Glaucoma Today - Pitfalls in Optical Coherence Tomography Imaging


• Clinicians need to confirm a few rules of accurate optical coherence tomography imaging before accepting the results: signal strength, motion artifact, and proper acquisition of the image.

• When assessing progression, physicians must determine whether or not changes are clinically significant and, if so, whether they are a result of glaucoma or something else.


Assessing progression presents different challenges. The software must be capable of aligning to the baseline or previous image acquired in terms of location as well as angulation, because a small but different tilt of the head can result in erroneous interpretation. The physician must also determine if the change detected by the machine is clinically significant (greater than 2 standard deviations of the measurement reproducibility2). When reviewing macular measurements, clinicians must consider whether a change is a result of glaucoma, release of the posterior vitreous attachments to the RNFL, or improvement of overall blood sugar control (Figure 2). Moreover, in the presence of uveitis, coexisting RNFL edema and subclinical macular edema can result in erroneous interpretation of normal-appearing thickness.3,4 Upon subsequent resolution of such edema (with uveitis treatment), the thickness of these layers can dramatically decrease once again, giving an erroneous interpretation of glaucomatous progression.

Cystic spaces in the RNFL or subretinal space in the peripapillary region in myopia as well as cystic changes in the outer plexiform layer in rapidly advancing glaucoma can also confound interpretation.4 Masqueraders of glaucoma such as neurosyphilis, optic disc drusen, ischemic optic neuropathy, hemianopia, and optic neuritis present another set of challenges to the assessment of OCT results (Figure 3).5



Teleophthalmology: improving patient outcomes?

A high satisfaction level and acceptance is reported in the majority of the studies because of increased accessibility and reduced traveling cost and time. Considering the improved quality of patient care and patient satisfaction reported for these telemedicine services, this review explores how teleophthalmology helps to improve patient outcomes.


Omana Kesary Sreelatha1 and  Sathyamangalam VenkataSubbu Ramesh2

1Ophthalmology Department, Sultan Qaboos University Hospital, Muscat, Oman, India

2Department of Optometry, School of Allied Health Sciences, Manipal University, Manipal, India

Correspondence: Sathyamangalam VenkataSubbu Ramesh, Department of Optometry, School of Allied Health Sciences, Manipal University, Manipal 576104, India, Tel +91 886 133 0950, Email 



Teleophthalmology is gaining importance as an effective eye care delivery modality worldwide. In many developing countries, teleophthalmology is being utilized to provide quality eye care to the underserved urban population and the unserved remote rural population. Over the years, technological innovations have led to improvement in evidence and teleophthalmology has evolved from a research tool to a clinical tool. The majority of the current teleophthalmology services concentrate on patient screening and appropriate referral to experts. Specialty care using teleophthalmology services for the pediatric group includes screening as well as providing timely care for retinopathy of prematurity (ROP). Among geriatric eye diseases, specialty teleophthalmology care is focused toward screening and referral for diabetic retinopathy (DR), glaucoma, age-related macular degeneration (ARMD), and other sight-threatening conditions. Comprehensive vision screening and refractive error services are generally covered as part of most of the teleophthalmology methods. Over the past decades, outcome assessment of health care system includes patients’ assessments on their health, care, and services they receive. Outcomes, by and large, remain the ultimate validators of the effectiveness and quality of medical care. Teleophthalmology produces the same desired clinical outcome as the traditional system. Remote portals allow specialists to provide care over a larger region, thereby improving health outcomes and increasing accessibility of specialty care to a larger population. A high satisfaction level and acceptance is reported in the majority of the studies because of increased accessibility and reduced traveling cost and time. Considering the improved quality of patient care and patient satisfaction reported for these telemedicine services, this review explores how teleophthalmology helps to improve patient outcomes.



Teleophthalmic Approach for Detection of Corneal Diseases: Accuracy and Reliability.

Woodward, Maria A.; Musch, David C.; Hood, Christopher T.; Greene, Jonathan B.; Niziol, Leslie M.; Jeganathan, V. Swetha E.; Lee, Paul P. Less


Purpose: Corneal and anterior segment diseases cause most of the urgent visits to eye care professionals. We evaluated the diagnostic accuracy of detecting corneal diseases using external photographs from 2 portable cameras for telemedicine purposes.

