Mohamed Abou Shousha

Ultra-high resolution optical coherence tomography for differentiation of ocular surface squamous neoplasia and pterygia.

OBJECTIVE To assess the use of an ultra-high-resolution (UHR) optical coherence tomography (OCT) as an adjuvant diagnostic tool in distinguishing ocular surface squamous neoplasia (OSSN) and pterygia. DESIGN Prospective case series. PARTICIPANTS Thirty-four eyes of 34 patients with conjunctival lesions clinically suspicious for OSSN or pterygia. METHODS All patients were photographed and then imaged with a custom-built UHR OCT device. Subsequently, each patient underwent excisional or incisional biopsy with histopathologic diagnosis. MAIN OUTCOME MEASURES Comparison of preoperative UHR OCT images and the corresponding histopathologic specimen; comparison of epithelial thickness between the 2 groups as measured by UHR OCT. RESULTS Preoperative UHR OCT images of OSSN demonstrated similarities to the histopathologic specimens. Both optical and pathologic specimens showed a thickened layer of epithelium, often with an abrupt transition from normal to neoplastic tissue. Likewise, preoperative UHR OCT images of patients with pterygia were well correlated with the histopathologic specimens. As opposed to OSSN, both UHR OCT and pathologic images of pterygia demonstrated a normal thin epithelium, with underlying thickening of the subepithelial mucosal layers. Differences in the measured epithelial thickness on UHR OCT between OSSN and pterygia were statistically significant, with an average epithelial thickness of 346 μm (standard deviation [SD], 167) in OSSN patients and 101 μm (SD, 22) in pterygium patients (P<0.001). By receiver operating characteristic curve, the sensitivity and specificity of UHR OCT for differentiating between OSSN and pterygia was found to be 94% and 100%, respectively, using a cutoff value of 142 μm. CONCLUSIONS Ultra-high-resolution OCT may show promise as a noninvasive diagnostic tool to evaluate ocular surface lesions. In addition to a statistically significant difference in epithelial thickness, a significant degree of morphologic correlation with the histopathologic results demonstrates its potential in evaluating ocular surface squamous neoplasia and pterygia.

Topographic Thickness of Bowman's Layer Determined by Ultra-High Resolution Spectral Domain–Optical Coherence Tomography

PURPOSE To characterize the thickness profile of the corneal epithelium and the Bowmans layer across the horizontal meridian. METHODS Forty-four eyes of 22 healthy subjects were investigated in this study. Ultra-high resolution anterior segment spectral domain-optical coherence tomography (SD-OCT) was used to assess the topographic thickness of the epithelium and the Bowmans layer across the cornea. Thicknesses at five locations, including the center, midperiphery, and periphery close to the limbus, on both the nasal and the temporal sides along the horizontal meridian, were analyzed. RESULTS Mean epithelial thickness at the central cornea was 52.5 ± 2.4 μm. It increased gradually from the center to the periphery (P < 0.001). There was no significant difference between the nasal side and the temporal side for epithelial thickness. The central Bowmans layer thickness was 17.7 ± 1.6 μm, and it remained constant from the center to the midperiphery (P > 0.05). However, thicknesses at the nasal and temporal periphery, 20.0 ± 1.9 μm and 19.8 ± 2.2 μm, respectively, were significantly greater than the central and midperipheral thicknesses (P < 0.001). Nasal and temporal thicknesses were similar on either side of the center. CONCLUSIONS The epithelium and the Bowmans layer were not evenly distributed across the horizontal meridian of the cornea. SD-OCT provided useful information about topographic thickness of the different corneal layers in vivo.

Long-Term Results of Femtosecond Laser-Assisted Sutureless Anterior Lamellar Keratoplasty

