Eric K. Chin

High-resolution spectral domain anterior segment optical coherence tomography in type 1 boston keratoprosthesis

Purpose: To report the results of imaging using high-resolution, Fourier domain anterior segment optical coherence tomography (AS-OCT) to evaluate patients with a type 1 Boston Keratoprosthesis (KPro). Methods: We performed a retrospective comparative study of patients in whom we implanted the Boston KPro. A total of 26 eyes of 23 patients from the Cornea Service at the University of California Davis Eye Center were included. Subjects were evaluated with the Spectralis AS-OCT (Heidelberg Engineering GmbH). Results: Preoperative diagnoses for KPro surgery included failed corneal transplant (69%), chemical burn (23%), and aniridia (8%). The average age of patients was 63.2 years (range, 17–88 years). Fifty-four percent of the patients were female. The mean duration between the KPro surgery and the acquisition of high-resolution AS-OCT imaging was 35.8 months (range, 2–90 months). The most commonly observed finding was retroprosthetic membrane formation, which we found in 77% of KPro eyes. In 65% of KPro eyes, we identified epithelium behind the front plate, and in 54%, we identified an epithelial lip over the anterior surface of the KPro front plate. In 31% of KPro eyes, we identified periprosthetic cysts, gaps or spaces, and thinning in the corneal carrier graft. Conclusions: Fourier domain AS-OCT is a useful noninvasive imaging technique in patients with a KPro and provides the ability to identify changes that are sometimes difficult to appreciate by clinical evaluation. The higher resolution Fourier domain systems may aid in the clinical diagnosis and management of pathology that might not be imaged with instruments of lower resolution. AS-OCT has the potential for monitoring the anatomic stability of an implanted KPro and may also help to monitor for complications. Moreover, high-resolution imaging may enhance our understanding of periprosthetic anatomy.

Comparison of retinal nerve fiber layer and central macular thickness measurements among five different optical coherence tomography instruments in patients with multiple sclerosis and optic neuritis.

Background: To compare the mean central macular thickness (CMT) and the mean average optic nerve retinal nerve fiber layer (RNFL) thickness in the eyes of patients with a history of optic neuritis and/or multiple sclerosis (MS) using 5 commercially available optical coherence tomography (OCT) instruments. Methods: Cross-sectional study including 46 patients (92 eyes) with a history of optic neuritis and/or MS. Both eyes were imaged on the same day with 5 OCT instruments: 1 time-domain OCT (Stratus) and 4 different Fourier-domain (spectral-domain) OCT (3D OCT-1000, Cirrus, RTVue-100, and Spectralis). Results: Twenty-five patients (50 eyes) were included in the final analysis after excluding patients with diabetes, glaucoma, ocular hypertension, or retinal pathology and inadequate scan quality. Randomized block analysis of variance revealed statistically significant differences across instruments (P < 0.001) for both eyes for mean CMT and mean average optic nerve RNFL. When testing for significant differences in measurements from instrument to instrument, some difference was noted between the right and left eyes. Conclusions: Statistically significant differences exist among commercially available OCT instruments in measuring mean CMT and mean average RNFL thickness in patients with optic neuritis and/or MS. These findings likely result from the differences in data acquisition and segmentation algorithm software among OCT instruments. Awareness of these variations among OCT instruments will be important in using these instruments for clinical trials and management of patients with optic neuritis and/or MS.

Reproducibility of macular thickness measurement among five OCT instruments: effects of image resolution, image registration, and eye tracking.

BACKGROUND AND OBJECTIVEnTo study the effect of image resolution, eye tracking, and image registration on central macular thickness reproducibility (rCMT) among spectral-domain and time-domain optical coherence tomography (SD-OCT and TD-OCT) instruments.nnnPATIENTS AND METHODSnSeventy-six eyes were imaged (44 normal, 32 maculopathy) either twice using four SD-OCT and one TD-OCT devices or three times using Spectralis SD-OCT (with and without eye tracking) (Heidelberg Engineering, Inc., Heidelberg, Germany). Cirrus images (Carl Zeiss Meditec, Dublin, CA) were further analyzed with three-point image registration.nnnRESULTSnAll instruments had superior rCMT in normal versus pathologic eyes (P < .001). No difference in rCMT was noted among instruments in normal eyes (P = .92), but TD-OCT was superior to SD-OCT (P = .017) in pathologic eyes. Cirrus image registration improved rCMT for normal eyes (P = .04), with borderline improvement in pathologic eyes (P = .06). Spectralis eye tracking improved rCMT in normal (P = .01) and pathologic (P = .004) eyes.nnnCONCLUSIONnHigher image resolution with SD-OCT may not improve rCMT, but image registration and eye tracking options may improve rCMT.

