Aqueous Humor dynamics changes and Predictive factors of IOP response to Latanoprost.

<h2 id="Background">Background:</h2><ul><li>Latanoprost, a first-line glaucoma treatment, shows variable Intraocular Pressure (IOP) lowering responses, with non-response rates ranging from 3-64%.</li><li>Factors like low baseline IOP and Primary Open-Angle Glaucoma (POAG) have been linked to poor response.</li><li>While genetic testing and early IOP measurements have been explored, no studies have assessed whether baseline aqueous humor dynamics can predict latanoprost response.</li><li>Previous studies show latanoprost lowers IOP mainly by increasing uveoscleral outflow, but they did not compare baseline aqueous humor dynamics between responders and non-responders.</li></ul><h2 id="Purpose">Purpose:</h2><p>To explore how baseline characteristics and changes in aqueous humor dynamics (AHD) relate to variable IOP responses to latanoprost in healthy subjects.</p><h2 id="Methods">Methods: Multicenter trial.</h2><ul><li>Aqueous humor dynamics in 226 eyes from 113 healthy participants before and after one week of latanoprost 0.005% once-daily treatment was evaluated.</li><li>Non-invasive measurements included IOP, aqueous flow, outflow facility, and Episcleral Venous Pressure(EVP), with uveoscleral outflow calculated via the modified Goldmann equation.</li><li>IOP responses were categorized as non-responders (&lt;10%) and responders( 10%), further divided into medium (10-20%) and high responders (&gt;20%).</li></ul><h2 id="Response">Definition of Response:</h2><ul><li>Response criteria vary across studies, with IOP reduction cutoffs ranging from 5% to over 20%.</li><li>A 1-week duration was selected based on prior evidence showing stable AHD changes within this period and to ensure adherence.</li></ul><h2 id="Results">Results</h2><ul><li>BMi was higher in high- and all-responders (P = 0.02, 0.03); trend in medium-responders (P = 0.05).(Table 1).</li><li>BMI correlated with baseline IOP (r = 0.17, P = 0.04) and IOP reduction (r = -0.18, P = 0.02).(Table 1).</li><li>IOP, outflow facility, and uveoscleral outflow increased in all responder groups; no change in non responders.(Table 1).</li><li>EVP, aqueous flow, Central Corneal Thickness (CCT), axial length, and Diastolic Blood Pressure (DBP) showed no significant changes.(Table 1).</li><li>Systolic Blood Pressure (SBP) decreased in medium-responders; trend in all-responders.(Table 1).</li><li>IOP reduction was greater in high-vs.medium-responders (-4.5 vs.-2.4 mmHg, P &lt; 0.001).(Table 1).</li><li>Uveoscleral outflow increased more in high- and all-responders vs. non-responders (P = 0.004, 0.01).(Table 1).</li><li>No group differences in outflow facility, aqueous flow, or EVP (P &gt; 0.4).(Table 1).</li></ul><p style="text-align:center;"><img src="https://cdn.megawecare.com/GHBY/Internal-Images/Comparison_of_Ocular_and_Systemic_Parameters_Across_lntraocular_Pressure_%28IOP%29_Response_Groups_to_Latanoprost_Treatment.webp" alt="Comparison of Ocular and Systemic Parameters Across lntraocular Pressure (IOP) Response Groups to Latanoprost Treatment" width="809" height="500"></p><h2 id="Conclusion">Conclusion</h2><ul><li>Latanoprost increases uveoscleral outflow and outflow facility. In this study, both parameters significantly increased in responders after 7 days, but not in non-responders.</li><li>Studies showed that individuals with higher BMI responded better to latanoprost. Additionally, there were weak but statistically significant linear correlations between BMI and both baseline IOP and the change in IOP.</li></ul>

Opthal Update   Issue 4   2025

<ul><li><a href="#Background">Background</a></li><li><a href="#Purpose">Purpose</a></li><li><a href="#Methods">Methods</a></li><li><a href="#Response">Definition of Response</a></li><li><a href="#Results">Results</a></li><li><a href="#Conclusion">Conclusion</a></li></ul>

Aqueous Humor dynamics changes and Predictive factors of IOP response to Latanoprost.

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