Congenital Glaucoma

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amtul sami    on Mar 13, 2013 Says :

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2 : GLAUCOMA It is defined as a symptom complex which is chronic progressive optic(ischemic) neuropathy characterized by -Raised IOP(which is modifiable risk factor) -Optic disc changes -Visual field changes
3 : CLASSIFICATION OF CONGENITAL AND DEVELOPMENTAL GLAUCOMAS Primary congenital glaucoma(without asso. anomalies) > True congenital glaucoma > Infantile congenital glaucoma > Juvenile glaucoma
4 : 2. Developmental glaucoma(with asso. anomalies) > Glaucoma asso. with iridocorneal dysgenesis > Glaucoma asso. aniridia > Glaucoma asso. with ectopia lentis syndromes > Glaucoma asso. with phakomatosis > Miscellaneous conditions
5 : Pathogenesis of congenital/developmental glaucoma Primary congenital glaucoma is due to failure or abnormal development of the trabecular meshwork . Maldevelopment of trabeculum including the iridotrabecular junction (trabeculodysgenesis) is responsible for impaired aqueous outflow resulting in raised IOP. Trabeculodysgenesis is characterized by absence of the angle recess with iris having a flat or concave direct insertion into the surface. The iris may not completely separate from the cornea that the angle remains closed by persistent embryonic tissue.
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7 : Pathogenesis of Glaucomatous Ocular Damage Main Theories are: 1 Mechanical changes due to the rise of intraocular pressure; and 2 Vascular perfusion of the optic nerve head 3 Defective autoregulation
8 : Above is shown a typical nerve appearance with damage from glaucoma.  Note that the center of the nerve has an excavated or "scooped out" appearance.
10 : CLINICAL FEATURES OF CONGENITAL GLAUCOMA Photophobia,blepharospasm,lacrimation & eye rubbing are often occur together. These are thought to be caused by irritation of corneal nerves, which occurs as a result of the elevated IOP. Photophobia is usually the initial sign, but is not enough by itself to arouse suspicion in most cases.
11 : 2. Corneal signs : Corneal signs include its oedema, enlargement and Descemet’s membrane. Corneal oedema – It is frequently the first sign which arouses suspicion Corneal enlargement- It occurs along with enlargement of globe-buphthalmos especially when the onset is before the age of 3yrs. Tears and break in Descement’s membrane(Haab’s straie)-These occur because Descement’s membrane is less elastic than the corneal stroma. Tears are usually peripheral and concentric with the limbus.
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13 : 3. Sclera becomes thin and appears blue due to underlying uveal tissue. 4. Anterior Chamber becomes deep. 5. Iris may show iridodonesis and atrophic patches in late stage 6. Lens becomes flat due to stretching of zonules and may even subluxate.
14 : 7. Optic disc may show variable cupping and atrophy especially after third year. 8. IOP is raised which is neither marked nor acute 9. Axial myopia may occur because of increase in axial length which may give rise to anisometropic ambylopia.
16 : CLINICAL FEATURES Symptoms - epiphora - photophobia - blepharospasm Examination - reduced visual acuity - buphthalmos - corneal diameter > 12 mm - corneal edema - Haab’s striae - elevated IOP - optic atrophy
17 : The same infant as the previous photo. Although the red reflex from the flash can be partially seen, a whitish haze covers the entire corneal surface. This infant presented with hazy bilateral corneal opacities on the initial newborn exam. The diagnosis of was relatively easy as there was a strong family historyof congenital glaucoma.
18 : Examination under General Anaesthesia IOP normal is 10-15 mm Hg under anaesthesia - anaesthetics and preoperative dehydration lowers IOP. Vernier callipers are used to measure the corneal diameter in infants. Gonioscopy anterior chamber deep with normal iris structure angle open with high and flat insertion of iris root with abnormal tissue giving shagreen, glistening appearance may also have absent angle recess, peripheral iris hypoplasia, tenting of peripheral iris pigment epithelium, thickened uveal trabecular meshwork.
19 : The left eye of this congenital glaucoma patient is noticeably larger than the right eye. The patient has buphthalmos of the left eye
20 : Examination under General Anaesthesia Optic nerve - normally pink with small cup - preferential neural loss of superior and inferior poles - cupping may be reversible if IOP lowered initially Axial length - enlarged but may reverse with reduced IOP
