Clinical Methods in Ophthalmology

Clinical Methods in Ophthalmology

COMMON OCULAR SYMPTOMS AND THEIR CAUSE

Sudden painless loss of vision

  • Central retinal artery occlusion
  • Massive vitreous haemorrhage
  • Retinal detachment involving macular area
  • Ischalmic central retinal vein occlusion

Sudden painless defective vision

  • Central serous retinopathy
  • Optic neuritis
  • Methyl alcohol amblyopia

Sudden painless loss of vision

  • Acute congestive glaucoma
  • Acute iridocyclitis
  • Chemical injuries to the eyeball
  • Mechanical injuries to the eyeball

Gradual painless loss of pain

  • Progressive pterygium involving pupillary area
  • Corneal degeneration
  • Corneal dystrophies
  • Development cataract
  • Senile cataract
  • Optic atrophy
  • Chorioretinal degeneration
  • Diabetic retinopathy
  • Refractive errors

Gradual painful loss of vision

  • Chronic iridocyclitis
  • Corneal ulceration

Transient loss of vision (amaurosis fugax)

  • Carotid artery disease
  • Papilloedema
  • Giant cell arteritis
  • Migraine
  • Raynauld’s disease
  • Severe hypertension
  • Prodromal symptom of CRAO

Night blindness (Nyctalopia)

  •  Vitamin A deficiency
  •  Retinitis pigmentosa and other tapetoretinal degenerations
  •  Congenital stationary night blindness
  •  Pathological myopia
  •  Peripheral cortical cataract
  •  Advanced case of POAG

Day blindness (Hamarlopia)

  •  Central nuclear or polar cataracts
  •  Central corneal opacity
  •  Central vitreous opacity
  •  Congenital deficiency of cones (rarely)

Defective vision for near only

  •  Presbyopia
  •  Cycloplegia
  •  Internal or total ophthalmoplegia
  •  Insufficiency of accommodation

Flashes of light in front of the eyes (Photopsia)

  •  Prodromal symptom of retinal detachment
  •  Vitreous traction on retina
  •  Retinitis

Micropsia (small size of objects), macropsia (large size of objects) and metamorphopsia (distorted shape of objects).

  •  Central chorioretinitis

Coloured halos

  •  Acute congestive glaucoma
  •  Early stages of cataract
  •  Mucopurulent conjunctivitis

Diplopia

(a) Uniocular diplopia

  •  Subluxated lens
  •  Double pupil
  •  Incipient cataract
  •  Keratoconus

(b) Binocular diplopia

  •  Paralytic squint (paralysis of third, fourth or sixth cranial nerve)
  •  Myasthenia gravis
  •  Diabetes
  •  Thyroid disorders
  •  Blow-out fracture of floor of the orbit
  •  Anisometropic glass (e.g., uniocular aphakic glass)
  •  After squint correction in the presence of abnormal retinal correspondence (paradoxical diplopia).

Clinical Methods in OphthalmologyCOMMON OCULAR SIGNS AND THEIR CAUSES

CONJUNCTIVA

Conjunctival follicles

• Trachoma
• Acute follicular conjunctivitis
• Chronic follicular conjunctivitis
• Benign folliculosis

Conjunctival papillae

• Trachoma
• Spring catarrh
• Allergic conjunctivitis
• Giant papillary conjunctivitis

Concretions

• Trachoma
• Degenerative conditions
• Idiopathic

CORNEA

Decreased corneal sensations

• Herpes simplex keratitis
• Neuroparalytic keratitis
• Leprosy
• Herpes-zoster ophthalmicus
• Absolute glaucoma
• Acoustic neuroma

Superficial corneal vascularization

• Trachoma
• Phlyctenular keratoconjunctivitis
• Rosacea keratitis
• Superficial corneal ulcers

Deep corneal vascularization

• Interstitial keratitis
• Deep corneal ulcers
• Chemical burns
• Sclerosing keratitis
• After keratoplasty

Increased corneal thickness (corneal thickness Is best measured by pachymeter)

• Corneal oedema.

Abnormal corneal surface (Placido’s disc is used to detect smoothness or irregularities of corneal surface).

