Vitreoretinal Surgery

Retinal detachments generally develop from a retinal tear or hole. If a full-thickness retinal tear forms and isn’t treated, fluid in the vitreous can migrate through the defect and accumulate under the retina. This causes the retina to progressively lift away, or detach, from its normal position. A retinal detachment is a serious ocular emergency which requires urgent treatment to prevent vision loss or blindness. (see also Retinal tears and retinal detachment).

Surgery is the only treatment for retinal detachment. Retinal detachments can be successfully repaired in 98% of cases, although in 15% of cases a second surgery is required. The two goals of surgery are to reattach the retina, and to reverse or prevent further vision loss. The prognosis for vision following surgery depends on whether the central vision has been affected by the retinal detachment. If the macula has already detached (macula-off retinal detachment), the ability to read and see fine detail will already be significantly affected and may not recover fully even following successful reattachment of the retina. Only 60 to 70% of patients restore good central vision in these cases, as compared to 90 to 95% of patients with macula-on retinal detachments.

The status of the macula in a retinal detachment will also determine how urgently surgery is required. If the macula is still attached, surgery will be performed on a semi-urgernt basis to protect the central vision. If the macula has detached, surgery may be performed within 10 days of the loss of central vision without having a significant effect on the final outcome.

The two most common methods of repairing a retinal detachment are vitrectomy surgery and scleral buckling. Both of these are day surgery procedures. The cause, location and type of detachment will usually determine which surgical procedure will work best. Co-existing eye conditions may also influence the type of surgery chosen. The success of each procedure in each reattaching the retina and restoring good vision will vary from case to case.

Vitrectomy surgery is performed under local anaesthesia and ample sedation. Three small incisions are made around the front of the eye, each approximately half a millimetre wide. Very fine surgical instruments are inserted via these incisions and the vitreous is removed under microscopic guidance.

The fluid under the retina (subretinal fluid) is also drained, and the retinal tear(s) are sealed with either laser (endolaser) or freezing (cryotherapy). The retina is always 100% attached at the conclusion of vitrectomy surgery. Finally the eyeball cavity is filled with a gas bubble which will press down on the tear(s) and support the retina as it heals (laser takes a few weeks to become fully effective). Depending on the location of the tear you may need to position your head for a few days after surgery to maximise the effect of the gas. The gas bubble can last anywhere from 1-8weeks, depending on the type of gas used and its concentration, and you cannot fly during this time. Vision through a gas bubble is very poor but it will gradually improve as the gas is reabsorbed by the eye. In some cases, silicon oil is used instead of a gas bubble. Silicon oil is much denser than gaze and will stabilise the retina for a longer period of time. Silicon oil is not reabsorbed by the body and a second will be required at some point to remove the oil. Although there is some vision through silicon oil, it will be blurry, and most patients become long-sighted while oil is in the eye.

There is typically no pain following vitrectomy surgery, although you may experience temporary mild-to-moderate redness and grittiness, and swelling and drooping of the eyelid.

Vitrectomy surgery is highly successful, with an 85-95% single surgery reattachment rate. Approximately 5-15% of patients will develop a recurrent retinal detachment after surgery. The most common reason for this is growth of scar tissue across the surface of the retina (proliferative vitreoretinopathy) which causes new retinal tears to form. Recurrent detachments will require further surgery. It is not possible to prevent this scar tissue from growing.

Vision recovery occurs very slowly. If the macula was attached at presentation, good vision will usually return in 4-6 weeks, after the gas has fully reabsorbed. However if the central vision was affected at the time of detachment then it can take anywhere from 3 to 12 months for full vision recovery, and the final vision may still not be as clear as it was prior to the retinal detachment.

In patients who have not had cataract surgery, cataract progression is more rapid following vitrectomy surgery and cataract surgery is usually required within 6 to 12 months. The retinal detachment itself can also predispose certain people to the formation of an epiretinal membrane across the surface of the macula. If the membrane becomes visually significant, it may need to be surgically removed.

In some cases, vitrectomy surgery is combined with scleral buckling to improve success rates in certain types of retinal detachment. Scleral buckling surgery is performed under general anaesthesia either in isolation or in combination with a vitrectomy. The retinal tears are usually treated with laser or cryotherapy and the subretinal fluid is drained. A thin band of plastic (the scleral buckle) is then sewn to the external wall or the eye (sclera) and wrapped around the eyeball like a belt. The buckle will ‘push in’ the eye at the site of the tears, and support the retina for 360 degrees.

In order to place the scleral buckle, significant manipulation of the eye’s external tissues and muscles must be performed. Therefore the eye is often red and swollen following surgery and it can take up to six weeks for the eye to fully recover. The eyeball will look completely normal once it has healed – the scleral buckle is hidden under the outer lining of the eye (conjunctiva) and is almost never visible afterwards. The scleral buckle is generally left in the eye permanently. In rare cases, the buckle must be removed if there is associated infection or if it works its way through the surface tissues (a process known as extrusion).

Most patients who undergo scleral buckling also experience increased short-sightedness, and there may be a discrepancy in the size of objects between the eyes. This is correctable to some extent with spectacles or contact lenses. In some cases, the buckle may cause a droop in the eyelid or limit full movement of the eyeball, causing double vision.

Vision recovery after scleral buckling occurs slowly. The vision in the eye is generally poor until an optometrist updates spectacles to the required prescription. This will usually be a minimum of 6-8 weeks after surgery, once the eye is fully healed. Additionally if the central vision was affected at the time of detachment, it can take anywhere from 3 to 12 months for full vision recovery, and the final vision may still not be as clear as it was prior to the retinal detachment.

