The aim of this study was to evaluate specular microscopy of chronic primary angle-closure glaucoma (CPACG) eyes at least one year after Nd:YAG iridotomy, and compare them with CPACG eyes without an iridotomy and age-matched, normal eyes. Nd:YAG laser causes photodisruption of target tissues as compared with the photocoagulative thermal mechanism of an Argon laser. Laser iridotomies have been known to produce a temporary increase in intraocular pressure (IOP), hyphema, focal lenticular opacities and very occasionally focal corneal endothelial damage.

A total of 100 eyes of 100 consecutive patients of CPACG with an Nd:YAG iridotomy performed ≥1 year before, 60 consecutive CPACG eyes without an iridotomy, and 60 age and refraction-matched control eyes were enrolled. CPACG patients had a mean age of 62±8 years, a mean intraocular pressure of 18±5.3mmHg, a mean specular count of 2536±224 cells/mm2, and mean duration after iridotomy of 3.2±2 years. There was a significant correlation of specular endothelial counts with age (r=−0.39; P<0.001) and interval after iridotomy (r=−0.25; P=0.01). CPACG eyes without an iridotomy had a mean age of 62±5 years and a mean specular count of 2469±199 cells/mm2. Normal control eyes with a mean age of 61±6 years had a mean specular count of 2729±299 cells/mm2. There was no significant difference in specular count between CPACG eyes with or without an iridotomy (P=0.19); however, both CPACG groups had a specular count significantly lower than controls (P=0.01 and 0.02, respectively). There was no statistically significant difference seen in polymegathism (coefficient of variation) and pleomorphism (% of hexagonal cells) in endothelial cells among the three groups. The authors conclude that Nd:YAG laser iridotomy did not produce any significant change in the central corneal endothelial status of patients with CPACG, measured by confocal microscopy, when compared with patients who had not undergone Nd:YAG laser iridotomies. However, patients with CPACG, with or without Nd:YAG laser iridotomies, were found to have significantly lower central corneal endothelial cell counts in comparison with age-matched controls without glaucoma.

Long-term evaluation of specular microscopic changes following Nd: YAG iridotomy in chronic primary angle-closure glaucoma eyes.
Ramanjit S, Esha A, Mathew J, et al.
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Chrysostomos D Dimitriou

Essex County Hospital, Colchester, Essex, UK.

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