Session Title: Vitreoretinal Surgery II
Session Date/Time: Friday 18/09/2015 | 08:00-10:00
Paper Time: 08:24
First Author: : B.Lindtjørn NORWAY
Co Author(s): : V. Forsaa J. Krohn
PURPOSE:The aim of this study is to determine the incidence of full thickness macular holes (MH) in a well-defined Norwegian population, and to classify them according to the International Vitreomacular Traction Study (IVTS) Group Classification.
This retrospective study was conducted at the Department of Ophthalmology at Stavanger University Hospital, which is a tertiary referral hospital serving a population of 450 000 inhabitants.
A population-based retrospective chart review was performed for all patients operated for full thickness MH at Stavanger University Hospital between January 2008 and December 2014. Only a few patients were not operated in this period, and those patients were also included. Patients living in the outskirts of the referral area were excluded from the analyses, because of some likelihood of being referred elsewhere. Therefore the incidence rates are based on the number of 350 000 inhabitants (per January 2014). The MH were defined as primary or secondary. Primary MH were then classified according to the IVTS Group Classification in clinical stages i.e.; small ≤250μm, medium between >250 and ≤400μm and large >400μm. The MH diameter was measured with help of spectral domain optical coherence tomography (SD-OCT) at the narrowest point in the mid-retina, parallel to the retinal pigment epithelium, as described in the IVTS Group Classification. Yearly crude incidence rate for each age and gender group was calculated and adjusted to the total Norwegian population. Population data was retrieved from Statistics Norway.
A total of 175 eyes with MH in 164 patients could be identified. Of them, 147 primary and 28 secondary MH. The mean age of patients diagnosed with primary MH was 70.4 years and the female-male ratio was 2.2:1. Secondary MH were caused by retinal detachment in 11 patients, high myopia in 6, trauma in 5, complication to vitreoretinal surgery in 5, and following ocriplasmin injection in 1 patient. Of the 147 eyes with primary macular holes, 146 MH were confirmed and analysed by SD-OCT. The mean MH diameter was 425 µm (range, 101-1093µm). 14.4%(21) of MH were small, 33.6% (49) medium and 52.1% (76) large MH. The yearly overall mean MH crude incidence was 7.5 per 100 000 population. After adjustment, the incidence was 9.3 (CI 8.0-10.8) MH per 100 000 population per year. The mean crude incidence for primary MH was 6.3 per 100 000 population and the adjusted incidence was calculated to 7.9 (CI 6.6-9.3) MH per 100 000 population per year. Females had an adjusted incidence of 10.8 (CI 8.8-13.2) primary MH per 100 000 population per year, whereas the adjusted incidence for males was 4.9 (CI 3.6-6.6) MH per 100 000 population per year.
Data on the incidence of MH are scarce. The present study allows an estimation of MH incidence in a northern European, predominantly Caucasian population. The yearly estimated overall incidence of 9.3 MH per 100 000 population is in close accordance with a previous study from Minnesota, USA, with a similar population compromised of Caucasian from northern European heritage. In addition to the epidemiological data, the presents study provides morphological characteristics assessed by SD-OCT. Just over half of the MH were classified as large, whereas only 14% as small. Consistent with earlier studies, we also found a majority of female MH patients.