Abstract
Abstract: :
Purpose: Infrared photography is the most sensitive method to detect iris transillumination defects. Recent technological advances have made examination by this method more practical in the routine clinical setting. In this study we investigated interobserver agreement in the assessment of iris transillumination defects (ITDs) due to pigment dispersion syndrome (PDS) and in normals with the aid of digital infrared photography. Methods: Digital infrared iris photography of iris transillumination was performed on 185 total eyes belonging to 101 subjects (24 PDS, 77 normals). PDS subjects consisted of 13 Blacks, 8 Whites, and 3 Hispanics. Normals consisted of 49 Blacks, 23 Whites, 3 Asians, and 2 Hispanics). A diagnosis of PDS had been based on the presence of Krukenberg's spindles, significant trabecular meshwork pigmentation, and equatorial lens pigmentation and/or ITDs consistent with PDS. ITDs among PDS subjects varied from minimal to pronounced. Each practitioner, inexperienced with infrared iris photography prior to the study, participated in an identical written training module, and afterwards they were shown random infrared images of the iris without other accompanying clinical information. They were asked to assess each image according to whether he felt ITDs indicative of PDS were present or not present. An analysis of agreement was then carried out. Results: Of the total group of subjects, both practitioners agreed that no abnormal iris transillumination was present in 115 eyes, and they agreed that PDS associated iris transillumination defects were present in 21 eyes. One practitioner indicated that abnormal iris transillumination was present in 20 eyes that the other did not. The other practitioner indicated that iris transillumination was present in 28 eyes that the other did not. Concordance was 73.9%, but the Kappa coefficient was .30. Kappa coefficient was .39 for just the blue eyes and .18 for the brown eyes. It was .60 for the PDS eyes and .30 for the normal eyes. Conclusions: Iris transillumination associated with PDS and in normals should be assessed with caution when using sensitive infrared technology to examine the iris. Interpretation of abnormal iris transillumination in normal and PDS eyes can be difficult and may suffer from poor interobserver agreement in some groups of patients. Significant examiner training may be needed to interpret mild PDS–related iris transillumination from normal iris transillumination.
Keywords: imaging/image analysis: clinical