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Joanne C Wen, Scott W Cousins, Stefanie Schuman, R. Rand Allingham Allingham; Intravitreal injections cause anterior chamber angle narrowing in patients receiving anti-VEGF treatment. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):4980.
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A post-hoc analysis of the MARINA and ANCHOR trials reported four cases of eyes receiving laser peripheral iridotomies during the course of anti-VEGF treatment presumably for the development of angle-closure. We hypothesize that the sudden increase of vitreous volume produced by intravitreal injections may affect anterior segment anatomy and increase risk of acute angle closure. In this study, we use AS-OCT to evaluate the dynamic changes of the anterior chamber angle following routine intravitreal injections to evaluate changes in the iris-lens configuration induced by intravitreal injections.
Patients receiving intravitreal anti-VEGF injections for the treatment of NVAMD were recruited after informed consent. Pre- and immediate post-injection IOP and AS-OCT images were acquired. Measurements of the anterior segment included angle opening distance (AOD) and trabeculo-iris space area (TISA) at 500 µl and 750 µl from the scleral spur (AOD500, AOD 750, TISA-500 and TISA 750, respectively), scleral spur angle and distance between temporal and nasal scleral spurs were compared.
Twenty-one eyes from 21 patients were studied. The mean increase in IOP following injection was 23.4±11.4 mmHg. The mean (±SD) differences between pre- and post-injection images of the temporal angle were: 0.05±0.11 mm (AOD500) (p=0.03), 0.07±0.13 mm (AOD750) (p=0.01), 0±0.04 mm2 (TISA500) (p=0.7), 0.02±0.07 mm2 (TISA750) (p=0.17) and 2.55±4.5 degrees (p=0.02). There was no significant difference between pre- and post-injection image measurements of the nasal angle. However, there was significantly more narrowing of the nasal TISA in phakic compared to pseudophakic eyes (nasal TISA 500 and TISA750 measurements; p=0.03 and 0.02, respectively). Post-injection distance between temporal and nasal scleral spurs (11.82 ± 0.3 mm) was significantly greater than pre-injection distance (11.74 ± 0.3 mm) (p=0.007).
Intravitreal injections are associated with narrowing of the temporal anterior chamber angle in all eyes and with increased narrowing of the nasal angle in phakic eyes compared to pseudophakic eyes. Physicians performing intravitreal injections should be aware of these changes as they may increase risk of angle closure with prolonged elevation of IOP in eyes that are predisposed.
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