Low vision intervention in end-stage corneal disease

Dear Editor,

Visual impairment (VI) remains a challenging disability to manage.[1] The World Health Organization defines individuals needing low vision care as those with a visual acuity less than 6/18 to light perception or a visual field under 10 degrees, despite treatment, but who can still potentially use vision for tasks.[2] According to the International Classification of Diseases, 10^th revision (ICD-10), VI is classified into four levels: mild, moderate, severe, and blindness.[2]

The National Blindness and Visual Impairment Survey India (2015–2019) identifies corneal blindness (CB) as the third leading cause of blindness.[3] End-stage corneal disease results in irreversible vision loss with limited potential for improvement, significantly affecting quality of life (QOL). In such cases, low-vision clinics play a crucial role in rehabilitation.

This study assesses the impact of low-vision aids (LVAs) on the QOL, in patients with corneal pathologies.

A retrospective review of 99 patients referred to the low-vision clinic from January 2020 to March 2021 was conducted. These patients had insufficient visual potential for daily tasks and were ineligible for surgical correction.

Patient assessment included detailed history, prior vision correction, best-corrected visual acuity (distance and near), low-vision devices (LVDs) prescribed, and vision evaluation using the Bailey–Lovie logMAR and Minnesota Low Vision Reading (MNREAD) Acuity Charts. LVAs were prescribed accordingly, and a follow-up via telephonic survey after 1 year evaluated their impact on the QOL using the Indian Vision Function Questionnaire (IND VFQ-33).

Statistical analysis was performed using SPSS v19.0 with the Chi-square test, and P values <0.05 were considered significant.

The mean age of patients was 34.71 ± 22.00 years; 75% were males. Most patients (83%) had severe visual impairment, and the majority were educated (82.82%) and employed (78.78%). Total corneal opacity was the most common diagnosis (n = 30). Management included provision of LVDs, environmental modifications, referrals to vision enhancement clinics, or a combination of all the above. Optical devices were used for distance and near vision, while nonoptical devices assisted patients with no light perception. The most common optical aid was the half-eye spectacle (n = 21); the video magnifier (n = 19) was the most used nonoptical aid. For distance, monocular telescopes (n = 10) and binocular telescope (n = 1) were preferred, and for near vision, portable and stand magnifiers (n = 19 each) were most used [as shown in Fig. 1]. Functional assessment of the participants was carried out [as shown in Table 1].

Figure 1.

Bar graph showing the various low vision device interventions

Table 1.

Visual characteristics of patients

Variables		n (99)		%
Refractive error
Myopia		5		5.05
Hyperopia		87		87.87
Presbyopia		22		22.22
Visual difficulties
Distance		95		95.95
Near		68		68.68
Intermediate (Mobile phone/computer usage)		50		50.50
Mobility		61		61.61
Activities of daily living		18		18.18
Pre LVA Distance BCVA (Mean, SD)		3.08±1.18
Pre LVA Near BCVA (Mean, SD)		1.07±1.02
Post LVA Distance BCVA (Mean, SD)		3.08±1.13
Post LVA Near BCVA (Mean, SD)		0.83±1.08
Glare
Yes		39		39.39
No		60		60.60
Delayed adaptation
Yes		11		11.11
No		88		88.88
Type of refractive correction
Spectacle		40		40.40
Contact Lens		4		4.04

The follow-up survey revealed that LVAs significantly improved patients’ QOL, even among those with severe impairment. Mobility issues were more common in older, male, and literate participants but were mitigated with appropriate LVDs. The IND VFQ-33 assessed general functioning, psychosocial impact, and visual symptoms on a structured four-point response scale, capturing patient-reported outcomes effectively.

Participants were trained to use mobile and computer accessibility features. This aligns with Crossland et al.,[4] who emphasized the value of smartphones and tablets in low-vision care. Similarly, Oeverhaus et al.[5] concluded that proper LVA selection—optical aids for low magnification and portable electronic devices—improves outcomes. CCTV was particularly helpful for tasks requiring both near and far viewing. Faye[6] also emphasized the importance of personalized training and selection based on reading needs and user preference.

Unlike prior studies focused on age-related macular degeneration, this study addresses the unexplored area of LVA use for corneal blindness. Given the scant literature on this topic, the use of both traditional and modern low-vision rehabilitation methods, along with patient-reported outcomes via IND VFQ-33, adds valuable insight.

This study emphasizes the importance of early referral, individualized rehabilitation, and further prospective research to evaluate the long-term benefits of LVAs in corneal blindness.

Conflicts of interest:

There are no conflicts of interest.

Funding Statement

Nil.