PURPOSE To evaluate the long-term results of femtosecond laser-assisted anterior lamellar keratoplasty (FALK) for anterior corneal pathologies. DESIGN Retrospective, noncomparative, interventional case series. PARTICIPANTS Thirteen consecutive patients who underwent FALK for anterior corneal pathologies. INTERVENTION Femtosecond laser-assisted sutureless anterior lamellar keratoplasty. MAIN OUTCOME MEASURES Best spectacle-corrected visual acuity (BSCVA), manifest refraction, need for adjunctive surgery, and complications. RESULTS Follow-up ranged from 12 to 69 months (mean = 31 months). The BSCVA was significantly improved over preoperative values at the 12-, 18-, 24-, and 36-month visits. A BSCVA greater than 20/30 was achieved in 54% of patients at the 12-month visit when all 13 patients were available for follow-up, in 50% and 33% of patients at the 18- and 24-month visits, respectively, when 12 patients were available, and in 60% and 50% of patients at the 36- and 48-month visits when 5 and 2 patients were available, respectively. The BSCVA of the eye that completed the 60- and 70-month visits was 20/50. Patients achieved a mean gain of 5 lines of BSCVA at the 6-, 12-, 18-, and 24-month visits, 4 lines at the 36-month visit, 5 lines at the 48-month visit, and 6 lines at the 60- and 72-month visits. Two patients lost a mean of 1.5 lines of BSCVA because surface haze developed after photorefractive keratectomy (PRK) and granular dystrophy recurred in the graft. At a mean of 5 weeks postoperatively, 83.3% of patients achieved BSCVA within 2 lines of that recorded at the 24-month visit. At the 12-month visit, mean spherical equivalent and refractive astigmatism were -0.4 diopters (D) and 2.2 D, respectively, with no significant shift from preoperative values or values recorded in different follow-up visits. Adjunctive surgeries included phototherapeutic keratectomy, PRK, cataract extraction, and epithelial ingrowth debridement. Complications included residual corneal pathology, mild interface haze, anisometropia, recurrence of pathology, haze after adjunctive PRK, dry eye, epithelial ingrowth, and suspicious ectasia. CONCLUSIONS Femtosecond laser-assisted sutureless anterior lamellar keratoplasty improves the BSCVA of patients with anterior corneal pathologies with rapid visual rehabilitation and no significant induced astigmatism. Our preliminary results indicate that FALK results remained stable throughout the follow-up period.

Diagnosis and Management of Conjunctival and Corneal Intraepithelial Neoplasia Using Ultra High-Resolution Optical Coherence Tomography

PURPOSE To report a novel diagnostic technique and a case series of conjunctival and corneal intraepithelial neoplasia (CCIN) diagnosed and followed up using prototype ultra high-resolution (UHR) optical coherence tomography (OCT). DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Seven eyes of 7 consecutive patients with CCIN treated using topical interferon alfa-2b or 5-fluorouracil and 7 eyes of 6 consecutive patients with history of surgically excised pterygia. INTERVENTION Ultra high-resolution OCT imaging of the ocular surface at primary diagnosis of CCIN and during the follow-up period until resolution of the lesion. Ultra high-resolution OCT images of sites of excised pterygia also were captured and compared with images from resolved CCIN patients. MAIN OUTCOME MEASURES Clinical course and photographs, UHR OCT images, and histopathologic findings. RESULTS Ultra high-resolution OCT was capable of providing a noninvasive optical biopsy of all examined CCIN lesions. Ultra high-resolution OCT images of the lesions disclosed a thickened hyperreflective epithelium and abrupt transition from normal to hyperreflective epithelium in all 7 cases. Ultra high-resolution OCT images showed excellent correlation with histopathologic specimens obtained at primary diagnosis of the cases that had incisional biopsies before treatment. All patients were treated medically and were followed up for clinical resolution. In 4 patients, at clinical resolution, UHR OCT images also showed normal epithelial configuration at the site of the treated lesions. In 3 patients, despite apparent clinical resolution, the UHR OCT was able to detect residual disease that was clinically invisible. Continuation of treatment resulted in complete resolution of the residual lesions on the UHR OCT images in all cases. Ultra high-resolution OCT images of patients with surgically excised pterygia demonstrated similar findings to resolved CCIN cases. CONCLUSIONS Ultra high-resolution OCT is a novel noninvasive technique to diagnose and manage medically treated CCIN. Using UHR OCT to guide medical treatment could prevent the premature termination of topical treatment in the presence of subclinical disease. A larger sample size is needed for further validation of its sensitivity and specificity. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Ultra-high resolution optical coherence tomography for imaging the anterior segment of the eye.

Developments in optical coherence tomography (OCT) have expanded its clinical applications for ultra-high resolution imaging of the anterior segment of the human eye. This review presents the latest advances for imaging the anterior segment of the eye using ultra-high resolution OCT (UHR-OCT). Unique applications of UHR-OCT technology in clinical and basic scientific laboratory research are discussed and a summary of the results is provided. The authors focused on the use of UHR-OCT for imaging of tear dynamics, contact lens interactions with the corneal surface, and in vivo histological diagnosis of disorders of the cornea, as well as the future direction in this field.

Ultra high-resolution anterior segment optical coherence tomography in the evaluation of anterior corneal dystrophies and degenerations.

