“A small hole not mended in time will become a big hole much difficult to mend.”
-Someone very wise
The eye is the organ of the body that receives a light stimulus, converts the light signals into electrical signals in the retina which is then transmitted to the brain via the Optic Nerve. The retina is the innermost part of the posterior segment of the eye is the retina, which consists of 10 layers. The central part of the retina, with a diameter of about 5.5mm, which is responsible for the central vision, is called the macula. The central part of the macula is called the fovea, where the retina is thinnest with just 6 layers. This region is primarily responsible for the central 5° of vision, contrast sensitivity, and vision in dim light.
Macular hole refers to dehiscence or defect in the centre of the retina (fovea). A lamellar hole is a condition where some layers are intact while a full thickness hole is pathology where in there is a total defect.
FACTORS CAUSING MACULAR HOLE
The most common type of macular hole is idiopathic, that is, it does not have a definitive cause. Macular holes have been noticed in patients after a blunt trauma to the eye.Other common causes of macular holes are chronic cystoid macular edema(CME) in long term diabetic patients as well as other chronic inflammatory conditions of eye. Some macular holes have been associated with Rhegmatogenous retinal detachment of the eye. Patients having anatomically large eyes (e.g. Myopia, posterior staphyloma etc.) have a slightly higher risk of macular hole. Sometimes, macular holes can be found in eyes after undergoing laser procedures in eye like Nd:YAG laser capsulotomy.
The posterior cavity is filled by gel like substance called vitreous, which overlies the retina. The vitreous is strongly attached to the retina at the macula.The vertical traction on the macula by the shrinkageof the vitreous, along with horizontal traction from the internal limiting membrane (ILM)is a known causation of macular hole formation.
CLINICAL EVOLUTION OF AMACULAR HOLE
The formation of macular hole has been described in four stages.
Stage 1indicates an impending hole.
1ais foveolar detachment indicated by a yellow spot, while
1b is seen as a small yellow ring.
Stage 2 is the formation of a small(<250µm) and medium macular hole (>250µm to ≤400µm).
Stage 3shows a progressive increase in size of macular hole into a large macular hole (>400µm).
Stage 4is indicated by a macular hole with posterior vitreous detachment.
Patients with macular holes generally suffer from a decrease in vision depending on the stage of hole. The most common complaint of a patient with macular hole is central scotoma that is a black spot in front of the eye and metamorphopsia that is appearance of wavy and disfigured objects. The additional symptoms observed in patients are decreased contrast sensitivity, darkness in central vision and an altered colour vision.
On examination of retina, presence of ahole can be seen clinically on 90/78 D slit lamp bio microscopy. The appearance of MH varies from a yellowish spot to a holein the centre of macula.
Amsler grid chart- It is used to check macular function. Normally, these lines appear as horizontal and vertical lines to a normal eye. In patients with macular hole, these lines appear wavy or distorted or broken. It is useful for detection of metamorphosiaand also for self-assessment of patients regarding progression or regression of disease.
Watzke-Allen Sign- The test is conducted by projecting a thin slit lamp beam on the macular hole and asking the patients to tell what they appreciate. Typically they see a break in the continuity of thebeam in large full thickness holes.
Optical coherence tomography- mainstay in the precise diagnosis and treatment of macular holes. Various indices like Hole Forming Factor (HFF) and Macular Hole Index (MHI)are ratios calculated based on the parameters of the hole. Higher HFF and MHI values are associated with better visual results.
Management of macular holes depends on the stage and coexisting factors that affect the improvement of vision. The mainstay of treatment is surgery, which gives satisfactory results if done at the right time. In general, macular holes eyes in stage 3 and 4 with decreasingvisual acuity are ideal candidates for macular holesurgery. Coexisting conditions like long duration of macular hole, choroidal rupture, RPE damage in macular area, chronic CME, optic nerve disorders etc. will obviously give a poor result from the surgery.
Surgical principle aims at removal of factors influencing the hole formation which would lead to closure of the hole. Thus surgery comprises of vitrectomy with ILM peeling after which a gas tamponade is provided. The patients are encouraged to lie prone for initial few days after surgery. Newer modalities of the treatment involves filling of hole with TGF beta, autologous serum, autologous platelet concentrate (APC) and thrombin and fibrin mixtures as well as inversion of ILM flap over the hole.
In patients presenting with a cataract, a combined phacoemulsification with Intraocular lens implantation withvitreoretinal surgery for macular hole is performed.Early presentation and intervention is the cornerstone of a better prognosis in patients with macular holes.
A 70-year-old elderly female came to our institution with complaints of wavy distortion in her right eye vision. A thorough examination revealed that she had macular hole stage 3. We explained the diagnosis and surgery required to treat the disease. She was reluctant to get operated as she couldn’t digest the fact that surgery of such high intensity is necessary to rectify such a small symptom. She later reviewed with us after 6 months, by the time which her symptoms had progressed and she had also started experiencing a central black spot in her vision. The macular hole had progressed to stage 4. She finally agreed and underwent the surgery. She is on regular follow-up and is now extremely happy to regain a quality vision. But as a doctor, I always felt I could have given her a better vision had I operated on the condition early. To each his own though!