This study is about understanding how a condition called pachychoroid changes over time. Pachychoroid refers to an anatomic choroidal characteristic with abnormally thick choroid or abnormally dilated Haller's vessels. Pachychoroid can range from mild forms which does not cause any problems to more serious ones that might cause vision loss.This study will recruit participants with pachychoroid, to learn more about how this condition develops, how it affects people in the long run, and what factors might make it worse.

This study aims to document the longitudinal progression pattern and the incidence rate of progression of choroidal venous alteration (defined as either an increase in number of quadrants with pachyvessels or formation of new anastomoses which violates the physiological watershed It will provide valuable natural history data to study the pattern of evolution of choroidal vessels over time and validate the proposed multi-hit theory over a period of three years.

Inclusion Criteria:

1. Adults aged 45 years or older.
2. Presence of pachyvessels on ultra-widefield (UWF) imaging in at least one quadrant.
3. Willing to undergo pupil dilation, and protocol-required procedures for both eyes
4. Willing to provide written informed consent

Exclusion Criteria:

1. Presence of disorders of the ocular media which interfere with visual acuity and other ocular assessments during the study period
2. Eyes with other ocular pathology such as trauma, inflammation, previous intraocular surgery (except for cataract surgery)
3. Systemic diseases that might affect ocular blood flow such as uncontrolled hypertension, autoimmune disease, and haematological disorders
4. Pregnant or nursing women
5. Persons who are unable to give informed consent

This study will aim to recruit 170 participants in Singapore National Eye Centre (SNEC) and 50 participants in National University Hospital, 30 participants from the University of Malaya