Methods: This is a prospective study of adults with a clinical diagnosis of corneal pathology including corneal abrasions, ulcers, scars, and pterygia. A cornea specialist provided the gold standard diagnosis by slit-lamp examination. Images of both eyes were obtained using iTouch 5S and Nidek VersaCam cameras in multiple gazes and interpreted by 3 cornea specialists for the presence of pathology. Accuracy to detect disease was compared with gold standard diagnosis, stratified by the camera and grader. Reliability was evaluated with weighted kappa statistics. Graders assessed image quality on a Likert scale from 1 (poor) to 9 (optimal).

Results: A total of 198 eyes (110 subjects) were photographed. By gold standard diagnosis, 59 eyes (30%) had corneal scars, 34 (17%) had ulcers, 13 (7%) had abrasions, 10 (5%) had pterygia, and 82 (41%) were normal. Sensitivity to detect AS pathology ranged from 54% to 71% for the iTouch and 66% to 75% for the Nidek, across graders; specificity ranged from 82% to 96% for the iTouch and 91% to 98% for the Nidek. The intergrader reliability was moderate to strong (kappa ranges: 0.54-0.71 for the iTouch; 0.75-0.76 for the Nidek). Quality ratings were variable between graders.

Conclusions: External photographs taken by standard, nonenhanced portable cameras and interpreted remotely by ophthalmologist graders yielded sensitivity values that are not yet suitable for telemedicine applications. Additional work is needed to improve the ability to detect AS pathology remotely.



What gas and face-down positioning to recommend in macular hole surgery?

The question arises what gas to use if I have macular hole surgery?  Also, does face-down positioning or posturing after macular hole surgery make a difference. 

A Cochrane review on the second question (face-down position) found the following. "We conducted a systematic review of outcomes for individuals with idiopathic macular holes following postoperative face-down positioning. We found three randomized controlled trials (RCTs). Two of the three trials suggested a benefit in holes larger than 400 microns in diameter. None demonstrated evidence of a benefit in smaller holes."

Large studies on the first question are lacking but the two articles below may be helpful.

In summary, the 2012 BJO article concluded: "Macular-hole surgery with SF(6) gas achieves similar results to C(2)F(6) and is absorbed faster, allowing quicker visual rehabilitation for the patient."  A recent paper from 2017 in Retina concluded "The macular hole closure rate was similar with sulfurhexafluoride and perfluoropropane, irrespective of hole size, stage, or duration. However, sulfurhexafluoride exhibited a decreased incidence of cataract and ocular hypertension with shorter tamponade duration. Perfluoropropane may have a role as the preferred endotamponading agent in failed primary surgeries.."

Br J Ophthalmol. 2012 Feb;96(2):185-8. doi: 10.1136/bjo.2010.201699. Epub 2011
May 17. Outcomes of sulfur hexafluoride (SF6) versus perfluoroethane (C2F6) gas tamponade
for non-posturing macular-hole surgery.

Rahman R(1), Madgula I, Khan K.

Author information: 
(1)Department of Ophthalmology, Calderdale Royal Hospital, Salterhebble, Halifax
HX3 0PW, UK.

AIM: To compare the outcomes of non-posturing macular-hole surgery using sulfur
hexafluoride (SF(6)) gas versus perfluoroethane (C(2)F(6)) for idiopathic macular
hole repair. Design Interventional, comparative cohort study.
METHODS: 39 eyes of 38 patients undergoing macular-hole surgery with SF(6) were
compared with another consecutive group of 39 eyes (39 patients) in whom C(2)F(6)
was used. All patients were operated on by a single surgeon and underwent 23G
transconjunctival phakovitrectomy with no prone posturing in the postoperative
period. The best-corrected Snellen's visual acuity (VA) was converted to the
logarithm of minimal angle of resolution (logmar) visual acuity for analysis.
Optical coherence tomography documentation of anatomical closure and
complications of surgery were recorded.
RESULTS: Primary hole closure was achieved in 89.75% in the C(2)F(6) group and
87.2% in the SF(6) group. Secondary closure after non-posturing redo surgery with
heavy oil (Oxane-HD) was 100% in both groups. The mean preoperative VA in the
C(2)F(6) group and SF(6) group was 0.81 logMAR and 0.78 respectively. 2 weeks
after surgey, SF(6) was completely absorbed in all cases, and the mean VA
improved to 0.5 logMAR; however, it remained 1.9 logMAR in the C(2)F(6) group.
The final mean VA at 6 months was 0.44 (range 0-0.78) and 0.38 (range 0-1) in the
C(2)F(6) and SF(6) group respectively. There were no instances of pupillary
capture in the SF(6) group, whereas there were four in the C(2)F(6) group.
CONCLUSION: Macular-hole surgery with SF(6) gas achieves similar results to
C(2)F(6) and is absorbed faster, allowing quicker visual rehabilitation for the

DOI: 10.1136/bjo.2010.201699
PMID: 21586794  [Indexed for MEDLINE]


Retina. 2017 Feb;37(2):283-290. doi: 10.1097/IAE.0000000000001124.