PURPOSE To evaluate the clinical usefulness of a spectral-domain ultra high-resolution anterior segment optical coherence tomography (UHR OCT) in examination, diagnosis, and management of various anterior corneal dystrophies and degenerations. DESIGN Noncomparative case series. PARTICIPANTS Fifty-nine eyes of 38 consecutive patients were enrolled in the study and included 28 eyes of 14 patients with anterior corneal dystrophies, 21 eyes of 19 patients with anterior corneal degenerations or neoplasia, and 10 eyes of 5 patients with normal corneas. METHODS Subjects were imaged using a novel custom-built UHR OCT. Images were used to evaluate and describe the characteristics of anterior corneal dystrophies and degenerations. Nineteen patients underwent surgical management, and those histopathologic specimens were analyzed and correlated with the UHR OCT images. MAIN OUTCOME MEASURES Comparison of clinical findings, UHR OCT images, and corresponding histopathologic specimens. RESULTS The UHR OCT provided clear delineation of corneal anatomic features and pathologic corneal deposits in most cases. The characteristics and depth of these deposits are illustrated and can be localized to specific layers of the cornea. When available, there was significant correlation between UHR OCT images and histopathologic features, providing a noninvasive confirmation of the clinical diagnosis. CONCLUSIONS Ultra high-resolution OCT is an innovative technique to perform in vivo optical biopsies and a promising research and clinical tool for the evaluation of corneal pathologic features in a noninvasive manner. The future use of this novel technology will evolve and increasingly is becoming a vital tool in the clinical and surgical management of corneal diseases.

Diagnosis of Ocular Surface Lesions Using Ultra-High Resolution Optical Coherence Tomography

PURPOSE To assess the use of ultra-high-resolution (UHR) optical coherence tomography (OCT) in the diagnosis of ocular surface lesions. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS Fifty-four eyes of 53 consecutive patients with biopsy-proven ocular surface lesions: 8 primary acquired melanosis lesions, 5 amelanotic melanoma lesions, 2 nevi, 19 ocular surface squamous neoplasia lesions, 1 histiocytosis lesion, 6 conjunctival lymphoma lesions, 2 conjunctival amyloidosis lesions, and 11 pterygia lesions. INTERVENTION Ultra-high-resolution OCT imaging of the ocular surface lesions. MAIN OUTCOME MEASURES Clinical course and photographs, UHR OCT image, and histopathologic findings. RESULTS Ultra-high-resolution OCT images of all examined ocular surface lesions showed close correlation with the obtained histopathologic specimens. When clinical differential diagnosis of ocular surface lesions was broad, UHR OCT images provided optical signs indicating a more specific diagnosis and management. In cases of amelanotic melanoma, conjunctival amyloidosis, and primary histiocytosis and in 1 case of ocular surface squamous neoplasia, UHR OCT was instrumental in guiding the diagnosis. In those cases, UHR OCT suggested that the presumed clinical diagnosis was incorrect and favored a diagnosis that later was confirmed by histopathologic examination. CONCLUSIONS Correlations between UHR OCT and histopathologic findings confirm that UHR OCT is an adjunctive diagnostic method that can provide a noninvasive means to help guide diagnosis and management of ocular surface lesions. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Reduced Tear Meniscus Dynamics in Dry Eye Patients With Aqueous Tear Deficiency

PURPOSE To measure the tear meniscus dynamics in aqueous tear deficiency dry eye patients using optical coherence tomography. DESIGN Clinical research study of a laboratory technique. METHODS Twenty-five aqueous tear deficiency dry eye patients and 30 healthy subjects were recruited. Upper and lower tear menisci of 1 randomly selected eye of each participant were imaged during normal and delayed blinking using optical coherence tomography. Measured parameters included upper tear meniscus height and volume, lower tear meniscus height and volume, the blink outcome defined as the meniscus volume change during blink action, and open eye outcome defined as the meniscus volume change during the open eye period. RESULTS During normal blinking, both tear meniscus height and volume before blink in dry eye patients were significantly smaller than those in healthy subjects, except for the upper tear meniscus volume. During normal blinking, the blink outcome and open eye outcome of lower tear meniscus were significantly smaller in dry eye patients compared with healthy subjects. During delayed blinking, the upper and lower tear menisci heights and volumes significantly increased in both groups. However, dry eye patients had smaller increases than healthy subjects. During delayed blinking, the open eye outcomes of upper and lower tear menisci were smaller in dry eye patients than healthy subjects. CONCLUSIONS Dry eye patients seem to have reduced tear meniscus dynamics during normal blinking and smaller increases of meniscus volume during delayed blinking. Analysis of tear meniscus dynamics may provide more insight in the altered tear system in dry eye patients.

