striated opacities that present the same appearance may be pro- duced by bichloride of mercury, when a solution of this drug has been used to irrigate the anterior chamber after operation. Deep Punctate Keratitis This name has been applied to the deposit of bits of fibrin on Descemet’s membrane, but this condition is symptomatic of cyclitis and not a keratitis at all. Quite a number of brown dots are to be seen congregated, more or less in the form of a triangle, on the posterior surface of the lower quadrant of the cornea in the majority of cases, but occasionally the dots are larger, fewer, and whitish in color, when they are called by English writers “mutton fat” deposits. <Callout type="warning" title="Warning: Misdiagnosis Risk">Misidentifying cyclitis as keratitis can delay appropriate treatment.</Callout> Sclerosing Keratitis During an attack of grave inflammation of the eye characterized by a livid discoloration and bulging of the sclera in the neighborhood of the cornea, the sclera may seem to encroach on the cornea by the 192 DIAGNOSIS FROM OCULAR SYMPTOMS formation of an opacity that extends over the limbus toward the center. This opacity is broadest at the limbus, generally is irregu- lar in shape, though sometimes it has a fairly curved, indistinct edge, and it causes the margin of the cornea to have a jagged appearance. It is of a dull white or yellowish color, is situated in the parenchyma, and is a symptom of deep scleritis. After the inflammation has subsided the opacity may clear up partially, but in most cases it changes to a tendinous, bluish white, and is per- manent. <Callout type="important" title="Important: Permanent Damage">Sclerosing keratitis can lead to permanent corneal damage if untreated.</Callout> KERATOMALACIA When we see an extremely emaciated patient who has xerosis of the conjunctiva, and a more or less grayish or bluish, insensitive cornea, perhaps covered with scales, we know that this tissue is in imminent danger of breaking down into a large purulent ulcer and melting away. This keratomalacia is a bad sign for the life of the patient. It is met with at all ages, but most often shortly before death in marasmic children who are suffering from cholera infan- tum. In older persons it may appear late in the course of such exhausting diseases as dysentery, typhoid fever, puerperal fever, cholera, or scarlet fever, and may be produced by starvation. As a rule, the patients are in a stuporous condition, Keratomalacia is the breaking down of the cornea because of insufficient nutrition. Infection with pus agents takes place secon- dary. The only diseases with which it is in danger of being con- fused are keratitis e lagophthalmo and neuroparalytic keratitis. The former sometimes appears in the same exhausting diseases, but it is to be distinguished by the absence of xerosis, the presence of reddened, swollen conjunctiva in the region of the palpebral fissure, and the location of the lesion in the lower portion of the cornea, while in keratomalacia the entire tissue is involved. <Callout type="risk" title="Risk: Secondary Infection">Secondary infections can be life-threatening if not treated promptly.</Callout> Neuroparalytic keratitis appears in patients who present symptoms referable to a lesion of the central nervous system, rather than to the diseases mentioned, and presents a central opacity, or a round, purulent ulcer. TUMORS OF THE CORNEA A tumor may be situated on the surface of the cornea, or it may have burst through from within the eye; in either case it is met with rarely. A superficial tumor ordinarily starts from the conjunctiva, though a few have been reported from time to time as primary growths of the cornea itself. It may be an epithelioma, a sarcoma, a myxoma, a fibroma, a papilloma, a keloid, or a dermoid, but it is seldom that the elinical characteristics are such as to enable us to determine the nature of a growth without a microscopical ex- amination. Cysts seldom are large enough to be seen, but occa- sionally they cause slight protrusions. A congenital growth with a dry, downy or hairy surface, usually at the corneoscleral junction, is a dermoid. All of the rest start, as a rule, near the margin of the cornea as little spots that gradually increase in size until they impair the vision. Sometimes a portion of one can be lifted up so as to expose the cornea beneath it; in other cases this cannot be done, because the tissue itself has been invaded. As a rule, a space can be found where the cornea is sufficiently clear to allow us to make out an anterior chamber of ordinary depth, and an iris that is not tightly stretched. When a pigmented, vascular tumor has invaded the entire cornea we may have to depend on the history to differentiate it from a staphyloma, but it is not very often that we have any difficulty in recognizing a tumor to be such. <Callout type="tip" title="Tip: History Matters">A detailed patient history can help distinguish between different types of tumors.</Callout> When an intraocular tumor has burst through the cornea we have a history of blindness that came on before any external lesion became apparent, followed later by glaucomatous pain, which per- sisted while the eyeball became enlarged and deformed by a pro- trusion of the cornea, and ceased, or at least was much relieved, coincidentally with the rupture of the tumor through the coat of the eye. We always find the shape of the eyeball to be distorted otherwise as well, and the freed tumor grows rapidly.
Key Takeaways
- Recognize keratomalacia by xerosis of the conjunctiva and a grayish or bluish cornea.
- Distinguish sclerosing keratitis from other conditions like cyclitis and neuroparalytic keratitis.
- Be aware that tumors on the cornea can be various types, including epithelioma and sarcoma.
Practical Tips
- Always take a detailed patient history to aid in diagnosis of corneal tumors.
- Look for signs of secondary infection when dealing with keratomalacia or other corneal conditions.
- Use the presence of xerosis as an early indicator of potential keratomalacia.
Warnings & Risks
- Misidentifying cyclitis as keratitis can delay appropriate treatment.
- Secondary infections from keratomalacia can be life-threatening if not treated promptly.
- Tumors on the cornea can be difficult to diagnose without a microscopic examination.
Modern Application
While the specific techniques and terminology in this chapter are historical, the principles of recognizing and managing severe ocular conditions remain relevant. Modern survival preparedness should include basic ophthalmic knowledge and access to emergency medical supplies for treating eye injuries or infections.
Frequently Asked Questions
Q: What is keratomalacia?
Keratomalacia is the breaking down of the cornea due to severe malnutrition, often seen in emaciated patients. It can lead to large purulent ulcers and is a serious condition that may be fatal.
Q: How can one differentiate between keratomalacia and other corneal conditions?
Keratomalacia presents with xerosis of the conjunctiva, a grayish or bluish insensitive cornea, and possibly scales. It is distinguished from cyclitis by the absence of fibrin deposits on Descemet’s membrane.
Q: What are some signs that a tumor may be present in the cornea?
Signs include the presence of pigmented, vascular tumors that have invaded the entire cornea, or a history of sudden blindness followed by glaucomatous pain and an enlarged eyeball.