In 1985, Miyake and Miyake1 devised a technique to prepare autopsy globes for posterior photography to study intraocular lenses. The technique made it possible to film the anterior and posterior segments of cadaver eyes simultaneously when performing phacoemulsification. In 1990, Apple et al.2 modified the technique of preparing the eyes and improved the technique for filming the procedure. We have modified the preparation of postmortem eyes to improve the quality of the eyes to be studied, decrease the learning curve for the preparation of Miyake–Apple style eyes, and reduce the margin of error for better quality surgery. Our modifications to the Miyake–Apple method simplify globe preparation.
The following materials are used in the Ophthalmic Pathology Laboratory at the John A. Moran Eye Center to prepare the globe: recently harvested cadaver eyes, Gillette Super Stainless Super Inoxydable razor blades, rubber gloves, a 2 inch × 2 inch glass slide, a Weck-Cel® spear (Medtronic Solan), 4 inch × 4 inch gauze pads, an ophthalmic viscosurgical device (OVD), a blue pencil or surgical marker, Super Glue, and a bowling pin and ball 16-cavity chocolate mold #819-R* (Sugarcraft; www.sugarcraft.com). Similar materials can be substituted as they are available.
Glass Slide and Mold Preparation
Before the procedure, the glass slides are cleaned with ethanol and 4 inch × 4 inch gauze pads to remove dirt or fingerprints. The bowling pin and ball chocolate mold is cut in half widthwise for easier maneuvering.
The eye is removed from the container and inspected for perforations, lacerations, or evidence of prior surgery that could decrease globe integrity. If there is evidence of surgery or violation to the globe, it should not be used. Preservative is wiped off with a paper towel, and the eye is dried. Excess extraocular tissue is removed (eg, conjunctiva, muscles, orbital fat) from the globe using a tissue forceps and corneal-scleral scissors.
The globe is placed in the bowling-ball portion of the mold with the cornea centered at the bottom of the mold; a mark is made around the eye with a colored pencil at the junction of the mold. Because of the depth of the mold, the mark on the globe is positioned between the limbus and the equator and runs parallel to both.
Bisection of the Globe
The eye is taken out of the mold and placed on its side with the cornea facing the bowling-ball portion of the mold. The razor blade is broken in half. The eye is held between the thumb and index finger, with the thumb placed on the cornea and the index finger on the optic nerve. With the blade in the dominant hand, a sawing motion is made to cut through the eye 2.0 to 3.0 mm posterior to the blue line. It is easier to start by grasping the blade at 1 end, and when it is approximately halfway through the eye, grasping the blade at the end (Figure 1). Once the razor blade is approximately two-thirds to three-fourths through the globe, the 2 sections have a tendency to fall apart. The blade should be pushed down into the eye as far as possible, creating a mark on the retina. This mark can later be followed with scissors to create a smoother corneal rim.
The cornea is placed face down in the bowling-ball part of the mold with the posterior segment still attached. The posterior portion of the globe is removed with a tissue forceps and scissors, cutting 1.0 to 2.0 mm above the line marked on the retina (Figure 2). After the posterior segment is removed from the eye, any large piece of vitreous that remains adherent to the anterior segment of the eye is cut. The posterior segment of the eye is discarded. With the line etched in the retina as a guide, the scleral rim is made level by using the tissue forceps in the nondominant hand to guide the eye toward the mouth of the scissors held in the dominant hand and trimming away excess sclera (the eye turns in the mold as it is pulled) (Figure 3). The scleral rim is inspected to see if it is level; the same method is used to trim high spots on the eye if it is not level. Ideally, 2.0 to 3.0 mm of sclera should remain above the top of the mold once cutting is complete.
Preparation of the Eye for Mounting
The anterior section of the globe is transferred to another bowling-ball section of the mold (it is easiest to put the globe closer to the cut edge of the mold), and extra fluid or tissue that remains on the mold is removed. To remove opacities in the media, Weck-Cel spears are carefully dabbed at the vitreous, taking care to not remove the remaining retina or dislodge the lens. The media is pulled up and cut away (Figure 4). Vitreous is removed until it is approximately 1.0 mm below the scleral rim. A Weck-Cel spear is used to dry the outer part of the eye around and on top of the scleral rim. This makes a tighter seal on the slide.
Mounting the Eye
Using Super Glue and the thin applicator tip, a thin bead is placed around the cut edge of the sclera (Figure 5). An OVD is used to fill the eye to a level slightly above the height of the Super Glue, making sure that no bubbles form in the media. Applying the OVD in a circular fashion around the inside of the globe works best. The glass slide is centered over the eye and carefully placed obliquely on the eye. Placing the slide proximal side down first and slowly putting it down distally works best to avoid bubble formation (Figure 6). The glue should set for 2 minutes before the eye is manipulated. After 2 minutes, the slide with the eye attached is gently rocked to free the eye from the mold. The sides of the slide are supported with the fingers of 1 hand, while the mold and eye are gently flipped over with the other hand (Figure 7). The mold is taken off the eye carefully, and the slide is set down.
The eye should be inspected for leaks, which are dabbed with a Weck-Cel spear (Figure 8). A medium bead of glue is applied around the eye at the junction between the sclera and the slide (Figure 9). The slide is allowed to dry for approximately 20 minutes. To prevent the eye from drying, a 1.5 cm × 1.5 cm square of 4 inch × 4 inch gauze is cut, saturated with saline, and placed on the cornea (Figures 10 and 11).
This method requires 10 to 20 minutes of preparation for each eye. The method described by Apple et al.2 is time consuming, difficult, and has a larger margin of error, risking a disruption in the eye's anatomy and introducing bubbles into the media. One of the most difficult parts of the procedure is turning the eye over between 2 glass slides because the media has a tendency to come out or bubbles can form.
The process we describe is an improvement over the previous one. It is less time consuming, easier, and reduces the margin of error for preparing a quality product. Those who prepare Miyake eyes usually have a limited amount of time to construct them because the eyes can dry out. If they are performing a study, a supply of eyes is needed on a timely basis. Additionally, the eyes should be free of debris and bubbles. Our method requires less time to master, resulting in a better quality product for novices. We think our technique reduces the margin of error in constructing Miyake–Apple style eyes.
1. Miyake K, Miyake C. Intraoperative posterior chambers lens haptic fixation in the human cadaver eye. Ophthalmic Surg 1985; 16:230-236
2. Apple DJ, Lim ES, Morgan RC, et al. Preparation and study of human eyes obtained postmortem with the Miyake posterior photographic technique. Ophthalmology 1990; 97:810-816