**3. Results**

In total, 21 eyes from 15 patients were enrolled in the study (Table 1). Most of these patients (9/15) had degenerative spinal disorders.

**Table 1.** Clinical characteristics and outcomes of patients who underwent cataract surgery in inclined positions.



**Table 1.** *Cont.*

BCVA: Snellen best corrected visual acuity. \* Surgeon comfort was assessed with a questionnaire (scale: 1–3; 1: comfortable, 2: mild discomfort, 3: uncomfortable).

Patients were inclined at angles of 20◦ to 80◦, with a mean angle of 47.62◦. The surgeon considered red reflex perception and the impression of depth to be good and stable in all cases, as in surgeries performed with patients lying flat. No ocular complications occurred in any of the interventions. None of the patients required corneal suture. Operating time was slightly longer for the patients inclined at angles of more than 50◦ (*p* < 0.01).

Surgeon comfort was rated "1" (comfortable) in all cases in which the patient was inclined at less than 60◦ and "2" (mild discomfort) for patients inclined at angles exceeding 60◦. Onthefirstdayaftersurgery,BSCVAwas20/25orbetterinallcases.

## **4. Discussion**

In this series, we evaluated the facilitating role of the ocular-free design of the 3D visualization system to the performance of surgeries in unusual challenging positions using the microscope rotation, in cataract surgery on patients unable to remain supine.

Microscope tilting is used in other indications in patients undergoing operations in a supine position. Indeed, by displacing the angle of view, this technique allows the visualization of the trabecular meshwork in stent implantation or the extension of the peripheral retinal view in retinal surgery [9,10].

At high angles of standard microscope rotation, the surgeon becomes very uncomfortable and must change his posture and modify the surgical approach, sometimes even modifying the location of the incision, which may increase the risk of operative complications. In a series of 32 eyes, Richard et al. reported the results for a face-to-face upright seated position for cataract surgery in patients who cannot lie supine, with the surgeon either seated or standing, and facing the patient [2]. Inferior, temporal or inferotemporal corneal incisions were made. Capsular rupture occurred in two cases, with nucleus drop. The authors considered this surgical positioning technically challenging and recommended its use only by experienced surgeons. Muraine et al. recently reported a series of four eyes in which face-to-face phacoemulsification was performed, with a slit lamp and the surgeon sitting facing the patient and performing a temporal incision [11].

In our series of 21 eyes, due to the ocular-free design of the 3D system, the surgical procedure and the positioning of the surgeon for patients undergoing cataract surgery in an inclined position remained almost identical to that for patients undergoing surgery in a supine position. The safety of the standard surgical approach was, therefore, maintained.

Within the eye, the quality of visualization, the impression of depth and red reflex perception were considered to be very good and similar to those in standard operating conditions.

A fast and good visual recovery was recorded in all cases on the first day after surgery. The good visualization conditions and the perceived depth of field may have ensured the safety of intraocular maneuvers, accounting for this result.

In conclusion, we reported here the facilitating role of the ocular-free design of the 3D system for the performance of ocular surgery in unusual challenging positions in patients who are unable to lie flat. This system makes it possible to maintain the usual position and the safety of the standard surgical approach in such challenging conditions.

**Supplementary Materials:** The following supporting information can be downloaded at: https://www. mdpi.com/article/10.3390/jcm11071865/s1, Video S1: Video highlighting the surgeon's installation and the surgical procedure in a patient who underwent cataract surgery in an inclined position.

**Author Contributions:** O.S.: conceptualization, methodology, validation, investigation, data curation, writing–original draft preparation. R.T.J.H.: conceptualization, methodology, validation. A.A.B.: data curation, validation. M.E.S.: formal analysis, data curation. V.B.: validation, original draft preparation. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** The data that support the findings of this study are available from the corresponding author, O.S., upon request.

**Conflicts of Interest:** The authors declare no conflict of interest.
