Large plasma screens have been erected in the 19th-century St Mary's Cathedral in Killarney to allow Massgoers a better view of the altar.
The cathedral's stone pillars, as well the arrangements of some of its chapels, have long meant that hundreds of worshippers could hear but not see Mass being celebrated.
Fr Declan O'Connor, parish priest of Killarney, said yesterday the screens would take getting used to, but technology not available to architect Augustus Pugin (1812-52) was being used to allow people fuller participation in the liturgy.
Ten 42-inch screens on column stands have so far been installed in the aisles of the cathedral .
Constructed during the years of the Famine, the unfinished but roofed building was used to shelter the sick and dying.
The cathedral, considered one the finest examples of neo-Gothic architecture in Europe, was consecrated in 1855, with a 285-ft spire completed later.
The plasma screens are part of a programme of restoration to celebrate its 150th anniversary in August.
They are the first major renovations of the cathedral since a controversial programme led by then Bishop Éamonn Casey in the early 1970s, which undid Pugin's vision of a rich interior and rugged exterior.
Coinciding with liturgical changes, the Victorian cathedral was stripped of its internal plaster, its ornate brass, wrought iron, marble and rich furnishings, exposing rubble stone and keeping practically nothing of the original interior and furnishings.
Town councillors in 2001 included the cathedral in a list of protected structures despite opposition by Bishop Bill Murphy, who said churches were not museums and internal arrangements of churches should be determined by the needs of the liturgy, not those of conservation.
Fr O'Connor said before Vatican II people had been "at Mass" but they were now invited to participate in the liturgy. The screens were experimental and would undergo a full assessment in the coming weeks.