Purpose: to measure changes in lens transparency in patients who
underwent either trabeculectomy or deep sclerectomy.
Methods: prospective, two-center randomized single-masked clinical
trial, lasting three years. 79 eyes (79 patients, age > 65 years) enrolled
and randomised to deep sclerectomy (Group A, n = 41) or trabeculectomy (Group
B, n = 38). Main outcome: Changes in lens transparency (LOCSII at slit lamp,
one step change at two consecutive visits) . Evaluation of the lens transparency in the fellow unoperated
eye (when applicable) was also performed.
Results: 79 operated and 73
unoperated fellow eyes were evaluated. 6 fellow eyes, being pseudophakic, were excluded from the study. Changes in lens transparency were as
follows:
Cortical: 42% TE vs 38% DS; Nuclear: 66% TE vs 15% DS; Posterior
Subcapsular: 7% TE vs 9% DS. Worsening of nuclear transparency proved
significantly different between the two cohorts (Fisher exact test, p =
0.00008, with a 95% c.l. OR for TE vs DS ranging between 3.9 and 53.2). Changes
in lens transparency in the fellow unoperated eye were as follows:
Cortical: 40% TE vs 41% DS; Nuclear: 16% TE vs 14% DS; Posterior
subcapsular: 6% TE vs 8% DS. An estimate of the Odds ratio (95% c.l. = 3.5 –
50.4) shows that trabeculectomy was associated with a 13-fold higher risk for
developing a worsening of nuclear transparency within the same patient.
Conclusion: Trabeculectomy was more cataractogenic than deep
sclerectomy.