Oxymap - Analysing oxygenation of vitreoretinopathies and oxygen related disease in children.

Oxygen plays a major role in many ocular diseases in adults and children. A
state of hypoxia can lead to neovascularization or abnormal vessel development
under influence of Vascular Endothelial Growth Factor (VEGF). The development
of neovascularizations or abnormal vessels may lead to blindness in children
and adults. Abnormal vascularization of the peripheral retina and retinal
detachment are common clinical characteristics of many paediatric (vitreo-)
retinopathies such as Norrie disease, M. Coats, Familial Exsudative
Vitreoretinopathy (FEVR) and retinopathy of prematurity (ROP). In early stages
of hereditary ocular disease such as retinitis pigmentosa, it has been found
that there are discreet changes to the calibers of the vessels. These caliber
changes in the retinal vessels will have its effect on the oxygen metabolism of
the eye. Recently, a small pilot study reported, a difference in oxygen
saturation levels in the retinal vessels between the healthy eye and the
amblyopic eye in patients with amblyopia.

In recent years, a retinal oximeter (Oxymap) has become available for clinical
and investigational use. The Oxymap application is attached to a regular
clinical Topcon fundus camera and it uses two different wavelengths of light to
image the fundus of the eye; one wavelength is sensitive to changes in oxygen
saturation, the other wavelength is not. The algorithm of the Oxymap software
calculates the relative oxygen saturation in all major arterioles and venules
of the retina; comparisons can be made between vessels as well as in time. The
Oxymap has been used to investigate various diseases in adults, such as
diabetic retinopathy, retinal vein occlusion, glaucoma and radiation
retinopathy in melanoma of the eye. In a pilot study in Reykjavik, a difference
was found between saturation levels within the vessels of the eye between
adults and children. However, knowledge about retinal oximetry in children is
very limited.

The objective of this study is to investigate the use of retinal oximetry in
children, between five and seventeen years of age, with (vitreo-) retinopathies
and oxygen-related diseases of the retina by means of an Oxymap T1 fundus
camera.

This study is a prospective observational case series of paediatric patients
diagnosed with (vitreo-) retinopathies and oxygen-related diseases of the
retina. Patients visiting the outpatient department of ophthalmology that will
need fundus imaging (normally 15-20 images) will be asked to participate in
this study. As part of the regular examination, children visiting the clinic
with one of the conditions mentioned above will receive mydriatic eye drops
from their ophthalmologist to dilate their pupils. After the infant and his or
her legal guardian(s) are informed, in word and written text, and have given
informed consent, we will obtain additional fundus images (five images) for
Oxymap research purpose. In regular follow-up consultation for the subjects, we
will ask the subjects for additional Oxymap images to follow up treatment as
well as disease of the eye. As pupils are already dilated, there are no
additional risks for the patients concerning participation in the study. All
images will be obtained in regular consultations; patients will not be asked to
make extra visits

For this study de burden and risks associated with the participation are
minimal due to the fact that all subjects will be recruited from ophthalmologic
consultation with dilation of the pupils therefore no additional medication is
required for study purposes. The additional time burden will take about 15-25
minutes per session and can be incorporated in to routine fundus photography.

Results of this study will be beneficial for the children with retinal disease
because at this point data is limited and much can be gained. A better
understanding of retinal oximetry in children with retinal disease will
possibly lead to better treatment modalities, management and even prevention.