College

Mary, a 65-year-old diabetic patient for more than 20 years, presents to her ophthalmologist with complaints of blurry vision and difficulty seeing objects clearly. She reports experiencing these symptoms progressively over the past few months, accompanied by occasional headaches and eye strain. Mary is concerned about her vision and seeks a thorough evaluation to identify the underlying cause and appropriate treatment.

**Clinical Findings:**

**Visual Acuity Testing:**
- **Distance Visual Acuity (with correction):**
- Right eye: 20/40
- Left eye: 20/50
- **Near Visual Acuity (with correction):**
- Right eye: 20/40
- Left eye: 20/50

Mary demonstrates reduced visual acuity in both distance and near vision, indicating a visual impairment.

**Refraction:**
- **Objective Refraction:**
- Mary exhibits mild hyperopia (farsightedness) in both eyes, with a spherical equivalent of +1.00 diopters.
- **Subjective Refraction:**
- Best-corrected visual acuity is achieved with a prescription of +1.00 D sphere in both eyes.

**Visual Field Testing:**
- **Confrontation Visual Field Testing:**
- Mary has full visual fields to confrontation, with no evidence of peripheral vision loss or defects.

**External Examination:**
- **Eyelids and Lashes:**
- Normal, no signs of ptosis or lid abnormalities.
- **Conjunctiva and Sclera:**
- Clear and white, no signs of inflammation or injection.
- **Tear Film:**
- Normal tear film quality, no signs of dryness or tear deficiency.

**Slit-lamp Biomicroscopy:**
- **Cornea:**
- Clear and transparent, no evidence of opacities or irregularities.
- **Anterior Chamber:**
- Deep and quiet, no signs of inflammation or cells.
- **Iris:**
- Normal color and architecture, no signs of abnormalities.
- **Lens:**
- Clear with no evidence of cataracts or lens opacities.

**Intraocular Pressure Measurement:**
- **Intraocular Pressure (IOP):**
- High, with values exceeding the normal range of 12-22 mmHg, measured at 35 mmHg in both eyes using Goldmann applanation tonometry.

**Dilated Fundus Examination:**
- **Optic Nerve Head:**
- Optic discs appear pink and healthy, with a cup-to-disc ratio of 0.3 in both eyes.
- **Macula:**
- No signs of macular edema, hemorrhage, or exudates. Foveal reflex present.
- **Retinal Vasculature:**
- Arteries and veins appear normal in caliber and course, with no signs of arteriolar narrowing or vascular changes.
- **Peripheral Retina:**
- Normal peripheral retina with no evidence of retinal tears, detachments, or lattice degeneration.

**Deliverables:**

1. **Discuss the role of the cornea and lens in the formation of a focused image on the retina. How do abnormalities in these structures contribute to Mary's symptoms of blurry vision?**

2. **Explain the pathophysiology of age-related macular degeneration (AMD) and its potential implications for Mary's central vision. How might AMD contribute to her symptoms, and what treatment options are available?**

3. **Explain the role of intraocular pressure in the pathophysiology of glaucoma and its potential impact on Mary's vision. How can elevated intraocular pressure lead to visual impairment, and what are the treatment options available for glaucoma?**

4. **Explain how diabetic retinopathy develops and its potential impact on Mary's vision. What are the key features of diabetic retinopathy, and how might they manifest in Mary's symptoms?**

5. **Based on the clinical findings, what are the causes of Mary's visual symptoms of blurry vision and difficulty focusing?**

Answer :

1. Role of the Cornea and Lens:

The cornea and lens focus light onto the retina. Abnormalities such as Mary's mild hyperopia cause light to focus behind the retina, leading to blurry vision and eye strain.

2. Pathophysiology of AMD:

Age-related macular degeneration (AMD) deteriorates the macula, affecting central vision. It can cause vision loss, particularly in detailed vision. Although Mary shows no signs of AMD, treatments include nutritional supplements and anti-VEGF injections.

3. Role of Intraocular Pressure in Glaucoma:

Elevated intraocular pressure (IOP) damages the optic nerve, leading to glaucoma. This condition causes progressive vision loss, starting with peripheral vision. Mary’s high IOP of 35 mmHg suggests glaucoma risk, treatable with medications, laser therapy, and surgery.

4. Development of Diabetic Retinopathy:

Diabetic retinopathy arises from high blood sugar damaging retinal blood vessels, leading to vision loss through macular edema and retinal detachment. Key features include microaneurysms and hemorrhages. Treatment involves blood sugar control, laser therapy, and anti-VEGF injections.

5. Causes of Mary’s Visual Symptoms:

Mary's blurry vision is primarily due to mild hyperopia, causing eye strain. Elevated IOP indicates a risk of glaucoma, which can impair vision over time. Regular monitoring is needed for AMD and diabetic retinopathy due to her age and diabetes.