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Ortho K Contact Lenses
Transcript of Orthokeratology_Refractive treatment
- Students name : Anis Suzanna Binti Mohamad Matrix number : A123369 Lecturers name : Prof. Dr. Norhani Mohidin
- Orthokeratology (OK) is a clinical technique that uses specially designed rigid contact lenses to reshape the cornea to temporarily reduce or eliminate refractive error (H.A Swarbick., 2006). Also known as corneal shaping lenses, corneal refractive therapy or CRT and vision shaping treatment or VST Mode of wear: Night therapy - during sleep for about 8 hours. Day therapy - half day of waking hours.
- 1. Base curve- flatter than the flattest central apical radius. 2. Reverse curve- steeper secondary curve forms a tear reservoir for excess tear. 3. Alignment curve- allows the shaping lens to centre and position properly on the eye. 4. Peripheral curve- allow for tear circulation under the shaper & easy removal of debris trapped.
- Age: juvenile to adult myopes Spherical refractive error: -1.00 D to -5.00 D spherical power correction Cylindrical refractive error: - 1.50 D or less with-the-rule corneal astigmatism - 0.75 D or less against-the-rule astigmatism Recreational and sports activities where periods without wearing visual correction are beneficial Those whose vocation requires unaided visual acuity for certain periods, such as police, firemen, military, or occupations where refractive surgery may be a cause for exclusion (deep-sea divers, high altitude pilots, etc.) Free of corneal dystrophies (e.g. keratoconus), ocular diseases, or any condition that may preclude the patient from wearing any type of GP lens Motivated to undergo full or partial myopia reduction and willing to return to the office for two to three months of active treatment and every six months for passive treatment Committed to the initial and ongoing cost of ortho-k treatment. Practitioners should consult fitting information provided by specific design/fitting systems.
- 2. Pre-fitting assessment 3. Post-fitting assessment/ Follow up examination Refraction and VA Baseline topography (keratometry optional, but topography is a must) Tear film analysis a. Schirmer test (quantitative) b. Tear Break-Up Time or TBUT (qualitative) Biomicroscopy-corneal health/fitting pattern Refraction and VA with and w/o CL Overefraction Corneal health Fitting pattern Topography Follow-up pattern:- 24 hour after wearing the lens 1 week after wearing the lens 2 week after wearing the lens 1 month 3 month
- Patients profile: F/14/C File. No: 5596 Visit 1: PCC Date: 7/1/2011 History taking: Chief complaint:-Come for ortho-K examination. Ocular history:-Patient start wearing contact lenses 8 years. Current Rx since last year. General health:-Allergic to dust. Others nil. Family history:-Bronchitis. RE LE Vision aided Distant Near Distant Near 6/6 With +1.00: 6/18 [email protected] 6/9+3 With pinhole: 6/6 [email protected] Current Rx -3.50/-0.25x180 -3.00/-0.50x180 Slit lamp Dusty eyelashes Papillae TBUT:7 secs Dusty eyelashes Papillae TBUT:7 secs Subjective refraction&VA -3.50/-0.50x10 (6/6) -2.75/-1.00x10 (6/6) Keratometry 7.9/[email protected] 7.55/[email protected] Lens to fit: 2P05 7.9/[email protected] 7.50/[email protected] Lens to fit: [email protected] 2P02
- Corneal topography Axial length 24.55mm 24.25mm Apical radius 7.718mm 7.648mm Diagnosis Papillae with dusty eyelashes. Management plan Suggest to use lid care for eyelashes hygiene Suggest do warm compression. To come again for ortho-K fitting. KIV to see papillae and eyelashes.
- Assessment of ortho-K fitting was done: delivery lens on 18.02.2011 24 hours after overnight wear assessment: 21.02.11 Right eye Left eye Ordered lens VIPOK 2N05 VIPOK 2003 Lens inspection Ok Ok Over-refraction and VA Plano, 6/5 Plano, 6/5 Remarks Deliver Deliver Right eye Left eye VA with CL Not done Not done Fitting assessment Not done Not done Over-refraction and VA without CL -2.50/-0.25x180, 6/6- VA without CL: 6/36-1 -2.25/-0.25x180, 6/6- VA without CL: 6/36 Lens inspection Small deposits Lens has eyelashes Slit lamp findings Cornea: clear Papillae Cornea: SPK Papillae
- Corneal topography Apical radius 7.724mm 7.833mm Keratometry [email protected] [email protected] Corneal astig:-1.81x133.2 [email protected] [email protected] Corneal astig:-1.99x99.6 Remarks To come again one week after wearing CL.
