Influence of cataract on image quality and macular thickness measured using spectral domain optical coherence tomography: a prospective cohort study
DOI:
https://doi.org/10.18203/2349-3933.ijam20171058Keywords:
Central macular thickness, Cataract, Optical coherence tomography, Retinal pathologiesAbstract
Background: Optical coherence tomography (OCT) is one of the most useful imaging techniques in the management of retinal diseases affecting the macula. Factors affecting the image quality of OCT may affect the macular thickness and hence treatment of retinal pathologies. This study was aimed to evaluate the influence of cataract on macular scans using spectral domain OCT.
Methods: The prospective study was done in 36 patients with cataract. Cataract was graded as cortical, nuclear or posterior cataracts. All patients underwent small incision cataract surgery. Pre and post-operative imaging of the macula (4 weeks after surgery) using spectral domain OCT. The signal strength and central macular thickness (CMT) measurements were made before and after the surgery and analysed statistically.
Results: The majority (66.7%) of patients had posterior cataracts. A statistically significant improvement in OCT image quality (as assessed by signal strength) was noted post operatively. This was maximum for posterior cataracts (2.9), followed by cortical cataract (1.6), while nuclear cataracts had the least increase in signal strength (1.3). The difference in signal strength gain between posterior and nuclear cataracts was found to be statistically significant (p = 0.05). The increase in CMT was clinically significant only in 8.2% of the study population. No patient with nuclear cataract had a clinically significant increase in CMT following surgery.
Conclusions: Cataract can influence OCT image quality as well as central macular thickness measurements. Both were found to be affected maximally by posterior cataracts, followed by cortical, while nuclear cataracts had the least influence.
References
Smith M, Frost A, Graham CM, Shaw S. Effect of pupillary dilatation on glaucoma assessments using optical coherence tomography. Br J Ophthalmol. 2007;91:1686-90.
Stein DM, Wollstein G, Ishikawa H, Hertzmark E, Noecker RJ, Schuman JS. Effect of corneal drying on optical coherence tomography. Ophthalmology. 2006;113:985-91.
Na JH, Sung KR, Lee Y. Factors associated with the signal strengths obtained by spectral domain optical coherence tomography. Korean J Ophthalmol. 2012;26:169-73.
Darma S, Kok PH, Berg TJ, Abràmoff MD, Faber DJ, Hulsman CA, Zantvoord F, Mourits MP, Schlingemann RO, Verbraak FD. Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation. Acta Ophthalmol. 2015;93:355-61.
Cheung CY Leung CK Lin D. Relationship between retinal nerve fiber layer measurement and signal strength in optical coherence tomography. Ophthalmology. 2008;115:1347-51.
Chylack LT Jr, Wolfe JK, Singer DM, Leske MC, Bullimore MA, Bailey IL, Friend J, Mccarthy D, Wu SY. The lens opacities classification system III. Arch Ophthalmol.1993;111:831-6.
Rao HL, Addepalli UK, Yadav RK, Choudhari NS, Senthil S, Garudadri CS. Factors affecting the ability ofthe spectral domain optical coherence tomograph to detect photographic retinal nerve fiber layer defects. PLoS One. 2014;9:116-7.
Browning DJ, Fraser CM, Propst BW. The variation in optical coherence tomography measured macular thickness in diabetic eyes without clinical macular edema. Am J Ophthalmol. 2008;145:889-93.
Velthoven ME, Linden MH, Smet MD, Faber DJ, Verbraak FD. Influence of cataract on optical coherence tomography image quality and retinal thickness. Br J Ophthalmol. 2006;90:1259-62.
Samarawickrama C, Pai A, Huynh SC, Burlutsky G, Wong TY, Mitchell P. Influence of OCT signal strength on macular, optic nerve head and retinal nerve fiber layer parameters invest. Ophthalmol Vis Sci. 2010;51:4471-5.
Gharbiya M, Cruciani F, Cuozzo G, Parisi F, Russo P, Abdolrahimzadeh S. Macular thickness changes evaluated with spectral domain optical coherence tomography after uncomplicated phaco emulsification. Eye. 2013;27:605-11.
