THEATRE / A leap of faith: Molly Sweeney- Gate Theatre, Dublin

When a dramatist has composed a work of genius, as Brian Friel did with Faith Healer (1979), to embark on a second play which - in both format and metaphorical theme - invites direct comparison with the earlier masterpiece must be judged as either extremely courageous or foolhardy. Yet with Molly Sweeney, premiered now in his own production in Dublin, this is precisely what Friel is hazarding.

Like Faith Healer, the new play is presented entirely by monologues delivered by two men and a woman. Again like Faith Healer, it reflects on the subject of healing - or rather 'curing', a procedure which, though it may be mistaken for healing, can turn out to be its tragic antithesis. The main focus of the earlier work had been on the self-estranged healer himself. Caught in the grip of a capricious gift that can be neither comprehended nor controlled, he stood for the creative artist in general and the Irish artist in particular, reluctant to exercise his gift at home in a society which only knows how to treat figures like him with either corrupting veneration or deadly contempt.

In Molly Sweeney, the spotlight shifts to the beneficiary / victim of a more orthodox form of healing. A beautiful woman in her early forties who has been blind since she was 10 months old, Molly (Catherine Byrne) is inveigled into having an eye operation by two men who, in their different ways, also hope to be restored by it. Frank (Mark Lambert), her likeable crank of a husband, takes up the cause of her blindness with the same well-intentioned, restlessly swotty enthusiasm he brings to all the crackpot schemes - such as breeding Iranian goats (whose bodily functions, alas, never adjust to Irish time) - that briefly give him the illusion of solving his unfulfilled existence. For Mr Rice (T P McKenna), the washed-up, whisky-fuelled ophthalmologist, operating on Molly seems to hold out the chance of rehabilitating the once brilliant career that slumped into seedy decline after the collapse of his marriage.

These are not dishonorable men, but with the blindness of those who have vested personal interests, each fails to acknowledge what Molly herself seems intuitively to foresee when she goes ape and performs a frenziedly defiant, devilishly dextrous hornpipe dance at the party on the eve of her operation. Exile has always been a potent theme in Friel, and here it emerges again in Molly's desolate eviction from the familiarity and special sensory privileges of the blind world to the alienated terror of baffling visual overload in a world where 'every shape (was) an apparition, a spectre that appeared suddenly from nowhere and challenged you'. The result is withdrawal first into 'blind sight', a condition where you have visual perceptions but they aren't available to consciousness, and finally into an asylum and the relative ease of what she calls 'my borderline country', where the distinction in her mind's eye between the real and the imaginary has effectively collapsed.

Friel stages the piece very simply, with the characters sitting before a cyclorama painted in bold swirls of the colours Molly has to learn to recognise, and elicits some fine performances from the trio of actors, with T P McKenna deftly suggesting the fleshy blightedness of the doctor and Mark Lambert almost overdoing the funny-sad, gesticulating enthusiasms of Frank. Through slight tilts of the head or narrowing of the eyes, Catherine Byrne catches Molly's blindness with an unsentimental but limpid loveliness and no white-stick schtik, conveying her final state as one troublingly poised between willed victory and self-delusion.

The evening is finally disappointing, though. You keep hearing more than the faint clank of engineering as tropes about seeing-but-not-understanding are worked as thematic links into the story of the doctor's failed marriage, or when what the two men have done to Molly is farcically mirrored in a story about Frank's attempts to rescue some half-blind badgers who escape and can't find their original set.

It makes you recollect Keats's saying that we are right to resist art which has too palpable designs on us. The philosophical issues raised never quite achieve the general poetic resonance of their equivalents in the earlier play, and the chopping and changing of speaker here at times puts you worringly in mind of That's Life]. Where Faith Healer was a work of genius, Molly Sweeney, a case of Brian Friel-meets-Oliver Sacks, feels like a masterpiece manque.

Booking: 010-353 1 874 4045