Posters

Comparative evaluation of functional ability of acquisition and operability of stereoscopic tele-ophthalmic drone slit lamp with a conventional slit lamp for imaging of anterior segment lesions

Poster Details

First Author: M.Taneja INDIA

Co Author(s):    A. Gonzalez   C. Rowaan   W. Lee   M. Aguilar   F. Cabot   J. Parel

Abstract Details

Purpose:

We designed this study to make a comparative evaluation of functional ability of acquisition and operability of Stereoscopic Tele-ophthalmic Drone Slit Lamp, developed at our center, with a conventional slit lamp for imaging of Anterior Segment Lesions by simulating anterior segment corneal lesions on model eyes.

Setting:

The latest precision computerized milling techniques were used to robotize an original Zeiss model 100 Slit-lamp to motorize all of the slit-lamp functions. Accurate stepper motors and servos have replaced the original Zeiss levers and knobs. The Slit-lamp was configured with two high resolution CCD cameras and computer controlled motorized magnification (5-30x), X-Y-Z movement, slit angle, width, height, and intensity controls making it operational by any computing device from any remote location having an internet connection. Real-time, 3-D stereoscopic viewing on any remote monitor is achieved with simple prismatic spectacles. Two custom designed model eyes were prepared by using the acrylates material using a 3-D printing technology with Solidworks designing software to simulate anterior segment corneal lesions which were then hand painted. The first one simulated penetrating keratoplasty with asymmetric suturing using 9-0 black coloured nylon and 10-0 blue coloured prolene sutures with few sutures deliberately broken. The second model eye simulated a corneal ulcer (2.7mm x 1.9mm, with an excavated base and irregular margins) and an elevated phlyctenular limbal nodule (4.2mm x 2.7mm) with surrounding vascularization. The lesions with excavation and elevation were specifically chosen so as to assess the 3-D stereoscopic differentiation between the two.

Methods:

Three well experienced and masked ophthalmologists were then asked to count the total number of intact and broken sutures on the first model eye, blue and black separately. Three sutures (one black and two blue) were deliberately broken to add to the complexity of the task as the ophthalmologists tried to localize the black and blue broken sutures using tele-ophthalmic controls on a desktop located in a distant and far off building and then on a conventional slit-lamp (Haag Streit Model BQ 900). In addition, the ophthalmologists were also asked to identify, localize and measure the two lesions in the second model eye on the robotized slit-lamp from a remote location and then on a conventional slit-lamp. A virtual caliper incorporated into the software was used to measure the dimensions of these lesions with the remote slit-lamp while the inbuilt calibrated slit scale with slit length controller was used to measure the lesions in the conventional slit-lamp. These were then compared with the actual parameters and between the two groups and the results were then analyzed.

Results:

The first model eye had ten black and five blue sutures. At the end of assessment all the three ophthalmologists were able to correctly localize and identify the number of different colored intact and broken sutures with 100% accuracy however the task took relatively more time with the tele-ophthalmic slit-lamp (191 seconds) compared to the conventional slit-lamp. (61 seconds) The measurements for the corneal ulcer lesion in the second model were recorded as 2.7x2.0 mm, 1.8x1.4 mm and 2.6x1.8 mm for observer 1, 2 and 3 respectively on conventional slit lamp, whereas the same lesion was measured as 2.9x1.8 mm, 3.3x2.6 mm and 4.4x3.0 mm respectively on tele-ophthalmic slit-lamp. The measurements for the limbal nodule were 4.1x2.9 mm, 3.3x2.6 mm and 4.4x3.0 mm for conventional slit-lamp vs 4.3x2.5 mm, 4.5x1.93 mm and 4.1x2.8 mm for the tele-ophthalmic slit-lamp. The accuracy of measurement of lesions was 97.48%, 67.02% and 87.41% for observer 1, 2 and 3 respectively on Conventional slit-lamp compared to 97.2%, 84.28% and 96.17% for observer 1, 2 and 3 respectively on tele-ophthalmic slit-lamp.

Conclusions:

The results showed that the tele-ophthalmic slit lamp developed at our center provides very good stereoscopic capability for examinations of anterior segment corneal lesions which compares favorably with the conventional slit lamp in acquisition and operability. All the three observers were comfortably able to operate the tele-ophthlamic slit lamp from a remote distant location. Real-time, 3-D stereoscopic view was easily acquired on a remote monitor by using simple prismatic spectacles. This in fact is the first tele-ophthalmic slit lamp that can provide three dimensional images on any interface namely desktop computer, tablet or even smart phones, even when the observer is at a remote location simply connected with internet to the tele-ophthalmic slit-lamp. In fact because of the more objective and digital nature of the virtual calipers in the remote slit lamp, the measurements of the lesions were actually more accurate compared to those taken manually over the conventional slit lamp. However the time taken for assessment was more for the remotely controlled slit lamp compared to the conventional slit lamp as there is a bit of learning curve in getting used to the slit lamp controls present on a computer keyboard or a touchscreen monitor. We believe that with further development, this technology can become immensely useful in providing eye care in remote rural areas. It can also be used as a screening tool as well as for follow up of patients who cannot travel long distances both in rural and urban areas. And this can also be easily used as an educational tool for teaching purpose as well as for cross consultations for complicated cases. FINANCIAL INTEREST: NONE