CASE 2-1
Visual Flare, Part 1
Figure 2-1
History
A 26-year-old Caucasian male presents for his first progress evaluation with complaints of flare with his new rigid gas-permeable (RGP) contact lenses (CL). This is his first experience wearing contact lenses. He notices the flare at night and indoors but does not notice it in daylight. He is otherwise satisfied with his contact lenses. His wearing time is up to 8 hours per day, but he removes the lenses as soon as he gets home from work because of the flare. He uses Boston Advance Comfort Formula to clean and disinfect his lenses. His ocular and medical histories are unremarkable. He takes no medications and has no allergies.
47
48 Clinical Cases in Contact Lenses
Symptoms
Visual flare with the RGP lenses, especially under low light conditions
Clinical Data
• Entering visual acuity with CL:
OD 20/20
OS 20/20
• CL specifications:
OD 7.85 / –2.25 / 9.0 / 7.8 / Polycon II OS 7.90 / –2.50 / 9.0 / 7.8 / Polycon II
• Over-refraction:
OD Plano sphere, 20/20 OS +0.25 sphere, 20/20
•CL fit assessment: Superior-central position, 2 mm movement on blink, lid attachment, apical alignment with moderate peripheral clearance OU (see Figure 2-1)
•Keratometry:
OD 43.00 / 43.75 @ 090
OS 43.00 / 44.25 @ 090
• Subjective refraction:
OD –2.25 –0.75 × 180, 20/20 OS –2.50 –1.25 × 180, 20/20
•Gross external exam: Eyes appear white and quiet OU
•Biomicroscopy: All structures appear clear and healthy OU
Develop your list of differential diagnoses. Then, based on the clinical data, determine your final diagnosis. Based on your diagnosis, develop your treatment plan.
Differential Diagnoses
•Optic zone diameter too small
•Lens decentration
•Incomplete adaptation
•Poor blending of optic zone junction
•Overminused
Diagnosis
Optic zone diameter is too small
Visual Flare, Part 1 49
Management
The lens diameter and optic zone diameter were increased to decrease the patient’s symptoms of flare:
OD 7.90 / –2.00 / 9.4 / 8.2 / Paraperm O2
OS 7.95 / –2.00 / 9.4 / 8.2 / Paraperm O2
The patient noticed markedly reduced flare, although it remained present to a small degree. He was educated about the reasons for the flare and explained that it diminishes with adaptation. He increased his wear time gradually to 14 hours and reported that the flare was noticeable only under very dark conditions.
Discussion
A rigid gas-permeable contact lens with a small optic zone often causes flare.1–4 From the photo of the lens fit, it is apparent that this contact lens has an optic zone too small for the patient’s pupil size. This is even more evident considering that the pupil size in an ocular photograph very likely is smaller than it would be under dark lighting conditions. Since this patient’s complaints occur under dimmer illumination conditions, it is important to measure the pupil size in a dark room. Also, because he is a young Caucasian male with blue irises, he is more likely to have larger pupils and therefore notice visual flare from the optic zone junction. The patient will be able to ignore some amount of flare as he adapts. However, in this case, the optic zone diameter should be increased.
Another consideration is the position of the lens. Because the lens rides superiorly in a lid attachment position, the optic zone is shifted upward. This brings the inferior edge of the optic zone toward the pupil, which makes the flare even more noticeable. Therefore, it is helpful, in this case, to improve lens centration to further decrease the flare. The two simplest changes to improve centration are increasing lens diameter and steepening the base curve.1–5 Since we already increased the optic zone diameter, it makes sense to also increase the lens diameter by the same amount. In general, a 0.3–0.4 mm increase in both diameters is sufficient. This change improves centration by covering more of the cornea and also by steepening the fit. Any increase in the optic zone diameter, and to a lesser extent the overall diameter of an RGP lens, steepens the fitting relationship. This is visible during fluorescein pattern assessment. Too steep a fitting relationship can be offset by flattening the base curve radius.
50 Clinical Cases in Contact Lenses
Other possible lens changes include increasing the blend of the optic zone–secondary curve junction or changing to a junctionless aspheric back surface design.1–3 In this case, it is obvious that the primary cause of the patient’s flare is the small optic zone diameter. However, in cases where the optic zone is larger than the pupil, blending the optic zone helps diminish flare. In extreme cases, an aspheric back surface design can be used as well, but the flare will remain present to some degree because of the changing refracting power in the lens periphery as the back surface flattens.1
The patient’s symptom is much reduced by changing the overall diameter and optic zone diameter of the lens. Although he still notices some flare in dark environments, it is tolerable. Patient education on the cause of his visual flare also decreases the patient’s concerns. It is good practice to present visual flare as a potential observation for all new RGP wearers, particularly during the adaptation stages. By presenting this potential symptom prior to the lens fitting, the patient is more likely to accept it and adapt to it.
Clinical Pearls
•Visual flare can be caused by a large pupil, small optic zone, or lens decentration.
•Visual flare is common early in RGP adaptation.
•Patient education prior to fitting RGP lenses helps reduce complaints of visual flare after initial dispensing.
References
1.Hodur NR, Gandolfi B, Wojciechowski S. Flare with rigid contact lenses. Contact Lens Forum. 1986;11(3):48–49.
2.Hom MM. Rigid lens design and fitting. In: Hom MM (ed). Manual of Contact Lens Prescribing and Fitting with CD-ROM, 2nd ed. Boston: Butterworth–Heinemann, 2000:77–103.
3.Rakow PL. Spherical rigid gas-permeable contact lenses. Ophthalmol Clin North Am. 1996; 9(1):31–51.
4.Josephson JE, Caffery BE, Rosenthal P, et al. Symptomatology and aftercare. In: Ruben M, Guillon M (eds). Contact Lens Practice. London: Chapman and Hall, 1994:565.
5.Theodoroff CD, Lowther GE. Quantitative effect of optic zone diameter changes on rigid gas-permeable lens movement and centration. Int Contact Lens Clin. 1990;17(2):92–95.