I don't have the name of the company but there is one in Connecticut that I met at the Newport Boat Show a few years ago. You can probably find them if you Google hatch repair and Ct.

The company in CT is: https://hatchmasters.com/contact/
They are also known as Select Plastics located in Norwalk.

I am planning to replace my lenses this spring so please  post details on your experience. 

I replaced all of my hatch lenses and rebedded all of the opening hatches a couple of years ago.  I sent the large trapezoid hatch in the v-berth to Hatchmasters, but I redid all of the others myself.  Some notes and steps:

1. Hatchmasters does a great job, but they are expensive.  I don't recall exactly, but I want to say that the one hatch they did for me was north of $300, which included a new lens and new handles and shipping.
2. If you replace the lenses yourself, it isn't that difficult, and the materials will cost somewhere around $40 per hatch.  I ordered the lenses from eStreet Plastics online.  You need 3/8" thick sheets in #2064 Gray.  You can order 24x24 panels and cut them to size yourself with a jig saw with a "plastics" blade.
3. The old lens can be removed from the frame very easily by spraying either "Debond Marine Formula" or a product called "Release" from Boatlife on the old caulk.  I have used both, and they both work very well.  They break the adhesive properties of the caulk and allow you to easily pry the old lens out of the frame and clean up all of the old caulk around the frame.  The release spray turns a 2 hour job into a 30-minute one.  Highly recommend.
4. You can use the old lens as a template for the new.  Curves and holes can be transcribed to the paper cover on the new lens.  
5. I used 3M VHB double-sided adhesive foam tape to install the new lens.  This bonds the lens to the frame while the new adhesive caulk does the sealing work.
6. At this point, green frog tape around the frame.  You're also going to want to remove the underside brown paper off of the lens, and pre-pull a corner of the brown paper that covers the top of the new lens (pull up a corner and then push it back down before you caulk).  This will give you starting point for pulling the paper up after you have caulked.
7. I used Dowsil 795 silicone sealant to caulk the new lenses.  Goop a heavy bead all the way around the lens joint, and wipe with a finger.
8. Before the caulk sets, carefully pull the brown paper off of the hatch lens and the frog tape off of the frame.  Let it cure, and you'll be ready to install the handles and hinge hardware.  If you want new handles and hinge covers, you can buy those separately from Hatchmasters too.  Catalina Direct used to have some as well, but I'm not sure if they still do.
9. I would recommend removing the whole hatch from the deck of the boat and doing all of the lens work at home.  So much easier than trying to do this one your knees on the boat.  It also gives you an opportunity to rebed the hatch to the deck.  When I did this, I found the source of a major deck leak that had been eluding me for years.  When I removed the hatch over the salon table, I found a spot where there was very little sealant under the frame, and it probably came from the factory this way.  The hatch itself never leaked, but the condition allowed water to get into the plywood deck core and over the years, the leak eventually emerged in the port side dorade vent opening in the cabin and also through the light fixture over the stove.  I had already rebedded everything else I could think of that would have caused it, but I finally found it under that hatch.  I epoxied all around that opening, rebedded the hatch, and have not had a drip since.

I have a few photos attached.  Hope this helps.

Don Lincoln

Don,

Thank you so much for the detailed reply.   I will follow these steps this spring!

Also, 
www.catalinadirect.com 
Sells lenses with or without the hardware for an easy swap out that you could do yourself.
JEB

I just got done replacing all of my lenses, following Richard's directions, which are excellent.  A few comments on the process fwiw:

1) Catalilna Direct sells a pre-machined lens for for the v-berth hatch.  If you don't need to save the $150 or so difference between the cost of materials and the cost of the lens, this can save you a bit of work and time. 

2) For whatever reason they don't sell lenses for the low-profile Lewmar hatches which are used for the other 5 hatches, at least for the 1-piece frame version.  CD claims these can't be user-replaced, which is silly, because the v-berth hatch is a 1-piece frame, and it's the exact same process to replace that lense as it is for the low-profile hatches.