• Corneal abrasion
• Corneal ulcer
• Keratoconus

ANTERIOR CHAMBER

Shallow anterior chamber

• Primary angle closure glaucoma
• Hypermetropia
• Malignant glaucoma
• Postoperative shallow anterior chamber due to
– Leaking wound
– Ciliochoroidal detachment
• Corneal perforation
• Intumescent (swollen cataractous) lens
• Iris bombe formation
• Adherent leucoma

Deep anterior chamber

• Aphakia
• Total posterior synechiae
• Myopia
• Keratoglobus
• Keratoconus
• Anterior dislocation of lens in the anterior chamber
• Posterior perforation of the globe
• Buphthalmos

Hyphaema

Ocular injuries
• Post-operative
• Herpes-zostcr iritis
• Gonococcal iritis
• Intraocular tumour
• Spontaneous (from rubeosis iridis)

Hypopyon

• Comeal ulcer
• Iridocyclitis
• Retinoblastoma (pseudohypopyon)
• Endophthalmitis
• Panophthalmitis

IRIS

Nodules on the iris surface

• Granulomatous uveitis (Koeppe’s and Busacca’s nodules)
• Melanoma of the iris
• Tuberculoma
• Gumma

Rubeosis iridis (Neovascularization of iris)

• Diabetes mellitus
• Central retinal vein occlusion
• Chronic iridocyclitis
• Sickle-cell retinopathy
• Retinoblastoma

Iridodonesis

• Dislocation of lens
• Aphakia
• Hypermature shrunken cataract
• Buphthalmos

PUPIL

Normal pupil

• Diameter 3 to 4 mm
• In infancy pupil is smaller than at birth
• Myopes have larger pupil than hypermetropes.

Miosis 

• Effect of miotic drugs (Parasympathomimetic drugs e.g., pilocarpine)
• Effect of systemic morphine
• Iridocyclitis (narrow, irregular non-reacting pupil)
• Homer’s syndrome
• Head injury (pontine haemorrhage)
• Senile rigid miotic pupil
• During sleep
• Argyll-Robertson pupil
• Poisonings
– Alcohol
– Barbiturates
– Organophosphorus compounds
– Morphine
– Carbolic acid
• Hyperpyrexia

Mydriasis

• Topical sympathomimetic drugs such as adrenaline and phenylephrine
• Topical parasympatholytic drugs such as atropine, homatropine, cyclopentolate, irnpicamide
• Acute congestive glaucoma (vertically oval, large, immobile pupil)
• Absolute glaucoma
• Optic atrophy
• Retinal detachment
• Internal ophthalmoplegia
• Third nerve paralysis
• Belladona poisoning
• Coma
• Sympathetic stimulation

– Aortic aneurysm
– Cervical rib
– Irritative lesions in neck
– Mediastinal sarcoma, lymphosarcoma, Hodgkin’s disease and pulmonary carcinoma
– Emotional excitement
• Severe anaemia
• Adie’s tonic pupil is larger than its fellow.

Leukocoria (white reflex in pupillary area)

• Congenital cataract
• Retinoblastoma
• Persistent hyperplastic primary vitreous
• Retrolental fibroplasia
• Toxocara endophthalmitis
• Coat’s disease

Marcus Gunn Pupil

(In swinging flash light test, the pupil on the diseased side dilates on transferring light to it)

• Optic neuritis
• Optic atrophy
• Retinal detachment
• Central retinal artery occlusion
• Central retinal vein occlusion

LENS

Subluxation of lens

• Trauma
• Marfan’s syndrome
• Homocystinuria
• Weil-Marchesani syndrome

RETINA

Cherry red spot

• Central retinal artery occlusion
• Commotio retinae (Berlin’s oedema)
• Taysach’s disease
• Niemann-Pick’s disease
• Gaucher’s disease
• Sialidosis .
• Gangliosidosis

Macular oedema

• Trauma
• Intraocular operations
• Uveitis
• Diabetic maculopathy

Superficial retinal haemorrhages

• Hypertensive retinopathy
• Diabetic retinopathy
• Central retinal vein occlusion
• Anaemic retinopathy
• Leukaemic retinopathy
• Retinopathy of AIDS

Soft exudates on the retina

• Hypertensive retinopathy
• Retinopathy of toxaemia of pregnancy
• Diabetic retinopathy
• Anaemic retinopathy
• OLE, PAN and Scleroderma
• Leukaemic retinopathy
• Retinopathy of AIDS

Hard exudates on the retina

• Diabetic retinopathy
• Hypertensive retinopathy
• Coat’s disease
• Circinate retinopathy

Sub-retinal neovaacular membrane

• Wet ARMD
• Presumed ocular histoplasmosis syndrome (POHS)
• Angiod streaks
• Choroidal naevus
• Choroidal rupture
• High myopia
• Inappropriate photocoagulation
• Optic disc drusen

Bull’s eye maculopathy

• Chloroquine toxicity
• Cone dystrophy
• Benign concentric annular macular dystrophy
• Batten’s disease
• Bardet-Biedl syndrome
• Occasionally Leber’s Amaurosis

