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This article explains the indications, prescription, fitting, and complication management of rigid gas permeable (RGP/hard) contact lenses for keratoconus. It provides a practical, detailed description including base curve selection using BFS values from anterior segment OCT (Itoi Method), fluorescein pattern evaluation, and criteria for transitioning to scleral lenses.

A rare subtype of sarcoidosis characterized by four main symptoms: anterior uveitis, parotid gland swelling, facial nerve palsy, and fever. Also known as uveoparotid fever, it occurs in 4–6% of sarcoidosis patients.

Infantile hemangioma of the eyelid (formerly called strawberry hemangioma) is the most common benign vascular tumor in infancy, and 70% regress spontaneously before school age. Oral propranolol is the first-line treatment when there is a risk of form deprivation amblyopia due to difficulty opening the eyelid.

An overview of keratitis caused by herpes simplex virus (HSV). This article explains the pathophysiology, diagnosis, and treatment of each disease type—epithelial (dendritic keratitis), stromal (disciform and necrotizing), endothelitis, and neurotrophic keratopathy—based on the Japanese Infectious Keratitis Clinical Practice Guidelines, 3rd edition, and the classification of the Ocular Herpes Infection Study Group.

Anterior uveitis caused by intraocular reactivation of herpes simplex virus (HSV). It is a representative cause of unilateral anterior uveitis with elevated intraocular pressure, accounting for 5–10% of all uveitis cases.

Herpes zoster caused by reactivation of varicella-zoster virus (VZV) in the first division of the trigeminal nerve, leading to various ocular complications such as keratitis, uveitis, and optic neuritis. Explained in accordance with the Japanese Infectious Keratitis Clinical Practice Guidelines, 3rd edition.

Optic neuritis occurring as a rare complication of herpes zoster ophthalmicus (HZO). Varicella-zoster virus (VZV) damages the optic nerve, causing vision loss.

Anterior or posterior uveitis caused by reactivation of varicella-zoster virus (VZV). It occurs in 40–60% of herpes zoster ophthalmicus (HZO) cases and is characterized by elevated intraocular pressure, chronicity, and sectoral iris atrophy.

A clinical test to record dysfunction or overaction of the extraocular muscles and evaluate incomitant strabismus. This article explains the Hess chart, which uses red-green goggles to diagrammatically record ocular deviation.

This article explains the background, principles, devices, and clinical significance of home intraocular pressure measurement (home tonometry). It details the features and limitations of the iCare HOME rebound tonometer, Triggerfish contact lens sensor, and EyeMate implantable sensor, as well as the importance of out-of-office intraocular pressure monitoring.

A congenital amino acid metabolism disorder caused by deficiency of cystathionine beta-synthase (CBS). It is an autosomal recessive disease that frequently involves lens dislocation, skeletal abnormalities, thromboembolism, and intellectual disability.

Horner syndrome is a syndrome characterized by the triad of miosis, ptosis, and anhidrosis due to disruption of the ocular sympathetic pathway. It is classified into central, preganglionic, and postganglionic types, and is diagnosed by pharmacological pupil testing and the apraclonidine test. It is essential to rule out serious causes such as carotid artery dissection and Pancoast tumor.

Explains the SITA algorithm, test program selection, result interpretation, Anderson-Patella criteria, GHT/MD/VFI/PSD indices, and progression assessment for Humphrey static perimetry (HFA). It is the standard visual field test for glaucoma diagnosis and management.

Hyperopia is a refractive error in which parallel light rays focus behind the retina. This article covers detection of latent hyperopia, its association with accommodative esotropia and amblyopia, and the importance of early correction in children.

Hypertension and dyslipidemia are risk factors for hypertensive retinopathy, retinal vein occlusion, retinal artery occlusion, and ischemic optic neuropathy. The ocular fundus is the only part of the body where blood vessels can be directly observed, playing an important role in assessing cardiovascular risk.

A disease in which retinal blood vessels are damaged by systemic hypertension. Through vasospasm, arteriosclerosis, and breakdown of the blood-retinal barrier, fundus changes such as hemorrhages, exudates, and papilledema occur. Severe cases are also a risk indicator for cardiovascular disease and stroke.

Hypertropia is a vertical strabismus in which one eye is deviated upward relative to the other. The most common cause is superior oblique muscle palsy, which can be congenital or acquired. Diagnosis involves the Parks three-step test and the Bielschowsky head tilt test. Treatment options include prism correction and strabismus surgery, depending on the cause.

A condition in which blood accumulates in the anterior chamber (between the cornea and iris). Blunt trauma is the most common cause, and it can lead to vision-related complications such as elevated intraocular pressure and corneal blood staining.