Author information: 
(1)Vitreoretina Services, Giridhar Eye Institute, Cochin, India.

PURPOSE: To compare outcomes of macular hole surgery using sulfurhexafluoride
(SF6) versus perfluoropropane (C3F8) gas.
METHODS: This is a retrospective, interventional, comparative study. A total of
177 eyes of 166 patients operated over a 3-year period for idiopathic macular
holes were included. Sixty-seven eyes had tamponade with SF6 gas (Group 1),
whereas 111 eyes received C3F8 (Group 2) as the tamponading agent. The primary
outcome measure was the macular hole closure rate. Statistical analysis was done
using SPSSv16.
RESULTS: Spectral domain optical coherence tomography-based stagewise
distribution of macular holes were similar across both groups (P = 0.99). The
hole closure rate was 57/66 (86.4%) with SF6 and 96/111 (86.5%) with C3F8 gas (P
= 0.98). Subanalysis demonstrated no significant difference in closure rates
regarding macular hole size, stage, or duration. Best-corrected visual acuity
improved by a mean of 0.28 logMAR in the SF6 group (P = 0.00) and 0.42 logMAR in
the C3F8 group, corresponding to 3 lines and 4 lines of improvement,
respectively, on the Early Treatment Diabetic Retinopathy Study chart (P < 0.05).
The difference was not significant (P = 0.06). Rise in intraocular pressure was
higher in the C3F8 group (P < 0.05). Progression of cataract was also greater in
the C3F8 group (83.3 vs.73.9%), but it was not statistically significant (P =
0.20). Resurgery was done in 9/177 eyes. The closure rate with C3F8 and SF6
reinjections was 3/4 (75%) and 1/5 (20%). Moreover, anatomical hole closure after
resurgeries was better in Group 1 (4/5 eyes) than in Group 2 (0/4 eyes).
CONCLUSION: The macular hole closure rate was similar with sulfurhexafluoride and
perfluoropropane, irrespective of hole size, stage, or duration. However,
sulfurhexafluoride exhibited a decreased incidence of cataract and ocular
hypertension with shorter tamponade duration. Perfluoropropane may have a role as
the preferred endotamponading agent in failed primary surgeries.

DOI: 10.1097/IAE.0000000000001124
PMID: 28118283 



Should we treat high risk AMD patients with Statins?

Large studies answering this question are still lacking.  Evidence-based medicine recommending Statins for AMD is premature at this point as mentioned below.  

A highly-respected Cochrane review concluded "Evidence from currently available randomized controlled trials (RCTs) is insufficient to conclude that statins have a role in preventing or delaying the onset or progression of AMD."  KEY RESULTS: "Neither trial provided sufficient evidence to determine whether statins are effective in delaying the onset or progression of AMD. Information was lacking for outcomes related to vision, quality of life, and adverse events."

However, an intriguing article from Mass Eye & Ear found that "High-dose statins may result in resolution of drusenoid pigment epithelial detachments (PEDs) and improvement in [vision]. 

EBioMedicine. 2016 Feb 4;5:198-203. doi: 10.1016/j.ebiom.2016.01.033. eCollection
2016 Mar.

Regression of Some High-risk Features of Age-related Macular Degeneration (AMD)
in Patients Receiving Intensive Statin Treatment.

Vavvas DG(1), Daniels AB(1), Kapsala ZG(1), Goldfarb JW(1), Ganotakis E(1),
Loewenstein JI(1), Young LH(1), Gragoudas ES(1), Eliott D(1), Kim IK(1),
Tsilimbaris MK(1), Miller JW(1).

Author information: 
(1)Retina Service, Department of Ophthalmology, Mass. Eye and Ear Infirmary,
Harvard Medical School, Boston, MA, USA.

Comment in
    EBioMedicine. 2016 Mar;5:26-7.

