Choroidal Thickness In Acute Primary Angle-closure

Objective: Choroidal thickness of acute primary angle-closure eyes and normalsubjects were compared.Methods: Acute primary angle-closure subjects and normal subjects were collectedfrom October2012to March2013in zhongshan Ophthalmic Center, and divided intotwo groups：group1include35fellow eyes diagnosed as PACS of35subjects whohad experienced APAC and35eyes of35normal subjects; group2include16participants with unilateral APAC affected eyes and16fellow eyes diagnosed asPACS. Using enhanced depth imaging optical coherence tomography (EDI-OCT),subfoveal choroidal thickness(SFCT), SFCT at1mm/3mm temporal, nasal, superior,inferior to the fovea were measured and CT at1mm/2mm temporal, nasal, superior,inferior to the optic disk were measured. A360-degree3.4mm diameter peripapillarycircle scan was performed for CT assessment by EDI-OCT. The peripapillary andmacular choroidal thickness of the APAC eyes, PACS eyes and the normal eyes werecompared at each location or segment and determined its influence factors. Forcomparison between the two different groups, an independent sample t test was usedto evaluate differences in the average. Repeated measures ANOVA and LSD-t testwere used to analyze differences in CT by peripapillary location. Pearson correlationanalysis and multivariable regression model were used to evaluate the relationshipsbetween choroidal thickness and related factors.Results: The PACS eyes had a thicker choroid than the normal eyes at all macularlocations (P<0.05), except at3mm superior from the fovea (P=0.174). Our findingsshowed a significant increase in the choroidal thickness in the APAC eyes in themacular area compared with the PACS eyes at all the nine locations(P<0.05).Bothgroups showed similar trends: at all locations, the choroid was thinnest nasally andgenerally decreased, moving distally from the subfoveal. The thickness of theperipapillary choroid generally increased, moving distally from the optic disc. At each location, the mean peripapillary choroi-dal thickness of the PACS eyes was thinnerthan that of the normal eyes and the APAC eyes was thicker than the PACS eyes.However, there were no statistically significant differences in the choroidal thicknessbetween both groups at any peripapillary location or segment (P>0.05). The choroidalthickness was uneven distribution at peripapillary segment. In the APAC eyes andPACS eyes, the peripapillary choroidal thicknesses was thickest superote-mporallyand superonasally, then temporally and nasally, and was thinnest inferonasally andinferotemporally. The inferonasal, inferotemporal peripapill-ary choroidal thicknesseswere significantly thinner than temporal, superote-mporal, superonasal and nasalthicknesses in the normal eyes (p<0.05). Pearson correlation analysis andmultivariable regression model showed that A PACS diagnosis (PACS subjects had asubfoveal choroidal thickness that was, on average,62.66μm thicker than that of thenormal controls) and age were most commonly associated with the subfoveal macularchoroidal thickness (Beta=-2.96,P=0.001), followed by axial length (Beta=-29.08,P=0.003) and gender (P=0.009). A APAC diagnosis (APAC subjects had a subfovealchoroidal thickness that was, on average,53.43μm thicker than that of PACS subjects)and age were commonly associated with the subfoveal macular choroidal thickness(Beta=-2.86, P=0.002), followed by axial length (Beta=-31.42, P=0.031) and systolicblood pressure (Beta=1.46, P=0.041).Conclusion: Choroidal thickness of acute primary angle-closure and normal eyes isuneven distribution. At all locations, the choroidal thickness was thickest at thesubfoveal. The subfoveal choroidal thickness was significantly thinner in associationwith older subjects and longer axial length eyes. APAC eyes had a higher level ofmacular choroidal thickness than PACS eyes when IOP reduced. PACS eyes had athicker macular choroid than the normal eyes. A thicker choroid may play animportant role in APAC.