Table I.

Clinical presentations of the four affected members.

Parameter	Family 1: IV:3	Family 1: V:2	Family 1: V:3	Family 2: II:1
Age (years)	34	6	3	4
Gender	Male	Female	Male	Female
Birth history	Full-term	Full-term	Full-term	Full-term
BCVA (decimals)
OD	0.4	0.2	Unable	0.1
OS	0.3	0.2	Unable	0.2
Refractive error
OD	+0.50/+2.00	+2.00/+5.00	+2.00/+1.00	−0.25/+1.00
OS	+1.00/+2.50	+1.50/+2.50	+2.00/+1.50	+1.25/+1.75
Stereopsis (butterfly)	Nila	Nil	Nil	Nil
Strabimus	Hypo with Eso	Hypo with Eso	Hypo	Hypo with Eso
Eye movement
OD	Restrictive UAHM	Fixed	Restrictive UAHM	Restrictive UAHM and HM
OS	Restrictive UAHM and HM	Fixed	Restrictive UAHM	Variable restrictive upgaze and HM
Ptosis
OD	Moderate	Severe	Severe	No
OS	Severe	Severe	Severe	Severe
Bell's phenomenon	Absent	Absent	Absent	Absent
Forced duction test
OD	Positive	Unable	Unable	Unable
OS	Positive	Unable	Unable	Unable
Nystagmus	On upgaze	In all directions of gaze	Absent	Absent
Synergistic convergence	On upgaze	In all directions of gaze	Absent	Absent
Pupil size	Normal	Normal	Normal	Normal
Pupillary light reflex	Normal	Normal	Normal	Normal
Compensatory head position	Chin up	Chin up and mouth open	Chin up	Chin up
Proptosis ocular	No	No	No	No
Upper eyelid lag	No	No	No	No
Other ophthalmic examinations	Unremarkable	Unremarkable	Unremarkable	Unremarkable

^aThe result of 'nil' in the stereopsis test indicates that the patient cannot identify any figures present on the test, and the patient has no stereopsis. BCVA, best corrected visual acuity; OD, oculus dexter (the right eye); OS, oculus sinister (the left eye); Hypo, hypotropia; Eso, esotropia; UAHM, upgaze above horizontal midline; HM, horizontal motility.