Article

PRESCRIBING FOR ASTIGMATISM

IRREGULAR ASTIGMATISM AND INCREASED RISK FOR TRAUMA

Many patients pursue contact lenses to be free of spectacles while participating in contact sports. For patients who rely on GP lenses to optimally correct irregular astigmatism resulting from corneal pathology such as keratoconus, special considerations may be necessary before determining the most appropriate lens modality to prescribe. In one particular case, a 26-year-old male who had keratoconus presented with the question of whether scleral GP lenses could sustain the impact of blows to the oculofacial area while engaging in Muay Thai, a form of Thai boxing. This brings into focus the multifaceted prescribing considerations that must be made for patients who contend with irregular astigmatism and increased risk for ocular trauma.

Ocular Trauma with GP Lens Wear

It is important to educate patients about the risks associated with activities that could result in ocular trauma, such as contact sports. In patients who have compromised corneal integrity due to corneal ectasia, it is imperative to thoroughly educate them on the possibility of corneal damage such as corneal abrasions or perforation. Patients who wear corneal GP lenses may also have to contend with the repercussions associated with lens ejection or dislocation, whereas those who wear scleral GP lenses may be more at risk for breakage upon impact due to the higher likelihood of direct contact with the larger lens diameter.

Prescription sports goggles or plano sports goggles worn over GP lenses can provide ocular protection. However, in some sports such as water polo and martial arts, regulations prohibit the use of headgear and eyewear.

Alternatives to GP Lens Wear

Soft contact lenses can be a viable option in certain circumstances. However, most commercial soft contact lenses may not provide adequate quality of vision for patients who have irregular astigmatism. In addition, vision is likely to fluctuate with soft lenses, similar to vision through spectacle correction.

It may be worthwhile to trial an extended-range soft lens to assess whether the resultant vision is adequate for a patient’s needs. For some patients who have mild astigmatism or mildly impaired spectacle vision, it is possible to pursue this route if an adequate fit is achieved (i.e., no significant lens edge fluting).

Soft contact lens designs for keratoconus present another option to mask irregular astigmatism. However, before initiating diagnostic lens fitting, inform patients that custom lenses generally require multiple visits before the prescription is finalized and might not provide adequate visual correction.

Practical Considerations

Ideally, clinicians should attempt to dissuade patients who have corneal ectasia from partaking in contact sports. However, several practical considerations need to be made when patients are unwilling to discontinue.

One possible option is for patients to not wear contact lenses while participating in high-impact activities. However, forgoing optical correction can increase the chance of blows to the ocular/orbital region due to reduced vision and depth perception.

In addition to corneal and orbital concerns, it is also important to raise awareness of retinal trauma that can lead to permanent vision loss, such as retinal detachment and choroidal rupture. Over the long term, angle recession glaucoma also needs to be addressed. Educate patients about these risks before moving forward with contact lens fitting regardless of whether or not they have irregular astigmatism.

Conclusion

Special attention is required when prescribing for patients who have irregular astigmatism and participate in activities with increased risk of ocular trauma. In these cases, it is imperative to consider patients’ visual and lifestyle needs before recommending a particular treatment for their astigmatism. CLS