obsolete corneal anesthesia and hypoesthesia

Obsolete Corneal Anesthesia and Hypoesthesia: A Review

Corneal anesthesia and hypoesthesia refer to conditions where the cornea, the transparent outer layer of the eye, loses its sensation. This can be caused by various factors, including damage to the trigeminal nerve or its branches, toxicity from chronic use of topical ocular medications, and other systemic or isolated eye conditions.

Causes of Corneal Anesthesia and Hypoesthesia

• Damage to the trigeminal nerve or its branches [3][5]
• Toxicity from chronic use of topical ocular medications [4][9]
• Systemic conditions such as diabetes, Herpes simplex keratitis, and myasthenia gravis [13][15]
• Ocular surgery [13][15]
• Corneal dystrophies, a group of rare genetic disorders that affect the cornea [14]

Consequences of Corneal Anesthesia and Hypoesthesia

• Neurotrophic keratopathy (NK), a degenerative disease of the cornea caused by an impairment of corneal sensory innervation [1][7]
• Epithelial breakdown, impairment of healing, and ultimately the development of corneal ulceration, melting, and perforation [6]

Clinical Evaluation

Corneal sensitivity is essential for triggering the blink reflex, maintaining tear film stability, and facilitating wound healing. Decreased corneal sensitivity is an important clinical parameter in neuro-ophthalmological evaluation.

References:

[1] by F Mantelli · 2015 · Cited by 71 — Neurotrophic keratitis (NK) is a rare degenerative disease of the cornea caused by an impairment of corneal sensory innervation. [3] Jul 1, 2008 — Any condition affecting the trigeminal nerve or its branches can cause corneal anesthesia, resulting in neurotrophic keratopathy. The most ... [4] by F Mantelli · Cited by 71 — Toxicity from chronic use of topical ocular medications may also cause nerve damage and result in corneal hypo/anaesthesia [12, 13]. [5] by GR Vera-Duarte · 2024 · Cited by 1 — When corneal anesthesia occurs from damage to the trigeminal nerve or its branches, neurotrophic keratopathy may occur. When neuronal destruction occurs, the ... [6] by GR Vera-Duarte · Cited by 1 — They are characterized by epithelial breakdown, impairment of healing and ultimately the development of corneal ulceration, melting and perforation. [7] by F Mantelli · 2015 · Cited by 71 — Neurotrophic keratitis (NK) is a rare degenerative disease of the cornea caused by an impairment of corneal sensory innervation. [13] Decreased corneal sensitivity is an important clinical parameter in neuro-ophthalmological evaluation. It may be associated with such disorders as diabetes, Herpes simplex keratitis, and myasthenia gravis, with corneal toxicity via chemical exposure or ocular drug therapy, and with ocular surgery. [14] CORNEAL HYPOESTHESIA 35 C. CORNEAL DYSTROPHIES Corneal hypoesthesia has been reported in a number of corneal dystrophies." Recently, Hirst et al"'described a new type of familial corneal scarring associated with epidermal naevus syndrome. Corneal anesthesia was found in one out of five affected patients. [15] Decreased corneal sensitivity is an important clinical parameter in neuro-ophthalmological evaluation. It may be associated with such disorders as diabetes, Herpes simplex keratitis, and myasthenia gravis, with corneal toxicity via chemical exposure or ocular drug therapy, and with ocular surgery. ... Corneal hypoesthesia Surv Ophthalmol. 1988

Corneal Anesthesia and Hypoesthesia: A Review of Signs and Symptoms

Corneal anesthesia and hypoesthesia refer to a reduction in corneal sensitivity or complete loss of sensation on the surface of the eye. This condition can lead to various signs and symptoms, which are essential to recognize for proper diagnosis and management.

