FP1704 : Smartphone Gonio-imagingDR. PRITHVI CHANDRAKANTH
Dr. sneha chavan, DR. PRITHVI CHANDRAKANTH, Dr. GANESH V. RAMAN, Dr.ATUL GUJARATHI
Semi Final
Abstract
Gonioscopy, which is an integral part of glaucoma evaluation, has a steep learning curve. With smartphones revolutionising tele ophthalmology, we present novel method of using smartphone for gonio-imaging. We have previously reported use of smartphone with 10D IOL for anterior segment imaging.In this study we compare use of similar method for gonio-imaging with standard slit lamp imaging. Gonio-images of 120 patients were taken with slit lamp, smartphone and smartphone with attached 10 D IOL and images were graded for quality and diagnosis from 1 to 5 on the basis of Noise, Sharpness, contrast, diagnostic confidence and artefacts by 3 medical officers.and were compared.No statistically significant difference was observed between smartphone with 10D IOL and slit-lamp imaging.
Conclusion- Smartphone Gonio-imaging has a unique role in glaucoma screening in remote areas along with hand held tonometers. It serves both as imaging and connectivity device.
Full Text
Article Type: Brief Report
Authors: Prithvi Chandrakanth (MS), Sneha Chavan (DNB), Ganesh V Raman (DNB), Atul Gujarathi
Conflict of Interest: Nil
Financial Support: Nil
Presenting Author: Sneha Chavan (DNB)
Gonioscopy, which is an integral part of glaucoma evaluation, has a steep learning curve. With smartphones revolutionising tele ophthalmology, we present novel method of using smartphone for gonio-imaging. We have previously reported use of smartphone with 10D IOL for anterior segment imaging.In this study we compare use of similar method for gonio-imaging with standard slit lamp imaging. Gonio-images of 120 patients were taken with slit lamp, smartphone and smartphone with attached 10 D IOL and images were graded for quality and diagnosis from 1 to 5 on the basis of Noise, Sharpness, contrast, diagnostic confidence and artefacts by 3 medical officers.and were compared.No statistically significant difference was observed between smartphone with 10D IOL and slit-lamp imaging. Conclusion- Smartphone Gonio-imaging has a unique role in glaucoma screening in remote areas along with hand held tonometers. It serves both as imaging and connectivity device.
Keywords
Gonioscopy
Smartphone imaging
Gonio-imaging
Anterior chamber angle
Introduction
Glaucoma is the second most common cause of blindness after cataract and the leading cause of irreversible blindness.1 The global prevalence of glaucoma is estimated at 3.54%.2 The studies showing the prevalence of glaucoma between 0.94% to 4.73% among them in various part of Asia, with angle-closure glaucoma being more frequent among Asian populations.3,4 The estimated prevalence of glaucoma cases in India is reported to be 11.9 million with an equal proportion of primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG). 4 Visual field loss and progressive optic neuropathy in glaucoma are often slow with many patients oblivious to their underlying glaucomatous disease.
Population studies in India have proposed periodic screening of high risk populations for diagnosing the disease at an early stage. Imaging the anterior chamber angle via gonioscopy forms an integral part of glaucoma screening, diagnosis and management. Previously anterior chamber angle could be imaged only with slit-lamp based gonio-photography, however recently smartphone based anterior chamber angle imaging techniques have been described.5,6
These techniques utilize an adapter placed on a smartphone camera which is then used to image the anterior chamber angle via a goniolens devoid of a slit lamp. We have previously reported anterior segment imaging using an intraocular lens (IOL) attached to a smartphone camera called anterior segment photography with intraocular lens (ASPI)7 and in this report we extend as well as describe its use to photograph the anterior chamber angle aided with a goniolens which can be used as a cost effective screening tool.
Methods
This study was conducted in a secondary eye care centre located in an underserved area of South India. The study was conducted according to the tenets of declaration of Helsinki. An ethics committee approval was 66 obtained for this retrospective review. An informed consent was taken from all patients.Patients presenting for a routine ocular exam as well as those suffering from glaucoma were included in the study. A routine ocular examination was performed using a slit lamp. Following anterior segment examination, with the patient in a seated or supine position, topical anaesthetic eye drops (Proparacaine HCL, 0.5%, Aurolab, Madurai, India) are instilled in the patient’s eye and a Goldmann 4-mirror goniolens with flanges (Volk Optical Inc., Ohio) is placed over the cornea.
Utilizing the smartphone (IOS operating agent- iPhone 5s; Apple, 73 Los Altos, CA) after attaching a 10D IOL over its camera with a micropore and switching on the in-built flash (ASPI) [Figure 1]7 . The image or video of the anterior chamber angle of all quadrants was focused by tapping on the smartphone screen. A highly magnified image was also obtained. Additionally slit images of the anterior chamber angle was also obtained where a second observer would hold the goniolens along with a direct ophthalmoscope (Heine, Optotechnik, Germany) which would provide a focused beam of light onto the superior gonio-mirror and the primary observer would advance the ASPI to capture the angle image. All images were graded from 1 to 5 according to Noise, Sharpness, Contrast, Diagnostic confidence, Artifacts, Blotchy appearance by 3 individua medical officers with at least 3 years of experience as a consultant.
