Die brilvoorskrif verander, behalwe dat die lenssterkte dieselfde bly.

Afrikaans, like Dutch and German, very often forms compound nouns by writing them as a single word.

So:

• bril = glasses
• voorskrif = prescription

Together, brilvoorskrif means glasses prescription or eyeglass prescription.

This is very normal in Afrikaans. A few similar examples are:

• huisdeur = house door / front door
• tafeldoek = tablecloth
• oogarts = eye doctor

So if you see a long noun in Afrikaans, it is often just several ideas combined into one word.

Die is the Afrikaans definite article, meaning the.

In this sentence:

• Die brilvoorskrif = The glasses prescription
• die lenssterkte = the lens strength

Afrikaans uses die for all nouns, whether singular or plural, and it does not change for gender. That is much simpler than languages like German or French.

So:

• die man = the man
• die vrou = the woman
• die kinders = the children

It appears twice simply because there are two definite nouns in the sentence.

No. In Afrikaans, verbs usually do not change form according to the subject in the present tense.

So:

• Ek verander = I change
• Jy verander = you change
• Die brilvoorskrif verander = the prescription changes
• Hulle verander = they change

This is one of the easier parts of Afrikaans grammar for English speakers. Unlike English, you do not usually need a special -s form like changes.

So even though English says the prescription changes, Afrikaans simply says die brilvoorskrif verander.

Behalwe dat means except that.

It introduces an exception to what was just said.

So the sentence structure is:

• Die brilvoorskrif verander = The prescription changes
• behalwe dat die lenssterkte dieselfde bly = except that the lens strength stays the same

You can think of behalwe as except, and behalwe dat as except that when a full clause follows.

Compare:

• behalwe die rame = except the frames
• behalwe dat dit duur is = except that it is expensive

So dat is added when what follows is a whole statement, not just a noun phrase.

Dat means that, and it introduces a subordinate clause.

In this sentence:

• main clause: Die brilvoorskrif verander
• subordinate clause: dat die lenssterkte dieselfde bly

Afrikaans often uses dat in the same kind of way English uses that, especially after expressions like behalwe dat, omdat, and certain reporting verbs.

Without dat, the sentence would sound incomplete or ungrammatical in this structure.

So:

• behalwe dat... = except that...
• omdat... = because...
• ek dink dat... = I think that...

This is because dat introduces a subordinate clause, and in Afrikaans subordinate clauses, the verb typically goes to the end.

So:

• main clause: Die brilvoorskrif verander
• subordinate clause: dat die lenssterkte dieselfde bly

That word order is very typical:

• Ek weet dat hy kom. = I know that he is coming.
• Sy sê dat die boek duur is. = She says that the book is expensive.
• behalwe dat die lenssterkte dieselfde bly = except that the lens strength stays the same

For English speakers, this is one of the biggest word-order differences to get used to.

Lenssterkte is another compound noun:

• lens = lens
• sterkte = strength / power

So lenssterkte means lens strength or lens power.

In an optometry context, this refers to how strong the corrective lenses are. Even if the overall prescription changes, the sentence says that the actual lens power remains the same.

Dieselfde means the same.

It is treated as a fixed form in standard Afrikaans. Learners should usually just memorize dieselfde as the normal way to say the same.

Examples:

• Ons het dieselfde probleem. = We have the same problem.
• Dit bly dieselfde. = It stays the same.
• Die lenssterkte bly dieselfde. = The lens strength stays the same.

So in this sentence, dieselfde is describing lenssterkte and means that it remains unchanged.

Yes, exactly. Bly often means stay, remain, or keep being.

In this sentence:

• die lenssterkte dieselfde bly = the lens strength remains the same

Afrikaans often uses bly with an adjective or description to express that something continues in the same state.

Examples:

• Hy bly kalm. = He remains calm.
• Die prys bly hoog. = The price stays high.
• Alles bly dieselfde. = Everything stays the same.

So bly is a very natural choice here.

The comma separates the main statement from the exception clause.

Here the sentence first says one thing:

• Die brilvoorskrif verander

Then adds an important qualification:

• behalwe dat die lenssterkte dieselfde bly

The comma helps show that the second part is an added explanation or exception. In writing, this makes the sentence clearer and easier to read.

Yes, fairly literally:

• Die brilvoorskrif verander = The glasses prescription changes
• behalwe dat = except that
• die lenssterkte dieselfde bly = the lens strength stays the same

A very literal translation would be:

The glasses prescription changes, except that the lens strength stays the same.

Depending on context, a more natural English version might be:

• The prescription changes, except the lens strength stays the same.
• The glasses prescription changes, although the lens strength remains the same.

So the Afrikaans structure is actually quite close to English here, except for the verb-at-the-end word order after dat.

Yes. The sentence is in the present tense.

• verander = changes / is changing
• bly = stays / remains

Afrikaans present-tense forms are often used where English might use either a simple present or a present progressive, depending on context.

So:

• Die brilvoorskrif verander could mean The prescription changes or The prescription is changing, depending on the situation.
• die lenssterkte bly dieselfde means the lens strength stays the same or remains the same.

In this sentence, the most natural English meaning is the general statement: The prescription changes, except that the lens strength remains the same.