Naevi Characterization Using Hyperspectral Imaging: A Pilot Study.

PURPOSE: The prevalence of choroidal naevi is common and has been found to be up to 10%. Little is known regarding the optical properties of choroidal naevi. A novel hyperspectral eye fundus camera was used to investigate choroidal naevi's optical density spectra in the retina. METHODS: In an ophthalmology clinic setting, patients with choroidal naevi were included in the study. Visual acuity and pressure were tested. Following mydriatics, optical coherence tomography and fundus photography were taken as a reference, after which a hyperspectral image with 12 nm spectral resolution at 450-700 nm was taken. The optical density spectra was measured across the area of the naevus. RESULTS: Nine patients with 11 naevi were examined. The visual acuity was not affected by any of the naevi. All the naevi were flat as measured either with the optical coherence tomography and/or on inspection, and only one naevi had a risk factor (orange pigmentation). The Wasserstein distance between the background and the naevi was higher at 695 nm compared to 555 nm (p = .002). The naevi could be grouped into three clusters based on the extracted optical density spectra. CONCLUSION: Choroidal naevi are better visible in longer wavelengths compared to shorter wavelengths. This finding can be used to contour and follow choroidal naevi. Choroidal naevi expose different optical density spectra that can be grouped into three different clusters. One of these clusters has an optical density spectra resembling the absorption spectra of lipofuscin, which may indicate the content of this pigment.

Ready for OR or not? Human reader supplements Eyesi scoring in cataract surgical skills assessment.

PURPOSE: To compare the internal computer-based scoring with human-based video scoring of cataract modules in the Eyesi virtual reality intraocular surgical simulator, a comparative case series was conducted at the Department of Clinical Sciences - Ophthalmology, Lund University, Skåne University Hospital, Malmö, Sweden. METHODS: Seven cataract surgeons and 17 medical students performed one video-recorded trial with each of the capsulorhexis, hydromaneuvers, and phacoemulsification divide-and-conquer modules. For each module, the simulator calculated an overall score for the performance ranging from 0 to 100. Two experienced masked cataract surgeons analyzed each video using the Objective Structured Assessment of Cataract Surgical Skill (OSACSS) for individual models and modified Objective Structured Assessment of Surgical Skills (OSATS) for all three modules together. The average of the two assessors' scores for each tool was used as the video-based performance score. The ability to discriminate surgeons from naïve individuals using the simulator score and the video score, respectively, was compared using receiver operating characteristic (ROC) curves. RESULTS: The ROC areas for simulator score did not differ from 0.5 (random) for hydromaneuvers and phacoemulsification modules, yielding unacceptably poor discrimination. OSACSS video scores all showed good ROC areas significantly different from 0.5. The OSACSS video score was also superior compared to the simulator score for the phacoemulsification procedure: ROC area 0.945 vs 0.664 for simulator score (P = 0.010). Corresponding values for capsulorhexis were 0.887 vs 0.761 (P = 0.056) and for hydromaneuvers 0.817 vs 0.571 (P = 0.052) for the video scores and simulator scores, respectively. The ROC area for the combined procedure was 0.938 for OSATS video score and 0.799 for simulator score (P=0.072). CONCLUSION: Video-based scoring of the phacoemulsification procedure was superior to the innate simulator scoring system in distinguishing cataract surgical skills. Simulator scoring rendered unacceptably poor discrimination for both the hydromaneuvers and the phacoemulsification divide-and-conquer module. Our results indicate a potential for improvement in Eyesi internal computer-based scoring.

Cataract surgeons outperform medical students in Eyesi virtual reality cataract surgery: evidence for construct validity.