Nonmydriatic Fundus Photography for Teleophthalmology Diabetic Retinopathy Screening in Rural and Urban Clinics

PURPOSEnTo evaluate the relative diagnostic value of nonmydriatic fundus photography (nFP) among patients screened for diabetic retinopathy in remote rural medical clinics and an urban academic medical center for nonadherence to recommended annual dilated eye examination.nnnSUBJECTS AND METHODSnA retrospective cross-sectional study was performed among diabetic patients seen in primary outpatient clinics between 2006 and 2011 who were screened for diabetic retinopathy with nFP for history of nonadherence to recommended annual dilated eye examination. A single nonstereoscopic, 45°, 10-megapixel digital image of the disc and macula of both eyes was obtained locally and transmitted electronically to a retinal specialist for remote review. The results from remote rural Native American Indian reservations were compared with those from an urban academic family practice clinic. The proportion of subjects diagnosed with diabetic retinopathy and the quality of fundus images were compared.nnnRESULTSnAmong 872 patients (1,744 eyes) screened from rural sites and 517 subjects (1,034 eyes) screened from an urban site, images were of good quality for evaluation in 82.4% and 85.7% of subjects, respectively. Diabetic retinopathy was noted in 12.6% of rural subjects and 29.6% of urban subjects (p<0.001).nnnCONCLUSIONSnnFP can be a useful tool in both rural and urban settings to screen for diabetic retinopathy in patients who are nonadherent to the recommended dilated annual eye exam. In our study population, a surprisingly higher percentage of diabetic subjects screened from the urban clinic had retinopathy compared with subjects screened in rural clinics.

Improving visual outcomes by preserving outer retina morphology in eyes with resolved pseudophakic cystoid macular edema

Purpose To use ultra‐high‐resolution optical coherence tomography (OCT) subclinical anatomic alterations to explain suboptimum vision despite pseudophakic cystoid macula edema (CME) resolution. Setting University of California–Davis, Sacramento, California, USA. Design Case study. Methods This study comprised patients who had cataract phacoemulsification surgery. Cases of resolved postoperative CME (diagnosed postoperatively by 1 month and resolved by 1 year) were included. Exclusion criteria included any other cause for decreased vision or compounding factors. Patients with a history of resolved pseudophakic CME were imaged using a purpose‐built ultra‐high‐resolution OCT system with 4.5 &mgr;m axial resolution and an acquisition speed of 9 frames/sec (1000 A‐scans/frame). The corrected distance visual acuity (CDVA) was determined by Early Treatment Diabetic Retinopathy Study standards. Statistical analysis was by the unpaired t test. A P value less than 0.05 was considered significant. Results The review identified 56 patients with a pseudophakic CME diagnosis at least 1 month postoperatively. Fifteen eyes (26.8%) had less than 20/20 CDVA despite resolution of CME; 7 participated. Four patients with 20/20 CDVA after resolution of pseudophakic CME participated. Eyes with reduced CDVA after macula edema showed ultra‐high‐resolution OCT evidence of blurring of outer segments of photoreceptors, while controls showed normal outer retina morphology (P < .05). Conclusions Persistent anatomic alteration of photoreceptors visualized by ultra‐high‐resolution OCT correlated with reduced CDVA in patients with pseudophakic CME compared with patients who had 20/20 CDVA after macula edema. This anatomic alteration in outer photoreceptor morphology is a plausible explanation for the reduced CDVA in this disease. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Staging of Macular Telangiectasia: Power-Doppler Optical Coherence Tomography and Macular Pigment Optical Density

PURPOSEnTwo methods were used to study the stages of macular telangiectasia (MACTEL): Power-Doppler optical coherence tomography (PD-OCT), which allows imaging of the retinal circulation in three dimensions, and macular pigment optical density (MPOD), which quantifies the distribution of macular carotenoids.nnnMETHODSnAmong 49 patients with MacTel identified, 12 eyes (6 patients) with MacTel and 7 age-matched control eyes (7 patients) were imaged with a custom-built Fourier-domain OCT instrument to acquire PD-OCT images. MPOD was measured using heterochromatic flicker photometry in 10 eyes (5 patients) with MacTel and compared with 44 age-matched control eyes (44 patients). Clinical staging of MacTel was based on best-corrected visual acuity, fundus biomicroscopy, fluorescein angiography, and OCT.nnnRESULTSnStage 1 eyes (n = 2) had subtle punctate vascular signal confined to the inner portion of the outer plexiform layer (OPL) on PD-OCT. Stage 2 (n = 2) showed larger oblique vascular signal extending into deeper OPL. Stage 3 (n = 5) had disruption of outer retinal layers with abnormal vasculature extending into the outer nuclear layer. Stage 4 (n = 3) showed diffuse blurring of the retinal layers with vascular channels extending the full thickness of the retina. MPOD values in four eyes with stage 1 or 2 MacTel correlated well with age-matched controls. Six eyes with stage 3 or 4 MacTel had loss of MPOD especially at the fovea.nnnCONCLUSIONSnPD-OCT shows penetration of the retinal capillaries into the deeper retinal layers in early stages of MacTel, with full thickness vascular proliferation in advanced disease. MPOD is commonly depleted but may appear normal in early stage MacTel.

