When the Optic Nerve Can't Tell the Whole Story: Longitudinal Glaucoma Assessment in Ocular Coloboma

Background

Ocular coloboma is a congenital malformation that can threaten vision through macular, optic disc, and retinal involvement. Its relationship to ocular hypertension (OHT) and glaucoma is poorly characterized, and coloboma-related anatomic changes may limit conventional glaucoma assessment. We characterized glaucoma-related diagnoses, longitudinal IOP control, and surgical outcomes in a coloboma cohort.

Methods

We performed a retrospective chart review of patients with congenital ocular coloboma subsequently diagnosed with ocular hypertension (OHT), glaucoma suspect status (GSS), or glaucoma at a single tertiary referral center between January 2010 and November 2021. Baseline demographics and clinical data was collected, as well as follow-up/post-treatment intraocular pressure (IOP), visual acuity (VA), and management strategy (observation, medication, or surgery). Descriptive statistics summarized baseline and outcome variables. Kaplan-Meier analysis estimated IOP-control survival, stratified by OHT/GSS versus glaucoma status, and surgery-free survival among eyes initially managed non-surgically.

Results

Among 22 patients (35 coloboma-affected eyes) baseline mean age was 19.4±6.0 years, VA was 1.37±1.01 logMAR, and pre-treatment IOP was 26.8±9.2 mmHg. Out of 35 colobomatous eyes 16 (46%) were classified as OHT/GSS and 10 (29%) as glaucoma; cup-to-disc ratio (C/D) could not be assessed in 22(63%) eyes. Management consisted of observation in 16 (46%) eyes, antiglaucoma medication in 14 (40%), and glaucoma surgery in (14%). Among the 26 eyes with an OHT/glaucoma-spectrum diagnosis, Kaplan-Meier analysis showed a median IOP-control survival of 3.9 years in the OHT/GSS group, 75% maintaining IOP control at year 2 and 50% at year 4. In the glaucoma group, fewer than half of eyes lost IOP control during follow-up and 60% maintained IOP control at year 6. Among the 21 eyes initially managed non-surgically, median surgery-free survival was 5.5 years.

Discussion

Coloboma-related involvement of the macula and optic disc limits the reliability of conventional glaucoma metrics, making IOP trends a central, though imperfect, monitoring tool. The earlier loss of IOP control among OHT/GSS eyes suggests that diagnostic uncertainty in coloboma may contribute to under-treatment, while the high eventual conversion to surgery highlights the limits of medical therapy alone in this population.

Conclusion

Coloboma carries a substantial burden of glaucoma-spectrum disease that is difficult to assess with standard structural and functional metrics. Long-term, individualized IOP-based monitoring with a low threshold for treatment escalation is warranted. Larger prospective multicenter studies are needed to clarify risk stratification and optimal surveillance in this population.