What's Wrong With This Macula?

Case 1:

Macular Hole

For several weeks, an 82-year-old woman had experienced blurred vision while reading. She was unable to localize the problem to either eye.

The patient's best corrected visual acuity was 20/25 in the right eye and 20/20 in the left. She had undergone cataract surgery about a decade earlier, and her intraocular implants were properly positioned. The patient could not completely comprehend the Amsler grid test, so her answers were thought to be unreliable. Findings from the rest of the eye examination were normal, except for the macular evaluation of the right eye. A circular reddish defect that resembled a piece of pepperoni was faintly visible in the foveal region of the macula (A). No subretinal fluid or foveal edema was evident.

A Watzke-Allen test was performed to determine whether this was a true defect and not a pseudohole. This test involves pointing a thin slit-lamp beam directly at the suspected retinal hole during biomicroscopic examination of the contact lens.¹ The patient is asked whether the vertical beam is interrupted at any point or whether it simply narrows. A perceived interruption in the light beam is a positive sign that is useful in diagnosing a macular hole. A normal-appearing or only nar- rowed beam is a negative result. This patient reported that the beam was distorted and that its center was missing. This constituted a positive Watzke-Allen sign.

Most macular holes are idiopathic and result from contraction of the prefoveal vitreous cortex that adheres to the macular retinal tissue. Vitreous traction leads to foveal pseudocyst formation, which is followed by dehiscence of the pseudocyst and separation of the underlying tissue.²

Macular holes occur twice as often in women as in men; the mean age at presentation is 65 years.³ In one study, 45% of eyes with idiopathic macular holes underwent a loss of at least 2 Snellen lines and 28% lost 3 lines.⁴ One third of the macular holes enlarged during a 4.5-year period. Vision eventually stabilized at 20/200 to 20/400, and retinal pigment epithelial atrophy surrounding the full-thickness hole developed.^3,4

Figure B shows a long-standing full-thickness macular hole with a ring or cuff of subretinal fluid and adjacent yellow spots containing clumped xanthophyll. This patient's visual acuity was only 20/400 in the affected eye.

Patients with macular holes are referred to a retinal specialist for vitrectomy and tamponade of the hole with either gas or silicone oil. This treatment stabilizes the eye and prevents further progression.

REFERENCES:1. Morse LS, Wendel RT, Yip PT. Macular hole surgery, In: Packer AJ, ed. Manual of Retinal Surgery. 2nd ed. Woburn, Mass: Butterworth-Heinemann; 2001: 105-117.
2. Spaide RF. Closure of an outer lamellar macular hole by vitrectomy: hypothesis for one mechanism of macular hole formation. Retina. 2000;20:587-590.
3. Colucciello M. Evaluation and management of macular holes. Focal Points Clinical Modules for Ophthalmologists. Vol. 21, No. 1. San Francisco: American Academy of Ophthalmology; 2003:1-17.
4. Chew EY, Sperduto RD, Hiller R, et al. Clinical course of macular holes: the Eye Disease Case-Control Study. Arch Ophthalmol. 1999;117:242-246.

Case 2:

Dry Age-Related Macular Degeneration

A 69-year-old-woman reported that she could no longer drive at night because of poor depth perception. She was concerned that cataracts might be developing.

Her best corrected visual acuity was 20/70 in the right eye and 20/25 in the left. Some early nuclear sclerotic cataract changes were found, but a funduscopic evaluation also revealed numerous "soft" yellowish deposits--some of which were confluent--scattered throughout the maculae (A and B). No macular edema or hemorrhaging was noted. A fluorescein angiogram confirmed dry age-related macular degenerative changes.

Age-related macular degeneration (AMD) is the leading cause of untreated vision loss among persons 65 years or older and accounts for 45% of all visual disability in the United States.¹ Nonmodifiable risk factors include older age, family history, light-colored irides, and female sex. Modifiable risk factors include smoking, cumulative exposure to sunlight or short-wavelength blue light, excessive intake of dietary fat, obesity, hypertension, and lack of exercise. Advise patients with AMD that modification or elimination of these risk factors may prevent disease progression.

Supplementation with vitamins C and E, beta-carotene, zinc, and copper is also recommended. The Age-Related Eye Diseases Study (AREDS), sponsored by the National Eye Institute, found that progression of AMD was reduced by 25% in patients who took these supplements.² Supplementation is not recommended for smokers, however, because of an increased risk of lung cancer in smokers given high-dose beta-carotene, an essential component of the AREDS formulation.³

This patient was not a smoker and was advised to start AREDS supplementation. She was also given an Amsler grid to use at home daily, with instructions to return immediately if she noticed any metamorphopsia or scotomatous changes on the grid. Surgery was not indicated because her cataracts were not clinically significant.

REFERENCES:1. Klein R, Klein BE, Linton KL. Prevalence of age-related maculopathy. The Beaver Dam Eye Study. Ophthalmology. 1992;99:933-943.
2. Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled clinical trial of high-dose supplementation with vitamins C and E, beta-carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch Ophthalmol. 2001;119:1417-1436.
3. Albanes D, Heinonen OP, Taylor PR, et al. Alpha-tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance. J Natl Cancer Inst. 1996;88:1560-1570.

