Color matching and foveal densitometry in patients and carriers of an X-linked progressive cone dystrophy
J. E. Keunen, J. A. van Everdingen, L. N. Went, J. A. Oosterhuis and D. van Norren
E. C. Donders Institute of Ophthalmology, State University, Utrecht, the Netherlands.
We describe a family with an as yet undescribed form of X-linked
progressive cone dystrophy in a five-generation pedigree, from which we
report here the results of 17 male patients and 31 obligate and 13 possible
female carriers. The affected males showed the characteristic picture of
cone dystrophy. Foveal cone photopigment density was impaired (judged from
anomaloscope settings and foveal densitometry), even at an early stage of
the disease. The carriers showed no fundus abnormalities, except occasional
changes due to myopia. The anomaloscope demonstrated mild pseudoprotanomaly
in 27 of 31 obligate carriers and in six of 13 possible carriers. Foveal
densitometry findings performed in 11 carriers always agreed with the
anomaloscope findings. We conclude that the findings of pseudoprotanomaly
and abnormal density differences in females of this family were the only
ocular abnormalities and thus are indicative of the carrier state.
