Macular Hole

What is a macular hole?

 

 

Some patients develop a small hole in the very centre of the retina (photographic film at the back of the eye) called a macular hole. It causes an area of central blurring of vision and sometimes distortion of vision (straight lines becoming kinked or wavy). If left untreated you remain with a blurred patch in the centre of the vision but the peripheral (side) vision remains unaffected so there is still useful vision in the eye and it is rare that the other eye develops the condition as well (only in 10% to 20% of cases).

The eye is like a camera with the lenses at the front and the photographic film (retina) at the back and between the two in the “body” of the camera is a clear jelly called vitreous. In patients with macular hole this jelly pulls on the very centre of the retina and pulls the tissues apart to create a hole. The treatment for this condition is a surgical procedure called a phacovitrectomy and gas procedure.

 

What is the surgical treatment of macular hole?

 

 

A macula hole develops by the vitreous jelly within the main eye cavity pulling on the central part of the retina and pulling the retinal tissue apart to create a hole. Surgery involves removing this pulling force by removing the vitreous jelly and replacing it with a pushing force to push the tissue together and close the hole. This pushing force is produced by replacing the jelly with a large gas bubble inside the main eye cavity. It was initially thought that in order to “push hard” on the macular hole the patient had to posture “face down” for up to 2 weeks day and night to allow the gas bubble to float up to the back of the eye.

I performed some research in 2000 which was published in the British Journal of Ophthalmology to show that this posturing was not required in order to produce a good result in most patients and only needs to be performed in patients with large macular holes. Most patients with macular holes either need no “face down” posture or only limited posture in this position for the first 24 to 48 hours after surgery. The only restriction in positioning is that patients should avoid lying on their back for the first week following surgery as the gas bubble is least effective in closing the hole in this position.

The gas bubble lasts about 6 weeks and gradually gets absorbed back into the blood stream over this period. The eye is initially almost completely full of gas and the vision is very blurred immediately after surgery. As the gas bubble disappears the vision slowly returns. You first see something at the top of your field of vision and this slowly descends down and usually by about 2 to 3 weeks following surgery you become a “human spirit level” with a “blob” in your vision with the upper half of the vision seeing well and the lower half still being blurred (this corresponds to the remaining gas bubble floating at the top of the eye). The vision then continues to improve until usually the bubble breaks up into a few smaller bubbles (which you see at the bottom of your vision) before they disappear completely. It is advisable not to drive until the gas bubble has completely disappeared and you must certainly not fly. If you have a general anaesthetic for any other condition whilst there is still some gas in the eye then do please ensure that the anaesthetist knows about your gas bubble.

The vitrectomy operation alone will eventually result in the development of a cataract and the large gas bubble will usually cause the cataract to develop more rapidly. I have been very keen to perform what is called “combined surgery” for patients with macular holes for many years. This involves removing the lens of the eye at the time of the vitrectomy surgery and replacing it with a new plastic intraocular lens. This is identical to the cataract surgery which occurs when the lens is cloudy. The advantage of this “combined” approach is that it prevents you having to come back for further cataract surgery months or years after the vitrectomy operation.

The surgery can be under general or local anaesthetic as a day case procedure. It involves creating three very small incisions in the sclera (white of the eye) at the front of the eye and all instruments are inserted through these small incisions. When the combined operation occurs (cataract removal as well as vitrectomy) drops have to be placed onto the eye every 2 hours during the day for the first 2 days then 4 times a day for one month. An assessment by the optician occurs about 3 months following surgery.

Patients with macular hole complain of blurring and distortion of central vision. The operation has a 9 out of 10 chance of successfully closing the hole. The central retina (macula) is the most sophisticated piece of tissue in the body and it is not surprising that despite successful closure of the hole it is rare that the vision completely returns to normal. The aim of surgery is to improve rather than cure your symptoms and most patients notice an improvement in vision and a reduction in distortion but may be aware of a slight visual disturbance remaining. Most of the improvement in vision occurs within the first few months following surgery but sometimes things can continue to gradually improve many months after surgery.