ABSTRACT
Purpose: To study the retinal and choroidal thickness variations on enhanced depth imaging optical coherence tomography scans in ocular albinism (OA) and compare with age?matched healthy subjects. Methods: This retrospective observational study had 48 eyes of 24 patients diagnosed clinically as OA and age, sex, and axial length?matched control healthy subjects. All patients underwent detailed ophthalmic examination and a single?line horizontal?raster enhanced depth imaging – optical coherence tomography scan (Spectralis, Heidelberg Engineering). Retinal and choroidal thickness was measured, compared, and analyzed between the two groups. Mann–Whitney U test was used for analysis between the two groups. P < 0.05 was considered significant. Results: The mean age was 28.3 ± 11.6 and 29.9 ± 10.6 years in the OA group and control group, respectively. Spherical equivalents ranged from ?8.5D to +10.5D in the OA group and from ?8.0D to +10.0D in the control group. The mean axial length between the two groups (P = 0.652) were comparable. The average retinal thickness (272 ± 34.3 vs. 213 ± 13.8 ?m; P < 0.001) was greater in the OA group as compared to controls. The mean choroidal thickness (184 ± 78.4 vs. 287 ± 46.4 ?m; P < 0.001) was significantly thinner in the OA group. Conclusion: Acquisition of OCT scans in OA can be challenging. This study showed that the subfoveal retinal thickness and choroidal thickness measured across the scans were significantly different in the OA group compared to controls. In the future, more studies are required to evaluate the role of the choroid and its relationship to emmetropization in albinism.
ABSTRACT
Purpose: To study the intraoperative retinal macular morphology during macular surgery using handheld spectral domain optical coherence tomography (SDOCT). Design: Prospective, observational case series. Methods: A handheld SDOCT device was used to characterize the preoperative and intraoperative OCT images in 10 eyes of 10 patients undergoing vitrectomy for macular hole (MH) and epiretinal membrane (ERM). I intraoperative imaging was repeated after removal of the internal limiting membrane or the ERM and the images were analyzed. Results: Intraoperative SDOCT images from patients undergoing surgery (5 for full thickness MH including 2 previously failed surgeries and 5 for ERM were reviewed and quantitatively analyzed. In the 5 eyes undergoing surgery for MH, the minimum diameter of the hole showed a significant decrease (P = 0.031; the mean reduction 15.18%; range 6.14- 34.88%). Basal diameter increased in 2 eyes (mean change 9.96%), reduced in 2 (mean reduction 3.28%) while it remained unchanged in 1 case. The MH height decreased in 2 eyes (mean reduction 5.43%) and increased in 3 (mean change 20.04%). Intraoperative imaging in 5 eyes undergoing surgery for ERM revealed immediate decrease in retinal thickness in 3 eyes (mean change 5.00%), and increase in 2 eyes (mean change 17.76%). Comparison of the preincisional and intraoperative handheld SDOCT images demonstrated distinct changes in retinal macular morphology. Conclusion: The intraoperative use of handheld SDOCT provides a novel method for visualizing and quantifying changes in retinal anatomy during macular surgery. Further study is warranted to determine whether intraoperative macular morphological changes could affect and prognosticate MH closure.
ABSTRACT
Purpose: Optical coherence tomography (OCT) is an important imaging tool assessing retinal architecture. In this article, we report a single centers experience of using handheld spectral domain (SD)‑OCT in a pediatric population using the Envisu 2300 (Bioptigen Inc., Research Triangle Park, NC, USA). Methods: We studied SD‑OCT images from 975 patients imaged from January 2011 to December 2014. The variety of cases that underwent an SD‑OCT was analyzed. Cases examples from different case scenarios were selected to showcase unique examples of many diseases. Results: Three hundred and sixty‑eight infants (37.7%) were imaged for retinopathy of prematurity, 362 children (37.1%) underwent the test for evaluation of suboptimal vision or an unexplained vision loss, 126 children (12.9%) for evaluation of nystagmus or night blindness, 54 children (5.5%) for an intraocular tumor or a mass lesion such as retinoblastoma, and 65 children (6.7%) for other diseases of the pediatric retina. The unique findings in the retinal morphology seen with some of these diseases are discussed. Conclusion: The handheld SD‑OCT is useful in the evaluation of the pediatric retinal diseases. The test is useful in the assessment of vision development in premature children, evaluation of unexplained vision loss and amblyopia, nystagmus and night blindness, and intraocular tumors (including retinoblastoma).
ABSTRACT
Optical coherence tomography (OCT) has revolutionized imaging of ocular structures and various disease conditions. Though it has been used in the clinic for some decades, the OCT has only recently found its way into the operating theater. Early attempts at intraoperative OCT, hand‑held and microscope mounted, have already improved our understanding of the surgical pathology and the role it might play in surgical decision‑making. The microscope‑integrated OCT now allows seamless, high‑resolution, real‑time imaging of surgical maneuvers from the incision to wound closure. Visualization of instruments and intraoperative tissue manipulation are possible with this in vivo modality and, therefore, help improve the outcome of surgery. In this article, we describe the advantages it offers during various vitreoretinal procedures.