The use of Bowman's layer vertical topographic thickness map in the diagnosis of keratoconus.

PURPOSE To evaluate the use of Bowmans layer (BL) vertical topographic thickness maps in diagnosing keratoconus (KC). DESIGN Prospective, case control, interventional case series. PARTICIPANTS A total of 42 eyes: 22 eyes of 15 normal subjects and 20 eyes of 15 patients with KC. INTERVENTION Bowmans layer 2-dimensional 9-mm vertical topographic thickness maps were created using custom-made ultra high-resolution optical coherence tomography. MAIN OUTCOME MEASURES Bowmans layer average and minimum thicknesses of the inferior half of the cornea, Bowmans ectasia index (BEI; defined as BL minimum thickness of the inferior half of the cornea divided by BL average thickness of the superior half of the cornea multiplied by 100), BEI-Max (defined as BL minimum thickness of the inferior half of the cornea divided by BL maximum thickness of the superior half of the cornea multiplied by 100), keratometric astigmatism (Ast-K) of patients with KC, and average keratometric (Avg-K) readings. RESULTS In patients with KC, BL vertical thickness maps disclosed localized relative inferior thinning of the BL. Inferior BL average thickness (normal = 15±2, KC = 12±3 μm), inferior BL minimum thickness (normal = 13±2, KC = 7±3 μm), BEI (normal = 91±7, KC = 48±14), and BEI-Max (normal = 75±8; KC = 40±13) all showed highly significant differences in KC compared with normal subjects (P< 0.001). Receiver operating characteristic (ROC) curve analysis showed excellent predictive accuracy for BEI and BEI-Max with 100% sensitivity and specificity (area under the curve [AUC] of 1) with cutoff values of 80 and 60, respectively. The AUC of inferior BL average thickness and minimum thickness were 0.87 and 0.96 with a sensitivity of 80% and 93%, respectively, and a specificity of 93% and 93%, respectively. Inferior BL average thickness, inferior BL minimum thickness, BEI, and BEI-Max correlated highly to Ast-K (R = -0.72, -0.82, -0.84, and -0.82, respectively; P< 0.001) and to Avg-K (R = -0.62, P< 0.001; R = -0.59, P = 0.001; R = -0.60, P< 0.001; and R = -0.59, P = 0.001, respectively). CONCLUSIONS Bowmans layer vertical topographic thickness maps of patients with KC disclose characteristic localized relative inferior thinning. Inferior BL average thickness, inferior BL minimum thickness, BEI, and BEI-Max are qualitative and quantitative indices for the diagnosis of KC that accurately correlate with the severity of KC. In our pilot study, BEI and BEI-Max showed excellent accuracy, sensitivity, and specificity in the diagnosis of KC.

Epithelial ingrowth after descemet stripping automated endothelial keratoplasty: Description of cases and assessment with anterior segment optical coherence tomography

Purpose: To describe 5 cases of epithelial ingrowth after Descemet stripping automated endothelial keratoplasty (DSAEK) and the use of anterior segment optical coherence tomography (AS-OCT) to describe the areas of ingrowth. Methods: Five cases with epithelial ingrowth after DSAEK were examined with commercially available AS-OCT and/or a novel custom-built ultrahigh resolution (UHR) AS-OCT. Argon laser photocoagulation was also used to confirm epithelial ingrowth on the iris surface. Pathological evidence of epithelial ingrowth was noted in an eye that underwent corneoscleral grafting for extensive ingrowth through a fistulous tract. Results: Epithelial ingrowth was solely in the graft-host interface in 1 case and in both the interface and retrocorneal and iris surfaces in 4 cases. Argon laser photocoagulation on the iris confirmed epithelial ingrowth in 4 cases. The areas of epithelial ingrowth were imaged in 1 case with the Visante AS-OCT and in 3 cases with an UHR-OCT. In 1 case, block excision with corneoscleral grafting was required. Conclusions: Epithelial ingrowth can occur after DSAEK. This series reports 5 cases of epithelial ingrowth into the interface and/or the retrocorneal surface after DSAEK. Imaging with AS-OCT, specifically the UHR-OCT, and argon laser photocoagulation can help confirm the diagnosis. UHR-OCT imaging of the interface and retrocorneal surfaces can provide clues to the origin of epithelial ingrowth. Four cases were observed. One case underwent corneoscleral grafting with histological confirmation of epithelial ingrowth.