A 65-year-old white female presented with decreased visual acuity following uncomplicated cataract surgery in her right eye. The one-week post-op did not uncover any significant problems; however, the three-week follow-up exam found a decrease in best-corrected visual acuity from 20/25 to 20/60 O.D.
On dilated fundus exam, her right macula appeared thickened and slightly elevated, with no foveal reflex. On Cirrus HD-OCT (Carl Zeiss Meditec), the macula was elevated, with fluid-filled cysts in the neurosensory retina and abnormal foveal pit architecture. We diagnosed the patient with pseudophakic cystoid macular edema (CME) and started her on Nevanac (nepafenac, Alcon) q.i.d. and Pred Forte 1% (prednisolone acetate, Allergan) q.i.d.
At the five-week follow-up, our patient reported improved vision. Her best-corrected visual acuity measured 20/30+ O.D. We obtained a macular change analysis with Cirrus HD-OCT, which indicated a reduction in pseudophakic CME O.D. The macular change analysis revealed both quantitative and qualitative CME reduction. Also, we noted that our patient’s central foveal thickness decreased from 414µm to 253µm.
We tapered our patient’s medications during the next three weeks. At the eight-week follow-up, her best-corrected visual acuity measured 20/20 O.D. Additionally, a final macular change analysis showed complete CME resolution as well as a normal central foveal thickness of 249µm.
Spectral-domain OCT allows for unprecedented image capture speed and resolution as well as improved analytic capability.1-4 This increase in acquisition speed and resolution yields enhanced image quality. Also, greater scan density and area coverage facilitate improved volumetric measurements and C-scan capability.5
Our ability to precisely document anatomical improvements between visits using SD-OCT allowed us to manage our patient very effectively. But most notably, the macular change analysis feature available in the new Cirrus HD-OCT 4.0 software package provided excellent clinical data that ultimately helped us eliminate our patient’s CME.
Software Improvements
The latest Cirrus HD-OCT software system features macular normative databases, macular change analysis, a nerve fiber layer normative database, guided progression analysis and anterior segment imaging.6 The software evaluates the potential efficacy of therapeutic intervention for various retinal conditions, including central serous chorioretinopathy, macular thickening in atrophic AMD, the formation of choroidal neovascularization associated with wet AMD, macular edema secondary to branch retinal vein occlusion, vitreomacular traction and macular holes.6
The new capabilities of the Cirrus HD-OCT 4.0 software also include macular change analysis, which compares data from two retinal exams with thickness difference maps. Both RTVue FD-OCT (OptoVue) and Spectralis (Heidelberg Engineering) also feature a macular change analysis component. But, Cirrus HD-OCT is unique in that its macular change analysis feature records the precise location of each patient’s fovea, which can be used as a baseline for future scans or for visual comparison of imagery between appointments. This application aided in documenting our patient’s response to the therapeutic regimen outlined above.
A macular thickness normative database is also available, which allows for evaluation of retinal thickness measurements that are outside the normal limits. The database uses color ETDRS thickness grids, which are placed on top of the laser scanning ophthalmoscope fundus image and copied onto various custom reports.6
In addition to the macular thickness normative database, the Cirrus HD-OCT 4.0 software includes both a retinal nerve fiber layer (RNFL) normative database and guided progression analysis to help evaluate and monitor glaucoma patients.6 The guided progression analysis module allows for up to an eight-exam comparison, with trend analysis and flags that denote significant progression.
Finally, the Cirrus HD-OCT 4.0 software provides high-resolution imaging of the anterior chamber angle and central corneal thickness. This permits critical observation of the iris, the iris root and the angle anatomy at the corneoscleral junction. By isolating the scleral spur and Schwalbe’s line, you can visualize the anatomical relationship between the trabecular meshwork and the iris.6 Evaluation of these anatomical relationships, with or without illumination, allows you to assess iris and anterior chamber morphologies during physiologic changes. Further, you can attain virtual biopsies of plateau iris syndrome, reverse pupillary block and angle recession.6
SD-OCT technology improves patient care, reduces ocular morbidity, and provides clinicians with confidence when visualizing details of retinal anatomy. Future software updates for this technology will continue to enhance clinical expertise across all fields of ocular disease management.
Thanks to Jeff Miller, O.D., of Stillwater, Okla., for contributing this article. Dr. Miller lectures on behalf of Carl Zeiss Meditec.
1. Stopa M, Bower BA, Davies E, et al. Correlation of pathologic features in spectral domain optical coherence tomography with conventional retinal studies. Retina. 2008 Feb;28(2):298-308.
2. Izatt JA, Hee MR, Swanson EA, et al. Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography. Arch Ophthalmol. 1994 Dec;112(12):1584-9.
3. Thomas D, Duguid G. OCT—a review of the principles and contemporary uses in retinal investigation. Eye. 2004 Jun;18(6):561-70.
4. Costa RA . Retinal assessment using optical coherence tomography. Prog Retin Eye Res. 2006 May;25(3):325-53.
5. Sakamoto A. Spectral-domain optical coherence tomography with multiple B-scan averaging for enhanced imaging of retinal diseases. Ophthalmology. 2008 Jun;115(6):1071-1078.e7.
6. Carl Zeiss Meditec. Cirrus HD-OCT 4.0 Software: Track Change With Confidence. Available at: www.meditec.zeiss.com/88256DE3007B916B/0/54C80BBC43D11935882575C200733EEF/$file/cirrus_4_0_broschuere_en.pdf (Accessed October 11, 2009).