Overview
The goal of this observational study is to define the course of the retinal degeneration in a ZSD patient cohort.
The objective of this study is to gather information so the investigators can:
- define the course of the retinal degeneration in a ZSD patient cohort with retinal degeneration
- define what tests best monitor the progression of the retinal degeneration
- generate prognostic information about vision loss in ZSD.
At each yearly visit, the participants will answer a functional vision questionnaire, have a physical evaluation, blood test, and participate in a variety of vision tests. The investigators will also collect pertinent medical history.
Participants will travel to study site. The study will provide financial support for board and travel.
Description
Participants/guardians will have a 1-hour virtual interview before the first visit to review the tests and determine which tests the participant is able to perform.
Below is a list of the vision tests used for this study:
Prior to each visit, the participant will complete the PedEyeQ or VFQ-25 questionnaire about functional vision.
At each clinic visit :
- Refraction and glasses test: this is a general vision test, as commonly conducted by an optometrist, before and after pupil dilation
- Best corrected visual acuity: the participant's vision will be tested using cards or a chart.
- Contrast sensitivity: the participant's ability to detect contrast will be tested using a chart.
- Visual field: the participant's field of vision will be tested by asking them to indicate when they see a stimulus.
- Reading test: the participant's ability to see written text will be tested using the International Reading Speed Test
- Color vision test: the participant's ability to see color will be tested using cards
- Eye exam: the participant's eyes will be examined with a lamp
- Pupil dilation: to allow the completion of some tests, the participant's pupils will be dilated using medicated eye drops
- Microperimetry: the participant's macula (central retina) will be visualized.
- Fundus photography: the participant's fundus (central retina) will be photographed in light and dark conditions
- Full field stimulus threshold test: the participant's ability to perceive light in different parts of their visual field will be tested
- Optical coherence tomography (OCT): detailed images of the participant's retina will be taken
- Fundus autofluorescence: the participant's retinal health will be assessed by imaging the natural fluorescent properties of their retinal pigment epithelium
- Chromatic pupillometry: the function of different cells in the participant's retina will be determined by measuring their response to light
- Multi-luminance mobility test (MLMT): the participant will walk through an obstacle course at varying light levels to test their functional vision in different light conditions.
- Blood collection: a blood sample will be collected and banked to measure peroxisome functions.
Eligibility
Inclusion Criteria:
- confirmed ZSD with deleterious variants in PEX genes identified
- confirmed or expected retinal involvement
Exclusion Criteria:
- unable to perform a minimum of one vision test
- severe ZSD disease