Progression of visual field loss in untreated glaucoma patients and glaucoma suspects in st. lucia, west indies

The additional yield of a periodic screening programme for open-angle glaucoma: a population-based comparison of incident glaucoma cases detected in regular ophthalmic care with cases detected during screening

“…We re-estimated the number of undetected iOAG cases that would develop end-stage OAG before death, now using data from the study by Wilson et al 19. They analysed progression of VFL in untreated black OAG cases in the West Indies.…”

“…Obviously, this is only a rough estimate. For example, we assumed that the disease severity of our 55 undetected iOAG cases at follow-up could be compared with the baseline findings of Wilson et al ,19 and we based our estimate on average life expectancy, assuming that the lower incidence of glaucoma blindness in those dying earlier than average balances the higher incidence in those living longer than average. Both our estimates suggest, however, that the real yield of a periodic OAG screening programme in terms of preventing severe visual impairment or blindness (estimated to be 0.1%) is much lower than the yield as estimated from the prevalence of undetected OAG (typically 1%) 6 7…”

Interpretation of the glaucoma "landmark studies"

“…The black population of St Lucia, in the West Indies, was screened for glaucoma and the untreated glaucoma cases were re-examined 10 years later. Despite receiving no treatment and being a high-risk population,8 15 10 years later some 40% of the glaucoma eyes showed no progression of visual field loss 14. In the 60% of eyes in the St Lucia study that did show progression, the severity of progression was related to age, not to mean IOP 14.…”

“…However, there was no control group of untreated eyes in CIGTS and yet, without treatment, 38% of eyes in EMGT and 65% in CNTGS at 6 years showed stability 2 5. An important study of visual field loss progression in untreated black patients with glaucoma was reported by Wilson et al 14. The black population of St Lucia, in the West Indies, was screened for glaucoma and the untreated glaucoma cases were re-examined 10 years later.…”

“…Despite receiving no treatment and being a high-risk population,8 15 10 years later some 40% of the glaucoma eyes showed no progression of visual field loss 14. In the 60% of eyes in the St Lucia study that did show progression, the severity of progression was related to age, not to mean IOP 14. In the US, the Glaucoma Laser Trial showed that after a 7-year follow-up with a mean IOP of 18–19 mmHg, the mean visual fields score improved and 50% of eyes showed no progression 16…”