4.1.1 Screening Visit and Procedures Screening visit and procedures will be done on a separate day. Participants referred from TTSH will be allocated a time slot to come to SERI for the ocular examinations. On the day of procedure, SERI coordinator will screen for eligible subjects by asking them some questions base on the inclusion and exclusion checklist. If found to be eligible and participants are interested, consent will be taken at SERI and SERI optometrist will proceed with the ocular assessments.