James Wawrzynski

Optical Coherence Tomography Imaging of the Proximal Lacrimal System

Abstract Introduction: There are currently no routinely used imaging modalities for the proximal lacrimal system. Optical Coherence Tomography (OCT) is a safe and non-invasive method of high resolution cross-sectional imaging of tissue microstructures using infra-red radiation. In this study we investigate whether OCT may be used to image the punctum and proximal canaliculus. Methods: A cohort of healthy subjects with normal ocular anatomy and no symptoms of epiphora were prospectively invited to enrol. Spectral OCT images of the lower punctae were captured with a Topcon 3D Optical Coherence Tomography 2000 machine. Measurements were made of the maximal punctal diameter, canalicular diameter and canalicular depth. Our data for depth of the vertical canaliculus was compared to the widely quoted figure of 2 mm using a two-tailed t-test to check for a statistically significant difference at p < 0.05. Results: Thirty-six punctae of 18 subjects were scanned. The punctum was recognisable on the OCT image in all cases. The mean depth, width and cross- sectional area of the visualised canaliculi were 0.753 mm (SD 0.216), 0.110 mm (SD 0.067) and 9.49 × 10−3 mm2, respectively. The mean width of the punctum was 0.247 mm (SD 0.078). Discussion: We have demonstrated the first in-vivo high resolution images of normal punctal and vertical canalicular anatomy using spectral OCT. There is currently no other practical way to accurately image punctal and proximal canalicular morphology in vivo. OCT is a convenient and readily available tool in most eye clinics with resolution ideally suited for imaging of the punctum and proximal canaliculus.

An Automated Detection System for Microaneurysms That Is Effective across Different Racial Groups

Patients without diabetic retinopathy (DR) represent a large proportion of the caseload seen by the DR screening service so reliable recognition of the absence of DR in digital fundus images (DFIs) is a prime focus of automated DR screening research. We investigate the use of a novel automated DR detection algorithm to assess retinal DFIs for absence of DR. A retrospective, masked, and controlled image-based study was undertaken. 17,850 DFIs of patients from six different countries were assessed for DR by the automated system and by human graders. The systems performance was compared across DFIs from the different countries/racial groups. The sensitivities for detection of DR by the automated system were Kenya 92.8%, Botswana 90.1%, Norway 93.5%, Mongolia 91.3%, China 91.9%, and UK 90.1%. The specificities were Kenya 82.7%, Botswana 83.2%, Norway 81.3%, Mongolia 82.5%, China 83.0%, and UK 79%. There was little variability in the calculated sensitivities and specificities across the six different countries involved in the study. These data suggest the possible scalability of an automated DR detection platform that enables rapid identification of patients without DR across a wide range of races.

Fingerprick autologous blood: a novel treatment for dry eye syndrome

PurposeDry eye syndrome (DES) causes significant morbidity. Trials of blood-derived products in treatment of the condition show promising results. However, their production is expensive and time-consuming. We investigate fingerprick autologous blood (FAB) as an alternative low-cost, readily accessible treatment for DES.Patients and methodsProspective, non-comparative, interventional case series. In total, 29 eyes of 16 DES patients (2 males and 14 females) from two NHS sites in the United Kingdom. Patients instructed to clean a finger, prick with a blood lancet, and apply a drop of blood to the lower fornix of the affected eye(s), 4 times daily for 8 weeks then stop and review 4 weeks later. Follow-up visits occurred ~3 days, 2, 4, 8 weeks into therapy, and 4 weeks post-cessation. At each visit, visual acuity, corneal staining, Schirmer’s test, tear break-up time (TBUT), and ocular comfort index (OCI) were measured, and photographs taken. Results were analysed using Student’s paired t-test.ResultsAt 8 weeks, there was improvement in mean Oxford corneal staining grade (3.31 to 2.07 (P<0.0001)), TBUT (5.00 to 7.80 s (P<0.05)), visual acuity (0.08 to 0.01 LogMAR equivalent (P<0.05)), and OCI score (56.03 to 39.72 (P<0.0001)). There was no statistically significant change in Schirmer’s test results. Four weeks post-cessation versus immediately after completion of FAB therapy, mean staining grade worsened from 2.07 to 2.86 (P<0.0001). OCI score worsened from 39.72 to 44.67 (P<0.05).ConclusionsIn our limited case series FAB appears to be a safe and effective treatment for DES.

