Use of the Optomap with lid retraction and its sensitivity and specificity.

Background: Optomap uses the ultra-wide field scanning laser ophthalmoscopy to provide retinal examination. It permits fundus examination without the use of a mydriatic, which is more comfortable for the patients. This paper determines the sensitivity and specificity of the Optomap for detecting retinal signs under non-mydriatic conditions.

Methods: Fifty-four eyes identified with retinal/choroidal signs and eight normal eyes were recruited from 31 Hong Kong Chinese subjects. Photo-documentation of fundal changes was obtained with the Optomap under non-mydriatic conditions before a dilated fundus examination by a clinician using standard procedures. The eyelid was retracted using a cotton bud when necessary. Dilated fundus examinations were performed by another clinician using binocular indirect ophthalmoscopy and slitlamp biomicroscopy with a fundus lens. The Optomap images were evaluated by four other investigators under masked condition. The International Classification of Disease, Ninth Revision (ICD-9-CM) was adopted for recording retinal features. Screening results were compared with those obtained using the dilated fundus examination as the gold standard.

Results: The cotton bud method for eyelid retraction showed an improvement in the area of retina that could be visualised. The sensitivity and specificity of the Optomap averaged 76.4 and 71.9 per cent, respectively. Some fundal signs were missed by all observers in the Optomap but not with the biomicroscope. These included white-without-pressure, lattice degeneration, paramacular drusen and pigmentary changes at central fundus.

Conclusion: Optomap serves as a reliable screening tool for fundus examination especially because it covers a much wider area of the peripheral retina than other digital instruments for fundus photography.