The severity and spatial distribution of visual field defects in primary glaucoma: a comparison of primary open-angle glaucoma and primary angle-closure glaucoma

OBJECTIVE

To compare the characteristics of visual field defects in primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG).

METHODS

Subjects with primary glaucoma aged 30 years and older were prospectively considered for inclusion. Automated static white-on-white perimetry was performed. A minimum of 2 reliable tests was required with a mean deviation (MD) within 2 dB on 2 tests. Subjects with previous symptomatic angle-closure, normal-tension glaucoma, visually significant cataract, or previous intraocular surgery were excluded.

RESULTS

Of 234 subjects assessed, 129 had POAG, and 105 had PACG. The MDs (POAG group, -13.3 dB; PACG group, -18.0 dB) indicated more severe visual loss in subjects with PACG. In subjects with POAG, the superior hemifield was more severely affected than the inferior. This was less pronounced in subjects with PACG. Following stratification by MD, the difference between hemifields was marked in the mild (-10 dB<or=MD) and moderate (-20 dB<or=MD<-10 dB) subgroups but was not present in the severe (MD<-20 dB) subgroup. We detected differences between POAG and PACG in retinal sensitivity between the superior and inferior hemifields, independent of severity of damage.

CONCLUSIONS

The pattern of visual field loss was different in the 2 diseases. This may give insight into the pattern of visual loss in predominantly pressure-dependent glaucomatous optic neuropathy.

Effect of diode laser contact transscleral pars plana photocoagulation on intraocular pressure in glaucoma

PURPOSE

To evaluate the efficacy of diode laser contact transscleral pars plana photocoagulation (CTPPP) for intraocular pressure (IOP) control in glaucoma and its clinical application.

METHOD

A prospective, non-randomized hospital-based pilot study was conducted. Fourteen patients with poor visual acuity (VA worse than 6/60) and medically uncontrolled, refractory glaucoma were recruited, and CTPPP was performed after informed consent.

RESULTS

Mean preoperative IOP was 41.0 mmHg (SD 12.6, range 27-70, n = 14). At 1 week postoperatively, IOP was reduced in 12 of 14 (86%) patients to a mean of 28.6 mmHg (SD 15.8, range 3-55, n = 14). This represented a mean decrease of 12.4 mmHg. Mean IOP was 34.0 mmHg (SD 17.4, range 5-71, n = 14) and 31.6 mmHg (SD 13.4, range 5-22, n = 12) at 4 and 12 weeks, respectively. The IOP reduction was significant at 1 week (P = 0.001, paired t-test) and at 12 weeks (P = 0.04, paired t-test). The two patients with preoperative pain reported abolition of pain after the procedure. Seven of 13 patients on preoperative antiglaucoma eye drops did not require eye drops postoperatively.

CONCLUSION

Diode laser CTPPP was found to significantly reduce IOP in the majority of patients at 1 week postoperatively, with less but still significant effect at 12 weeks. Its potential application as a procedure for short-term IOP reduction in medically uncontrolled glaucoma requiring filtering surgery needs to be further investigated.

Efficacy of latanoprost in reducing intraocular pressure in patients with primary angle-closure glaucoma

Two independent, prospective trials were recently conducted to assess the efficacy of latanoprost in reducing intraocular pressure (IOP) in patients with primary angle-closure glaucoma (PACG). The first study was a 2-week, randomized, double-masked comparison of latanoprost treatment and timolol treatment in patients with PACG. Patients were randomized to one of two parallel treatment groups, receiving either placebo in the morning and latanoprost 0.005% in the evening, or timolol 0.5% twice daily. The mean IOP reduction in latanoprost group was 8.8 +/- 1.1 mm Hg (mean +/- SEM, p < 0.001; 34.2%) from a mean baseline IOP of 25.7 +/- 0.9 mm Hg, and the corresponding figures for the timolol group were 5.7 +/- 0.9 mm Hg (p < 0.001; 22.6%) from a mean baseline IOP of 25.2 +/- 1.1 mm Hg. A significantly greater IOP reduction of 3.1 +/- 1.5 mm Hg (95% confidence interval: 0.1 to 6.0) was achieved in the latanoprost group compared to the timolol treatment group (p = 0.04). In the second study, latanoprost 0.005% once a day was added adjunctively to PACG patients with persistently elevated IOP after iridectomy, despite treatment with beta-blockers and pilocarpine. The IOP decreased by about 21% during the first 3 months, and showed a reduction of about 36% at the end of 1 year. At the 1-year follow-up, IOP was <20 mm Hg in all eyes. In both studies, latanoprost was well tolerated with few adverse events. These results demonstrate that latanoprost is effective in reducing IOP in patients with PACG.

Review of recent advancements in the understanding of primary angle-closure glaucoma

Primary angle-closure glaucoma is a leading cause of blindness worldwide. However, the terminology used for angle-closure in the literature is inconsistent, with inappropriate emphasis on symptomatology. A new nomenclature for primary angle-closure glaucoma focuses on the presence of end-organ damage and limits the use of the term "glaucoma" only for people who have suffered injury to the optic nerve. This review describes the various modalities of treatment for primary angle-closure glaucoma. The role and limitations of laser peripheral iridotomy in the management of the different forms of the disease are summarized. Recent developments have led to improvements in the understanding of the epidemiology, clinical course, and treatment of the condition.

Additive effect of unoprostone and latanoprost in patients with elevated intraocular pressure

AIMS

To assess the additive effect of unoprostone and latanoprost in patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT) METHODS: 32 patients with POAG or OHT were randomised to receive either latanoprost once daily or unoprostone twice daily for 4 weeks. After 4 weeks, all patients received both latanoprost and unoprostone for another 4 weeks. The IOP was measured at 9 am and 5 pm on the baseline, day 28, and day 56 visits, and at 9 am on day 14 and day 42 visits. The medications were given to the patients in an open label fashion. The observer was masked to the treatment given. The mean of the measurements was calculated. Safety parameters were also recorded. The additive effect of the medications was assessed by the reduction in intraocular pressure (IOP) when both medications were used, compared with when one medication was used.

RESULTS

28 patients completed both treatment periods and had IOP data available for evaluation. After 1 month of treatment, latanoprost significantly reduced IOP (mean by 6.1 (SEM 0.8) mm Hg (p<0.001) and unoprostone by 4.9 (1.0) mm Hg (p<0.001) from the baseline of 24.4 (0.6) mm Hg and 24.4 (1.1) mm Hg respectively (p = 0.18). When latanoprost once daily was given to patients treated with unoprostone, there was additional IOP lowering of 1.9 (0.6) mm Hg (p = 0.012). However, adding unoprostone to those being treated with latanoprost produced an IOP change of +0.4 (0.5) mm Hg (p = 0.42). Ocular symptoms and findings were mild and equally distributed between treatment groups, and after combined therapy. Hyperaemia and ocular irritation were the most frequently reported events. Over a third of patients experienced ocular irritation with the combination of medications.

CONCLUSIONS

Latanoprost once daily causes additional IOP lowering in eyes which were being treated with unoprostone twice a day. However, there was no additional IOP lowering when unoprostone was added to eyes which were being treated with latanoprost. Both drugs were well tolerated together with few ocular adverse events.