Case 3:

Diabetic Maculopathy

An 81-year-old woman was seen for a routine eye examination. She had type 2 diabetes, for which she was taking glipizide. Her blood glucose level averaged 130 mg/dL.

After refraction, her best corrected visual acuity was 20/25 in each eye. She was pseudophakic in both eyes. A dilated-fundus examination identified normal optic nerves with scattered microaneurysms, dot and blot hemorrhages, and cotton-wool spots (soft exudates) (A and B). No neovascularization of the optic disc or the retina was evident.

The patient had moderate background diabetic retinopathy. Microaneurysms result from weakening in the capillary walls and typically leak fluid into the retina, which causes retinal edema. Dot and blot hemorrhages represent ruptures in the capillary walls of the deeper retinal layers and suggest deep retinal edema. An increase in widespread dot and blot hemorrhages suggests retinal ischemia and is a risk factor for progression of diabetic retinopathy. Cotton-wool spots result from long-standing hypoxia of the nerve fiber layer. They are usually located close to the optic nerve.

Other common diabetic retinopathy findings include hard exudates (lipid deposits that represent areas of chronic retinal edema attributable to leaking microaneurysms) and venous beading and tortuosity. Proliferative changes, such as neovascularization of the optic disc and retina, occur in patients with more severe ischemia.

Because this patient's vision was not correctable to 20/20 in either eye, closer evaluation of the macula was indicated to rule out macular edema. This condition develops in up to 10% of persons with diabetes; up to 4% of these patients have edema that involves the central fovea.¹ Approximately 75,000 new cases of diabetic macular edema are reported annually.¹ Fluorescein angiography helps identify leaky microaneurysms that cause macular edema and serves to guide laser treatment.

This patient's fluorescein angiogram confirmed diabetic macular edema in both eyes, and focal diode laser therapy was scheduled.

REFERENCE:1. Karpecki PM, Nelson RC. Extend diabetes care beyond retinopathy. Rev Optom. 2004;141:100-112.

Case 4:

Postoperative Cystoid Macular Edema

A cataract developed in the right eye of a 50-year-old woman who had a history of idiopathic nongranulomatous iritis. The cataract was attributed to recurrent episodes of inflammation and the topical corticoste- roids that were used to treat the uveitis. Her vision had deteriorated to 20/70, which made it difficult for her to continue to work as a pharmacy assistant. The patient underwent uneventful phacoemulsification surgery with implantation of a posterior chamber intraocular lens. Because of her history of chronic iritis, the eye was treated with a topical corticosteroid and topical nonste- roidal agent for 1 week preoperatively and 1 month postoperatively.

The patient's initial recovery was unremarkable; her visual acuity had improved to 20/25 1 week after surgery. But by 6 weeks postoperatively, her vision had deteriorated to 20/60. Examination of the fundus identified blunting of the macular reflex and cystic changes from fluid that had accumulated within the macular retina. A fluorescein angiogram confirmed that dye was leaking from the retinal vessels and was forming a characteristic petaloid pattern within the macular area.

Cystoid macular edema (CME) after uncomplicated cataract extraction is seen angiographically in approximately 20% of pseudophakic eyes, although clinical visual disability develops in only 1.5% to 3% of these eyes.¹ Patients with a history of uveitis are also at a greater risk for CME, especially after intraocular surgery. These patients require pretreatment with topical corticoste- roids and nonsteroidal agents. Some authors also advocate using systemic corticosteroids for 4 to 14 days before surgery.²

CME occurs when there is damage to the blood-retina barrier, which is formed by the retinal vascular endothelium and the retinal pigment epithelium.² If this barrier is disrupted, fluid may accumulate within the macula both intracellularly and extracellularly, which disturbs cell function and retinal architecture and reduces central vision.

In many cases, CME is self-limited and resolves spontaneously. However, this disorder may become chronic, especially in patients with a history of uveitis. This patient was told to restart both the topical cortico-steroid and topical nonsteroidal agents. One month later, her visual acuity had not improved and the macula still exhibited cystic changes with edema. A periocular injection of triamcinolone acetonide, 40 mg, was given in the sub­Tenon space, and the topical therapy was continued.

For patients who respond poorly or insufficiently to a single periocular corticosteroid injection, a series of 3 injections given 1 month apart may be tried. If the patient responds to a periocular injection, the typical duration of effect is 3 months.² This patient will be seen in 4 to 6 weeks to evaluate her response to the injection. If there is no improvement after 3 injections, treatment with systemic corticosteroids may be warranted.

REFERENCES:1. Jaffe GJ. Cystoid macular edema. Focal Points Clinical Modules for Ophthalmologists. Vol. 12, No. 11. San Francisco: American Academy of Ophthalmology; 1994:1-12.
2. Lightman S, McCluskey P. Cystoid macular edema in uveitis. Focal Points Clinical Modules for Ophthalmologists. Vol. 21, No. 8. San Francisco: American Academy of Ophthalmology; 2003:1-10.

