Page 26 - Envision-11-2022

Helping

Misalignment

DROPOUTS

Making Contact

By Shirley Ha, BSc. (Hons), O.D.

ontact lens dropout continues to be a problem for lens practitioners categorized as CLD or non-CLD, and/

everywhere. A 2020 literature review found that dropout rates ranged or as BVD or non-BVD. The Ocular
between 12 and almost 30 per cent worldwide. This can have a huge Surface Disease Index (OSDI) was
Cimpact on the bottom line of any contact lens practice. used twice in the study to measure CL
dissatisfaction from CLD and BVDs,
The two most-often-cited reasons for the cornea and perceived as dry eye based on reported correlations between
discontinuing wear are contact lens sensations. Often in BVD cases, there the CLDEQ-8 and the CISS with the
discomfort (CLD) and vision-related are few or no clinical dry eye signs, the OSDI.
problems associated with multifocal osmolarity readings are normal, and
and toric lenses. Other reasons include patients tend not to respond to traditional STUDY RESULTS AND INTERPRETATIONS

cost and inconvenience, as well as dry eye treatments. Additionally,
the often-overlooked symptoms of sympathetic arousal can inhibit the From the questionnaires, investigators
binocular vision disorders (BVD). blink rate, which further exacerbates found that, compared with those
the dry eye sensation. diagnosed with non-BVD, the 25 per
CLD is defined by the The Tear Film cent who were diagnosed with BVD
and Ocular Surface (TFOS) Society Researchers from the School of scored significantly higher for the OSDI
International Workshop as, “adverse Optometry and Vision Science, University
ocular sensations resulting from of New South Wales, Australia, found and CISS, but not for the CLDEQ-8.
reduced compatibility between the lens that BVDs contribute to contact lens Participants in the CLD group scored
and ocular environment.” In general, dissatisfaction independent of CLD, in higher for the OSDI and the CISS than
it occurs when the lenses are in vivo, a cohort of 76 myopic, non-presbyopic, those in the non-CLD group.
either with or without clinical signs. adult, single-vision contact lens wearers. Interestingly, no questionnaire suggested
The team’s definition of contact lens
Binocular vision disorders, on the dissatisfaction is comparable to contact a significant interaction between BV
other hand, can masquerade as dry eye lens discontinuation in other studies. status and CL comfort status for OSDI
symptoms since they affect the ocular scores. The reason for their dissatisfaction
surface. The visual stress of constantly Symptoms of CLD and BVDs were with contact lenses was therefore
maintaining ocular alignment, commonly measured using the Contact Lens Dry interpreted as symptoms arising from
associated with BVD, such as in Eye Questionnaire-8 (CLDEQ-8) and the BVD. The significantly higher OSDI
convergence insufficiency (CI), can Convergence Insufficiency Syndrome scores cannot be attributable to CLD,
lead to the overstimulation and/or Survey (CISS), respectively. Each and BVD is independent of the CLD.
irritation of the ophthalmic branch (V1) participant had a comprehensive There was also no significant difference

of the trigeminal nerve. This results in binocular vision assessment, slit lamp within the BVD group in the
pain impulses that are transmitted to bio-microscopy, and their status was CLDEQ-8, which further supports the

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