Results
Clear and magnified images utilizing our ASPI gonio-imaging technique were obtained from 120 patients. This technique was also found to be replicable by different observers. Mean score and SD of each image with ASPI gonio was 10.25, 1.08 and for SLIT lamp it was 9.5 and 1.11 . There was no statistical difference between image qualities of ASPI Gonio and slitlamp photography. (p Value-3.53).
Discussion
The use of mobile ophthalmic imaging devices has been an asset in revolutionizing ophthalmic care with the incorporation of smartphones having taken a major leap over the last decade. In recent times, smartphones have aided as an adjunct to clinical examination and are often used for imaging the ocular anterior or posterior segment.8 There is an increased urge to develop compact health monitoring systems especially in small clinical setups or peripheral health centres.9 In non-ideal clinical setups, smartphones are often used to document external photographs of the eye especially in emergency rooms. It can be used in patients in supine position as opposed to slit-lamps which are static and require the patient to sit in front of the examiner
They also provide a convenient way of delivering information regarding ophthalmic conditions and treatment options to patients and their families.9Assessment of the anterior chamber angle and its imaging and documentation in glaucoma is of cardinal importance. The use of smartphone for imaging the anterior chamber angle has been described previously. Kumar et al described unaided smartphone based gonio-imaging where a 4-mirror goniolens was placed on the patient’s cornea and the angle was photographed with the patient being in supine position. They obtained clear images of all quadrants in 65% of patients, however the images were obtained using diffuse illumination, the study field was large with subtle findings being missed.5
Pujari et al in their report used the wide angle mode of a high resolution smartphone (iPhone 11 Pro Max) 6 clipped with a macro lens to obtain better quality magnified images and videos. They also performed corneal wedge examination and documentation using the slit beam of a slit lamp as well as that of a direct ophthalmoscope.6 Their technique however required the use of a relatively expensive smartphone. We have utilised an intraocular lens as a magnifying lens attached to a smartphone camera and obtained high resolution, clear and magnified images of the anterior chamber angle thereby expanding the use of ASPI for gonio-imaging.
Our technique of gonio-imaging using ASPI could be performed with the patient in supine as well as sitting position. Diffuse light of the smartphone could be used for imaging the angle as well as slit beam of light from a direct ophthalmoscope could be used for imaging the corneal wedge and hence grading of the angle could also be performed. The other advantages of utilizing ASPI include employing any smartphone, using expired, unsterile IOLs including those with broken haptics. Our technique of imaging is quick, inexpensive and can be readily carried out in peripheral eye care centres or in camps as a screening tool as well as to assess the anterior chamber angle before dilatation.
It is of a huge advantage in primary or secondary eye care centres where expensive slit-lamp based photography is unavailable and is also of valuable use in resident training and education as well as for obtaining a specialist opinion. To conclude, we broaden the use of ASPI as a cost effective tool for screening, imaging, documentation as well as grading of the anterior chamber angle and thereby adding it in the armamentarium of smartphone gonio-imaging techniques. 7
References
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3. Zhang N, Wang J, Chen B, Li Y, Jiang B. Prevalence of Primary Angle Closure Glaucoma in the Last 20 Years: A Meta-Analysis and Systematic Review. Front Med. 2021 Jan 18;7:624179.
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9. Pujari A, Saluja G, Agarwal D, et al. Clinically useful smartphone ophthalmic imaging techniques. Graefes Arch Clin Exp Ophthalmol 2021;259:279–287.
Figure Legends
Figure 1: (A) A 20D IOL attached to the smartphone camera (ASPI) used for gonio-imaging (B, C) ASPI assisted gonio-imaging using a 4 mirror goniolens with the patient’s chin resting on the slit lamp; (D, E) ASPI assisted gonio-imaging with the patient in supine and sitting position respectively thereby showing the ease of use by a single observer.
Figure 2: Gonio images obtained using ASPI showing (A) Superior wide open angle; (B) High magnification gonio-image of the enclosed area shown in the first figure revealing all the angle structures from bottom to top (arrows) CB – ciliary body band, TM – trabecular meshwork, SS – scleral spur; (C) internal ostium and surgical iridectomy in a post trabeculectomy eye; (D) High magnification of the enclosed area in the previous figure revealing all angle structures clearly along with internal ostium (IO) and surgical iridectomy (SI); (E) Accumulation of emulsified silicone oil seen in the superior angle; (F) Open angle visualised using the thin slit light source of a direct ophthalmoscope.
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Fig.2
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