Case 5:

Branch Retinal Vein Occlusion

A sudden decrease in vision prompted a 76-year-old woman to seek medical attention. She had a long-standing history of open-angle glaucoma and was using topical latanoprost 0.005% and timolol 0.25% in both eyes. She had hyperlipidemia, which was being treated with atorvastatin, and she took aspirin, 325 mg/d, prophylactically. She denied hypertension, diabetes, and thyroid disease.

The patient's entrance visual acuity was 20/100 in the right eye and 20/20 in the left. Results of the external eye examination were normal, as were intraocular pressures. On funduscopic examination, both optic nerves showed significant cupping from long-standing glaucoma. The right fundus also showed extensive retinal hemorrhaging that originated from the superior nerve head and extended into the macula and periphery (A).

The patient had a supratemporal branch retinal vein occlusion (BRVO) with macular involvement in the right eye. A BRVO is a focal blockage of a retinal vein at an arteriovenous crossing site. The occlusion is presumed to arise from turbulence induced in the retinal vein by arteriosclerotic changes in the overlying arteriole, which result in venous flow abnormalities, blood stagnation, and eventual occlusion.¹ Systemic risk factors for BRVO include cardiovascular disease, hypertension, diabetes mellitus, hyperlipidemia, and hypercoagulopathy.

Other findings often seen with BRVO include venous tortuosity and dilation, retinal edema, cotton-wool spots (soft exudates) and, if ischemia persists, neovascularization of the optic disc or retina.

In nonischemic BRVO (no neovascularization), it is reasonable to wait at least 3 months from the time of occlusion to see whether the macular hemorrhages and edema resolve and whether the vision improves spontaneously.² Laser photocoagulation is indicated if the vision does not improve or if ischemia develops.

This patient's hemorrhages resolved spontaneously during the first 3 months, and by 7 months, her visual acuity had improved to 20/30 in the right eye. Residual retinal hemorrhages persisted, and collateral vessels developed between the retinal circulation and ciliary vessels at the optic disc (B). The persistence of mild pigmentary disruption of the macula indicates that the patient's visual acuity will not improve to more than 20/30.

REFERENCES:1. Christoffersen NL, Larsen M. Pathophysiology and hemodynamics of branch retinal vein occlusion. Ophthalmology. 1999;106:2054-2062.
2. Folk JC, Pulido JS. Laser Photocoagulation of the Retina and Choroid. San Francisco: American Academy of Ophthalmology; 1997:97-121.

References:

REFERENCES:

1.

Morse LS, Wendel RT, Yip PT. Macular hole surgery, In: Packer AJ, ed.

Manual of Retinal Surgery.

2nd ed. Woburn, Mass: Butterworth-Heinemann; 2001: 105-117.

2.

Spaide RF. Closure of an outer lamellar macular hole by vitrectomy: hypothesis for one mechanism of macular hole formation.

Retina.

2000;20:587-590.

3.

Colucciello M. Evaluation and management of macular holes.

Focal Points Clinical Modules for Ophthalmologists.

Vol. 21, No. 1. San Francisco: American Academy of Ophthalmology; 2003:1-17.

4.

Chew EY, Sperduto RD, Hiller R, et al. Clinical course of macular holes: the Eye Disease Case-Control Study.

Arch Ophthalmol.

1999;117:242-246.

REFERENCES:

1.

Klein R, Klein BE, Linton KL. Prevalence of age-related maculopathy. The Beaver Dam Eye Study.

Ophthalmology.

1992;99:933-943.

2.

Age-Related Eye Disease Study Research Group. A randomized, placebo-controlled clinical trial of high-dose supplementation with vitamins C and E, beta-carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8.

Arch Ophthalmol.

2001;119:1417-1436.

3.

Albanes D, Heinonen OP, Taylor PR, et al. Alpha-tocopherol and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of base-line characteristics and study compliance.

J Natl Cancer Inst.

1996;88:1560-1570.

REFERENCE:

1.

Karpecki PM, Nelson RC. Extend diabetes care beyond retinopathy.

Rev Optom.

2004;141:100-112.

REFERENCES:

1.

Jaffe GJ. Cystoid macular edema. Focal Points Clinical Modules for Ophthalmologists. Vol. 12, No. 11. San Francisco: American Academy of Ophthalmology; 1994:1-12.

2.

Lightman S, McCluskey P. Cystoid macular edema in uveitis. Focal Points Clinical Modules for Ophthalmologists. Vol. 21, No. 8. San Francisco: American Academy of Ophthalmology; 2003:1-10.

REFERENCES:

1.

Christoffersen NL, Larsen M. Pathophysiology and hemodynamics of branch retinal vein occlusion.

Ophthalmology.

1999;106:2054-2062.

2.

Folk JC, Pulido JS.

Laser Photocoagulation of the Retina and Choroid.

San Francisco: American Academy of Ophthalmology; 1997:97-121.