- Aftercare 2 weeks later: 7/3/2011 Symptom: Vision is still not improved. Patient complaint of seeing haloes or double vision at all time. Patient wore contact lenses 8 hours every night since 2 weeks ago. Right eye Left eye VA with CL 6/6 6/6 Fitting assessment Too much pooling Too much pooling Over-refraction and VA without CL -1.75/-0.25x140, 6/6 VA without CL: 6/24 -1.50/-0.50x140, 6/6 VA without CL: 6/24 VA without CL on both eyes: 6/18
- Corneal topography Apical radius 8.101mm 7.839mm Lens inspection Not done Not done Slit lamp findings NAD NAD Remarks To fit with flatter lens on both eyes. Lens to fit: RE: 2M05 LE: 2N03
- Assessment of ortho-K fitting was done: delivery lens on 7.3.2011 Symptom: Get double vision after takeoff CL occasionally. Patient wore contact lenses 11 p.m. to 7 p.m. every night since 2 weeks ago. Aftercare 2 weeks after new ortho-K wearing on 18.3.2011 Right eye Left eye VA with CL 6/9+1 6/6+ Fitting assessment x = 0, y = 0 x = -1, y = 0 Over-refraction and VA without CL -0.50Ds, 6/6 VA without CL: 6/6-3 -0.25Ds, 6/6 VA without CL: 6/6 VA without CL on both eyes: None
- Corneal topography Keratometry [email protected] [email protected] Corneal astig:-2.57x123.6 [email protected] [email protected] Corneal astig:-2.60x99.6 Apical radius 8.013mm 7.833mm Lens inspection Not done Not done Slit lamp findings Remarks To continue with contact lens wear. To come again 15/4/2011 for review.
- Patient start wearing ortho-k lenses since 18.02.11: Fitting acceptable, lens can deliver. First aftercare after 24 hours wearing on 21.2.11: still a residue of the steep cornea changes of corneal curvature and refractive error still continue over first few days reach stable usually after 7-10 night. Aftercare after 2weeks on 7.3.11: The fitting at first was unsuccessful/unable to obtain bull eye pattern. Change to flatter lenses. Aftercare after 2 weeks on 18.3.11: improvement in topographic pattern were shown and been follow up monthly
- There are three possible outcomes from wearing ortho-K lenses:- The centred treatment pattern (Bulls eye). A well-centred area of flattening. A circle of mid-peripheral corneal steepening. Little/no perpheral corneal change. Decentered treatment pattern. Smiley Face Pattern- lens superior and too flat. Frowny Face Pattern- alignment curve too steep or tight. Lateral decentration- lens diameter too small or cornea flattens much faster on nasal compare to temporal. Central island pattern. Due to overestimating the corneal sagittal height or underestimating the eccentricity. Therefore, corneal topography is useful in orthokeratology.
- Pre-fitting analysis Post-fitting analysis Screening for pathologic corneas Establishing the baseline corneal shape Predicting the outcome based on the pre-fitting apical radius and corneal eccentricity. Accurate shape analysis to assist in selecting optimum lens parameters Identifying and documenting induced corneal changes Assisting with problem solving and lens design refinements Patient education
- 7/1/2011 (PCC) 21/2/2011 (A/care 24hrs) 7/3/2011 (A/care 2wks) 18/3/2011 (A/care 2wks) Vision aided 6/6 6/6- 6/6 6/9+3 Vision unaided Not done 6/36- 6/24 6/6-3 Corneal topographic Apical radius 7.718 7.724 8.101 8.013 Remember that the position of the contact lens in the open-eye environment is not necessarily representative of where the lens positions in the closed eye. Therefore, corneal mapping provides the only reliable means of knowing precisely where the lens positioned during sleep.
- 7/1/2011 (PCC) 21/2/2011 (A/care 24hrs) 7/3/2011 (A/care 2wks) 18/3/2011 (A/care 2wks) Vision aided 6/9+3 6/6- 6/6 6/6+ Vision unaided Not done 6/36 6/24 6/6 Corneal topographic Apical radius 7.648 7.833 7.839 7.833 Good fit: treatment zone composes the pupil diameter The size of central treatment zone will influence the subjective visual outcome
- Vision unaided after removal of the ortho-K lens is satisfied on both eyes. The fitting is determine the vision and corneal mapping after the lens removal. According to the last visit, for the right eye, the corneal topographic showed that the centered treatment pattern. However, for the left eye, there are some residual steepening of corneal topographic. It looks like smile face pattern. The management is quite confusing. Smile face pattern or decentered pattern showed the lens is decentered superiorly or lens too flat. However, the examiner just advice patient to continue wear the glasses.