Do prostaglandin analogue-based eye drops (Latanoprost/Xalatan, etc.) used for glaucoma help patients who have a concurrent allergic conjunctivitis?

Not likely.

Latanoprost is a prostaglandin analogue and we already know that anti-prostaglandin therapy is effective in vernal conjunctivitis in particular: http://www.ncbi.nlm.nih.gov/pubmed/3115287

One would expect some worsening of allergic conjunctivitis in patients treated with prostaglandin analogues for glaucoma but the evidence is not very convincing: http://www.ncbi.nlm.nih.gov/pubmed/11789860

However, ocular allergic reactions induced by prostaglandin analogues themselves are well-described in the literature: http://www.ncbi.nlm.nih.gov/pubmed/16750448

Bottom line: Prostaglandin analogue eye drops used in glaucoma do not help in allergic conjunctivitis and are possibly harmful.



Ocular antihistamines (eye drops) (click to enlarge the image)

Related:

Bono from U2 reveals he always wears sunglasses because of glaucoma for 20 years - Telegraph http://buff.ly/1wdtlWi

Image source: OpenClipArt.org.