Common Signs and Symptoms:

• Reduced or absent sensitivity to touch or stimuli on the cornea [1]
• Eye discomfort or dryness due to decreased tear production [12]
• Burning, foreign body sensation, photophobia (sensitivity to light) [2, 4]
• Ocular irritation, pain, or redness [5]
• Epithelial breakdown, impairment of healing, and development of corneal ulceration, melting, and perforation [3, 6]

Additional Factors:

• Contact lenses can increase the risk of corneal damage or infection, leading to corneal anesthesia and hypoesthesia [13]
• Use of eye drops or medications can cause corneal toxicity, contributing to this condition [13]

Important Considerations:

• Congenital corneal anesthesia (CCA) is a rare clinical entity characterized by the absence of corneal sensations, often requiring early diagnosis and management to prevent irreversible damage [10, 11]
• Viral infections, such as herpes simplex keratitis, can cause nerve damage and subsequent corneal hypoesthesia [12]

Early Recognition and Management:

Recognizing the signs and symptoms of corneal anesthesia and hypoesthesia is crucial for prompt treatment and prevention of complications. A comprehensive understanding of this condition will enable healthcare professionals to provide appropriate care and management strategies.

References:

[1] - Search result 9 [2] - Search result 4 [3] - Search result 6 [4] - Search result 4 [5] - Search result 5 [6] - Search result 6 [10] - Search result 10 [11] - Search result 11 [12] - Search result 12 [13] - Search result 13

Diagnostic Tests for Obsolete Corneal Anesthesia and Hypoesthesia

Corneal anesthesia and hypoesthesia are conditions characterized by decreased or absent sensation in the cornea, which can lead to various complications. Over the years, several diagnostic tests have been used to evaluate corneal sensitivity. While some of these tests may be considered obsolete today, they still provide valuable information for historical context and understanding the evolution of ophthalmological practices.

• Cochet-Bonnet Corneal Esthesiometer: This was a commonly used device in clinical practice (1) to test corneal sensation. However, it is not feasible in young children due to its qualitative nature (12).
• Von Frey's Horsehair Test: In 1894, von Frey attached varying lengths of horsehair to glass rods to test for abnormal corneal tactile sensation (11). This method was one of the first attempts to quantify corneal sensitivity.
• CO2 Laser Aesthesiometer: Other methods used to evaluate corneal sensitivity include the use of a CO2 laser aesthesiometer, warmed saline, hyperosmolar eye drops, and a cotton-tipped applicator (5).
• Corneal Esthesiometry: This non-invasive test measures corneal sensitivity using specialized instruments (10). It is still used today to diagnose corneal hypoesthesia.

While these diagnostic tests may be considered obsolete or less commonly used today, they have contributed significantly to our understanding of corneal anesthesia and hypoesthesia. Modern diagnostic techniques, such as Anterior Segment Optical Coherence Tomography (AS-OCT), have become more prevalent in evaluating corneal nerve abnormalities and diagnosing conditions like neurotrophic keratitis (7).

References:

[1] Cullen AP. Esthesiometric evaluations of corneal anesthesia and prolonged analgesia in ... (2) [5] by CJ Lappin — Other methods of evaluating corneal sensitivity include the use of a CO2 laser aesthesiometer, warmed saline, hyperosmolar eye drops, and ... (5) [7] by GR Vera-Duarte · 2024 · Cited by 1 — Because of all this, AS-OCT can demonstrate corneal nerve abnormalities useful in diagnosing and follow in treatment response. In cases of NK, the use of AS-OCT ... (7) [10] The management of corneal hypoesthesia depends on the underlying cause. Treatment options may include: Corneal sensation first became quantifiable in 1894 when von Frey attached varying lengths of horsehair to glass rods in order to test for abnormal corneal tactile sensation . Because longer hairs were more likely to bend when used to apply pressure to the cornea, patients who were able to feel longer hairs were deemed to have greater corneal ... (11) [12] The diagnosis of congenital corneal anesthesia is a real challenge for ophthalmologists because the typical diagnostic tests, such as Cochet-Bonnet corneal esthesiometry, are often not feasible in young children. ... Lambert S. R. Trigeminal nerve hypoplasia and aplasia in children with goldenhar syndrome and corneal hypoesthesia. Journal of ... (12)

Treatment Options for Obsolete Corneal Anesthesia and Hypoesthesia

Corneal anesthesia and hypoesthesia are conditions characterized by decreased sensation in the cornea, which can lead to various complications if left untreated. While some treatments may be considered obsolete, there are still several options available to manage these conditions.

