gg5: ～する〔短縮する〕 contract; shrink

I don't think we need a separate sense for a specific type of contraction.

@@ -30,8 +30,2 @@
-</sense>
-<sense>
-<pos>&n;</pos>
-<pos>&vs;</pos>
-<pos>&vi;</pos>
-<xref type="see" seq="2582050">瞳孔縮小</xref>
-<misc>&abbr;</misc>
-<gloss>contraction (of the pupil)</gloss>
+<gloss>contraction</gloss>
+<gloss>shrinkage</gloss>

You don't usually have antonyms of physical processes.

@@ -25 +24,0 @@
-<xref type="ant" seq="1205200">拡大</xref>
@@ -36 +34,0 @@
-<xref type="ant" seq="2128980">散大</xref>
@@ -37,0 +36 @@
+<misc>&abbr;</misc>

https://eow.alc.co.jp/search?q=pupil+contraction
contraction of the pupil
瞳孔収縮

瞳孔収縮	249	52.0%
瞳孔縮小	230	48.0%

sankoku gives this antonym for [1], weblio has exactly one antonym and it is the same:
https://thesaurus.weblio.jp/antonym/content/縮小
対義語・反対語	縮小	⇔	拡大

I made a mistake.  sankoku does not [ant] to 散大, it xrefs to 拡大(i.e. it doesn't mention this "eye" usage at all). I've also found a related formulation for pupil contraction (which we don't have) 瞳孔収縮.   収縮 has a more easily comprehensible gloss in this context. (while ngrams are similar, google finds far more for 瞳孔縮小).

The wikipedia article on miosis uses 縮小 and 収縮 in the same breath, with the latter (perhaps coincidentally, perhaps not) used as a verb to describe the normal contraction of the pupil:
~とは医学において、疾患や薬物、外傷によって瞳孔が過度に縮小する現象である。瞳孔は普通日向では収縮、...

@@ -24,0 +25 @@
+<xref type="ant" seq="1205200">拡大</xref>

瞳孔縮小	230	8.9%
瞳孔散大	2359	91.1%

瞳孔縮小	230	8.3%
瞳孔散大	2359	85.0%
瞳孔は縮小	38	1.4%
瞳孔が縮小	104	3.7%
瞳孔を縮小	45	1.6% <-- note: 瞳孔を縮小させる, not [vt]
瞳孔を散大	130	<-- dilation, also [vi] /させる

散大 is apparently limited to pupils.  This entry is more broad, but is the [ant]/analogue for pupil contraction.  See xrefs for confirmation. 

I used [ant] because it was already in use for 瞳孔散大, but [see] is fine with me. sankoku seems to flags as [ant].

sankoku gives two senses, neither of which is *limited* to eyes.  (So, maybe there is a 3rd sense here, i.e. a split of [1], or maybe it's fine as is). But I split [2] off because it would seem to *not* be [vt] (sankoku otherwise agrees that [1] is [vt,vi]), and I think the xref is valuable.

@@ -29,0 +30,8 @@
+</sense>
+<sense>
+<pos>&n;</pos>
+<pos>&vs;</pos>
+<pos>&vi;</pos>
+<xref type="ant" seq="2128980">散大</xref>
+<xref type="see" seq="2582050">瞳孔縮小</xref>
+<gloss>contraction (of the pupil)</gloss>