IMPORTANCE: Age-related macular degeneration (AMD) remains the leading cause of
blindness in developed countries, and affects more than 150 million worldwide.
Despite effective anti-angiogenic therapies for the less prevalent neovascular
form of AMD, treatments are lacking for the more prevalent dry form. Similarities
in risk factors and pathogenesis between AMD and atherosclerosis have led
investigators to study the effects of statins on AMD incidence and progression
with mixed results. A limitation of these studies has been the heterogeneity of
AMD disease and the lack of standardization in statin dosage.
OBJECTIVE: We were interested in studying the effects of high-dose statins,
similar to those showing regression of atherosclerotic plaques, in AMD.
DESIGN: Pilot multicenter open-label prospective clinical study of 26 patients
with diagnosis of AMD and the presence of many large, soft drusenoid deposits.
Patients received 80 mg of atorvastatin daily and were monitored at baseline and
every 3 months with complete ophthalmologic exam, best corrected visual acuity
(VA), fundus photographs, optical coherence tomography (OCT), and blood work
(AST, ALT, CPK, total cholesterol, TSH, creatinine, as well as a pregnancy test
for premenopausal women).
RESULTS: Twenty-three subjects completed a minimum follow-up of 12 months.
High-dose atorvastatin resulted in regression of drusen deposits associated with
vision gain (+ 3.3 letters, p = 0.06) in 10 patients. No subjects progressed to
advanced neovascular AMD.
CONCLUSIONS: High-dose statins may result in resolution of drusenoid pigment
epithelial detachments (PEDs) and improvement in VA, without atrophy or
neovascularization in a high-risk subgroup of AMD patients. Confirmation from
larger studies is warranted.

DOI: 10.1016/j.ebiom.2016.01.033
PMCID: PMC4816836
PMID: 27077128  [Indexed for MEDLINE]






Erich Knop1 , Nadja Knop1
1 Ocular Surface Center Berlin (OSCB), Univ Charite Berlin, Dept Cell & Neurobiol, Berlin, Germany

Disclosure Block:Erich Knop, None; Nadja Knop, None

Purpose:Dry Eye Disease (DED) is a complex alteration of the functional anatomy of the ocular surface that is still insufficiently understood and current concepts are often oversimplified.

Methods:A pubmed based review of the literature on DED was performed and pathogenetic mechanisms identified. These were arranged in a patho-physiologic hierarchy that reflects the causative relations of events in DED and also reflects clinical findings but is independent of assumed clinical importance.

Results:Structural and functional alterations of the integrity of the ocular surface and the secretory elements as aqueous lacrimal glands (LG dysfunction, LGD) and the Meibomian glands (MG dysfunction, MGD) together with the integrity of the eyelids and the regular blinking mechanism (termed lid and blinking dysfunction, LBD) are defined as basic primary causative factors for DED. They result in tear film deficiency and ocular surface tissue damage that are both defined as primary pathologies. Tear film deficiency as well as ocular surface damage are both governed by secondary pathogenetic factors. In tear film deficiency there are e.g. tear instability, dry spots, friction and hyperosmolarity. Surface damage is governed by e.g. epithelial activation, inflammation and impaired tissue differentiation. The primary causative factors are influenced by underlying regulatory systems such as the neural innervation, endocrine and immune systems. Overlying influence factors act either on the differentiation of the tissues as internal factors and on their secretions as external factors. The nervous system regulates function but also pain sensation that is modulated by higher order mechanisms and can lead to chronic pain syndromes. In contrast to present over-simplified models we have identified several, different, interacting vicious circles or disease aggravation and perpetuation.

Conclusions:This new concept on the pathophysiology DED incorporates long established as well as new mechanisms in the pathophysiological order. It is complex but not complicated - intuitively understandable and suitable to assist basic scientist and practitioner alike. An educational computerized animation is made to promote the understanding of dry eye disease.

Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details.:Dry Eye Disease (DED) is a widespread pathologic condition of the ocular surface characterised by irritation, unstable visual acuity and pain - is is the most frequent diagnosis in opthalmological practice but can often only insufficiently be treated. DED reduces work productivity and the quality of life and it is a financial burden to the social system. Since the rate of DED increases with advancing age it will be of growinig importance in an aging society.
The disease is complex and the enormous amount of new data in research and clinics on ocular surface and DED makes the understanding of this condition more and more multifaceted, complicated and increasingly unintelligible to many people. Therefore we have developed a completely new way to see and view the normal ocular surface and its pathological changes in DED. This is a holistic way that allows to see the full picture at first glance like a landscape from above and it is thereby intuitively understandable.
This new concept on the basics and course of Dry Eye Disease incorporates long established as well as new findings in a natural pathophysiological order and can thereby instruct the clinical practitioner to identify and treat the specific primary problem/s in his individual patient more effectively.An educational computerized animation is made to promote the understanding of dry eye disease.




