Anomalies of Accommodation PDF

PRESENTATION LAY OUT  Accommodation…….. Overview  Anomalies of accommodation …..classification  Cli...

PRESENTATION LAY OUT  Accommodation…….. Overview  Anomalies of accommodation …..classification  Clinical presentation  Management 1 2 ANOMALY ANOMALIES OF ACCOMMODATION  CLASSIFICATION  Anomaly means a deviation from the normal state.  A: DIMINISHED OR DEFICIENT ACCOMMODATION  This deviation may be above or below the normal  1. physiological (presbyopia) state.  2. pharmacological (cycloplegia)  In case of accommodation, anomalies simply  3. pathological comprises of increase or decrease in accommodation.  insufficiency of acc;  ill-sustained acc;  inertia of acc;  paralysis of acc;  B: INCREASED ACCOMMODATION  1. excessive accommodation  2. spasm of accommodation 3 4 DIMINSHED ACCOMMODATION  PRESBYOPIA  It is not a state of refractive error but a condition of physiological insufficiency of accommodation.  The condition of failing near vision due to age related decrease in the amplitude of accommodation or  Increase in punctum proximum is called presbyopia. 5 6 1  Pathophysiology of presbyopia  With increasing age there is a decrease in the accommodative power of the crystalline lens due to  sclerosis ( hardening) of the crystalline lens with increasing age and/ or  age related decrease in the power of ciliary's muscles 7 8 Symptoms of presbyopia  Difficulty in near vision  Asthenopic symptoms  Intermittent diplopia at near ……..due to the interrelationship b/w accommodation and convergence. 9 10 Treatment of presbyopia  Optical  spectacles  contact lenses  Surgical  IOL,s with near add  LTK laser thermal keratoplasty 11 12 2  INSUFFICENCY OF ACCOMMODATION Causes of accommodative insufficiency  DEF;  When the accommodative power is significantly less  1.Premature sclerosis of lens than the normal physiological limits for the patient's  2. weakness of CM either due to age.  systemic causes e.g malnutrition ,DM ,  Should not be confused with presbyopia in which the pregnancy ,anemia ,toxaemia and stress. physiological insufficiency of acc is normal for the pt,  local causes e.g POAG, age. 13 14 Clinical features Clinical features  All these symptoms are stable in accommodative  Asthenopia symptoms such as headache ,fatigue, insufficiency of lenticular origin.however irritabilty of the eyes while doing near work  When the condition is due to CM weakness,then with  The pt remains comfortable if near work is not improvement in GH,or relaxation from overwork or attempted. worry, the symptoms may considerably improve.  Near work is blurred and difficult.  Intermittent diplopia for near. 15 16 Treatment Accommodation exercises  Treatment of the cause (systemic causes)  Accommodation exercises are helpful when the  Near vision spectacles general debility has passed and the lenticular  Weakest convex lenses should be given after sclerosis is not the cause of diminished distance correction if any. accommodation.  Accommodation exercises are carried out  BI prisms if there is associated convergence insufficiency. binocularly when there is associated convergence weakness otherwise  When convergence excess is associated then give  One eye should be covered while exercising. full spherical correction. 17 18 3  Accommodation test card exercises Accommodation test card  It is the most simple exercise  The card consist of a black vertical line drawn on a white card.  The pt should be instructed to hold the card at a considerable distance and then bring it closer until the line appears blurred.  He should be encouraged to attempt to bring his near point as close as possible 19 20 ILL-SUSTAINED ACCOMMODATION AETIOLOGY  It is also known as a condition of accommodation fatigue may be defined as the situation in which  It is the initial stage of true insufficiency. although the range of a accommodation is normal but Accommodation fatigue is characteristically known to it cannot be sustained for sufficient time period. occur in the following conditions.  It causes a tendency for the near point of  Stage of convalescence from debilitating illness accommodation of the patient to recede during close  Stage of general tiredness work.  When patient is relaxed in the bed 21 22 CLINICAL FEATURES TREATMENT  Since it is initial stage of true insufficiency, the  Avoiding the near work during situation described in symptoms are largely the same. Typically the patients etiology complain that while doing near work, they start feeling  General tonic measures. tired very soon. Their near point gradually recedes and  Improve visual hygiene with particular reference to the near visions become blurred. conditions of illumination and posture during study. 