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Xiaofei MAN, David M Reed, Joanna Queen, Bernadete Ayres, Sayoko Moroi; Interplicata distance as part of ciliary body biometry to understand complications of plateau iris configuration. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5886. doi: https://doi.org/.
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The mechanisms that cause non-pupillary block complications of plateau iris configuration (PIC) are not understood. We hypothesize that eyes with smaller inter-plicata distance are at risk for developing ‘in the bag’ uveitis-glaucoma-hyphema (UGH) syndrome with a single piece intraocular lens (IOL) implant
We performed a retrospective clinical study to compare high resolution ultrasound biomicroscopy (UBM) biometry parameters between PIC cases, primary angle closure (PAC) cases, and controls. This research was conducted in compliance with the “Declaration of Helsinki” and was approved by the institutional review board. A UBM imaging protocol was established to characterize anterior chamber depth (ACD), degree of angle opening (DOA), inter-plicata distance, sulcus-to-sulcus distance, ciliary body thickness, ciliary body area, and iris area. Using one eye of each subject, biometry parameters were analyzed by 1-way ANOVA
Among 69 participants, there were 19 controls (6 males, mean age 73.2 + 4.5 years; 13 females, 60.7 + 18.5 years), 37 PIC cases (17 males, 59.7 + 11.3 years; 20 females, 55.2 + 15.0 years), and 13 PAC cases (4 males, 68.8 + 7.1 years; 9 females, 55.7 + 8.7 years). ACD was significantly smaller (p<0.0001) in PIC (2.60 + 0.56 mm) and PAC (2.00 + 0.95 mm) cases compared to controls (2.92 + 0.69 mm). DOA was significantly smaller (p<0.0001) in PIC to PAC cases compared to controls. Ciliary body thickness and area and iris area were comparable between the PIC and PAC cases and controls. The inter-plicata distance was significantly smaller (p=0.0015) in PIC (10.3 mm) to PAC (9.5 mm) cases compared to controls (11.0 mm). The sulcus-to-sulcus distance was significantly smaller (p=0.0143) in PIC (10.8 mm) to PAC (10.4 mm) cases compared to controls (11.4 mm)
Our results support the hypothesis that smaller inter-plicata distance explains UGH syndrome after uncomplicated cataract surgery due to the square edge haptics of a single piece IOL implant apposing the anteriorly rotated ciliary processes in PIC. UBM imaging provides this important ciliary body biometry that is not possible with anterior segment optical coherence tomography. This UBM-based biometry provides evidence to expand the iris sponge dynamic theory to advance our understanding of the non-pupillary block complications of PIC.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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