Dry Eye Treatment can be individualized with TeleOphthalmology

Dry eye disease cannot be treated in a formulaic way.  The number of treatment parameters for a single individual can be overwhelming. As a result, this demands a highly iterative approach. Such an approach is difficult to achieve in the typical brick and mortar clinical scenerio.  I use the Telemedicine platform @eyecarelive to fit this niche approach.  



Arvo 2017 dry eye

Of the many wonderful posters at ARVO 2017 that I read on dry eye disease, I found these to be particularly interesting:

1)  Calcitriol Inhibits Dry Eye Related Ocular Surface Inflammation in vivo and in vitro Jing Zhang1,2 , Yiqin Dai1,2 , Dan Wu1 , JianJiang Xu1

2) Prevalence of Compromised Lid Seal in Symptomatic Refractory Dry Eye Patients and Asymptomatic Patients Donald R. Korb2 , Caroline A. Blackie 1, Amy C. Nau2

3) Randomised trial of acupuncture in dry eye found reduction in tear cytokine Louis Tong1,2 , Hla-Myint Htoon2,3 , Aihua Hou2 , U Rajendra Acharya4 , Jen-Hong Tan4 , Qi Ping Wei6 , Pat Lim5





(LuxIQ) for Quantitative Evaluation of Dry Eye Syndrome

Novel Light Intensity Device (LuxIQ) for Quantitative Evaluation of Dry Eye Syndrome


Posterboard #: A0295

Abstract Number: 2705 - A0295

Author Block: Harvey Fishman MD PHD1 , Peter Borden2 , Michele Klein2
1 FishmanVision, Palo Alto, California, United States; 2 Jasper Ridge, Inc., San Mateo, California, United States

Disclosure Block:Harvey Fishman MD PHD, FishmanVision (Code P (Patent) ); Peter Borden, Jasper Ridge, Inc. (Code P (Patent) ), Jasper Ridge, Inc. (Code E (Employment) ); Michele Klein, Jasper Ridge, Inc. (Code E (Employment) )

Purpose:To evaluate the effectiveness of a novel device (LuxIQ) that quantifies light sensitivity in patients reporting Dry Eye Syndrome (DES) symptoms, and whether light sensitivity measurement is an effective indicator of DES.

Methods:15 patients reporting DES symptoms were recruited during their regularly scheduled visit to a Dry Eye clinic. A routine screening exam was conducted, including Non-Invasive Tear Break-up Time (NIBUT), Schirmer strips, and Osmolarity. In addition, each patient was asked to adjust a device (LuxIQ™, Jasper Ridge Inc) to their preferred illuminance and white light color temperature on a 40-cm near vision chart (Colenbrander Mixed Contrast), over an illuminance range of 0-5000 lux and color temperature range of 2,700 to 6,500°K. Measurement was bilateral (both eyes open) Patients were not told the purpose of this measurement. 8 control subjects, who did not report DES symptoms, were also measured for illuminance and color temperature preference.

Results:The average illuminance and color temperature for the DES patients was 1750±753 lux and 4507±784°K, and for the controls 2643±1435 lux and 5000±852°K (see figure 1). The DES distribution shows a strong peak between 1000 and 2000 lux, and is significantly lower than the control (p=.21). The NIBUT, Schirmer and Osmolarity scores showed no correlation to one another. Interestingly, the sole correlation between methods seen is between illuminance and NIBUT for patients with illuminance <3000 lux and the time in both eyes <5 seconds, with a linear r2 correlation of 0.91.

Conclusions:We observed strong evidence of a measurable relation between preferred illuminance and DES symptoms. Of the four diagnostic methods used in this study, preferred illuminance was the most consistent, a promising result as it is also the quickest, simplest, and least invasive of the methods. The correlation between short NIBUT times and preferred illuminance further supports the conclusion that preferred illuminance is a valid indicator of DES. We are continuing this IRB-approved study, and expect to evaluate significantly more patients.

Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details.:We report on a novel light intensity device (LuxIQ) that help clinicians assess the severity of dry eye syndrome in a quantitative manner. Currently, the inability to quantify and accurately assess the severity of dry eyes is a huge impediment in characterizing DES. This novel device is a major advancement for both clinicians and researchers for the development of new therapies and treatments in the field of Dry Eye Syndrome.



TeleOphthalmology using EyeCareLive

The EyeCareLive App ( is platform that enables my patients to connect with me in a HIPAA secure format. They can send simple messages , pictures, or even video to me either asynchronously or via a live video visit.  I find that the post op patients find this App very useful to quickly update me on their procedure and get quick answers to questions that come up. Glasses updates and contact lens prescriptions are easily uploaded and sent to the patient.