(See also Flashes and floaters, Retinal tears and detachment, Cataract surgery)

There are currently no medications, eyedrops or laser treatments that can prevent an epiretinal membrane from growing. An epiretinal membrane is a thin layer of scar tissue that grows on the surface of the macula after a posterior vitreous detachment.

A mild epiretinal membrane causes mild blurriness and distortion, and does not usually require treatment. Your Doctor will recommend regular reviews to monitor the membrane. You may also be given an Amsler grid for self-monitoring purposes. This grid is highly sensitive to central distortion.

If an epiretinal membrane progresses to cause significant vision loss, your Doctor may recommend vitrectomy surgery and epiretinal membrane peeling. Vitrectomy surgery is performed under local anaesthesia and copious sedation. Three small incisions are made around the front of the eye, each approximately half a millimetre wide. Very fine surgical instruments are inserted via these incisions and the vitreous is removed under microscopic guidance. Following this, the epiretinal membrane is delicately separated from the underlying macula. At the completion of the surgery, the wounds self-seal and sutures are not usually required.

Vitrectomy will significantly reduce or eliminate visual distortion and prevent further vision lost. In 80% of cases, it can even restore part of the vision that has been lost. Approximately 20% of patients have no improvement in vision following vitrectomy but the surgery will have prevented further vision loss. In a small number of patients (2%), the vision may be mildly worse following surgery.

After epiretinal membrane surgery
There is typically no pain following vitrectomy surgery, although you may experience temporary mild-to-moderate redness and grittiness, and swelling and drooping of the eyelid. Vision is generally limited in the first week or so. Most patients return to their pre-operative level of vision one month after surgery. Complete vision improvement usually takes 6 to 12 months, and approximately half of the vision lost is regained. Some mild central distortion may persist. If you have not yet had cataract surgery, a vitrectomy will accelerate the growth of cataract and the cataract will require earlier surgical removal.

If an air bubble is inserted into the eye by your surgeon at the end of the vitrectomy, you will not be able to fly for at least a week. It is safe to return to light physical activity 24 hours after surgery, and moderate activity by 2 weeks. Heavy physical exercise should be delayed for at least 6-8 weeks. You may shower and bathe normally following surgery but take care to avoid getting water into the eyes during the initial two weeks after surgery.

Some very small partially developed macular holes may resolve without treatment and may just be monitored closely, but most should be treated to prevent permanent vision loss. If a hole is not treated it will almost always enlarge over time causing further deterioration in vision leaving a larger sized black spot in the central vision. For best results surgery should be performed within 6 to 12 months of the macular hole developing. In these cases, 90-95% of macular holes are successfully closed and 85-90% of people will gain a significant improvement in vision. Surgery on long-standing macular holes generally has a lower rate of successful closure and vision recovery.

Vitrectomy surgery is performed under local anaesthesia with moderate sedation. Three small incisions are made around the front of the eye, each approximately half a millimetre wide. Very fine surgical instruments are inserted via these incisions and the vitreous is removed under microscopic guidance. Following this, a gas bubble is inserted which will push on and help close the macular hole during the first few days after surgery. At the completion of the surgery the wounds self-seal and sutures are not usually required. To facilitate correct placement of the gas bubble, you will be required to position facedown for 50 minutes of each waking hour for 3-5 days following surgery. Positioning while asleep is not required and should be avoided.

After macular hole surgery
There is typically no pain following vitrectomy surgery, although you may experience temporary mild-moderate redness and grittiness, and swelling and drooping of the eyelid.

Vision is generally limited in the first 2-6 weeks due to the gas bubble. As the bubble is slowly absorbed, your vision will gradually return to normal. You will have a black wobbly horizontal line in your vision due to the gas bubble, and this will get smaller and smaller as the gas bubble slowly disappears. The gas is replaced by aqueous fluid, the natural fluid made by the eye. Complete vision improvement usually takes 6 to 12 months. Vision will usually be significantly better after surgery but does not recover to being fully normal. In particular, mild distortion of the central vision may persist, although it is usually not noticeable when using both eyes. Additionally if you have not yet had cataract surgery, a vitrectomy will accelerate the growth of cataract and earlier surgical removal will be required.

Facedown positioning
You will be required to use face-down positioning for the first three days following surgery. This really means eye down positioning: The eye should be perpendicular to the ground for 50 minutes per hour so the gas bubble can push up on the macula itself. The other 10 minutes can be used for normal activities, meals and bathing. No positioning is required while sleeping. Face down positioning aids are not essential but may be helpful for those with neck or back problems. There are companies who hire out such equipment so please talk to our staff if you would like more information.

There are important warnings to note when an intraocular gas bubble is present. You must NOT fly as the gas bubble expands with altitude, and could cause severe, painful and vision threatening pressure increase. Even driving at altitude can be problematic (eg travelling over the range to Toowoomba). Please discuss any travel plans with your doctor. In addition, if you require surgery of any kind over the following two months (or while the gas bubble is present) you must tell the anaesthetist about the gas bubble, as nitrous oxide (laughing gas) will cause the bubble to expand and cause severe pressure increase. It is important that your Doctor confirms that the gas has fully dissipated. You will be given a wristband to wear after surgery to inform all medical practitioners that you have gas in your eye.

It is safe to return to light physical activity after you have completed the required period of positioning. You can take up moderate physical activity after 2 weeks. Heavy physical exertion should be delayed for at least 6-8 weeks. You may shower and bathe normally following surgery but take care to avoid getting water into the eye during the initial two week after surgery. There is approximately a 10% risk of the other eye developing the same problem.

(See Macular Hole)