the localised field loss (i.e. as distinct from field loss that was generalised across the vis ual field) assessed by short-wavelength perimetry corresponded with th e clinical mapping of the area of diabetic macular oedema but the exte nt of this loss was generally greater than that suggested by clinical assessment. Short-wavelength automated perimetry offers improved sensi tivity for the psychophysical detection of clinically significant diab etic macular oedema.