ABSTRACT
To study the alterations in retinal oxygen saturations in healthy and diseased eyes. Patients presenting to our hospital underwent an additional non-invasive procedure to measure oxygen saturation in their retinal vessels. After dilatation, oximetry was done using the Oxymap T1 retinal oximeter (Oxymap hf, Reykjavik, Iceland). Normal patients and patients with arteriolar and venous occlusions, retinal dystrophies and glaucoma, were evaluated. Arteriolar, venous and arteryvenous saturation difference (AVSD) values were determined for each of the groups. In the normal subjects (n = 98), the average arteriolar saturation was 90.3 ± 6.5, and the venous saturation was 56.9 ± 6.3. The average AVSD was 33.4 ± 5.0. In arterial occlusions (n = 10), we have seen an initial fall in arteriolar (85.8%) and venous (49.7%) saturations in the acute stage in eyes with central retinal artery occlusion with subsequent increase in saturations. In venous occlusions (n = 18), there was an initial increase in all global saturation parameters in the acute stage (arteriolar: 105.8%, venous: 62.7%, AVSD: 43.3%), followed by a gradual decrease in saturations in the chronic stage (arteriolar: 99.8%, venous: 60.1%, AVSD: 39.8%). Eyes with retinitis pigmentosa (n=62) showed higher saturations (104.15%) and higher AVSD (44.15%) compared to macular dystrophies (n = 23) (96.7% and 41.61%) and normal controls (90.6% and 33.3%). Macular dystrophies showed higher global arteriolar values and AVSD but comparable venous values to the control group. In glaucoma (n = 44), we have seen raised arteriolar and AVSD values. Oximetry is sensitive in picking up changes in diseased eyes that are distinct from normal values. In the future, it may prove to be useful in pre-clinical screening studies and in therapeutic decision making.
ABSTRACT
Purpose: To study fundus autofluorescence (FAF) and spectral domain-optical coherence tomography (SD-OCT) characteristics in patients with typical retinitis pigmentosa (RP) and correlate them to visual acuity. Design: Retrospective observational case series. Methods: 110 eyes of 56 RP patients were included. FAF and SD-OCT imaging were done for all eyes. Extent of the autofluorescence ring, central foveal thickness, photoreceptor outer-segment length (PROS), foveal outer segment pigment epithelial thickness (FOSPET), and inner segment-outer segment (IS-OS) extent were defined and measured and correlated to logMAR best corrected visual acuity (BCVA) using linear regression. Results: Study included 110 eyes of 56 patients (34 male and 22 female). Mean BCVA was 0.33 logMAR with no difference between genders. The mean age of patients was 15.4 ± 15.1 years. Mean autofluorescence extent was 3590 ± 1994 μm horizontally, and 2880 ± 1836 μm vertically. These values were significantly correlated with preserved IS/OS junction extent (mean values horizontally = 2865 μm and vertically = 2464 μm). Mean central retinal thickness (218.74 μm) and PROS (44.85 μm) were significantly correlated to BCVA with correlation coefficient r = –0.189, P = 0.015; and r = –0.874, P = 0.0001, respectively. FOSPET (mean = 71.15 μm) did not show a significant correlation with BCVA, independent of PROS. Conclusions: Retinal microstructural changes as studied on SD-OCT, especially PROS length can be used as a surrogate marker to monitor degenerative diseases such as RP. Further, studies are required to clearly delineate the microstructuralfunctional relationship in the human retina.
ABSTRACT
Introduction: Diabetic macular edema (DME) is a vision-threatening complication of diabetic retinopathy. The current practice of management is a” trial and error “method of using intravitreal antivascular endothelial growth factor (VEGF)’’ or steroids to treat the patient and watch the response. However, if the patient’s genetic profi le helps us choose appropriate medicine, it would help customize treatment option for each patient. This forms the basis of our study. Materials and Methods: A case-control, prospective, observational series, where DME patients were treated with bevacizumab and subclassifi ed as treatment naïve, treatment responders, and treatment nonresponders. Blood samples of 20 subjects were studied, with fi ve patients in each of the groups (nondiabetic- group 1, treatment naïve- group 2, treatment responder- group 3, and treatment nonresponder-group 4). Whole blood RNA extraction followed by labeling, amplifi cation and hybridization was done, and microarray data analyzed. Genes were classifi ed based on functional category and pathways. Results: The total number of genes upregulated among all three experimental groups was 5, whereas 105 genes were downregulated. There were no common genes upregulated between the responders and nonresponders. There was only one gene upregulated between the diabetic and diabetic responders postt reatment. There were 19 genes upregulated and 8 genes downregulated in the infl ammatory pathway in group 2 versus group 1. There were no downregulated genes detected in vascular angiogenesis and transcription group. There were identical numbers of genes up- and downregulated in the infl ammatory pathway. Seventeen genes were upreguated and 11 genes downregulated in receptor activity, which remained the predominant group in the group classifi cation. Discussion: In summary, this study would provide an insight into the probable signaling mechanisms for disease pathogenesis as well as progression. This type of study eventually would aid in developing or improvising existing treatment modules with a rational approach towards personalized medicine, in future addressing the diff erential responses to treatment.
ABSTRACT
Photocoagulation is the standard of care for several ocular disorders and in particular retinal conditions. Technology has off ered us newer lasing mediums, wavelengths and delivery systems. Patt ern scan laser in proliferative diabetic retinopathy and diabetic macular edema allows laser treatment that is less time consuming and less painful. Now, it is possible to deliver a subthreshold micropulse laser that is above the threshold of biochemical eff ect but below the threshold of a visible, destructive lesion thereby preventing collateral damage. The advent of solid-state diode yellow laser allows us to treat closer to the fovea, is more eff ective for vascular structures and off ers a more uniform eff ect in patients with light or irregular fundus pigmentation. Newer retinal photocoagulation options along with their advantages is discussed in this review.