23 24 4  ACCOMMODATION INERTIA CLINICAL FEATURES  It is the condition in which there is difficulty in  Patient typically complains that it takes some time and adjusting the accommodation according to the involves some definite effort for him to focus a near distance of regard so as to gain clear vision.It is object after looking at a distance. Usually this comparatively rare condition condition does not assume any serious symptoms, but occasionally may give rise to some trouble and annoyance 25 26 TREATMENT PARALYSIS OF ACCOMMODATION  Correct any refractive error  It refers to complete absence of accommodation also  Practice of accommodation exercises known as cycloplegia 27 28 CAUSES CAUSES  Paralysis of accommodation as component of  Drug induced cycloplegia results due to the complete 3rd nerve paralysis may occur due to effect of parasympatholytics drugs such as intracranial or orbital causes. the lesion may traumatic atropine, homatropine and others. inflammatory or neoplastic  Internal ophthalmoplegia, it means paralysis of sphincter pupillae muscles and ciliary muscle may result from neuritis associated with diabetes, chronic alcoholism ,cerebral or meningial diseases including even a mild head injury 29 30 5  CLINICAL FEATURES TREATMENT  Blurring of near vision  Treat the systemic diseases such as diphtheria, syphilis etc.  It is the main complaint in previously emmetropic or hypermetropic patient. Blurring of vision may  Self recovery occur in drug induce paralysis. not be marked in myopic patient  Dark glasses to reduce the glare  Photophobia It is due to accompanying  In permanent paralysis plus lenses for near vision. mydriasis.Usually associated with blurring of near vision.  On examination there is abnormal receding of NPA and markedly decrease range of accommodation 31 32 INCREASED ACCOMMODATION  EXCESSIVE ACCOMMODATION EXCESSIVE ACCOMMODATION  It is a situation in which an individual exerts more than normal accommodation for performing certain  SPASM OF ACCOMMODATION near work. it is with in the voluntary control of the individual and is an intermittent process. 33 34 CAUSES CAUSES  Astigmatic errors in young persons may also be  Certain degree of excessive accommodation is occasionally with the use of excessive accommodation. frequently noted under following circumstances  Presbyopes in the beginning also use excessive accommodation to accomplish near work.  Young hypermetropes frequently use excessive  Use of improper or ill-fitting spectacles may also accommodation as a physiological adaptation to cause use of excessive accommodation attain clear vision.  Young myopes performing excessive near work may also use excessive accommodation in association with excessive convergence. 35 36 6  CLINICAL FEATURES Precipitating factors  Blurred vision of varying degree due to induced  Large amount of near work. pseudomyopia  Habitual near work in deficient or excessive  Symptoms of accommodative asthenopia illumination.  Both far point ant near point are brought nearer to the  General debility eye  Physical or mental ill health  Near vision also suffers in the more marked degrees and after reading for some time the printed page becomes confused and clears up only after a temporary rest. 37 38 SPASM OF ACCOMMODATION TREATMENT  Spasm of accommodation is a continuous prolonged  The treatment is usually effective with good prognosis use of excessive accommodation or it refers to the  Optical treatment correct refractive error while abnormally excessive accommodation which is out of performing cycloplegic refraction the voluntary control of the individual.  General treatment near work should be forbidden for a period  General conditions of the patient’s health should receive special attention 39 40 Causes Causes  Spasm of near reflex is a clinical syndrome often  Drug induced spasm of accommodation is known to seen in disturbed and tense individuals. who occur after use of strong miotics such as echothiophate presents with  Spontaneous spasm of accommodation  Excessive accommodation  Occasionally found in children usually in uncorrected hypermetropes but also in astigmatic and even in myopes  Excessive convergence and children.  Meiosis  It usually occur when the eyes are used for excessive near  Lesion of brainstem e.g. encephalitis and work in unfavorable conditions such as bad illumination , meningitis may be associated with ciliary spasm bad reading position, lowered vitality , state of neurosis , mental stress and anxiety.  Toxic reaction exogenous poisons e.g.  Iridocyclitis may be associated with ciliary spasm. sulphonamides, arsenic or even smoking can sometime cause spasm of accommodation 41 42 7  TREATMENT Clinical features  Relaxation of ciliary muscles  The most effective method of treatment is the  Varying blurred vision due to induced pseudomyopia production of complete ciliary paralysis with atropine.  Asthenopic symptoms are more marked than the  The cycloplegia should be kept for 4 weeks or more. visual symptoms (blurr).  Optical treatment  Headache and brow ache are typical features.  NPA is abnormally close.  correcting spectacle should be worn immediately  Macropsia may occur. when eyes are used again after period of cycloplegia. 43 44 TREATMENT REFERENCES  General treatment  Duke-Elders practice of refraction 10th edition  Near work should be forbidden for a period  Theory and practice of optics and refraction A K  The general condition of the patient health should KHURANA receive special attention.  Therefore, a holiday with a change of air usually has a greater effect than anything else. 45 46 8