Comparison of total keratometry with corneal power measured by optical low-coherence reflectometry and placido-dual Scheimpflug system.

PURPOSE: To compare the total keratometry (TK) and astigmatism measurements in eyes with cataract using automated keratometry of swept-source optical coherence tomography (ss-OCT), optical low-coherence reflectometry (OLCR), simulated keratometry (SimK), and total corneal power (TCP) of combined placido-dual Scheimpflug imaging system. SETTING: The study was conducted at LV Prasad Eye Institute, Hyderabad, India. DESIGN: Retrospective evaluation of electronic medical records of patients who were evaluated for cataract surgery. METHODS: Twenty-eight eyes of 28 patients were included in the study. All patients evaluated for cataract surgery underwent corneal power measurements using three devices: ssOCT, OLCR, and combined placido-dual Scheimpflug imaging were included in the study. Vector analysis was performed to evaluate corneal astigmatism and Bland-Altman analysis was conducted to evaluate the limits of agreement of similar parameters among devices. RESULTS: The mean TK was statistically significantly different from the keratometry obtained from optical biometers and values measured by the Scheimpflug imaging system. The magnitude of mean difference was greater between TK and TCP (0.75 ± 0.25) compared to other variables. The mean difference in astigmatism between TK, ss-OCT-K (0.09 ± 0.12, p = 0.48), OCLR-K (0.10 ± 0.48, p = 0.91), and TCP (0.09 ± 0.47, p = 0.31) was not statistically significant but was statistically significant between TK and SimK values (0.23D ± 0.49D). The axis of orientation (<20°) of astigmatism was comparable (100%, 28 eyes) between two keratometry variables measured by ss-OCT. CONCLUSION: There appears to be a greater correlation of automated keratometry, and TK values obtained from ss-OCT compared to other variables studied. The measurements from TK, Simk, and TCP cannot be used interchangeably.

Headache: tip of the iceberg.

We report the case of a 64-year-old pseudophakic patient in a rural area who chronically suffered from headache with eye pain and was on analgesics for pain relief but never turned up to an ophthalmologist. There was lack of awareness to visit an ophthalmologist for headache as he thought that after undergoing cataract surgery, the role of ophthalmologist was limited. His approach to our centre was only after intense headache with sudden loss of vision. He had actually developed secondary glaucoma due to pupillary block angle closure as a late complication following yttrium aluminium garnet capsulotomy. After medical and surgical management, he regained his complete vision with total relief from headache.