Commercial permethrin elicits chemoreceptive responses on different Anopheles gambiae sensory appendages.

The PreserFlo MicroShunt (PMS; Santen Pharmaceutical) is an 8.5-mm-long glaucoma filtration device composed of poly(styrene-block-isobutylene-block-styrene). It is implanted beneath the conjunctiva and Tenon capsule via an ab externo approach, following a relatively straightforward surgical technique []. The device facilitates the drainage of aqueous humor through its lumen, leading to the formation of a bleb in the fornix region. Since its introduction into clinical practice, numerous studies over the past decade have consistently demonstrated its efficacy and safety [–]. Although many patients report experiencing blurred vision following filtration surgery, this is often transient and primarily attributed to hypotony-associated retinal changes, such as hypotony maculopathy or choroidal detachment, which typically resolve as the intraocular pressure (IOP) stabilizes. Another important contributor to postoperative visual disturbance is surgically induced astigmatism (SIA) []. Unlike cataract surgery, controlling astigmatism while effectively reducing IOP after glaucoma filtration surgery remains a significant challenge. SIA may lead to an early postoperative reduction in visual acuity (VA) and, in some cases, may persist after surgery. In eyes undergoing trabeculectomy (Trab) with mitomycin C (MMC), SIA typically aligns with the orientation of the scleral flap and often presents as oblique astigmatism [, ]. This pattern is attributed to multiple factors, including slight sinking of the corneal edge at the ostomy site following scleral tissue block removal, scleral cauterization, and variations in the number and tightness of the scleral flap sutures [–]. Furthermore, studies have demonstrated a correlation between low postoperative IOP and the degree of induced regular astigmatism 1 month after Trab with iridectomy []; these findings suggest that the globe is more susceptible to deformation under hypotonic conditions, exacerbating astigmatic changes. In contrast, PMS implantation does not involve scleral block excision or scleral flap creation and is associated with a lower risk of hypotony than that with Trab. These factors may contribute to reduced structural disruption and a low incidence of SIA. SIA can be evaluated via 2 principal methods: the arithmetic mean of SIA (M-SIA), which considers only the magnitude of astigmatism irrespective of its axis, and the centroid of SIA (C-SIA), which incorporates magnitude and directional components []. Ando and colleagues have reported that the C-SIA provides a more comprehensive assessment of the overall trend of SIA than does the M-SIA []. Although several studies have evaluated the C-SIA following filtration surgery [, , ], no large-scale clinical study has assessed the C-SIA after PMS implantation. A previous study compared the effects of PMS and Trab on postoperative corneal astigmatism [], with astigmatic changes assessed by use of anterior segment optical coherence tomography and autorefraction; the findings indicated no significant change in astigmatism up to 5 months postoperatively in the PMS group, whereas the Trab group exhibited a significant increase in astigmatism, suggesting a lower astigmatic impact associated with PMS. However, the interpretation of these findings remains limited by the small size of the PMS group and the absence of a direct comparison of the M-SIA between the 2 procedures.