Abstract
Purpose: :
To determine the 10-year incidence of glaucomatous visual field loss (GVFL) in offspring of glaucoma cases.
Methods: :
Participants were offspring of glaucoma cases from the Rotterdam Study. Of 110 participants who participated in the baseline measurement, 94 (85%) agreed to participate in the follow-up [FU]. These participants underwent the same ophthalmologic examination (intraocular pressure [IOP] measurement, visual field testing, optic disc assessment and refraction) at baseline (1994 and 2000) and FU (2007-2008). Since no population-based incidence data are available in this age group, we therefore compared the total number of GVFL cases at FU with the prevalence of GVFL in the general population of similar age, using the Poisson distribution. The incidence of GVFL was determined as an incidence rate and recalculated to a 10-year risk. Characteristics of participants with and without GVFL at FU (high myopia, IOP, IOP treatment and linear cup-disc ratio) were assessed using univariate comparisons.
Results: :
After a mean follow-up duration of 11.5 years (standard deviation 2.0 years; range 7.4-13.7 years), four participants with GVFL were identified: three incident cases and a single case that already had GVFL at baseline. This yields a prevalence of GVFL amongst the offspring of OAG cases at FU of 4.3% (4/94), which is significantly higher than the prevalence of 0.7% in the general population of similar age (mean age of the four cases at FU 59 years; P=0.004). The incidence rate and 10-year risk of GVFL were 2.8/1000 person-years (95% confidence interval 0.9-8.8) and 2.8% (0.9-8.4) respectively. High myopia (P=0.003), IOP (P=0.032), IOP treatment (P=0.004) and linear cup-disc ratio (P=0.009) were associated with GVFL.
Conclusions: :
Our study confirms that being an offspring of a confirmed glaucoma case is a risk factor for developing GVFL. However, given a 10-year risk of only 2.8%, examinations for case finding in offspring of glaucoma patients may be widely spaced in time.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • clinical (human) or epidemiologic studies: risk factor assessment • clinical (human) or epidemiologic studies: natural history