Endoscopy offers advantages to the ophthalmologist across a wide array of surgical conditions compared to using the operating microscope alone. The operating microscope image is derived from the outside of the eye and extends to the inside, whereas the endoscopic image is generated from inside the eye. In situations where anterior-segment conditions preclude a posterior view, such as a hazy cornea, disruption of the anterior chamber, opaque lens, miosis, and others, the endoscope provides a clear view of the posterior segment. In addition, even with an adequate operating microscope view, there are certain portions of the intraocular anatomy that are difficult or impossible to view conventionally, yet are easily imaged endoscopically. These regions include the posterior aspect of the iris, intraocular lens haptics, ciliary body, pars plana, and peripheral retina.

Because endoscopy enables the surgeon to view the ocular interior despite adverse conditions, novel treatments may be applied (for example, endoscopic cyclophotocoagulation). The following cases illustrate the essential role of endoscopy in some common situations.

CASE 1: AVERTING UNNECESSARY MAJOR SURGERY

A patient with previous cataract surgery fell out of bed, rupturing the globe and causing the lens implant to extrude. A retinal surgeon repaired the ruptured globe, including silicone oil injection. The injury rendered the patient’s cornea partially opaque. Despite the surgeon’s limited view through the microscope, the retina was thought to be attached. The patient was referred for further evaluation.

To see beyond the opaque cornea without endoscopy, one would need to remove the cornea, place a temporary keratoprosthesis, examine the retina and repair it if possible, and finally perform a corneal transplant. This invasive procedure would take several hours and require significant postoperative recovery for the patient.

Instead, a 23-gauge trocar provided access for the endoscope (Figure 1). At first glance, it appeared as if the patient’s retina was attached, but closer inspection revealed no posterior blood vessels. The retinal pigment epithelium was bare. Off to one side, a long, thin band of tissue extended from the posterior pole to the pars plana region. The structure was the retina, which, having been detached completely, was now twisted into a tube that was adherent to the eye wall (Figure 2).

Unfortunately, it is not possible to unfurl and repair a retina in this state. On the other hand, a procedure of only a few minutes was required to define the state of the retina. The patient did not have to endure an unnecessary hours-long corneal procedure to acquire the same information. She was discharged without a single stitch.

CASE 2: GETTING A COMPLETE VIEW OF SUBRETINAL MEMBRANES

A patient with a detached retina had a corneal transplant that was still healing, resulting in a microscope view that was too hazy to perform the retinal repair. Endoscopically, it was clear that extensive subretinal membranes were preventing reattachment. During the course of endoscopic vitrectomy, a small hole was fashioned in the retina overlying the membrane, followed by insertion of forceps through the hole, grasping the membranes, and extracting them from the subretinal space (Figures 3 and 4).

In such cases, the panoramic endoscope view permits visualization to a portion of the ocular interior that cannot be seen through the operating microscope, even with a clear cornea. Endoscopically, the pathology could be easily viewed, and during the course of its removal (Figure 5), the intraocular widefield image revealed the surrounding retina and its increased mobility after release of underlying traction. The retina was then flattened and the repair was successful.

CASE 3: KEEPING SURGERY MOVING WITH A CONSISTENTLY CLEAR VIEW

In this instance, a patient with a corneal transplant (Figure 6) and a detached retina underwent endoscopic vitrectomy and silicone oil injection to achieve reattachment. When injecting oil into an air-filled eye, the endoscope simplifies the assessment of when a complete fill has been attained (Figure 7). The surgeon can clearly observe the top of the oil meniscus as it approaches the posterior aspect of the lens.

In this case, some air bubbles were present in the anterior chamber, obscuring the microscope view. Without a clear view, it was impossible to know if the eye was properly filled. To restore visibility through the microscope, one would need to remove the air bubbles from the eye through a paracentesis at the edge of the corneal transplant. Silicone oil injection could then resume (Figure 8). Although this process isn’t usually problematic, it does require the surgeon to stop the silicone oil injection, perform another maneuver, and then resume the injection. On the other hand, under endoscopic guidance, the unwanted bubbles in the anterior chamber do not require attention and the oil fill may proceed uninterrupted.

USING THE ENDOSCOPE ALL THE TIME

Some ophthalmologists reserve the endoscope for “special cases.” However, it is the author’s opinion that it is important to use the endoscope on every case. Not only does it provide a panoramic view inside the eye and overcome any anterior-segment condition that obscures a posterior view, but also it facilitates more efficient surgery.

The advantages of holding a 23-gauge instrument in one hand that provides simultaneous widefield imaging, illumination, and photocoagulation compared to holding an instrument of the same size that only supplies illumination seem obvious. Perhaps more subtlely, continued use of the laser endoscope will build the skills needed for heads-up 2-dimensional image monitoring of intraocular maneuvers such as vitrectomy, membranectomy, air–fluid exchange, lensectony, photocoagulation, and others. Finally, the more often the OR staff uses the technology, the more skilled they will become, which only serves to improve the surgeon’s experience. RP