PURPOSE: To investigate construct validity for modules hydromaneuvers and phaco on the Eyesi surgical simulator. METHODS: Seven cataract surgeons and 17 medical students performed capsulorhexis, hydromaneuvers, phaco, navigation, forceps, cracking and chopping modules in a standardized manner. Three trials were performed on each module (two on phaco) in the above order. Performance parameters as calculated by the simulator for each trial were saved. Video recordings of the second trial of the modules capsulorhexis, hydromaneuvers and phaco were evaluated with the modified Objective Structured Assessment of Surgical Skill (OSATS) and Objective Structured Assessment of Cataract Surgical Skill (OSACSS) tools. RESULTS: Cataract surgeons outperformed medical students with regard to overall score on capsulorhexis (p < 0.001, p = 0.035, p = 0.010 for the tree iterations, respectively), navigation (p = 0.024, p = 0.307, p = 0.007), forceps (p = 0.017, p = 0.03, p = 0.028). Less obvious differences in overall score were found for modules cracking and chopping (p = 0.266, p = 0.022, p = 0.324) and phaco (p = 0.011, p = 0.081 for the two iterations, respectively). No differences in overall score were found on hydromaneuvers (p = 0.588, p = 0.503, p = 0.773), but surgeons received better scores from the evaluations of the modified OSATS (p = 0.001) and OSACSS (capsulorhexis, p = 0.003; hydromaneuvers, p = 0.017; phaco, p = 0.001). CONCLUSIONS: Construct validity was found on several modules previously not investigated (phaco, hydromaneuvers, cracking and chopping, navigation), and our results confirm previously demonstrated construct validity for capsulorhexis and forceps modules. Interestingly, validation of the hydromaneuvers module required OSACSS video evaluation tool. A further development of the scoring system in the simulator for the hydromaneuvers module would be advantageous and make training and evaluation of progress more accessible and immediate.

Virtual reality cataract surgery training: learning curves and concurrent validity.

PURPOSE: To investigate initial learning curves on a virtual reality (VR) eye surgery simulator and whether achieved skills are transferable between tasks. METHODS: Thirty-five medical students were randomized to complete ten iterations on either the VR Caspulorhexis module (group A) or the Cataract navigation training module (group B) and then two iterations on the other module. Learning curves were compared between groups. The second Capsulorhexis video was saved and evaluated with the performance rating tool Objective Structured Assessment of Cataract Surgical Skill (OSACSS). The students' stereoacuity was examined. RESULTS: Both groups demonstrated significant improvements in performance over the 10 iterations: group A for all parameters analysed including score (p < 0.0001), time (p < 0.0001) and corneal damage (p = 0.0003), group B for time (p < 0.0001), corneal damage (p < 0.0001) but not for score (p = 0.752). Training on one module did not improve performance on the other. Capsulorhexis score correlated significantly with evaluation of the videos using the OSACSS performance rating tool. For stereoacuity < and ≥120 seconds of arc, sum of both modules' second iteration score was 73.5 and 41.0, respectively (p = 0.062). CONCLUSION: An initial rapid improvement in performance on a simulator with repeated practice was shown. For capsulorhexis, 10 iterations with only simulator feedback are not enough to reach a plateau for overall score. Skills transfer between modules was not found suggesting benefits from training on both modules. Stereoacuity may be of importance in the recruitment and training of new cataract surgeons. Additional studies are needed to investigate this further. Concurrent validity was found for Capsulorhexis module.

Stereoacuity and intraocular surgical skill: effect of stereoacuity level on virtual reality intraocular surgical performance.

PURPOSE: To evaluate the effect of stereoacuity on various intraocular surgical skills in inexperienced medical students using a virtual reality intraocular surgical simulator. SETTING: Department of Clinical Sciences, Malmö: Ophthalmology, Skåne University Hospital, Malmö, Sweden. DESIGN: Comparative case series. METHODS: Ninth-semester medical students performed 1 iteration on each of the following 3 cataract training modules: navigation, forceps, and capsulorhexis. Before the simulator training, the trainees received standardized instructions and were allowed to perform 1 training round on the cataract navigation training module. After completion of the training, the level of stereoacuity was measured using TNO charts. Surgical performance for each task was measured, and performance parameter scores were recorded. RESULTS: The study included 70 students. The simulator performance score correlated with the level of stereoacuity for the navigation training module (Spearman r = 0.377, P=.001) and forceps training module (Spearman r = 0.306, P=.01), showing a gradual increase in surgical performance with increasing stereoacuity. No such relationship was found for the capsulorhexis module (Spearman r = 0.18, P=.136). CONCLUSIONS: A gradual detrimental effect on initial intraocular surgical skill with decreasing stereoacuity was shown. This calls for studies of the impact of deficient stereopsis on long-term training effects.