I will try to explain how one should understand this
“Monks, there are these three topics for discussion. Which three?
“One may talk about the past, saying, ‘Thus it was in the past.’ One may talk about the future, saying, ‘Thus it will be in the future.’ Or one may talk about now in the present, saying, ‘Thus it is now in the present.’
“Bhikkhus, there are these three pathways of language,
pathways of designation, pathways of description, that are unmixed,
that were never mixed, that are not being mixed, that will not be
mixed, that are not rejected by wise ascetics and brahmins. What
three?
“Whatever form, bhikkhus, has passed, ceased, changed: the term,
label, and description ‘was’ applies to it, not the term ‘is’ or the
term ‘will be.’
“Whatever feeling … Whatever perception … Whatever volitional
formations … Whatever consciousness has passed, ceased, changed: the
term, label, and description ‘was’ applies to it, not the term ‘is’ or
the term ‘will be.’
“Whatever form, bhikkhus, has not been born, has not become manifest:
the term, label, and description ‘will be’ applies to it, not the term
‘is’ or the term ‘was.’
“Whatever feeling … Whatever perception … Whatever volitional
formations … Whatever consciousness has not been born, has not become
manifest: the term, label, and description ‘will be’ applies to it,
not the term ‘is’ or the term ‘was.’
“Whatever form, bhikkhus, has been born, has become manifest: the
term, label, and description ‘is’ applies to it, not the term ‘was’ or
the term ‘will be.’
“Whatever feeling … Whatever perception … Whatever volitional
formations … Whatever consciousness has been born, has become
manifest: the term, label, and description ‘is’ applies to it, not the
term ‘was’ or the term ‘will be.’
“These, bhikkhus, are the three pathways of language, pathways of
designation, pathways of description, that are unmixed, that were
never mixed, that are not being mixed, that will not be mixed, that
are not rejected by wise ascetics and brahmins.
“The past, reverends, is one end. The future is the second end. The present is the middle. And craving is the seamstress …
“Contact, reverends, is one end. The origin of contact is the second end. The cessation of contact is the middle. And craving is the seamstress...
what's called 'mind,' 'intellect,' or 'consciousness' by day and by night arises as one thing and ceases as another. Just as a monkey, swinging through a forest wilderness, grabs a branch. Letting go of it, it grabs another branch. Letting go of that, it grabs another one. Letting go of that, it grabs another one. In the same way, what's called 'mind,' 'intellect,' or 'consciousness' by day and by night arises as one thing and ceases as another.
In short when one talks about something, that something will be spoken in terms of past, present & future tense.
Whatever it is we are talking about will fit one of these categories but it will also be connected to everything else because it will have a past cause (origin is one end), it will be the caused in present tense (being in the middle) and it is a requisite cause for a future.
Therefore when we talk about there being 'consciousness', it will normally be associated with 3 points of reference as to the cause of it's coming into play, as to it's coming into play and as to the consequences of it's coming into play. The three are not one and the same consciousness.
The abnormal circumstances are the states associated with the cessation principle and the contact there is analogical because that seeing isn't classes among the 6 classes of sensory perception but as 'a seeing with dhamma eye' or 'consciousness unestablished [which doesn't land]'. In the Sutta Consciousness is also as conjoined with the Discernment faculty and discernment is that which discerns the change & persistence of the conditioned and it is said that no change is discerned in the persistence of the unconditioned.
Consciousness is that which cognizes, it cognizes eg 'a sour taste' but the sour sensation is also something one feels, perceives & fabricates (conceives to perceive) and these terms are in that conjoined but aren't the same in meaning such that a difference can be delineated but one can not separate them after the having done so, if one is true & real then the other is also true & real.
Form means generally the four elements are and are needed to grow a plant. Heat, solids, liquids and circulation. These elements and whatever is derived in dependence on these four elements will either be form or be associated with it somehow.
In the circumstance of 'eye-consciosuness'. Even tho the consciousness aggregate and the form aggregate aren't conjoined as the form aggregate doesn't have an object & is the object of the other 4 aggregates which are conjoined as they always accompany eachother.
Therefore eye-consciousness refers to any consciousness also accompanied by form, associated with form, generating form and cognizing it.
The aggregate of form is sometimes conceived & perceived, sometimes isn't conceived & perceived, it doesn't always accompany consciousness.
In the Sutta Consciousness is also as conjoined with the Discernment faculty and discernment is that which discerns the change & persistence of the conditioned.
The four great elements which are included in Form What is that form
which is not derived? The sphere of the tangible, the fluid
element—this is that form which is not derived. What is that form
which is the sphere of the tangible? The earthy (solid) element, the
lambent (calorific) element, the gaseous (aerial) element; the hard
and the soft; the smooth and the rough; pleasant (easeful) contact,
painful contact; the heavy and the light — such a tangible, invisible
and producing impact, as, with the body-sensibility, invisible and
reacting, one has touched, touches, will, or may touch … … against
which tangible, invisible, and producing impact, the body-sensibility,
invisible and reacting, has impinged, impinges, will, or may impinge …
… such a tangible, invisible and producing impact, as has impinged,
impinges, will, or may impinge against the body-sensibility, invisible
and reacting … … in consequence of which tangible and depending on the
body-sensibility, there has arisen, arises, will, or may arise bodily
contact … and … born of that bodily contact, a feeling … [or] a
perception … [or] thinking … [or] cognition of body … [further,]
having a tangible as its object and depending on the body
(-sensibility), there has arisen, arises, will, or may arise bodily
contact … and … born of that bodily contact, a feeling … [or] a
perception … [or] thinking … [or] cognition of body; this that is the
tangible, the sphere and element of the tangible—this is that form
which is the sphere of the tangible. What is that form which is the
fluid? That which is fluid and belongs to fluid, that which is viscid
and belongs to viscous, the cohesiveness of form—this is that form
which is the fluid element.
[All] this is that form which is not derived.
What is that form which is derived?
The spheres of vision
Smell,
Hearing
Taste,
body sensibility;
the spheres of sights, Odours, Sounds Tastes;
the faculties of femininity Masculinity, Vitality; intimation by act,
intimation by speech; the element of space; the buoyancy of form
plasticity of form wieldiness of form integration of form Maintenance
Decay impermanence solid nutriment.
What is that form which is the sphere of vision?
The eye, that is to say the sentient organ, derived from the four
Great Phenomena, included in the self-state, invisible and reacting,
(i.) depending on which eye, in consequence of some visible form,
there has arisen, arises, will, or may arise
visual contact; … (ii.) and depending on which eye, in consequence of
some visible form, there has arisen, arises, will, or may arise—(born
of that visual contact)
a feeling … [or iii.] a perception … [or iv.] thinking … [or v.] a
visual cognition … [further, vi.] depending on which eye, and having a
visible form as its object, there has arisen, arises, will, or may
arise
visual contact, (vii.) and depending on which eye, and having a
visible form as its object, there has arisen, arises, will, or may
arise, born of that visual contact,
a feeling … [or viii.] a perception … [or ix.] thinking … [or x.]
visual cognition —this that is sight, the sphere of sight, etc. https://suttacentral.net/ds2.2.3/en/caf_rhysdavids