Man versus Machine: Software Training for Surgeons—An Objective Evaluation of Human and Computer-Based Training Tools for Cataract Surgical Performance

This study aimed to address two queries: firstly, the relationship between two cataract surgical feedback tools for training, one human and one software based, and, secondly, evaluating microscope control during phacoemulsification using the software. Videos of surgeons with varying experience were enrolled and independently scored with the validated PhacoTrack motion capture software and the Objective Structured Assessment of Cataract Surgical Skill (OSACCS) human scoring tool. Microscope centration and path length travelled were also evaluated with the PhacoTrack software. Twenty-two videos correlated PhacoTrack motion capture with OSACCS. The PhacoTrack path length, number of movements, and total procedure time were found to have high levels of Spearmans rank correlation of −0.6792619 (p = 0.001), −0.6652021 (p = 0.002), and −0.771529 (p = 0001), respectively, with OSACCS. Sixty-two videos evaluated microscope camera control. Novice surgeons had their camera off the pupil centre at a far greater mean distance (SD) of 6.9 (3.3) mm, compared with experts of 3.6 (1.6) mm (p ≪ 0.05). The expert surgeons maintained good microscope camera control and limited total pupil path length travelled 2512 (1031) mm compared with novices of 4049 (2709) mm (p ≪ 0.05). Good agreement between human and machine quantified measurements of surgical skill exists. Our results demonstrate that surrogate markers for camera control are predictors of surgical skills.

Report on the incidence of squamous cell carcinomas affecting the eyelids in England over a 15-year period (2000–2014)

Aims The authors report on trends in the incidence of squamous cell carcinoma (SCC) affecting the eyelids in England over a 15-year period and identify associations between demographic factors and SCC risk. Methods The National Cancer Registration and Analysis Service identified all cases of eyelid SCC in England between 2000 and 2014. The crude and age-standardised rates of eyelid SCCs in England were calculated. The association of SCC with several known demographic risk factors was then examined to assess their importance in periocular cases. Results Over the 15 years studied, there were 4022 patients in England diagnosed with a first episode of SCC affecting the eyelids. The age-standardised number of reported cases rose between 2000 and 2014 by a mean of 0.0137 cases per 100 000 population per year (equivalent to a rise in SCC incidence of approximately 2% per year). The mean age-standardised incidence rate of SCC during the study period was 0.63 cases per 100 000 population per year. Age was exponentially correlated with incidence, with an approximate doubling of the risk for every decade over the age of 60. The relative risk of eyelid SCC in men compared with women was 1.9. Social deprivation quintile by income was not found to be associated with risk of SCC. Conclusion The incidence of eyelid SCC in England is rising. In addition, the age-standardised and population-standardised rate of SCC is also rising. A higher risk of SCC is strongly correlated with age and male sex but not with deprivation.

Scaling the punctum and canaliculus in patients undergoing punctoplasty surgery: A prospective cohort study

ABSTRACT Optical Coherence Tomography (OCT) is a safe and non-invasive method of high-resolution cross-sectional imaging of tissue microstructures using infrared radiation. This study investigates how the appearance of the punctum and proximal canaliculus differs pre- and post-operatively in patients undergoing punctoplasty surgery. Patients with symptomatic punctal stenosis warranting punctoplasty surgery were prospectively invited to enrol from a single centre. Spectral OCT images of the lower punctae were captured with a Topcon 3D OCT 2000 machine pre- and post-operatively (at their follow-up appointment). Measurements were made of the maximal punctal diameter, canalicular diameter and canalicular depth. Pre- and post-operative measurements were compared using a paired t-test. Twenty-three punctae of 18 patients with punctal stenosis were included in the study. They were 10 males and 8 females with a median age 71.0 (SD 12.1). Mean canalicular cross-sectional area was 56.9 × 10-3 mm2 pre-operatively and 267.2 × 10-3 mm2 post-operatively, showing a statistically significant increase (p = 0.0004). There was an increase in both mean canalicular width (0.253 to 0.524mm (p = 0.0001)) and depth (0.433 to 0.852mm (p = 0.0001)) from pre- to post-operatively. There was a significant improvement in symptoms from pre- to post-operatively, as measured subjectively by the Lac-Q questionnaire (p = 0.021). This study describes the change in the appearance of the punctum and proximal canaliculus in patients undergoing punctoplasty operations, by using spectral OCT to capture in vivo high-resolution images. It demonstrates that punctal OCT can be successfully applied to quantify the morphological changes of the punctum and canaliculus pre- and post-punctoplasty.

Reply: Comments on surgical iridotomy technique

Comments on surgical iridotomy technique We congratulate Athanasiadis et al. for documenting the surgical iridotomy technique. We have used this technique in several clinical scenarios and have a few observations to make. One advantage of the technique is the ease of placing an iridotomy in the superior iris so it is covered by the upper lid. A large number ofmodern cataract surgeries are performed using a temporal clear corneal section. It is virtually impossible to make a superior iridectomy using a scissors in this situation. It is cosmetically as well as optically undesirable to place an iridotomy in the temporal iris. When the main section is at the temporal limbus, one can easily use the side port (used for the second instrument) in the case of the right eye to create an iridotomy. In the left eye, a paracentesis can be created at the superior limbus tomake an iridotomy with the microvitreoretinal (MVR) blade. However, as opposed to the other methods of surgical iridectomy (using a scissors or a vitrectomy cutter), there is no countertraction to the posterior force when the MVR blade is used. This is especially