Eagleview Eye Clinic

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REFRACTION

๐Ÿ” Refraction is the bending of light as it passes through different mediums (e.g., air, lens, cornea). In the eye, it focuses light onto the retina.

Types:

  1. Emmetropia: Normal vision.
  2. Myopia (nearsightedness): Blurred distance vision.
  3. Hyperopia (farsightedness): Blurred near vision.
  4. Astigmatism: Distorted vision.
  5. Presbyopia: Age-related near vision loss.

Tests:

  • Visual acuity: Snellen chart.
  • Autorefraction: Objective measurement.
  • Subjective tests: Lens power adjustment.

Corrections:

  • Glasses/contact lenses: Adjust refractive power.
  • Surgery: LASIK, PRK, etc.

CYCLOPLEGIC REFRACTION

Cycloplegic refraction is an eye exam that temporarily paralyzes the ciliary muscle, relaxing the eye’s focusing power. This helps determine the true refractive error, especially in children or those with accommodative esotropia.

Key uses:

  1. Accurate prescription for glasses or contact lenses
  2. Diagnosing amblyopia or strabismus
  3. Managing accommodative esotropia
MIOTIC DRUGS

๐Ÿ‘จโ€โš•๏ธ Miotic drugs constrict the pupil (miosis) and reduce intraocular pressure (IOP). Used for glaucoma, post-surgery, or counteracting mydriasis.

Common examples:

  1. Pilocarpine (cholinergic)
    • Effect: 1โ€“2 hours, lasts 4โ€“8h.
    • Use: Open-angle glaucoma, miosis.
    • Side effects: Headache, dim vision, brow ache.
  2. Carbachol (cholinergic)
    • Effect: Strong, longer-lasting.
    • Use: Glaucoma, post-op care.
    • Risk: Retinal detachment risk.
  3. Acetylcholine (direct-acting)
    • Use: Intraocular surgery (short-acting).
  4. Echothiophate (anticholinesterase)
    • Use: Chronic glaucoma.
    • Risk: Cysts, systemic toxicity.

Precautions:

  • Night vision issues: Avoid driving in low light.
  • Retinal risk: Check for detachment symptoms.
  • Asthma/COPD: Caution (bronchospasm).
  • Tapering: Avoid sudden stop.

MYDRIATIC DRUGS

๐Ÿ‘๏ธ Mydriatic drugs dilate the pupil (mydriasis) by relaxing the iris sphincter muscle. Used for exams, surgery, or treating inflammation.

Common examples:

  1. Phenylephrine (ฮฑ-1 agonist)
    • Effect: Fast (30โ€“60 min), short (3โ€“6h).
    • Use: Diagnostic exams.
    • Risk: Hypertension, arrhythmia.
  2. Tropicamide (anticholinergic)
    • Effect: 30โ€“45 min, lasts 4โ€“6h.
    • Use: Routine dilation.
    • Risk: Blurred vision, photophobia.
  3. Atropine (strong, long-acting)
    • Effect: 1โ€“2 weeks.
    • Use: Uveitis, amblyopia.
    • Risk: Prolonged blur, dry mouth.
  4. Cyclopentolate
    • Effect: 24โ€“48h.
    • Use: Pediatric exams.
    • Risk: Behavioral changes in kids.

Precautions:

  • Avoid driving until pupils return to normal.
  • Glaucoma risk: Check IOP.
  • Monitor elderly/kids.
  • Side effects: Headache, stinging, dry eyes.

CYCLOPLEGIC DRUGS

๐Ÿ‘จโ€โš•๏ธ Cycloplegic drugs paralyze the ciliary muscle, blocking accommodation (focusing) and dilating the pupil. Used in eye exams, treating uveitis, or managing amblyopia.

Common examples:

  1. Atropine (long-acting, 1โ€“2 weeks)
    • Use: Amblyopia, uveitis.
    • Side effect: Dry mouth, blurred vision.
  2. Cyclopentolate (shorter, 24โ€“48h)
    • Use: Pediatric exams, refraction.
    • Risk: Hallucinations in kids.
  3. Tropicamide (fast, 4โ€“6h)
    • Use: Routine dilation.
    • Mildest side effects.
  4. Homatropine (moderate duration)
    • Use: Uveitis, post-surgery.

Precautions:

  • Avoid driving post-use.
  • Monitor IOP (glaucoma risk).
  • Children/elderly: Adjust doses.
  • Contraindicated: Narrow-angle glaucoma.

CYCLOPLEGIA

๐Ÿ” Cycloplegia is the temporary paralysis of the ciliary muscle, which controls the eyeโ€™s focusing (accommodation).

Key effects:

  1. Blurry near vision
  2. Difficulty focusing on close objects
  3. Pupil dilation (mydriasis)
  4. No pain, but uncomfortable for reading/near work

Common causes:

  1. Medications: Cyclopentolate, atropine (used in eye exams)
  2. Infections: Viral (e.g., herpes zoster)
  3. Trauma
  4. Toxins (e.g., botulinum)
  5. Conditions: Adieโ€™s tonic pupil

Management:

  • Reversible (lasts hoursโ€“days, depending on cause)
  • Use glasses for near tasks
  • Avoid driving until resolved
  • Consult an eye doctor if persistent ๐Ÿ˜Ž.
MIOSIS

Miosis is the constriction of the pupil. Itโ€™s the opposite of mydriasis ๐Ÿ˜Š.

Common causes:

  1. Bright light
  2. Medications: Opioids (e.g., morphine), eye drops (e.g., pilocarpine)
  3. Conditions: Hornerโ€™s syndrome, iritis, or neurological disorders
  4. Aging
  5. Substance use: Certain drugs (e.g., heroin)

Effects:

  1. Reduced light entry โ†’ dim vision in low light
  2. Increased depth of field (improved near vision)
  3. Headache or eye strain
MYDRIASIS

Mydriasis is the dilation of the pupil, often caused by:

  • Low light conditions
  • Certain medications (e.g., atropine)
  • Medical conditions (e.g., Adie’s pupil)
  • Substance use (e.g., stimulants)
  • Trauma or injury

Effects:

  1. Increased light sensitivity
  2. Blurred vision
  3. Difficulty focusing
NAVIGATING DRY EYE SYNDROME VIA NUTRITION

Managing dry eyes with diet involves incorporating foods rich in nutrients that support eye health. Here are some tips:

  • Omega-3 fatty acids: Include foods like salmon, sardines, walnuts, and chia seeds to reduce inflammation and promote tear production.
  • Vitamin A-rich foods: Eat carrots, sweet potatoes, spinach, and kale to support the health of the cornea.
  • Vitamin C-rich foods: Consume citrus fruits, bell peppers, and tomatoes to boost collagen production and tear quality.
  • Stay hydrated: Drink plenty of water throughout the day to keep your eyes moist.
  • Limit: Avoid foods high in sugar, salt, and processed ingredients that can exacerbate dry eyes.

Some specific foods that can help:

  • Salmon
  • Walnuts
  • Chia seeds
  • Spinach
  • Kale
  • Carrots
  • Sweet potatoes
  • Citrus fruits
  • Bell peppers.
MACULA

The macula is a specialized region at the back of the eye, responsible for central vision and fine detail.

Key functions:

  1. Central vision
  2. Color vision
  3. Fine detail vision

Location:

The macula is located at the center of the retina, including the fovea.