How did the eye test go?

Question

I've just got back from an eye check-up, where I had the weirdest experience... Most of the appointment went fine - I'm not colour-blind, my eyes are physically healthy, no blind spots, etc. - but when it came to the visual acuity test, things took an unexpected turn...

We'd been casually chatting throughout the appointment and at one stage stumbled upon a mutual love of a traditional pub quiz. At this point the optometrist paused, seemed to be contemplating something for a moment, and then said, "Perhaps you would like to try my special test?" They then directed my attention to a wall where not one, not two, but ten seemingly ordinary-looking Snellen charts were laid out.

"Why so many tests?" I asked.

"Oh, there's only one test," they replied. "The ground rules - you'll get two points for each of the missing ones that you find, and a bonus two points for a nine-letter meta-answer you can extract from them. However, the test isn't a complete success unless you can also extract a ten-word message. Are you game?"

Well, I had no idea yet what those rules meant, but - even so - of course I was! I didn't have to be asked twice! Here's an image depicting the wall of charts I was faced with:

To be fair, I did have to leave my seat and go up closer to read some of the letters on the bottom three rows, so here's a text transcription of each chart too...

H
CE
INO
RSTU
ACHI?
A?KUTW
A?DEILN
A?BNOSTW
AA??P?UY
AADHILNT
A?HIILNT?

E
AA
?GN
?PRU
CDKSU
BI??SU
E?IKS??
AEEH?SWY
AANPRSST
BCE?KSUY
AEINPR??T

C
CG
HIL
NOTX
ANP??
C?NOOP
AEFLORS
AACDG?NR
EO?RSSTU
IIMSS?UW
EEEJLLRWY

K
AC
EGO
RTXY
HACBI
GFEBIH
HCIABGF
AEIHCGDA
GBFGECDD
HCDADEFI
EDFABGHBC

B
DE
INS
XXXY
GNOOP
EGIL?T
ABFH?SU
DEFLNOR?
AEENPPR?
EEG?PPTT
EHINOSTWW

A
EE
ELM
NSTX
BNO?R
FLR?UU
AHI?SSU
AILMNPTU
CEH?LNOR
ACDIMNS?
IL?NOPTUU

D
AA
CIL
PSTX
?N?TU
A?K?SU
AABBE?N
A?GINOST
??DEPSTU
EEFNORTW
AC?GIOOPR

F
AE
?IL
?RSX
A?ELT
ADEHIT
AAINRRY
AEE?MRST
AE?IPRTY
AEFLO?RT
AAFHLNSTU

I
AA
CEP
SSTT
DEORV
AEJNUU
AGILNN?
?BCIKMRS
ABCI?MOU
HLLNOOUU
DE?I?NOSS

G
AK
PRS
SUXX
?EGST
A?EHRS
DDEOORW
A?BD?LNS
EEIMOSTY
ABCE?NSY
?EGORSUVY

Can you complete the eye test? A complete answer should provide a full list of 'the missing ones', the nine-letter meta-answer, and the text of the hidden ten-word message.

_{NB I have attempted to replicate as closely as possible the layout of the Snellen chart used to illustrate the associated Wikipedia page. The green and red lines are purely decorative and serve no hidden purpose.}

Answer 1

Since each line seems ordered alphabetically,

the natural thing to do is anagram them. In the first group, one of the full lines we do have is AADHILNT, which anagrams to THAILAND. The line A?KTUW can be filled in with an I, to anagram to KUWAIT.

We can continue this for all except the first four lines. Those don't do anything on their own... but together, the second through fourth lines make COUNTRIES!

And the missing letters spell out NICARAGUA, another country.

This can be done for all ten charts:

...except one, whose lines aren't ordered alphabetically. We'll come back to that later.


H: COUNTRIES: CHI[N]A, KUWA[I]T, I[C]ELAND, BOTSW[A]NA, PA[RAG]UAY, THAILAND, LITH[UA]NIA ==> NICARAGUA
E: N[C]AA GR[O]UP: DUCKS, B[R]UI[N]S, [HU]SKIE[S], HAW[K]EYES, SPARTANS, BUCK[E]YES, TE[R]RAPIN[S] ==> CORN HUSKERS
C: CLOTHING: PAN[TS], PONC[H]O, LOAFERS, CARD[I]GAN, T[R]OUSERS, SWIMSUI[T], JEWELLERY ==> T SHIRT
B: DISNEY: PONGO, [P]IGLET, BASHFU[L], FLO[U]NDER, PE[T]ER PAN, GEPPETT[O], SNOW WHITE ==> PLUTO
A: ELEMENTS: BOR[O]N, [S]ULFUR, HASSIU[M], PLATINUM, CHLOR[I]NE, SCANDI[U]M, PLUTONIU[M] ==> OSMIUM
D: CAPITALS: TUN[IS], [L]US[A]KA, [M]BABANE, S[A]NTIAGO, [B]UD[A]PEST, FREETOWN, PO[D]GORICA ==> ISLAMABAD
F: AIRL[IN]ES: [D]ELTA, ETIHAD, RYANAIR, EM[I]RATES, E[G]YPTAIR, AER[O]FLOT, LUFTHANSA ==> INDIGO
I: STATE CAPS: DOVER, JUNEAU, LAN[S]ING, BISM[A]RCK, CO[L]UMBIA, HONOLULU, D[E]S[M]OINES ==> SALEM
G: US PARKS: G[A]TES, AR[C]HES, REDWOOD, B[AD]LANDS, YOSEMITE, B[I]SCAYNE, VOY[A]GEURS ==> ACADIA

So now what?

The top letters are A to I. In that order, the extra members of each category are OSMIUM, PLUTO, T-SHIRT, ISLAMABAD, CORN HUSKERS, INDIGO, ACADIA, NICARAGUA, SALEM. The first letters of these spell out the nine-letter meta answer, OPTICIANS!

But what about that tenth chart?

Well, there are exactly as many letters on each row as the other 9 charts. So we can take the corresponding letters from those charts - after they've been anagrammed.
For instance, the 5-letter row is HACBI. The 5-letter entries from those categories are CHINA, BORON, PANTS, PONGO, DOVER. Taking the corresponding letters for each position spells out CONGR, which looks like the start of a message!

Doing this for every row spells out our final message:
"Congratulations for passing my eye test, twenty out of twenty!"