Neovascularization of retina

• Diabetic retinopathy
• Eales’ disease
• Sickle-cell retinopathy
• Central retinal vein occlusion

Proliferative retinopathy

• Proliferative diabetic retinopathy
• Sickle-cell retinopathy
• Eales’ disease
• Ocular trauma

Salt and pepper appearance of fundus

• Prenatal rubella
• Prenatal influenza
• Varicella
• Mumps
• Congenital syphilis

Arterial pulsations at the disc

• Visible arterial pulsations are always pathological
• True pulse waves are seen in:
– Aortic regurgitation
– Aneurysm
– Exophthalmic goitre
• Pressure pulse is seen in:
– Glaucoma
– Orbital tumours

Venous pulsations at the disc

• Visible in 10-20% of normal people
• Absent in papilloedema

Capillary pulsations

• Are seen in aortic regurgitation as a systolic reddening and diastolic paling of the disc.

VISUAL FIELDS

Enlargement of blindspot

• Primes open-angle glaucoma
• Papilloedema
• Medullated nerve fibres
• Drusen of the optic nerve
• Juxtapapiilary choroiditis

Tubular vision

• Terminal stage of advanced glaucomatous field defect
• Advanced stage of retinitis pigmentosa

Ring scotoma

• Glaucoma
• Retinitis pigmentosa

Central scotoma

• Optic neuritis
• Tobacco amblyopia
• Macular hole, cyst, degeneration

Bitemporal hemianopia

• Central lesions of chiasma
• Pituitary tumours (common)
• Suprasellar aneurysms
• Craniopharyngioma
• Glioma of third ventricle
• Meningiomas at tuberculum sellae

Homonymous hemianopia

• Optic tract lesions
• Lateral geniculate body lesions
• Lesions involving total fibres of optic radiations
• Visual cortex lesions (usually sparing of macula)

Binasal hemianopia

• Lateral chiasmal lesions
• Distension of third ventricle
• Atheroma of posterior communicating arteries

Altitudinal hemianopia

• Loss of upper or more rarely lower halves of field from pressure upon the chiasma
• Early loss in upper half of field – intra or extrasellar tumours
• Early loss in lower half of field- suprasellar tumours.

Quadrantic hemianopia

• Homonymous upper quadrantinopia (pie in the sky)- Temporal lobe lesions involving lower fibres of optic radiations.

• Homonymous lower quadrantinopia (pie on the floor) – anterior parietal lobe lesions involving upper fibres of optic radiations.

• Quadrantic hemianopia also occurs due to lesions in the occipital cortex involving the calcarine fissure.

OCULAR EXAMINATION TECHNIQUES AND DIAGNOSTIC TESTS

Loupe and lens examination

• Power of the corneal loupe is +41 DS
• Magnification of image with corneal loupe is 10 X.

Slit-lamp examination

• Slit-lamp was invented by Gullstrand in 1911.
• Aqueous flare and Keratic precipitates are best demonstrated by slit-lamp examination.

Testing of visual acuity

• Visual acuity in a child below 2 years of age can be tested by:
– Opto-kinetic nystagmus (OKN)
– Preferential looking test
– Pattern visual evoked potential
• Two distant points can be visible as separate only when they subtend an angle of one minute at the nodal point.
• Each individual letter of Snellen’s test type subtends an angle of 5 minutes at the nodal point. Whereas, each component part of the letter subtends an angle of 1 minute.

Tonometry

• Schiotz tonometer is an indentation tonometer.
• Concept of applanation was introduced by Goldmann in 1954. It is based on Imbert-Fich law.
• Applanation tonometers are: Goldmann tonometer, Perkin’s tonometer and Penumatic tonometer.
• Applanation tonometer is more accurate than the Schiotz tonometer because factor of scleral rigidity is not involved in the former.
• Normal range of intraocular pressure is 10-21 mmHg
• Best accuracy with Schiotz tonometer is attained with that weight with which a scale reading of 3- 4 is achieved.

Gonioscopy

• Angle structures cannot be examined directly since the light emitted from here undergoes total internal reflection at the anterior surface of the cornea.
• Goldmann and Zeiss gonioscopes are indirect goniolenses and provide a mirror image of the opposite angle.
• Koeppe goniolens provides a direct view of the angle.

Direct ophthalmoscopy

• It was invented by Babbage in 1848 and reinvented and popularized by Von Helmholtz in 1850.
• It should be performed from as close to the patient’s eye as possible (ideally 15.4 mm)
• Image formed is erect, virtual and 15 times magnified in emmetropes (more in myopes and less in hypermetropes).

