Developmental and Congenital Glaucomas

Overview & Classification - Eye Development Drama

• Developmental glaucomas: Group of disorders with ↑IOP from birth/early childhood due to abnormal aqueous outflow pathway development (trabeculodysgenesis).
• Embryology: Primarily due to maldevelopment of neural crest cells, which form the trabecular meshwork (TM) and Schlemm's canal.
• Classification:
  • Primary Congenital Glaucoma (PCG): Isolated trabeculodysgenesis.
  • Glaucomas with Ocular/Systemic Anomalies: e.g., Axenfeld-Rieger, Peters anomaly.
  • Secondary Developmental Glaucomas: e.g., due to phakomatoses, inflammation, trauma, tumors.

⭐ Congenital glaucomas result from developmental abnormalities of the anterior chamber angle (trabeculodysgenesis).

PCG: Features & Diagnosis - The Buphthalmos Burden

• Etiology: Trabeculodysgenesis (maldevelopment of trabecular meshwork).
• Genetics: Most commonly associated with CYP1B1 gene mutations.
• Clinical Triad (📌 Mnemonic: BLEP):
  • Blepharospasm
  • Lacrimation (Epiphora)
  • Photophobia
• Key Signs:
  • Corneal edema (hazy cornea).
  • Haab's striae (breaks in Descemet's membrane).
  • Increased corneal diameter: >12mm at 1 year, >13mm anytime.
  • Buphthalmos (enlarged globe, "ox eye").
  • Deep anterior chamber (AC).
  • Intraocular Pressure (IOP) >21 mmHg.
• Optic Disc: Cupping, initially reversible.
• Investigations:
  • Examination Under Anesthesia (EUA).
  • Tonometry (IOP measurement).
  • Corneal diameter measurement.
  • Gonioscopy (visualize angle structures).
  • Ophthalmoscopy (optic disc assessment).

⭐ Haab's striae, pathognomonic for congenital glaucoma, are horizontal or circumferential breaks in Descemet's membrane due to corneal stretching.

PCG: Management - Angle Attack Plan

• Goals: ↓IOP to safe levels, preserve vision, prevent amblyopia.
• Medical (Bridge to Surgery):
  • Topical: β-blockers (e.g., timolol), CAIs (e.g., dorzolamide).
  • PGAs generally less effective. Avoid miotics (may ↑IOP).
  • Systemic: Acetazolamide (short-term, pre-op).
• Surgical (Definitive):

*   If initial surgery fails or for older children: Combined Trabeculotomy-Trabeculectomy (CTT), Trabeculectomy + MMC/5-FU.
*   Refractory cases: Glaucoma Drainage Devices (GDDs).
*   Last resort: Cyclodestructive procedures.
> ⭐ Goniotomy and trabeculotomy are the primary surgical interventions for PCG, directly addressing the underlying trabeculodysgenesis.

• Prognosis: Better with early diagnosis and surgery; lifelong monitoring essential.

Syndromic & Secondary Glaucomas - Glaucoma's Entourage

• Axenfeld-Rieger Syndrome: PITX2/FOXC1 genes. Key signs: posterior embryotoxon, iris hypoplasia, corectopia. Glaucoma risk: ~50%.
• Peters Anomaly: Central corneal opacity (leukoma), iridocorneal & lenticulocorneal adhesions. Glaucoma risk: ~50-70%.
• Aniridia: PAX6 gene. Iris aplasia/hypoplasia, foveal hypoplasia, nystagmus. Glaucoma risk: ~50-75%.
• Sturge-Weber Syndrome: GNAQ gene. Facial port-wine stain (nevus flammeus).

  ⭐ In Sturge-Weber syndrome, glaucoma is typically ipsilateral to the facial port-wine stain and can be caused by elevated episcleral venous pressure or an anomalous angle.

• Neurofibromatosis Type 1 (NF1): Lisch nodules (iris hamartomas), developmental angle anomaly causing glaucoma.
• Lowe Syndrome (Oculocerebrorenal): X-linked. Congenital cataracts, renal tubular dysfunction. Glaucoma risk: ~50%.
• Briefly: Marfan, Weill-Marchesani, Rubella_._

Juvenile OAG - Teen Tension Trouble

• Onset: 4-35 years (Open-Angle Glaucoma).
• Presentation: Often asymptomatic; leads to advanced optic disc cupping.
• Management: Similar to adult POAG; more aggressive course, often needs early surgery.

⭐ Juvenile Open-Angle Glaucoma (JOAG) is strongly associated with mutations in the MYOC (myocilin) gene (Autosomal Dominant) and often presents with very high intraocular pressures.

High‑Yield Points - ⚡ Biggest Takeaways

• PCG often bilateral; presents with Haab's striae, buphthalmos, classic triad (photophobia, epiphora, blepharospasm).
• Most PCG: autosomal recessive, CYP1B1 gene.
• Goniotomy/trabeculotomy are key PCG surgeries.
• Axenfeld-Rieger syndrome: posterior embryotoxon, iris changes, glaucoma (50%); PITX2/FOXC1 genes.
• Peters anomaly: central corneal opacity, irido/lenticulocorneal adhesions; glaucoma (50-70%).
• Aniridia (PAX6 mutation): high glaucoma risk (50-75%), often later onset.
• Sturge-Weber syndrome: glaucoma via ↑ episcleral venous pressure.