21 : DIFFERENTIAL DIAGNOSIS Nasolacrimal duct Obstruction X-linked congenital megalocornea without glaucoma Birth trauma
22 : DIFFERENTIAL DIAGNOSIS Corneal dystrophies and dysgenesis Inborn errors of metabolism Intrauterine inflammations (congenital syphilis and rubella) Optic nerve pit, coloboma, or physiologic cupping
23 : TREATMENT Medical Temporary measures to control IOP and to clear cloudy cornea prior to surgery Administer beta-adrenergic antagonists, CAI’s(carbonic anhydrase inhibitors). avoid alpha2-adrenergic agonists under 3 years occlude nasolacrimal drainage system for 2 minutes after administration.
24 : TREATMENT Surgical mainstay treatment goniotomy for clear corneas trabeculotomy ab externo for hazy corneas ,success rates similar trabeculectomy and shunt procedures only when goniotomy or trabeculotomy fails
25 : GONIOTOMY Involves making a horizontal incision at the midpoint of the superficial layers of the trabecular meshwork May need to be repeated Eventual success rate is about 85% Results are poor if the corneal diameter is 14mm or more because Schlemm’s canal obliterated.
26 : The goniotomy surgery involves entering the anterior chamber with a sharp goniotomy knife and making an opening incision through the abnormally developed trabecular meshwork to allow greater outflow of the aqueous fluid and thereby, lower the IOP . Often 120 degrees (out of 360 degrees total) of the trabecular meshwork can be treated with goniotomy in a single setting.
27 : Goniotomy. A fine surgical knife is used to open the drainage angle (trabecular meshwork) in order to lower the intraocular pressure.
28 : TRABECULOTOMY If corneal clouding prevents visualization of the angle or when repeated goniotomy has failed Partial thickness scleral flap is fashioned Schlemm canal is found and a trabeculotome is inserted into Schlemm canal and then rotated into the anterior chamber Technically highly demanding, requires previous experience, and good anatomical landmarks to achieve predictable results Schlemm canal may be difficult to canalize because of hypoplasia or angle anomaly
29 : Trabeculotomy surgery involves making an external incision and identifying the Schlemm’s canal from the outside, inserting a fine instrument into the Schlemm’s canal, and breaking through the trabecular meshwork to increase the aqueous outflow . Typically, 120-140 degrees of trabecular meshwork can be treated by trabeculotomy in a single surgery.
30 : If one surgical technique is unsuccessful in decreasing the IOP, the other technique can be utilized in a fresh area of the trabecular meshwork (the area not previously operated upon) to increase the success of the surgery. Even after initial control of the intraocular pressure is established with surgery, a periodic monitoring is necessary to ensure the IOP doesn’t increase again and the glaucoma go out of control.
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32 : Medications can be used as an adjunct therapy either before or after the surgical treatment. Medications may be utilized temporarily after the diagnosis until surgery can be performed. If the initial surgery fails to completely control the IOP, topical medications can be used to bring the glaucoma under control. The systemic side effects of topical medications are greater in infants than in adults because of the smaller body mass. Because of potential systemic side effects, the first line of medications that are commonly employed is the topical carbonic anhydrase inhibitors.
33 : After the CAI, the next choices are topical prostaglandin analogs or beta-blockers . The prostaglandin analogs (e g.latanoprast) appear to be safe in children; however, there are no long-term data on the safety of these medications in children. Topical beta-blockers(eg .timolol , carvedilol) should be used with caution in children because of the well-known systemic side effects. Finally, topical alpha-2 agonist (brimonidine) should be AVOIDED in infants because it’s been associated with severe respiratory depression (breathing difficulty).
34 : PROGNOSIS Good in asymptomatic patients diagnosed before 24 months. Guarded in symptomatic patients diagnosed after 24 months even if IOP controlled after surgery.
35 : Developmental Glaucoma Associated With Ocular Or Systemic Abnormalities Microphthalmos Corneal anomalies (microcornea, megalocornea, cornea plana, sclerocornea, corneal staphyloma) Anterior segment dysgenesis (Axenfield-Rieger syndrome, Peters anomaly, iridoschisis) Aniridia Lens anomalies (congenital cataracts, lens dislocation, microspherophakia) Persistent hyperplastic primary vitreous Congenital ectropion-uvea syndrome ectropion


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