Distant direct ophthalmoscopy

• It is performed from a distance of 20-25 cm.
• It is useful in detecting opacities in the media of the eye, a hole in the iris, a detached retina and a suhluxated lens.
• The black shadow produced by an opacity in the pupillary plane remains stationary, that in front of the pupillary plane moves in the direction of the movement of the eyeball and that behind it will move in opposite direction.

Indirect ophthalmoscopy

• It was invented by Nagel in 1864.
• In it the examining eye is made myopic by placing a strong convex lens in front of patient’s eye.
• It is performed from a distance of an arm’s length (60-75 cms).
• Image in indirect ophthalmoscopy is formed in the air between the convex lens and examiner’s eye and it is real, inverted and about 5 times magnified with +13D lens
• Magnification of the image does not depend upon the refractive error of the observer’s eye but depends upon:
– power of convex lens used
– refractive error of the observed eye and
– position of the convex lens in relation to the eye.

Biomicroscopic examination of the fundus

Biomicroscopic examination of the fundus is performed with the help of any of the following:
• -58.6 D Hruby lens
• +78 D or +90 D small diameter lens
• Posterior fundus contact lens
• Goldmann’s three mirror contact lens.

Perimetry

• Normal extent of field of vision for white colour is:
– Superior : 60°
– Nasal : 600
– Inferior 70°
– Temporal : 90°
Field of vision for blue and yellow colour is roughly 10° less and that for red and green colour is about 20° less than that for white (smallest is with green colour).
Red colour perimetry is particularly useful in the diagnosis of bitemporal hemianopia with chiasmal compression and of central scotoma of retrobulbar neuritis.
• Kinetic perimetry can be performed with Lister’s perimeter, Goldmann perimeter and tangent screen
Static perimetry is performed with adapted Goldmann perimeter, Friedmann perimeter and automated perimeter.
Campimetry (scotometry) is performed to evaluate the central and paracentral area (30°) of the visual field on Bjerrum’s screen.

Fundus fluorescein angiography

• 5 ml of 10 percent solution of sterile sodium fluorescein dye is injected in the antecubital vein.
• In the blood fluorescein is readily bound to the albumin.
• Blue light (420-490 nm) is used for exciting the fluorescein present in the blood vessels.
• Yellow-green filter is used to receive the fluorescent light (510-530 nm.) for photography.
• Hyperfluorescence is seen in:
– Atrophy of retinal pigment epithelium (RPE)
– Detachment of RPE
– Central serous retinopathy
– Cystoid macular oedema
– Leakage of dye from neovascularization
– Drusens
– Papilloedema
• Hypofluorescence is seen in:
– Retinal haemorrhages
– Choroidremia
– Central retinal artery occlusion.

Electroretinography (ERG) and electro-oculography (EOG)

• Normal ERG consists of:
– a-wave is a negative wave possibly arising from the rods and cones
– b-wave is a large positive wave which is generated by Muller’s cells, but represents the activity of bipolar cells
– c-wave is a positive wave representing metabolic activity of pigment epithelium. ^
• ERG is abnormal in patients with:
– Retinitis pigmentosa and other tapetoretinal degenerations
– Central retinal artery occlusion
– Total retinal detachment
• ERG is normal in diseases involving ganglion cells and higher visual pathways, such as optic atrophy
• EOG is based on the resting potential of the eye which exists between the cornea (+ve) and back of the eye (-ve)
• EOG is abnormal in diseases such as retinitis pigmentosa, vitamin A deficiency, retinal uctachment
• EOG is more sensitive than ERG in diagnosis of retinitis’pigmentosa.

Visually evoked response (VER)

• VER refers to electroencephalography (EEG) recorded at the occipital cortex.
• VER assesses the functional state of the visual system beyond the retinal ganglion cells.
• Flash VER is based on light perception while pattern reversal VER is based on form sense and thus gives a rough estimate of the visual acuity.
• Clinically VER is used to:
– Assess visual acuity in infants and mentally retarded individuals
– Confirm malingering
– Confirm optic nerve diseases like retrobulbar neuritis.

Ultrasonography

• Ophthalmic ultrasound is based upon pulse-echo technique empolying frequencies in the range of 10 MHz.
• A-Scan (Time amplitude) produces unidimensional image echoes plotted as spikes. The distance between the two echo spikes provides an indirect measurement of tissue such as eyeball length, anterior chamber depth and lens thickness.
• B-scan (intensity modulation) produces two- dimensional dotted section of the eyeball.
• Uses of ultrasound are:
– Biometric studies using A-scan to calculate power of the intraocular lens to be implanted
– Assessment of the posterior segment in the presence of opaque media.
– Study of intraocular and intraorbital tumours
– Ultrasonographic pachymetry (measurement of comeal thickness).