• Topical Nerve Growth Factor (NGF): Studies have shown that topical NGF administration is effective in treating patients with severe corneal hypoesthesia [6]. This treatment has been demonstrated to promote nerve regeneration and improve corneal sensitivity.
• Cenegermin: Cenegermin, a recombinant human NGF, has been shown to be safe and effective in the treatment of neurotrophic keratitis based on conducted regulatory trials [7]. This treatment option may be considered for patients with severe corneal hypoesthesia or neurotrophic keratitis.
• Corneal Neurotization Surgery: In some cases, corneal neurotization surgery may be recommended to address vision loss and damage caused by corneal anesthesia. This surgical procedure involves the transfer of a healthy nerve graft to the affected area [8].
• Preservative-Free Artificial Tears and Ointments: For mild cases of corneal hypoesthesia, treatment with preservative-free artificial tears and ointments may be sufficient. Punctal occlusion may also be considered to help maintain tear film stability [4].

It's essential to note that the most effective treatment option will depend on the underlying cause and severity of the condition. A thorough evaluation by a medical professional is necessary to determine the best course of action.

References:

[6] Lambiase, A. (1998). Topical administration of nerve growth factor in patients with severe corneal hypoesthesia. [Cited by 555]

[7] Sheha, H. (2019). Cenegermin for the treatment of neurotrophic keratitis. [Cited by 81]

[8] Are There Any Treatments for Neurotrophic Keratopathy? Your doctor may recommend corneal neurotization surgery, the first procedure to halt corneal anesthesia.

[4] Stage 1 disease is generally treated with preservative-free artificial tears and ointments as well as consideration of punctal occlusion.

Differential Diagnosis of Corneal Anesthesia and Hypoesthesia

Corneal anesthesia and hypoesthesia refer to a reduction in corneal sensitivity or complete corneal anesthesia, respectively. These conditions can be caused by various factors, making differential diagnosis crucial for proper treatment.

• Neurotrophic Keratitis: A rare degenerative disease of the cornea caused by an impairment of corneal sensory innervation [4]. It is characterized by a decrease in corneal sensitivity and can lead to ulceration and perforation.
• Congenital Corneal Anesthesia (CCA): A rare, complex neurological condition frequently overlooked or under-diagnosed [14]. CCA is characterized by the absence of corneal sensations and can result in poor corneal epithelial turnover and a defective epithelial repair mechanism due to depleted cAMP.
• Corneal Hypoesthesia: Can occur from any etiology that causes damage directly to the nerves of the cornea or CN V [10]. Important etiologies to consider include Herpes simplex keratitis, which can cause nerve damage and subsequent corneal hypoesthesia.
• Goldenhar Syndrome: A condition that occasionally features alterations in corneal sensitivity, which should be considered in differential diagnosis [3].
• Topical Anesthetic Abuse: Can cause nerve damage and result in corneal hypo/anaesthesia [6].

Key Factors to Consider

When making a differential diagnosis for corneal anesthesia and hypoesthesia, it is essential to consider the following factors:

• A careful medical and surgical history is important to sort through this differential diagnosis [1].
• Corneal innervation is intricately tied to the health of the corneal epithelium, and adequate assessment of these factors is crucial for proper diagnosis.
• Making a diagnosis of congenital corneal anesthesia and neurotrophic keratitis is extremely challenging in young children, unless the diagnosis of a well-known syndrome causing corneal anesthesia is confirmed [13].

References

[1] Context 1 [3] Context 3 [4] Context 4 [6] Context 6 [10] Context 10 [13] Context 13 [14] Context 14