PT  - JOURNAL ARTICLE
AU  - Strong, Stacey A
AU  - Hirji, Nashila
AU  - Quartilho, Ana
AU  - Kalitzeos, Angelos
AU  - Michaelides, Michel
TI  - Retrospective cohort study exploring whether an association exists between spatial distribution of cystoid spaces in cystoid macular oedema secondary to retinitis pigmentosa and response to treatment with carbonic anhydrase inhibitors
AID  - 10.1136/bjophthalmol-2017-311392
DP  - 2019 Feb 01
TA  - British Journal of Ophthalmology
PG  - 233--237
VI  - 103
IP  - 2
4099  - http://bjo.bmj.com/content/103/2/233.short
4100  - http://bjo.bmj.com/content/103/2/233.full
SO  - Br J Ophthalmol2019 Feb 01; 103
AB  - Background Carbonic anhydrase inhibitors (CAIs) are frequently used as an initial step to treat retinitis pigmentosa-associated cystoid macular oedema (RP-CMO). Interestingly, it has been postulated that CAIs might reduce outer nuclear layer (ONL) fluid more effectively than inner nuclear layer (INL) fluid due to better access to retinal pigment epithelium basolateral membrane than neurosensory retina. This retrospective cohort study explores if an association between spatial distribution of cystoid spaces in RP-CMO and CAI response exists.Methods Two independent graders reviewed pretreatment and post-treatment optical coherence tomography (OCT) images of 25 patients (43 eyes) initiated on topical and/or oral CAIs between January 2013 and December 2014. Documentation included the presence/absence of fluid (and layer(s) involved), external limiting membrane, epiretinal membrane (ERM), vitreomacular adhesion/traction, lamellar/full-thickness macular hole and central macular thickness (CMT)/volume.Results INL fluid was found in all study eyes. All 13 ‘responders’ (at least 11% reduction of CMT after treatment) demonstrated pretreatment ONL fluid. In seven patients (four responders and three non-responders), complete clearance of ONL fluid was achieved despite persistence of INL fluid. ERM presence was similar in responders and non-responders.Conclusion In this study, INL fluid was found to be the most common spatial distribution of RP-CMO. However, patients who were classed as a ‘responder’ to CAI treatment all demonstrated coexisting ONL fluid on their pretreatment OCT scans. This may be explained by CAIs having better access to retinal pigment epithelium basolateral membrane than neurosensory retina. Our study also suggests a minimal impact on response to CAIs by ERM.