3) If you do order the material for the v-berth hatch, it uses 1/2" thick material, not the 3/8" used in the low-profile hatches.

4) I removed my old lenses by running a utility knife around the sealant between the frame and lense a couplle fo times.  Then just push the lens out.  I had gotten some sealant removal solvent from CD, but didn't find it effective.

5) CD sells the Dowsil 795 - black that RIchard recommends.  I needed two tubes to do the 6 lenses.  It's also available from Amazon.

6) After rough cutting the lenses to size to within 1/4 or less of the finial size, I used a 1/2" trim router bit in a Bosch trim router to finish them.  I used a couple of 2" strips of the VHB tape to glue the old lens to the new blank during the final routing.  The parts are then easily separated with a putty knife without harming the new lens.

7) VHB tape is available from Amazon.  You'll need a couple of rolls of 1/2" tape to do all 6 lenses.

8) Cut the nozzle of the Dowsil tube to as small an opening as you can and still squeeze sealant out - you need to squeeze it into the space between the lense and frame and there isn't a lot of room.

9) For the holes in the lenses, I first drilled a 3/8" hole, then came back with a 5/16" trim router bit to rout them to the correct shape and size using the original as the template.

10) I removed the paper from both sides of the plexiglass, and replaced it 1" masking tape slightly overlapped, then trimmed back wtih a razor blade.  The paper on mine just seemed to have too rough an edge to leave a neat sealant edge.  Same thing on the frames - 1" masking tape ovoerlapped, then trimmed back with a razor blade.  I left enough upturned overlong edges so the tape would be easy to rmoved.  After injecting sealant into the gap, I ran the end of a tongue depressor over the sealant all the way around to give a nice, neat, slightly concave surface, then remove the tape.  Actually, I used one end of the plastic spreader that West System Epoxy sells instead of a tongue depressor - but same shape.

11). Out of order here, but I removed all the old tape and sealant off the frame with a utility knife, and final cleaning with lacquer thinner.  You'll also need to remove the sealant from one each of the different old hatch lenses so it can be used as the template.  Again - cut and scrape it off with a utility knife.

12) The hatch handles need a blind hole drilled in the lens.  The handle turns within a base, and that base has a stud in the bottom of it that fits in that blind hole to keep the base from turning.  The hole is a weird size that I didn't have a bit for, but just used the next larger size and it worked fine.  Wrap tape around the bit to use as a gauge to limit the depth of the hole - it would be a shame to drilll through and ruin the part on the last step.  So drill a bit, test the depth with the part, drill a bit more, etc..

13) Lay the 1/2" tape on the 'ledge' of the frame.  The tape can't turn the corners, so cut separate pieces to put in those.  That will leave some gaps which will be visible from the outside through the lens, so squirt a bit of the sealer onto those gaps.

14) For the large hatches, the plastic pieces that accept the screws that attach the "hold open" devices, fit into oval slots you've cut in the lens, and pass through the lens and the frame.  So when joining the lens to the frame, use them to ensure the correct positioning of of the lens in the frame.  

15) Again, out of order.  Especially when you rout out the periphery of the lenses with the trim bits, you'll generate zillions of little plexiglass chips.  These have no weight, go everywhwere on the wind, and staticallly stick to whatever they contact.  So be prepared to clean up a mess - you'll need an effective shop vacuum to do it, no way to ever sweep them up.

16) The plastic parts holding the hold open device, and the handle bases, have gaskets.  I didn't use Lewmar's gaskets, I just used a bit of butyl rubber pulled thin and laid in where the gasket would go.  So far has worked great.

That's all the lessons I learned from this process.  It's very rewarding, and I'd encourage anyone with the interest to try it.  The alternative is to remove your hatch lids and send them off to someone to "re-lens" - which could and probably will take weeks.  Doing it yourself limits the time the boat will have to go with some sort of temporary cover on the hatch, plus you'll be able to control when this exposure occurs - i.e. pick a time with no rain in the near forecast.