Myopia

Case study: Bilateral moderate myopia and peripheral chorioretinal dystrophy

Patient: 19 years old, student (female).

Complaints: Very poor distance vision (inability to see writing on the classroom board and street signs), squinting, rapid eye fatigue in the evening. Decreased visual quality with current glasses (-3.5 D).

Medical history: Visual decline began at the age of 12. The glasses prescription has increased year by year. Noticed further blurring of vision within the last 6 months (Suspicion of progression).

Examination of the visual organs:

• General appearance: The patient squints when looking into the distance.
• Biomicroscopy (Slit lamp):
  • OD (Right eye) and OS (Left eye):
  • Eyelids: Quiet.
  • Cornea: Transparent, spherical, lustrous.
  • Anterior chamber: Deep (Anatomical feature characteristic of myopia). Aqueous humor is transparent.
  • Pupil: Round, reaction to light is brisk.
  • Vitreous body: Signs of liquefaction (destruction) — small "floaters" (filaments) are visible.
• Fundus of the eye (Ophthalmoscopy):
  • Optic nerve head (ONH): Pale pink, boundaries are distinct. A myopic conus (sign of scleral stretching) is present on the temporal side of the disc.
  • Macula: Reflex is preserved.
  • General appearance of the retina: "Tiger skin" (Tigroid) — choroidal vessels are visible due to the thinning of the pigment epithelium.
  • Periphery: Foci of "Lattice degeneration" and mild pigmentation were detected at the 11 and 5 o'clock positions. (Zone with a risk of tear!).

Examinations (Complete table)

Questions for case analysis:

1. What is your clinical diagnosis?
2. What is the management strategy for the changes in the retinal periphery?
3. The patient wants to undergo "Laser surgery (LASIK)". Will you clear them for it? (Provide a scientifically substantiated answer).
4. What does the "Tigroid" appearance in the fundus indicate in myopia?

Answers and Solution:

1. Final diagnosis:

Bilateral moderate myopia (-5.0 D).

Peripheral chorioretinal dystrophy (PCRD) of the retina - "Lattice" type.

2. Management strategy for dystrophy:

"Lattice degeneration" is a zone with a high risk of retinal detachment.

Solution: Prophylactic peripheral laser coagulation (PPLC) of the retina must be performed on a scheduled basis. The laser strengthens the "weak" area and prevents tearing.

3. Is there clearance for LASIK surgery?

Answer: YES, POSSIBLE, BUT NOT NOW (LATER).

Rationale and Algorithm:

• Anatomically: The patient is fully suitable for the surgery.
  • AXL 25.8 mm — this has not yet reached the borderline of "Pathological myopia" (26.5-27 mm), hence the postoperative risk is low.
  • Pachymetry >540 µm — the cornea is sufficiently thick (must be >500 µm for safety).
• Tactical obstacles:
  • PPLC: The dystrophy must first be treated with a laser, and one must wait 2-3 weeks for it to heal.
  • Stability: The patient reported worsening vision over the last 6 months. To determine if the refraction is stable, they must be observed for 6-12 months. If the "minus" does not increase within 1 year, the surgery can be performed.

4. "Tigroid" fundus:

This is not a pathology, but rather a sign of myopia. When the axial length of the eye elongates, the retinal pigment epithelium thins (becomes paler), and the large vessels of the underlying choroid become visible. This resembles tiger skin.