Five-year Follow-up Of Macular Morphologic Changes After Rhegmatogenous Retinal Detachment Repair: Fourier Domain Oct Findings

Purpose: To evaluate serially long-term macular morphologic changes after successful macula-involving rhegmatogenous retinal detachment repair and correlate changes with macular function. Methods: Repeat Fourier domain optical coherence tomography (FD OCT) imaging and microperimetry (MP-1) testing of 8 of the initial cohort of 17 eyes studied 5 years earlier. Results: The mean follow-up after rhegmatogenous retinal detachment repair was 3.4 months (range, 1–8.5 months) for the first FD OCT and 5 years (range, 3.75–5.75 years) for the follow-up FD OCT. The final postoperative best-corrected visual acuity mean was 20/201 (range, 20/20 to counting fingers). Six eyes with final best-corrected visual acuity >20/40 had an intact external limiting membrane and progressive resolution of photoreceptor inner segment–outer segment junction disruption and/or subretinal fluid on serial FD OCT, which correlated with improvement in macular function on MP-1. Two eyes with poor or worsening best-corrected visual acuity on follow-up had persistent or worsening inner segment–outer segment disruption on serial FD OCT. External limiting membrane was intact in one eye and persistently disrupted in the other. Conclusion: Macular function may progressively improve or worsen long-term after successful rhegmatogenous retinal detachment repair. Progressive resolution of subretinal fluid and/or inner segment–outer segment disruption on FD OCT correlated with improvement in macular function, whereas worsening or persistent inner segment–outer segment disruption correlates with worsening or persistently poor visual outcome.

Anterior segment OCT and confocal microscopy findings in atypical corneal intraepithelial neoplasia

Purpose: To report a case of biopsy-proven corneal intraepithelial neoplasia (CIN) diagnosed and followed clinically using high-resolution anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM). Methods: Observational case report. Results: A 57-year-old man presented with decreased vision in the right eye for 2 months before presentation. His best-corrected visual acuity was 20/70 in the affected eye, and the slit-lamp examination revealed superficial opacification of the anterior cornea originating from the temporal limbus with a “leopard-spot” pattern more centrally. The lesion was excised at his 2-month follow-up, and the histological examination revealed squamous dysplasia consistent with CIN. Visual acuity improved, and the slit-lamp examination revealed barely visible residual disease at the temporal limbus. However, AS-OCT showed a thicker and highly reflective epithelial layer near the temporal limbus, similar to initial presentation, highlighting this residual disease. IVCM demonstrated dysplastic cells consistent with residual disease. Therefore, we treated the patient with topical interferon alpha-2b (1 million IU/mL) 4 times daily in the affected eye. At 3-month follow-up, the patients best-corrected visual acuity was 20/20 in the affected eye with persistent but improved residual disease adjacent to the temporal limbus. In the mid-periphery of the inferonasal cornea, focal areas of iatrogenic linear scarring were confirmed to be limited to the anterior stroma by AS-OCT and IVCM at 6-month follow-up. Conclusions: AS-OCT and IVCM are noninvasive techniques that can be used to diagnose and aid in the management of CIN, which may present as subclinical disease through slit-lamp biomicroscopy alone.

Extraocular muscle enlargement leading to the diagnoses of Burkitt lymphoma and acquired immune deficiency syndrome.

Orbital involvement in nonendemic Burkitt lymphoma is rare. The authors report a unique case of a patient who sought treatment for extraocular muscle enlargement without a concurrent orbital mass, which subsequently led to the diagnoses of Burkitt lymphoma and acquired immune deficiency syndrome in an adult patient. The case report adhered to the principles of the Declaration of Helsinki and Health Insurance Portability and Accountability Act compliance. This single case report was institutional review board exempt, given that it does not meet the definition of human subjects research.

Optical Coherence Tomography Findings of Exophytic Retinal Capillary Hemangiomas of the Posterior Pole.

Exophytic retinal capillary hemangiomas (RCH) can be a diagnostic challenge in subjects without von Hippel-Lindau disease (VHL). This report of two cases describes the optical coherence tomographic (OCT) characteristics of RCH in two eyes of a subject with VHL and in one eye of an otherwise normal subject. Three different OCT instruments were used (Stratus, Cirrus and/or custom high resolution Fourier-domain OCT with 4.5 mum axial resolution) depending on availability. All instruments localized the tumor to the outer retina. A sharp border between the tumor and overlying inner retina was noted. The tumor bulged into the subretinal space and showed marked shadowing. Associated cystoid macular edema and subretinal fluid were noted. High-resolution Fourier-domain OCT showed a focal photoreceptor layer rip in the adjacent tumor-free macula in one eye with poor vision after treatment. OCT may be a useful tool in diagnosing RCH and studying associated morphologic changes.