Macular hole

MACULAR

HOLE

Anatomy of Macula

MACULA : Round yellow area at posterior pole 5.5 mm size – 3 mm temporal 1 mm inferior to

disc

Fovea - 1.5 mm wide , thin bottom- 22” clivity thick basement margin - prone for macular

holes -Henle’s layer-oblique

cones

Foveola - 0.35 mm wide , thin pit , Densely cones

Bowing vitreally- fovea externa

Umbo - Tiny depression - Foveal light reflex 0.15 mm - bouquet of cones -

narrowed gateau nucleaire

A dehiscence in the Retina at the location of Fovea.

In Lamellar hole - some layer are intact Full thickness hole - RPE exposed

Older female patientsYounger Myopic patientsPost Traumatic Chronic cystoid macular edemaAssociated with Retinal detachmentInadvertent exposure to laser therapy

RISK FACTORS

Loss of Central Vision Central ScotomaMetamorphospia

Clinical Presentation

Oblique/anteroposterior traction via a persistent vitreofoveolar attachment following perifoveal vitreous separation.

Tangential vitreoretinal traction.

Pathogenesis

Stage O – Premacular hole

- Perifoveal vitreous detachment - Loss of foveal depression - Subtle macular topograph changes - Normal visual acuity

Stages

Stage 1a: ‘Impending’ macular hole   - flattening of the foveal depression with an

underlying yellow spot. - Pseudocyst – a perifoveal vitreoretinal

detachment

   Pathology: inner retinal layers detach from the underlying photoreceptor layer, with the formation of a schisis cavity.

Stage 1b: Occult macular hole      Signs: a yellow ring with metamorphopsia

or a mild decrease in visual acuity. - Progression of pseudocyst to outer foveal

layer separation

  Pathology: loss of structural support with centrifugal displacement of photoreceptors.

Stage 2: Small /Early full-thickness hole    Signs: full-thickness hole < 400 µm in

diameter The defect may be central, eccentric or

crescent-shaped. Pseudo operculum – prefoveal cortical

vitreous contraction

Pathology: a dehiscence develops in the roof [inner layer]of the schitic cavity, often with persistent vitreofoveolar adhesion.

Stage 3: Full-size /Established macular hole   

   Signs: full-thickness hole > 400 µm in diameter red base with yellow-white dots seen. Surrounding grey cuff of subretinal fluid

Pathology: Avulsion of the roof of the cyst with an operculum and persistent parafoveal and optic disc attachment of the vitreous cortex.

Stage 4: Full-size macular hole with complete PVD

      Pathology: the posterior vitreous is completely detached, often suggested by the presence of a Weiss ring.

Fluorescein Angiography Hyperfluorescence -transmission defect

(RPE atrophy)

OCT Evaluation of retinal thickness and staging of

macular hole.

Diagnostic Procedures

Watzke Allen test On projecting a thin slit beam of light on to

the macula ,a broken or thinned out appearance is poistive.

Laser aiming beam test A spot of laser beam of 50 microns when

projected on macula has disappeared.

Surgery not recommended in stage 1 50 % chance of spontaneous resolution .

Stage 3 and 4 with visual acuity < 6/18 require surgery

Contraindications for surgery - Coexisting choroidal rupture - Traumatic RPE rupture - Chronic Cystoid macular edema - Optic nerve disorders

Management

Pars Plana Vitrectomy

Anaesthesia is local or general .

Conjunctival peritomy is done.

Three sclerotomies in superotemporal ,superonasal and inferotemporal at 3.5 mm from limbus .

Induction of Posterior vitreous detachment by suction of cutter , suction cannula or forceps close to disc.

Use of intravitreal triamcinolone acetonide for improving visualization.

Surgical procedure

Internal gas tamponade : A non expansile mixture of C3F8 and air is used and

patient lie down in prone for 14 hours for first 10 days .

Internal Limiting Membrane (ILM) Peeling :

Stains like trypan blue , Brilliant blue , ICG , Triamcinolone acetonide to improve visualization of ILM.

Special forceps to grasp ILM membrane in a circular fashion around macular hole for 2 disc diameters.

Cataract formation Iatrogenic retinal breaksRhegmatogenous retinal detachmentTransient rise in Intraocular pressure.

COMPLICATIONS

Following a macular pucker , there is a centripetal pull of the inner sides of epiretinal membrane – resembles Macular hole.

Macular Pseudo hole

Partial thickness macular hole where the inner layers of fovea are involved with traction and detached from underlying cellular layers.

Lamellar macular hole

Gass Atlas of Macular diseases by Anita Agarwal

American Academy of Ophthalmology , Vol 12 ,

Retina and Vitreous Kanski ,Clinical Ophthalmology , a Systemic

Approach 7 th edition

References